Seating Depth Consistency

truck driver

Ammo Smith
Mar 11, 2013
6,965
329
Until I got a Hornady comparator I never really double checked my bullet seating technique. I would set my bullet seater die with the first bullet and leave it alone. Once I started measuring off the Ogive for OAL I found I wasn't seating the bullet to the same depth each time and had to adjust the seating stem for each load. The load was also lightly compressed.
Will a micrometer seating die stem eliminate this problem or will I still have to play with the stem to get each bullet set to the same OAL?
 

jimbires

Handloader
Aug 16, 2011
2,505
476
how much varience are you getting ? I have redding micrometer seating dies , and I still get a couple thousance variance . compressed powder charges can cause this to be worse than normal . does it help if you reseat the bullets the next day ? are you using a drop tube funnel ?
 

truck driver

Ammo Smith
Mar 11, 2013
6,965
329
It depends on the bullet I guess since I don't sort and measure each one before I seat it sometimes as much as .05"with a compressed load. I do use a drop tube funnel for all my powder charging. I have never gone back and checked the next day since I back the stem off and with each load and seat the bullet where I want it which tends to take more time but now I have piece of mind that they are all the same. I was just trying to eliminate the extra steps.
 

ElmerThud

Handloader
Jul 16, 2011
769
15
If you're using good quality bullets, the problem of variation of seating depth is likely to be caused by cases not being all exactly the same length. If that's the case, variations will always occur unless/until trim to length is as near equal as practical.
Your +/- tolerance should be .001" so no more than .002" also, a crimp to secure will also help.
Cheers, ET
 

jimbires

Handloader
Aug 16, 2011
2,505
476
.050 is a lot . are you using the correct chrome insert ring in the tool for your bullet size ? try running them through your seating die again the next day , just to see what the COAL does . years back I used a highly compressed load and the powder was pushing the bullets back out over night . after I reseated them all was good .
 

Charlie-NY

Handloader
Mar 11, 2005
1,175
194
Case length should not affect your OAL when measured off the ojive. Mixed brass and compressed loads always degrade the consistency of your OAL. One of the reasons that I avoid compressed loads is to avoid the very problem you are having.

I'm guessing that your OAL variance is .005" and not .05" as you posted. A .005" variance isn't a big deal in a hunting rifle that is typically loaded at more than .030" off the rifling.
 

DrMike

Ballistician
Nov 8, 2006
35,473
2,256
As Charlie stated, fifty thousandths of an inch is a massive differential. Five thousandths is well within the differential noted for hunting ammunition. The sole exception would be if you were constructing competition ammunition or if you were planning on shots that reach out well beyond 500 yards.
 

truck driver

Ammo Smith
Mar 11, 2013
6,965
329
This has been occurring with 200gr AB in Nosler brass with the powder just in the bottom of the case neck.
OK I may have pushed the wrong key on the key board and it's more like. 010". I'm using Reading dies and a 6" drop tube. The ABs are being seated deep in the case with the boat tail in the powder.
 

Rol_P

Handloader
Nov 23, 2013
690
3
Rodger, earlier this year I talked to a tech at the Redding factory before I bought the Redding Competition seating die for my 30-06 and one trick he gave me was let the handle of your press fall free as it cams over the last bit as the seating stroke completes.
I guess this eliminates variable human muscle pressure in the process. It seems to help my consistence but I am not using compressed loads until I switch from H4350 back to Reloder 22. Good luck.. Rol
 

rick smith

Handloader
Apr 6, 2005
1,249
0
Neck tension can also cause a problem in seating depth consistency. If you are using an expander ball when sizing make sure it is polished to a mirror finish. I use both the Redding and Forster micrometer seaters. vary seldom do I get 0.001-0.002 variation. The amount of pressure you use to seat bullets can also be a problem. Try to be as uniform as possible with the press arm each time.A slam on the arm rather than an easy seating can easily cause a couple thou. difference. Rick.
 

truck driver

Ammo Smith
Mar 11, 2013
6,965
329
I'm annealing all my cases after each firing so neck tension shouldn't be a problem. Never knew I had a problem till I started chasing accuracy in a 35 Whelen AI loading Nosler ABs. As far as seating technique I seat the bullets in steps and turning the case so the bullet is seated as straight and uniform as possible.
 

Rol_P

Handloader
Nov 23, 2013
690
3
Do you have a concentricity gauge to check runout after the resizing process? I had to learn how to set the expander ball to keep runout to a minimum, generally less than 0.001".

I also check the new Nosler brass and find some is not running to my satisfaction. No seating die will set a bullet straight in a crooked neck.
 

Rol_P

Handloader
Nov 23, 2013
690
3
Do you have a concentricity gauge to check runout after the resizing process? I had to learn how to set the expander ball to keep runout to a minimum, generally less than 0.001".

I also check the new Nosler brass and find some is not running to my satisfaction. No seating die will set a bullet straight in a crooked neck.
 

truck driver

Ammo Smith
Mar 11, 2013
6,965
329
Rol_P; I don't have a concentricity gauge. So I don't know if the necks are straight or not and since this is a hunting rifle I'm not sure I need to be that precise. I was trying to find out if I was doing something wrong and I believe I'm just seeing things I never noticed before when reloading.
Dewey, Scotty, DrMike and others here have me looking differently the way I use to when reloading. I guess it's to much info for my pea brain to digest and to much time on my hands to think about it.
I might get a new seating stem since I think it will make my bullet seating more consistent.
 

Charlie-NY

Handloader
Mar 11, 2005
1,175
194
Try seating the same bullets on a few empty (resized) cases and see what you get. This should help identify the problem.
 

Darkhorse

Handloader
Mar 14, 2014
757
33
Truckdriver, are you, by any chance using a primer pocket uniformer tool? If not, then that can be the problem as some primers will not be seated flush or below, and you will measure that proud primer along with your case and bullet.
I seldom get over .001 to .002 variation in OAL and I don't use expensive loading tools.
 

truck driver

Ammo Smith
Mar 11, 2013
6,965
329
I don't use a primer pocket uniformer but I do clean my primer pockets and seat my primers just below flush or as far as they will go into the primer pocket which is always below the rim and check each one.
But thanks for the suggestion.
 

Darkhorse

Handloader
Mar 14, 2014
757
33
Yeah, I did the same thing for decades but no matter how I scraped or brushed out those pockets I still continued to get primers with measurable protrusion. Then I learned about the pocket uniformers and bought one. Now I wouldn't be without one.
The main thing to me is the little radius right at the bottom of the pocket. This tool cuts that radius out allowing the primer to seat square with the pocket bottom. I consider this a vital part of my case prep.
And you only do it once, not everytime you load a case.

http://www.midwayusa.com/product/106433 ... ormer-tool
 
Top