Differences in bullet seating depth (OAL)

Mad_Mikee

Mad_Mikee

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Alright. There has been some debate if the length of the brass affects the depth of the bullet seating. I cant see how it does but then again I'm no expert.

Anyways. Here's the problem/issue/question I have.

I'm using RCBS dies, and my brass has all been trimmed to the same length.

I've been loading Nosler accubonds, Nosler ballistic tips and Hornady interbonds (all bullets have a nice plastic tip) in my various calibers.

I set my die, lock the locking ring, etc. First bullet, get the legth I need (or close to). Seat another bullet in a new charged case, measure. It's different!

WTF?

Tonight I was loading some 22-250 with a length of 2.51 and I give myself 0.002 +/-. Anything from 2.508 to 2.512 is accurate enough for me.

Without adjusting anything, I was getting some 2.50, 2.49, 2.48, etc.

I seem to get bigger variations with other longer cartridges. Im measuring using a digital caliper and with the plastic tips, there wont be any issues of deformed or non-uniform (if thats even a word) tips.

It's really a pain when I'm loading up a few different lengths to test.

Are my dies f'd up? Should I be lubing the inside of the case necks before bullet seating?

I've tried to partially seat the bullet, lower the ram, twist the case 1/2 turn and then finish seating.

Maybe I'm expecting too much out of my dies.

Any ideas for more consistant seating depths and loaded cartridge OAL?
 
digital readouts are a pain at times..
close up your tool...
set it at the highest number you are getting between your longest and shortest reload...
i ll bet you cant even see a air gap on that amount..
if all else fails.. use the old style method if it dont fit in the mag..its no good
 
Yes, a good part, maybe all the trouble, is having equipment that measures too accurately. And, measures the tips, while the loading die rest further down the bullet, while too much loading information is given.
For many years the over all length was never given, in any loading chart. You loaded them with enough depth to hold the bullet and if they went through the magazine and the bolt closed, you were in business. If the bolt wouldn't close, or they wouldn't cycle through the mag, you seated them a little deeper.
No problems. Shooting matches were won and animals died from hits with them.
 
I know everyone has their own method for reloading but what seems to work for me is start with like 5 or 6 powder charges all using the same OAL. Shoot, see what seems to work. The take that powder charge for 5 or 6 new batches all with different OALs. On the lands, then 0.01, 0.02, 0.03, 0.04 and 0.05 off.

Once I get the sweet spot with the right powder charge and OAL, I want to ensure I can duplicate it.

I've gone with the plastic tip bullets partially becase the tips are never deformed so I figured it would be easier to use to measure OAL.

Im sure the dies are capable enough. Probably just some operator error.

I'm sure I just need to re-read the RCBS instructions for seating die setup.
 
Get a comparator. Even the ballistic tipped bullets have variance in the bullets base to tip length, the comparator will measure off the ogive of the bullet and not off the tip.

Once the die is set, the OAL will not change. The measurement to the tip of the bullet means nothing other than your first round to set the die.

Try using SP or HP bullets and you will see even greater variances.
 
I am very new to reloading but I am sure with all mechanical processes there is some variance involved. I mean heck no 2 grains of sand are identical for that mater. It could be the callipers too. Have you tested them? I mean, measure a round. Close them and measure that same round again. Are the numbers exactly the same? you could be on a slight angle, or just touching it slightly different to get that small amount of variance.
 
How sturdy is your bench? I have had issues with a light bench top flexing and not giving a consistant travel of my ram when operating my press. Other than that the others here have some good ideas. Problem may be the plastic tip in the first place. Have you tried using different projectiles? I shouldnt have anything to do with your brass thats for sure.
 
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