Reloading Question: Loading for Mag Length vs Lands

[luvmystang67]

Okay, new reloader here.

I see people talking about loading 10-20 thousands off the lands.  All good stuff.  Due to the magazine length in some of my rifles the closest bullet combination (shortest distance between ogive and bullet tip) would allow for 47 thousands off the lands, and that isn't even necessarily the bullet I want to shoot.  Others would be further away to continue to fit in the mag well.

My point would be, certain bullet configs might put me 100 thousands off the lands, just to load and fit within my mag.  Is there any point in messing with seating depth if I'm already that far out?  Can I reasonably expect any real improvement in accuracy or is it kind of a waste of time?

Thanks in advance.  Stang

[jrebel]

Depending on your bullet selection....yes seating depth can absolutely have a significant impact on accuracy.  With that said, that is usually the last thing I tweak and it is really fine tuning a load....that in most cases shoots very well as is.  For hunting bullets, I almost never seat less (closer to the lands) than 0.02 off the lands. 

As for mag length vs. seating to the lands.  Sometimes magazines will dictate your OACL / seating depth of the bullet.  In this case, you often cannot get to 0.02 starting point.... at which point you just start where you start and go from there.  Well...unless you want to turn a mag fed rifle into a single shot rifle.  It is acceptable to have longer jumps and some bullets actually prefer it.  Mono's like jump (in my experience) and absolutely do not like being jammed (jamming mono's can cause a dangerous premature pressure spike). 

Hope that helps...and I'm sure others will have good info as well.  Lots of experience on this and other boards with hand loaders.  I would follow up any advise with good research and load safe.  It really is addicting. 

[luvmystang67]

Depending on your bullet selection....yes seating depth can absolutely have a significant impact on accuracy.  With that said, that is usually the last thing I tweak and it is really fine tuning a load....that in most cases shoots very well as is.  For hunting bullets, I almost never seat less (closer to the lands) than 0.02 off the lands. 

As for mag length vs. seating to the lands.  Sometimes magazines will dictate your OACL / seating depth of the bullet.  In this case, you often cannot get to 0.02 starting point.... at which point you just start where you start and go from there.  Well...unless you want to turn a mag fed rifle into a single shot rifle.  It is acceptable to have longer jumps and some bullets actually prefer it.  Mono's like jump (in my experience) and absolutely do not like being jammed (jamming mono's can cause a dangerous premature pressure spike). 

Hope that helps...and I'm sure others will have good info as well.  Lots of experience on this and other boards with hand loaders.  I would follow up any advise with good research and load safe.  It really is addicting.

Altered my original post.  I forgot to say the important part.  Yes, its not that I think seating depth doesn't matter, but more... if my jump is already a long way... THEN does seating depth matter, if I'm ultimately loading hunting rounds that really ought to fit within the mag well.  And of course its helpful if they actually eject without pulling the bolt.  I'm just running into scenarios where the bullets I want to shoot might be 0.100" short of where most people would start their efforts, which makes me wonder if at that point it even makes much of a difference.  I can't see where 100 thousands off and 103 thousands off make that much of a heap of difference.

[hunter399]

Depending on your bullet selection....yes seating depth can absolutely have a significant impact on accuracy.  With that said, that is usually the last thing I tweak and it is really fine tuning a load....that in most cases shoots very well as is.  For hunting bullets, I almost never seat less (closer to the lands) than 0.02 off the lands. 

As for mag length vs. seating to the lands.  Sometimes magazines will dictate your OACL / seating depth of the bullet.  In this case, you often cannot get to 0.02 starting point.... at which point you just start where you start and go from there.  Well...unless you want to turn a mag fed rifle into a single shot rifle.  It is acceptable to have longer jumps and some bullets actually prefer it.  Mono's like jump (in my experience) and absolutely do not like being jammed (jamming mono's can cause a dangerous premature pressure spike). 

Hope that helps...and I'm sure others will have good info as well.  Lots of experience on this and other boards with hand loaders.  I would follow up any advise with good research and load safe.  It really is addicting.

Yup ,that's about right.
If your new to reloading,I would stick to reload data for a bit.
Max powder charge,bullet without any jump. Will always cause a pressure spike.
Now it's not necessarily a bad thing. Definitely be looking for pressure signs as you load closer to the lands.
Same with compressed powder charge,not necessarily a bad thing.
Always be looking for pressure signs.
Hard bolt lift, popped out primmer, all that.

[hunter399]

Depending on your bullet selection....yes seating depth can absolutely have a significant impact on accuracy.  With that said, that is usually the last thing I tweak and it is really fine tuning a load....that in most cases shoots very well as is.  For hunting bullets, I almost never seat less (closer to the lands) than 0.02 off the lands. 

As for mag length vs. seating to the lands.  Sometimes magazines will dictate your OACL / seating depth of the bullet.  In this case, you often cannot get to 0.02 starting point.... at which point you just start where you start and go from there.  Well...unless you want to turn a mag fed rifle into a single shot rifle.  It is acceptable to have longer jumps and some bullets actually prefer it.  Mono's like jump (in my experience) and absolutely do not like being jammed (jamming mono's can cause a dangerous premature pressure spike). 

Hope that helps...and I'm sure others will have good info as well.  Lots of experience on this and other boards with hand loaders.  I would follow up any advise with good research and load safe.  It really is addicting.

Altered my original post.  I forgot to say the important part.  Yes, its not that I think seating depth doesn't matter, but more... if my jump is already a long way... THEN does seating depth matter, if I'm ultimately loading hunting rounds that really ought to fit within the mag well.  And of course its helpful if they actually eject without pulling the bolt.  I'm just running into scenarios where the bullets I want to shoot might be 0.100" short of where most people would start their efforts, which makes me wonder if at that point it even makes much of a difference.  I can't see where 100 thousands off and 103 thousands off make that much of a heap of difference.

My experience,
Some bullets like it close.
Some like to jump.
Same goes ,some rifles like powder,bullet , whatever more than others. Harmonics of the barrel and all that.

Reloading is just running a bunch of test loads till find a keeper load. Sometimes it's the first load you try, sometimes it can take many.
Do you have factory loads that shoot well out your rifle.
Sometimes you can start there,and tweak your own load from there.
What I'm saying is.
Use a bullet and seating depth from a factory round that shoots well out your rifle. Then try adjusting seating depth or powder charge,see if it will shoot better than factory.

[jrebel]

Depending on your bullet selection....yes seating depth can absolutely have a significant impact on accuracy.  With that said, that is usually the last thing I tweak and it is really fine tuning a load....that in most cases shoots very well as is.  For hunting bullets, I almost never seat less (closer to the lands) than 0.02 off the lands. 

As for mag length vs. seating to the lands.  Sometimes magazines will dictate your OACL / seating depth of the bullet.  In this case, you often cannot get to 0.02 starting point.... at which point you just start where you start and go from there.  Well...unless you want to turn a mag fed rifle into a single shot rifle.  It is acceptable to have longer jumps and some bullets actually prefer it.  Mono's like jump (in my experience) and absolutely do not like being jammed (jamming mono's can cause a dangerous premature pressure spike). 

Hope that helps...and I'm sure others will have good info as well.  Lots of experience on this and other boards with hand loaders.  I would follow up any advise with good research and load safe.  It really is addicting.

Altered my original post.  I forgot to say the important part.  Yes, its not that I think seating depth doesn't matter, but more... if my jump is already a long way... THEN does seating depth matter, if I'm ultimately loading hunting rounds that really ought to fit within the mag well.  And of course its helpful if they actually eject without pulling the bolt.  I'm just running into scenarios where the bullets I want to shoot might be 0.100" short of where most people would start their efforts, which makes me wonder if at that point it even makes much of a difference.  I can't see where 100 thousands off and 103 thousands off make that much of a heap of difference.

I would not be afraid of a 0.10 jump.   I would start with your mag length for seating depth and work up a powder charge (I like ladder test) with cup and core bullets in .3 or .5 grain increments.   Find a good node and go from there.  As you work up in your powder always check each brass for pressure.   You should be just fine.  You may find the bullet likes jump…..you may also find it doesn’t.   You’ll never know unless you try. 


Out of curiosity….what bullet, caliber and rifle? 

[BULLBLASTER]

Imo just load at mag length. If it wont shoot there then switch bullets or powder. 
I quit making seating depth adjustments years ago. Its either .020-.040 off if mag allows it, or mag length if that is the limiting factor.
If a small seating depth adjustment makes a rifle shoot well or not, i dont want it.
This is assuming the rifle is capable of the accuracy you are after.

[Buckjunkie]

Good advice being given by members.

Only thing I would add is that if you load to mag length and you are still .1 off, you could run a test to see if longer bullets (closer to the lands) shoot better.  If they do, you can sometimes extend the mag length with the help of a gunsmith and products like a Wyatt’s Box. I am having to do this with a short action 22-250 that I am converting to a 6.5 PRC. I should be able to extend the mag length from 2.845 to 3.000

https://wyattsoutdoor.com/product-info/

[hunter399]

Reloading....
You will shoot more
Go to the gun range more
Overall just more work.

It is satisfying when you harvest ,with a load that is your own.

Every reloader does it different to find a keeper load.
I just reloaded some rounds for a gun.
My process is off the wall a little compared to others.
It's kinda a ladder test,I work my way down the ladder instead of up.

First load I always try is max charge ,with recomended seating depth . Right out the book ,right off the jug of hodgons powder bottle. With that said,that's me,my process,I don't lean towards the caution side of things.
Most load data is a little conservative,for older guns with calibers that have been around 50 plus years.

That's how I do it. Then go down the ladder till I find a powder charge that shoots well,then I may tweak seating depth and other stuff.

I only do it that way,cause many times I've started there.
I've had my rifles shoot MOA at 100. With the load data right on the bottle of powder. Most that work up,end up above max.
I'm just looking for a keeper load, with in the data. With the most MV and accurate. Without being over max.In least amount of rounds and range trips.

Seating depth is like powder charge
Normally there will be different stuff your gun likes.
One bullet might shoot well jammed,same bullet might shoot the same a 100 off jump.
Same as powder ,might shoot good at max,then shoot the same 5 grains below max.

It's all about figuring out what your rifle likes.
Factory ammo is designed to fire safely in all firearms.
Sometimes it does well, sometimes not.

[luvmystang67]

On the question of which caliber bullet and rifle.  I have many I want to work on, but I've started with my top 2.

First, is me chasing a dream.  I picked up a 1970 vintage 375 H&H Model 70.  I got it glass bedded and free floated.  I'd really like to get that thing shooting to the point where I'd feel like I can hit an elk out to 400 or 500 yards if I had to, even though that would NOT be my intent.  Still, I can't really justify carrying a rifle that I don't feel good with out to 400, because sometimes those shots come up.  I like it... because it is cool.  Nothing more.  Unlike my rifle below, I like this one in spite of its horrific performance.  It used to shoot maybe 4" with factory ammo before the work.  Now I'm closer to 1.5" with just some intro hand loads, which might be as good as I can get, but that doesn't mean that I don't have a desire to chase ~1" with it.

Second is starting to love a rifle I've never loved.  I have a Parker & Hale 300 WM.  It used to have a front site on it that I thought was ugly, and stock that was kind of beat up and just haven't ever loved the rifle.  It always shot well, even with factory ammo, there was no reason not to love it, it always outshot everything I had, even with federal.  I left it in a case after a hunt and the barrel rusted like h*ll, and then I realized a lot of work had been done to it (pillared, bedded, free floated), which is why I decided to do the same work to the 375.  That said, if I'm shooting maybe 1-1.5" with crappy federal, I thought maybe I could really turn it into a shooter with handloads and reach out say 800 yards or so with practice.

I have other rifles, but these are the ones I've decided to start with.  TRYING to use copper for shorter range, to avoid eating lead.  I realize the 300WM isn't likely to kill something at 800 yards with copper.

I did kill my elk and deer this year with hand loaded copper in the 300WM.  Elk at 350, deer at 20.  Recovered the deer bullet just before the hams on a frontal, with all weight retained.

[Stein]

I had the same issue before I changed magazines.  I set my maximum length that would fit in the mag and then did a seating depth test starting there and going shorter.

It made a significant difference as seating depth always will in my experience.  You may not have THE optimal load, but you can get AN optimal load for whatever limitations you have.

[Jolten]

On the question of which caliber bullet and rifle.  I have many I want to work on, but I've started with my top 2.

First, is me chasing a dream.  I picked up a 1970 vintage 375 H&H Model 70.  I got it glass bedded and free floated.  I'd really like to get that thing shooting to the point where I'd feel like I can hit an elk out to 400 or 500 yards if I had to, even though that would NOT be my intent.  Still, I can't really justify carrying a rifle that I don't feel good with out to 400, because sometimes those shots come up.  I like it... because it is cool.  Nothing more.  Unlike my rifle below, I like this one in spite of its horrific performance.  It used to shoot maybe 4" with factory ammo before the work.  Now I'm closer to 1.5" with just some intro hand loads, which might be as good as I can get, but that doesn't mean that I don't have a desire to chase ~1" with it.

Second is starting to love a rifle I've never loved.  I have a Parker & Hale 300 WM.  It used to have a front site on it that I thought was ugly, and stock that was kind of beat up and just haven't ever loved the rifle.  It always shot well, even with factory ammo, there was no reason not to love it, it always outshot everything I had, even with federal.  I left it in a case after a hunt and the barrel rusted like h*ll, and then I realized a lot of work had been done to it (pillared, bedded, free floated), which is why I decided to do the same work to the 375.  That said, if I'm shooting maybe 1-1.5" with crappy federal, I thought maybe I could really turn it into a shooter with handloads and reach out say 800 yards or so with practice.

I have other rifles, but these are the ones I've decided to start with.  TRYING to use copper for shorter range, to avoid eating lead.  I realize the 300WM isn't likely to kill something at 800 yards with copper.

I did kill my elk and deer this year with hand loaded copper in the 300WM.  Elk at 350, deer at 20.  Recovered the deer bullet just before the hams on a frontal, with all weight retained.

Have you strip cleaned the barrel? If you bought both used it can make a huge difference

[hunter399]

I was just gonna add.
If your heavy for caliber , pressure will build faster.
It's the same reason you'll see a longer coal on lighter for caliber bullets along with more powder.

Your 300 WM ,along with many older calibers.
7mag,30-06,270 , and some others.
You'll notice there is extra case capacity.
There is room to play a bit.

Myself ,I try to find the best powder charge . Over seating depth.
The jump is actually a pressure buffer.
Pressure starts when the bullet hits the rifling.
With that said ,it does add accuracy to load closer to the lands.
Or be jammed into the rifling,ask any professional shooters.
But I find ,when you find the correct powder charge, harmonics of your barrel. Seating depth is not as important.
When I started reloading,I would load hot,hot ,rounds all the time.
I learned it just burns out your rifle faster.

[okie john]

Interesting take on it here:

https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/


Okie John

[hunter399]

Interesting take on it here:

https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/


Okie John

I totally agree with your link.
Most bullets will shoot well jammed into rifling,then there will be a sweet spot loaded shorter with some jump.
Most professional shooters don't care about MV.
You can account for drop at any MV,there looking for accuracy.

I guess the point I've been trying to make, I would NOT take a heavy for caliber bullets,load it super hot,then jam it into rifling.
Target shooters just have to punch paper,or ring steel.
Your rifle may be able to take the pressure,it may shoot well.
Guaranteed you'll burn your barrel up faster.
There is a reason most target shooter junk there barrel between 1000-2000 rounds.

[hunter399]

Here's a good video from about three years ago.
Your just looking for accuracy.
Jump,lands, doesn't matter a long as your not jammed in the rifling.
Nothing really matters except it's accurate.

[luvmystang67]

Thought I'd post some results here.

I tested a few things on the 'ol .375 H&H.

First, during some ladder testing, I found pretty decent results with 74 grains of Varget and 270 grain barnes tsx fb using the only pseudo-magnum primers I could find in the last year, CCI 34s and Prvi Partizan brass.  So I did some experimentation here with seating depth.

Using the same load for each, I did 4 groups and a bonus 5th group with cheap factory 300gr prvi partizan loads as a sort of control.

Group 1 was 0.020 off the lands (about 3.800" OAL, and far from fitting in my magazine well @ 3.608", barely cleared for ejection)
Group 2 was 0.030 off the lands (and far from fitting in my magazine well, barely cleared for ejection)
Group 3 was right at max OAL for the mag well (3.600")
Group 4 was -0.010 or 3.590" OAL, just shy of the max for mag well.
Bonus Group: I shot the first two out of a clean cold barrel, and then after shooting all 4 groups, came back and shot a 3rd round.  I was SHOCKED by the factory accuracy from the cheapest ammo available.

The last thing I did was try a ladder with H4350 from 73-76gr (all somewhat compressed) with 300gr accubonds.  I did load up 4 rounds at 74 grains to see what kind of rough pattern we might be starting with.  I can say that 74 grains of H4350 was NOT impressive in any way.  Does look like I had some nodes with the H4350, so maybe we can find a different powder node that makes sense.

Summary: Distance from lands does matter with copper, but in this case my rounds loaded 0.200 from lands, and fitting in my mag well, and meeting the published OAL for 375H&H at 3.600" seemed to shoot the best.  Not that I did a true test here like some folks do at 0.003" seating depth changes, but I really didn't WANT that to be the best, because I wouldn't have been able to load my mag.  The ones loaded close to the lands at ~3.800" OAL shot hotter at ~2770 FPS, the ones further back shot more ~2725 fps.

My Factory Loaded 300gr round nose Prvi Partizan shot very accurately at 2350 fps with a spread of 41 fps between the fastest and slowest round.

My hand loaded test rounds 300 gr accubonds with H4350 shot fairly inaccurately in my "WAG" 74 grains 4 round test and shot at 2500 fps with a max deviation of 15 fps between all 4 rounds.  Maybe I need to slow them down a bit to match the factory Prvi rounds.  It was getting a little dark in my ladder, so accuracy on the "nodes" isn't super reliable here.

On ALL of these, I had a Magnetospeed hanging off my barrel, which hopefully primarily impacted POI and not general accuracy expectations.

[luvmystang67]

The ladder pic

[hunter399]

Great job on testing man.
It's all about learning what your rifle wants to chew on.
Looks like your figuring it out.👍

[jrebel]

Do you know that barrel twist rate?? 

[luvmystang67]

Do you know that barrel twist rate??

Appears to be 1/12" from running patches through.

[jrebel]

Do you know that barrel twist rate??

Appears to be 1/12" from running patches through.

Just from what I know about mono's.....and admittedly not a great deal as it pertains to Barnes Mono's....I would push a lighter bullet faster.  If you want to know if your rifle has the capability of shooting well, try one of the Hammer monolithic bullets.  They are not sensitive to jump at all....and actually prefer it.  They are stupid easy to load for.  I shoot them in multiple rifles and they are crazy accurate and deadly on game.  Just a quick glance at their 375 line of bullets, you could go with the 248 grain Hammer Hunter and likely reach speeds of 2900-3000 fps.  They also have options in the 200, 220 or even 270 grain, though the 270 would not be my first choice.     

Most of my hammers shoot sub 1.5 inches in a 4-6 grain ladder / pressure test.  My 300 wsm shot 1" with a 5 or 6 grain difference as I looked for pressure.  If you decide to give it a try.....please read up on hammers and know that it is a different loading game.  Your traditional ladder test will just waste time and money. 

[luvmystang67]

Do you know that barrel twist rate??

Appears to be 1/12" from running patches through.

Just from what I know about mono's.....and admittedly not a great deal as it pertains to Barnes Mono's....I would push a lighter bullet faster.  If you want to know if your rifle has the capability of shooting well, try one of the Hammer monolithic bullets.  They are not sensitive to jump at all....and actually prefer it.  They are stupid easy to load for.  I shoot them in multiple rifles and they are crazy accurate and deadly on game.  Just a quick glance at their 375 line of bullets, you could go with the 248 grain Hammer Hunter and likely reach speeds of 2900-3000 fps.  They also have options in the 200, 220 or even 270 grain, though the 270 would not be my first choice.     

Most of my hammers shoot sub 1.5 inches in a 4-6 grain ladder / pressure test.  My 300 wsm shot 1" with a 5 or 6 grain difference as I looked for pressure.  If you decide to give it a try.....please read up on hammers and know that it is a different loading game.  Your traditional ladder test will just waste time and money. 

I might give it a shot.  Part of my reason for not wanting to drop down to the 230-250 range is that is capable of being reached by 338 WM and isn't really doing what the 375H&H does uniquely.  I really should be probably sticking with 300 grain bullets, but I'm not sure I can stomach the drop at the longer ranges I'm hoping to achieve.

[jrebel]

Do you know that barrel twist rate??

Appears to be 1/12" from running patches through.

Just from what I know about mono's.....and admittedly not a great deal as it pertains to Barnes Mono's....I would push a lighter bullet faster.  If you want to know if your rifle has the capability of shooting well, try one of the Hammer monolithic bullets.  They are not sensitive to jump at all....and actually prefer it.  They are stupid easy to load for.  I shoot them in multiple rifles and they are crazy accurate and deadly on game.  Just a quick glance at their 375 line of bullets, you could go with the 248 grain Hammer Hunter and likely reach speeds of 2900-3000 fps.  They also have options in the 200, 220 or even 270 grain, though the 270 would not be my first choice.     

Most of my hammers shoot sub 1.5 inches in a 4-6 grain ladder / pressure test.  My 300 wsm shot 1" with a 5 or 6 grain difference as I looked for pressure.  If you decide to give it a try.....please read up on hammers and know that it is a different loading game.  Your traditional ladder test will just waste time and money. 

I might give it a shot.  Part of my reason for not wanting to drop down to the 230-250 range is that is capable of being reached by 338 WM and isn't really doing what the 375H&H does uniquely.  I really should be probably sticking with 300 grain bullets, but I'm not sure I can stomach the drop at the longer ranges I'm hoping to achieve.

I agree....and will say that Hammers offer a unique offering of outstanding terminal performance in lighter weight bullets.....AND....still offering great deep penetration with the shank.  I have yet to recover a shank of a hammer (complete pass through on all animals taken) and have had outstanding terminal performance with one shot kills.  Being that elk is your target animal, I would have no hesitation shooting the 250 gain HH.

To my point.....I shot 300 grain accubonds in my 338 laupa and loved them.  When I switched to HH's I moved to the 260 grain HH and couldn't be happier.  It will shoot 1/4 MOA all day long.  We shot a 500+ lb black bear in Alberta a couple years ago and it crushed it right where it stood.  Hard quartering too shot at 300+ yards.  Bullet entered in the neck / spine and exited off side back of the rib cage.   Complete pass through with unreal devastation to the vital organs.  Hammer's motto....speed kills (specific to their design and mono's in general). 

You will still get bone crushing capabilities.....and that is what the 375 is really designed for. 

[Platensek-po]

Do you know that barrel twist rate??

Appears to be 1/12" from running patches through.

Just from what I know about mono's.....and admittedly not a great deal as it pertains to Barnes Mono's....I would push a lighter bullet faster.  If you want to know if your rifle has the capability of shooting well, try one of the Hammer monolithic bullets.  They are not sensitive to jump at all....and actually prefer it.  They are stupid easy to load for.  I shoot them in multiple rifles and they are crazy accurate and deadly on game.  Just a quick glance at their 375 line of bullets, you could go with the 248 grain Hammer Hunter and likely reach speeds of 2900-3000 fps.  They also have options in the 200, 220 or even 270 grain, though the 270 would not be my first choice.     

Most of my hammers shoot sub 1.5 inches in a 4-6 grain ladder / pressure test.  My 300 wsm shot 1" with a 5 or 6 grain difference as I looked for pressure.  If you decide to give it a try.....please read up on hammers and know that it is a different loading game.  Your traditional ladder test will just waste time and money. 

I might give it a shot.  Part of my reason for not wanting to drop down to the 230-250 range is that is capable of being reached by 338 WM and isn't really doing what the 375H&H does uniquely.  I really should be probably sticking with 300 grain bullets, but I'm not sure I can stomach the drop at the longer ranges I'm hoping to achieve.

I agree....and will say that Hammers offer a unique offering of outstanding terminal performance in lighter weight bullets.....AND....still offering great deep penetration with the shank.  I have yet to recover a shank of a hammer (complete pass through on all animals taken) and have had outstanding terminal performance with one shot kills.  Being that elk is your target animal, I would have no hesitation shooting the 250 gain HH.

To my point.....I shot 300 grain accubonds in my 338 laupa and loved them.  When I switched to HH's I moved to the 260 grain HH and couldn't be happier.  It will shoot 1/4 MOA all day long.  We shot a 500+ lb black bear in Alberta a couple years ago and it crushed it right where it stood.  Hard quartering too shot at 300+ yards.  Bullet entered in the neck / spine and exited off side back of the rib cage.   Complete pass through with unreal devastation to the vital organs.  Hammer's motto....speed kills (specific to their design and mono's in general). 

You will still get bone crushing capabilities.....and that is what the 375 is really designed for.

I second the hammer bullets. Always performed great in all calibers.

[Blacklab]

Here's a good video from about three years ago.
Your just looking for accuracy.
Jump,lands, doesn't matter a long as your not jammed in the rifling.
Nothing really matters except it's accurate.

I just seen this guy on YouTube about less than a week ago. Really good insight and very easy to listen to.👍

Use the ojive on all bullet measuring. Most accurrate point of measure on all bullets 

[addicted]

Thought I'd post some results here.

I tested a few things on the 'ol .375 H&H.

First, during some ladder testing, I found pretty decent results with 74 grains of Varget and 270 grain barnes tsx fb using the only pseudo-magnum primers I could find in the last year, CCI 34s and Prvi Partizan brass.  So I did some experimentation here with seating depth.

Using the same load for each, I did 4 groups and a bonus 5th group with cheap factory 300gr prvi partizan loads as a sort of control.

Group 1 was 0.020 off the lands (about 3.800" OAL, and far from fitting in my magazine well @ 3.608", barely cleared for ejection)
Group 2 was 0.030 off the lands (and far from fitting in my magazine well, barely cleared for ejection)
Group 3 was right at max OAL for the mag well (3.600")
Group 4 was -0.010 or 3.590" OAL, just shy of the max for mag well.
Bonus Group: I shot the first two out of a clean cold barrel, and then after shooting all 4 groups, came back and shot a 3rd round.  I was SHOCKED by the factory accuracy from the cheapest ammo available.

The last thing I did was try a ladder with H4350 from 73-76gr (all somewhat compressed) with 300gr accubonds.  I did load up 4 rounds at 74 grains to see what kind of rough pattern we might be starting with.  I can say that 74 grains of H4350 was NOT impressive in any way.  Does look like I had some nodes with the H4350, so maybe we can find a different powder node that makes sense.

Summary: Distance from lands does matter with copper, but in this case my rounds loaded 0.200 from lands, and fitting in my mag well, and meeting the published OAL for 375H&H at 3.600" seemed to shoot the best.  Not that I did a true test here like some folks do at 0.003" seating depth changes, but I really didn't WANT that to be the best, because I wouldn't have been able to load my mag.  The ones loaded close to the lands at ~3.800" OAL shot hotter at ~2770 FPS, the ones further back shot more ~2725 fps.

My Factory Loaded 300gr round nose Prvi Partizan shot very accurately at 2350 fps with a spread of 41 fps between the fastest and slowest round.

My hand loaded test rounds 300 gr accubonds with H4350 shot fairly inaccurately in my "WAG" 74 grains 4 round test and shot at 2500 fps with a max deviation of 15 fps between all 4 rounds.  Maybe I need to slow them down a bit to match the factory Prvi rounds.  It was getting a little dark in my ladder, so accuracy on the "nodes" isn't super reliable here.

On ALL of these, I had a Magnetospeed hanging off my barrel, which hopefully primarily impacted POI and not general accuracy expectations.

As you are learning to reload, it may be worth your while to use a smaller/cheaper cartridge.  Finding magnum primers is such a pain that it may not matter even if price is no issue. You can perfect your process with something using small rifle primer(308, creeds, SAW,  223, ARC and many more).

Since round counts during matches are much higher than they were 20 years ago with the increase in prevalence of PRS and the like more and more guys are becoming less and less concerned with seating depth as it provides such a small(boarderline irrelevant) difference in so many cases. Modern bullet ogive shape seems to be part of it as well as probable more consistent manufacturing techniques.

A couple reasons not to pull your hair out over it: dirty/clean bore can change jump, lands are constantly eroding so they are running away from you as you shoot. This makes it so that even if there is a an ideal range for your load and rifle combo you would probably want to place it at the near end of the range so that you stay in it as long as possible as the throat erodes.

Below is a great podcast on where to focus your efforts early in your load development process. there is also a part two on the channel.

[hunter399]

My 7 mag can be reloaded past mag length by a lot.
So mag length it is.