Bullet Seating Depth

[sakoshooter]

Looking for everyone's opinions on bullet seating depth. I normally seat just a few thousands off the lands but have been considering experimenting with some loads touching the lands. I'm looking for better accuracy. Not that any of it's bad, just curious and I'm never satisfied. What are you guys doing and what kind of accuracy are ya getting?

[JimmyHoffa]

Most of the hunting ammo I reload is with bullets with cannelures.  I will seat to the center or the cannelure and then crimp.  If it is target ammo without a cannelure, I'll make a dummy round with a neck resized case.  I'll barely put a bullet in the case, then close the bolt and let the lands basically seat the bullet.  Then cycle the dummy a time or two, so that the lands will seat from different points on the bullet.  Then try to match the reloads to the dummy, maybe giving an extra couple thousandths off the lands.  I figure this is good enough for centering since I don't have the tool to turn the necks or measure the runout.

[carpsniperg2]

I like to seat as close to the lands as possible. Each gun is diffrent in what it likes. Some bullets like Barnes, even say to back off more then you would think, so the bullet jumps a little. I bought some Barnes a long time ago and could not get them to shoot. But one of my friends told me. He had the same issues and I read on Barnes web site. That they said to seat them a little deeper. You can play with the loads and see what your rifles like. Either the groups will get smaller or bigger

[KillBilly]

Here is a link to some very good info on this subject. Please read it......

http://blog.sinclairintl.com/2009/03/26/determining-bullet-seating-depth/

[C-Money]

I just seat mine just under the cartridge max overall length listed in the reloading manual. Has worked great for me!

[RClare1223]

I measure my chamber with the bullet I am going to load.then starting at .015" back I load 5 round groups backing off the lands .005" at a time.then I go test them and see where the gun likes the bullet to be seated.every gun is different so there is no set measurement to use.my 06 likes them to be .040" off the lands while my 270 like .030".

[GregMcFadden]

You really do need to try out different seating depths.  I rather recently tried increasing the jump on my 30-06 load with bergers...   increasing the jump from a few thou to .029 thou cut the group size in half.

[MDGrand]

The only thing you have to remember when seating a bullet in the lands is to keep an eye on pressure problems. Working up a super hot load and placing the bullet in the lands, can cause problems to your bore over time.

[jaymark6655]

I sometimes seat my target loads just off the lands, but they don't fit in the magazine so anything for hunting gets sized down to either MOL or max length that will fit in my mag.

[whacker1]

max length that will fit in my mag

My desired seating depth is 3.71, but the magazine only goes out to 3.69, so I seat all my bullets to 3.67 giving enough room to move in the magazine.

300 RUM.  This is a common issue for the RUM from most folks that I have talked to.

[lokidog]

I sometimes seat my target loads just off the lands, but they don't fit in the magazine so anything for hunting gets sized down to either MOL or max length that will fit in my mag.

Same here for my -06.  Seat  a tiny bit off but the plastic tip on my ballistic tips flattens slightly from recoil in the mag.  Makes me worry a little about trying the longer Barnes like I would like to do as my powder charge is pretty full using 165 gr bullets.

[JKEEN33]

considering experimenting with some loads touching the lands. 

Everything I have read says you should back off a minimum. Touching or seated could create pressure issues. I bought an OAL guage and measured all of my rifles. I then found the OAL for the magazine and worked from there to find a length that works in each rifle.

[KillBilly]

I believe my books state that you should back off .010 - .015" ....

[Ray]

Most of the hunting ammo I reload is with bullets with cannelures.  I will seat to the center or the cannelure and then crimp.  If it is target ammo without a cannelure, I'll make a dummy round with a neck resized case.  I'll barely put a bullet in the case, then close the bolt and let the lands basically seat the bullet.  Then cycle the dummy a time or two, so that the lands will seat from different points on the bullet.  Then try to match the reloads to the dummy, maybe giving an extra couple thousandths off the lands.  I figure this is good enough for centering since I don't have the tool to turn the necks or measure the runout.

Good advice. I had to learn that the hard way but the way you wrote it seems fairly sound. I ise a slight variation of what you described.

[sakoshooter]

Thanx a lot guys for the opinions. That's what makes these forums great. Lots of info that is best shared.

I usually use a blk marker to color a band around the bullet where the ogive meets the shank, seat too far out so that the lands leave marks in the blk colored band, then slowly seat deeper untill no marks show while refreshing the blk band with the marker. I then make a 'dummy round' out of a sized case with no primer/powder, save it and label it for all future loadings with that bullet. This has served me very well over many years with many sub moa groupings with quite an assortment of bullets. I've never practiced seating touching the lands and am mainly curious if I could achieve a bit more accuracy this way. I'm aware that more pressure would be created with the bullet touching the lands so each established load would have to be reduced and work up again but if better accuracy could be achieved, it'd be worth it.
Keep in mind also that crimping creates more chamber pressure also.
Magazine length of course, is the deciding factor for loaded ammo used for hunting.

[sakoshooter]

The link that Killbilly posted above has some great info, especially if you read all the way to the bottom. I'm copying and pasting one such post:
Thanks for your question.

To answer you, seating depth in relation to the distance from the lands should not affect the efficiency of the powder burning completely, if it is a powder/bullet combination that has performed well for you in previous occasions. However, the closer you are to the lands, you will see an increase in pressure, and this should be approached with caution, especially with hot/compressed loads. If you want to try closer to the lands, we suggest reducing your load for safety reasons.

Many bullets perform very well with some jump. In most of my rifles I have found that jump of .020″ to .030″ has been the “sweet spot”. This will differ from rifle to rifle, and bullet to bullet.

As for your nickel plated brass, we suggest it not be reloaded for a few reasons: First of all it is hard on dies, the nickel is harder than brass, and can scratch and ruin a good set of dies. Second, it is hard to size, it must be undersized to achieve the proper sizing. Third, nickel plating is used for corrosive conditions such as hunting, and is designed to be shot and “left”.

I hope this helps you out. If you have further questions, please feel free to contact our reloading technicians at 1-800-717-8211.

Good Shooting

Pete Petros
Lead Reloading Technician
Sinclair International

What I get out of this one post is that a cartridge with a COAL .025 off the lands might be a great place to start.

[high country]

It depends on the rifle, bullet and intention of the gun for me. I have found tsx bullets shoot well with .125 in my ultra's, yet bergers seem to want to make out with the lands.

[sakoshooter]

High Country, You're right. I was mainly posting the reply above because of the bullet seating depth info in it posted by Sinclair International's Lead Reloading Technician.

Another copied/pasted:  I use the rod down the barrel method. When using a brass rod the way I mark it is with a sharp knife held flat across the muzzle and pressed into the brass rod until a mark is left on the rod. The mark is razor thin and consistent and the only challenge to accurate measurement is getting the dial calipher blades exactly aligned to the marks when you measure between the lines left by knife. With a cleaning rod I usually place some masking or other tape on the rod where the knife contacts to make mark easier to see.

The above post was in relation to holding a bullet against the lands with a dowel and sliding a rod down the barrel from the muzzle end. First against the cocked bolt face, next, with bolt removed, against the bullet tip that would be just lightly held against the lands with a dowel.
I just went thru every caliber, weight and style of bullet on my bench for 3 rifles today. Measured exact CAOL. Wrote them down for future reference. Now I can set up a dummy round for each bullet and know for sure exactly how far off the lands I am.
Thanx for the info guys. I'm going shootin tomorrow - weather providing.

[sakoshooter]

I just loaded a batch for the range in 30-06 with 165gr Swift Scirroco IIs and 168gr Barnes TTSXs and used the rod down the barrel for seating depth. Simple and I'm sold on it without buying anything further than I already had in my shop. Accurate to within .001 or .002 I'd say. Basically as accurate as a person can see.
Does anyone else use this method?

[carpsniperg2]

Never heard of that method. How does it work? I would be interested 2 hear more about it.

[high country]

try loading some tsx's at .08 to .125 off.....see what it does for you. scirroccos can't do that they are too long and seem to like to be close to the lands.

[JLS]

I load my TSXs just short enough to fit in the magazine and have had very good luck with that.  Am I missing something here, because with my M70s I cannot seat right off the lands and still have the cartridge fit in the magazine?

[high country]

I load my TSXs just short enough to fit in the magazine and have had very good luck with that.  Am I missing something here, because with my M70s I cannot seat right off the lands and still have the cartridge fit in the magazine?

spend 3 bullets and try what what I said^^^^^^

[sakoshooter]

After reading that link Killbilly posted all the waaaaaaaaaaaaaaay to the bottom I put a few ideas together that I'd read on it and came up with this:
I'll word this the way I did it and you guys can adlib from there. Or PM me and I'll give ya my phone number.
To establish C.A.O.L.(case over all length) and/or seating depth with each bullet I'll ever use, here's what I did.
1) Put my gun in my cleaning rest on my reloading bench. Bolt cocked(gun empty of course)and closed. No protruding firing pin if it's cocked.
2) Using a wood dowel(long), small enough to fit down the barrel, insert it untill it touches the bolt face. Using a razor blade, make a slight cut/mark on the dowel exactly flush with the end of the muzzle.
3) Remove the bolt.
Both dowels could be the same diameter. Match the caliber.
4) Insert another dowel(short) (just small enough to fit into the bullet recess area of the chamber) into the chamber from the breech end with each bullet  you're going to use. One at a time of course. It takes a little finageling sometimes as some bullets want to slip into a bolt lug recess. Using the dowel from the muzzle end at the same time helps align the bullet so it enters the chamber correctly.
Anyhow, slowly slide the bullet into the chamber using the short dowel with your left hand while sliding the other dowel down the barrel from the muzzle end with your right hand untill the long dowel contacts the tip of the bullet.
Note: It's easy to push the bullet into the lands so be very gentle and use the same force on each bullet for a consistent measurement.
Remember that your bolt face measurement is already established and will be the same for all measurements with that particular gun.
I pushed the bullet off the lands a few times with my right hand dowel while pushing it back against the lands with my left hand dowel at the same time untill I was satisfied with it just barely making contact.
5) Now, slightly lift up on the long dowel to put pressure against the muzzle so the dowel won't move while you're reaching for the razor blade you forgot to set close enough to reach, LOL.
Providing that the dowel is still exactly in place against the bullet tip  and the bullet is barely touching the lands, make another cut or mark with the razor blade flush with the muzzle.
6) Remove the long dowel and using a reloading micrometer(knife edge), measure the distance between the two cuts. I used a fine point pen to make the cuts easier to see.
The resulting measurement(write it down)is the C.O.A.L. for THAT bullet TOUCHING the lands. Rember that this measurement is Touching The Lands. This might not be a safe seating depth for some established loads as greater chamber pressure will result with a bullet seated against the lands. Most of you already knew that but thought I'd better say it.
Based on a posting from Sinclair International stating that they'd found the 'sweet spot' to be between .020 and .030 off the lands with most guns/bullets, I adjusted my seating depth to be .025 off the lands based on all the new measurements I just took. My rifle magazies will allow this. Yours might not. Check it out as your magazine might be the determining factor for COAL.
Each bullet will extend into the lands differently, so rotate the dowel and make a new mark for each bullet you have on your bench.
I did this and wrote down the COAL for each cal(3 rifles)and 13 bullets. I then subtracted .025 from each measurement and am going to use this as my new starting point for working up loads. I recorded all of it so I won't have to do it again unless I try a different bullet.

Over the years I've always used a felt tip marker to color a band around a seated bullet right at the ogive, chamber it, re-seat it again and again untill no marks appeared from touching the lands. I established 'dummy' rds for most bullets over the years but really never knew exactly how far off the lands I was with any given bullet untill now.
Upon checking out some of my dummy rds that I thought were barely off the lands, surprise!! They all varied considerably. I adjusted them yesterday with an enertia bullet puller and re-seated them to my new COAL based on my new findings.
It's actually really easy to do this and now I know exactly where each bullet is seated and can use a micrometer to double check each time.

[quadrafire]

Good post. I am new to reloading, but I have 3 calibers at this time that I am working up loads. This sounds pretty strait forward. You described it well enough that even a dummy like me could do it.

[high country]

You can smoke a bullet with a candle, just hold it low in the flame. Remember you can only use col on like meplats and ogives. Change either and your measurement flies out the window.

[sakoshooter]

High Country,
You're right but as stated in my post, EVERY BULLET needs to be measured separately. Smoking is no different than a felt marker. It works but it is not very accurate and leaves you still guessing as to exactly how far or close you actually are to the lands.
Using the dowel method, the guessing is eliminated and is actually faster than smoking or marking.

[sakoshooter]

Has anyone gone to the trouble of checking their bullets with this method since we talked about it on here?
I did 3 cailibers and 13 different bullets in about 30 minutes on my bench.

[JackOfAllTrades]

I haven't done it since this thread started. But I've done it that way before.  I certainly don't have that many bullets/loads to validate for each gun.

My question to you is.. Now that you know exactly the distance of ogive to lands is, what have been your experiences with even a few of those loads regarding accuracy?

-Steve

[high country]

I would think that if you must use something down your bore, a rod might be more accurate. When you measure off the meplat there is a lot of room for error, measure off the ogive and it should be consistent.....or you could use one of the oal case gauges.

[JackOfAllTrades]

The problem with a OAL precision mic, is that they don't have the same shape Ogive as the different bullets.

The best way to know the distance from the bolt face to the lands is to make a cast of the chamber with Cerosafe with the bolt closed. Find the ogive of every bullet where it just reaches the cal/diameter of the inside land face. Compare this to the cast of the chamber

-Steve

[sakoshooter]

I haven't done it since this thread started. But I've done it that way before.  I certainly don't have that many bullets/loads to validate for each gun.

My question to you is.. Now that you know exactly the distance of ogive to lands is, what have been your experiences with even a few of those loads regarding accuracy?

-Steve

Steve, Only shot once since I adjusted my seater die and accuracy was good. I seated that batch .025 off the lands. Now I'll try em farther off and with a slightly reduced load, touching the lands.
As far as meplat goes: It could make a difference on some bullets but I did my measuring using Swift Scirroco, Barnes TTSX, TSX and X, Nosler BT and some Speer and Sierra HP bullets. Also TBBC and Swift A Frames have a very small, flat meplat with no exposed lead so measuring should be pretty consistent. When using an exposed lead tip bullet, you might want to measure a few just to get a good average. Even with that I'd venture to say that it is much more accurate than smoking or using a felt marker like I'd done for years. I do not have a chamber gage and was thinking of getting one until I'd read about this idea. I'm happy with my measuements now.

Yes, I used a small wood dowel down the barrel. A brass rod or old cleaning rod could also work fine. Anything with a flat end where it touches the bullet tip.

[KillBilly]

If you use a comparator you don't have to worry about the lead tips. Comparators measure from the ogive and are the best way to go in my opinion.

[Schwag173]

I normally seat just a few thousands off the lands but have been considering experimenting with some loads touching the lands. I'm looking for better accuracy.

I, too, normally try to seat my bullets a few thousandths off the lands but I discovered something by pure accident: While loading for my new 7mm Weatherby Mag I was having rotten luck with all the different powders, bullet weights and brands I tried.  I was loading some 175s and switched to loading 165s but had forgotten to reset the seating depth.  The result was a COL of 3.220" (standard COL is 3.360").  I remember thinking to myself, "What the hell, nothing else has worked" and decided to try a group that deep.  The same 165s that had grouped 3" at maximum length now grouped under 1/2 an inch!  Pure dumb luck, but I'll take it.       

[high country]

I normally seat just a few thousands off the lands but have been considering experimenting with some loads touching the lands. I'm looking for better accuracy.

I, too, normally try to seat my bullets a few thousandths off the lands but I discovered something by pure accident: While loading for my new 7mm Weatherby Mag I was having rotten luck with all the different powders, bullet weights and brands I tried.  I was loading some 175s and switched to loading 165s but had forgotten to reset the seating depth.  The result was a COL of 3.220" (standard COL is 3.360").  I remember thinking to myself, "What the hell, nothing else has worked" and decided to try a group that deep.  The same 165s that had grouped 3" at maximum length now grouped under 1/2 an inch!  Pure dumb luck, but I'll take it.       

I mentioned that earlier....try it!

[sakoshooter]

I normally seat just a few thousands off the lands but have been considering experimenting with some loads touching the lands. I'm looking for better accuracy.

I, too, normally try to seat my bullets a few thousandths off the lands but I discovered something by pure accident: While loading for my new 7mm Weatherby Mag I was having rotten luck with all the different powders, bullet weights and brands I tried.  I was loading some 175s and switched to loading 165s but had forgotten to reset the seating depth.  The result was a COL of 3.220" (standard COL is 3.360").  I remember thinking to myself, "What the hell, nothing else has worked" and decided to try a group that deep.  The same 165s that had grouped 3" at maximum length now grouped under 1/2 an inch!  Pure dumb luck, but I'll take it.       

Just to make sure I"m understanding you correctly: If you left your seater die set from loading 175gr bullets and then seated 165gr bullets, wouldn't the OAL be the same? If so, I guess you're saying that the 165s were seated out as far as the 175s?
Or are you saying you seated the 165s just as deep into the case so the OAL was less leaving a jump to the lands?
Please clarify for me. I'm a little slow this morning.

[JackOfAllTrades]

If you left your seater die set from loading 175gr bullets and then seated 165gr bullets, wouldn't the OAL be the same?

Within many brands, a lighter bullet is often shorter OAL, and/or shorter from the ogive to the tip. Seating a lighter bullet may have drastic OACL length if a dies was set/inteded for even the same brand/design of a heavier bullet.

-Steve

[high country]

it all depends on the shape of the bullet. take a berger out  and put a silver tip for a 30-30 in its place and it will be a huge difference. comparators that measure on the diameter of the intersect with the ogive are the preferred method, although......there are many ways to skin a cat.

[luvtohnt]

So I am new to this reloading thing and am not real familiar with the terms. But my brother-in-laws dad uses a method that seems to be a bit quicker than what was described earlier for distance to the lands. He has a case from each of the calibers he owns that he made a cross cut in the neck of the case and then pushed the brass inwards a little. You can put what ever bullet you are loading in the case, chamber the dead round, and slowly remove the dead round. When it comes out it gives you the exact measurement to the lands for that rifle and bullet combo. I think that is what sako was going towards with the black line on the bullet. I think another benefit to this would be you only have one case laying around for each caliber rather than a case for each caliber/bullet combo. Again I may be all wet behind the ears, but it would be nice to know what some pros think.

Brandon

[Skyvalhunter]

Yea thats what alot of the reloading books tell you to do.

[Schwag173]

 [/quote]
Just to make sure I"m understanding you correctly: If you left your seater die set from loading 175gr bullets and then seated 165gr bullets, wouldn't the OAL be the same? If so, I guess you're saying that the 165s were seated out as far as the 175s?
Or are you saying you seated the 165s just as deep into the case so the OAL was less leaving a jump to the lands?
Please clarify for me. I'm a little slow this morning.
[/quote]

The die had been adjusted for the conical-shaped Hornady 175s.  The plumper shape (ogive) of the 165 Sierra Gamekings caused them to be seated much deeper than intended.  The result was a short COL. 

[JackOfAllTrades]

The result was a short COL. 

Finding a more accurate load by accident is not our goal as reloaders. Let this be an eye opener to readers here; Measure your first round of a new recipe, (once changing anything from a previous bullet/component from the previous loading operation), and consult your load book before loading a potentially hazardous situation.

-Steve

[sakoshooter]

 

Just to make sure I"m understanding you correctly: If you left your seater die set from loading 175gr bullets and then seated 165gr bullets, wouldn't the OAL be the same? If so, I guess you're saying that the 165s were seated out as far as the 175s?
Or are you saying you seated the 165s just as deep into the case so the OAL was less leaving a jump to the lands?
Please clarify for me. I'm a little slow this morning.
[/quote]

The die had been adjusted for the conical-shaped Hornady 175s.  The plumper shape (ogive) of the 165 Sierra Gamekings caused them to be seated much deeper than intended.  The result was a short COL. 
[/quote]


Gotcha. I assumed by your earlier post that you were shooting 'like' bullets of slightly different weights in which the ogives would be very similar.

I'm not saying that the 'rod down the barrel' idea is better than a bullet chambering tool. I just said you could do it with for cheap with what's laying around the house and be pretty darn accurate also.
The ogive is taken into consideration with the 'rod down the barrel' because you're doing your measuring(for every different bullet)with the bullet's ogive slightly touching the lands.

[NRA4LIFE]

For my bolt actions I will color the bullet with a sharpie and work the seat down so the bullet is just touching the lands.  With much experimentation, I have found in my Brownings that is the optimum seating.  Unfortunately that did not work in my BAR as the overall length of the shell was too long and they did not cycle properly.  Those I seat in the cannelure and crimp.