Case trimming question

[ADA]

I am just getting into reloading and have a question. I measured the chamber in my 700P .308 and the result was 2.052". I measured three times and that was the average. I know factory chambers are long, but does that seem right?

The idea is to get the chamber length, and trim my brass 2 or 3 thousandths under that measurement. That puts me near 2.050". None of my fired cases are near that length, most being near 2.010. Is it realistic to think that they will grow over their useful life to a length near my chamber length?

Right now, I am trimming to 2.010 to get them uniform. That length seems to be the longest I can go and still get them all the same.

My questions are:

A. Does 2.052 seem like I am measuring my chamber correctly?
B. Will my brass go that long over the course of it's life?
C. In the interim, does it make sense to trim them to 2.010?

Thanks for any help.

 

[wirehand]

Re: Case trimming question

Yes, the Rem. chambers are long.

Mine in 5R is 2.046

I also trim to 2.010 just to be consistant.

 

[Victor N TN]

Re: Case trimming question

The brass will grow.

My chamber is a custom chamber. And it still measures 2.030"

Until you get a few thousand rounds under your belt. Just worry about the basics and being safe. Enjoy the extra economy of shooting more. Then the extra steps can be understood a tad better. Read EVERYTHING you can on handloading to learn as much as you can.

 

[ADA]

Re: Case trimming question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body"> Then the extra steps can be understood a tad better.</div></div>

I know that experience will show me what the brass will do over its useful life; however, the quote above begs the question "is there something wrong with my approach?" Is the method I am using wrong? Just making sure I aint screwing up.

Thank you both for your responses.

 

[Bucksquirelly]

Re: Case trimming question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: A.D.A.</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body"> Then the extra steps can be understood a tad better.</div></div>

I know that experience will show me what the brass will do over its useful life; however, the quote above begs the question "is there something wrong with my approach?" Is the method I am using wrong? Just making sure I aint screwing up.

Thank you both for your responses. </div></div>

I never found brass that was close to maximum length for the chamber to be anymore accurate than brass trimmed to trim length. Those are just my results though. I neck size everything so I dont have to trim my cases all that much but I normally keep them .005 under max length. It takes about 3 or 4 firings for the cases to stretch .005 of an inch in my experience. Once they go over that I trim them back to published trim-to length. All the guns I reload for shoot excellent with the way I do things so I have no plans on changing anything.

Just remember its important to keep the cases under max length. If they go over you can get very high pressure spikes. I experienced this the other day with some sized and primed brass I got from a friend. Trusting that he knew what he was doing I didn't bother to measure the lengths of the cases. I don't know what I was thinking but it could have turned out worse than it was. The brass was long enough to cause the mouth to get pinched in the throat slightly and caused a huge pressure spike that resulted in a pierced primer. The first one I didn't notice right off the bat but the second one the bolt was kinda sticky and I looked at the primers of both shells to find they were pierced. Fortunately I was running a fairly mild load so the results weren't as bad as they could have been. Nonetheless I learned my lesson to ALWAYS measure brass for max length.