I'm getting inconsistant bullet seating depths...why?

Dultimatpredator

Dultimatpredator

Well-known member
I own a RCBS rock chucker single stage press and use standard RCBS dies. I have noticed over the years that when I seat bullets the overall measurement still varies(up and down by a hair) when I measure it in my Micrometer. For example I loaded some 40g nosler ballistic tips the other day in 223. I loaded some at 2.2" and some at 1.196". When I measured them some of the 1.196" where at 2.2" and some were less. I tightened my die down as usual to make sure nothing moves to come out of adjustment. I then seated the bullets. When I measured them some are just a hair too tall, some are right on , and some are a hair too short. Are the bullets all seated at the correct depth and there is a variance in length in the plastic tips? I've noticed this on lead tipped bullets as well which I understand that the lead tip deforms or vary in length. Fro example core-locts. My question is, is the bullet, the dies, or am I doing something wrong? For the record I still get some pretty tight groups with this variance but wondering if I can do something to improve this step for more consistent reloading practices.
 
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Open a new box of bullets and mike ten random bullets. Record the measurements. I'll bet they vary in length by .010 or more, in some cases. Now you know why your OAL of loaded rounds varies.
 
The ogive of the round in relation to the chamber is what counts...If you measure the length of your chamber and seat your bullets to the ogive, the overall length of the cartridge itself is of little consequence..It's the amount of 'jump' from the ogive to the lands that is important for seating purposes..
 
If you are measuring off the tip of the bullet, you need to got to a little more advanced way of reloading your ammo. The Hornady comparator or the Davidson are both fantastic. Of course, you will have to have a dial caliper.

www.sinclairintl.com

and your problems with this issue are over with greater, repeatable accuracy being the fruit of your labor.

Good luck
 
Just curious why bullet length is affecting oal? I understand about the ogive measurement, but wouldnt a longer bullet just be seated deeper in the case?
 
Originally Posted By: bamacrowkillerJust curious why bullet length is affecting oal? I understand about the ogive measurement, but wouldnt a longer bullet just be seated deeper in the case?

No, because the seating plug doesn't engage the tip. Is seats on the body of the bullet.
 
This

Originally Posted By: midwestpredatorGet a hornady oal guage to measure off the ogive. The bullets will vary in length when measuring to the tip.
 
I get simliar readings from my chucker...you will get bullets that are not the same length....but i have nt seen any difference in accuracy with a couple thousands difference... Rusty
 
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