Reloading Question: Loading for Mag Length vs Lands

[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.