>308 Case trimming question.

[JRSherman]

The Lyman manual I have lists a trim-to-length of 2.005". Almost all of the brand new Remington brass I bought has an average of 2.010".

Should I be worrying about trimming that down the extra 5 thousandths? I'd be much more comfortable if there was a tolerance like there is when I'm machining stuff.

I have read that case length is a factor in accuracy in some studies, but it'll be awhile before I need to worry about that tight of accuracy(I think).

Thanks for the help guys!

 

[Mitch H.]

The Lyman manual I have lists a trim-to-length of 2.005". Almost all of the brand new Remington brass I bought has an average of 2.010".

Should I be worrying about trimming that down the extra 5 thousandths? I'd be much more comfortable if there was a tolerance like there is when I'm machining stuff.

I have read that case length is a factor in accuracy in some studies, but it'll be awhile before I need to worry about that tight of accuracy(I think).

Thanks for the help guys!

There is no need to trim new brass. The case length factor in regards to accuracy is CONSISTENCY in the OAL.

 

[JRSherman]

Just the answer I was hoping for! Thank you very much and I appreciate the noob help !

 

[SDarkRage]

With new rifle brass, I'll take a handful out of the box and try them in the chamber of my gun. If they work and don't get stuck then I don't need to full length size them. I'll also take a handful and just double check case lengths to be on the safe side, but I've never had to trim new cases, just neck size them and load em up. I've been using Remington for my .243 and .308 for awhile now and I've never had any problems with their size and dimensions, they've always been consistent for me.

 

[dugby]

On new brass I size them all and do not trim. The main thing sizing new brass does is to keep the neck tension the same when you use the dies to reload them later on. Not much difference but enough that I go to the trouble to do it.

 

[JRSherman]

I had already planned on sizing them all, as I noticed several slightly out-of-round necks where they had probably just bounced around during shipping.

 

[angsniper]

I do size new brass but not trim it. However, when I trim fired brass I trim it back to 2.010.

 

[MoBoost]

There is over 300 thou of bearing surface in 308 case, so even 5 thou in case length difference will result in less than 2% neck tension difference.
I would check to make make sure that it is square and not too long after first firing, wilson trimmer has been working for me the best.

 

[mec]

Most of my 2-3 times fired cases were in the 2.015 to 2.018 inch territory but I did have a few that were getting long in the tooth at 2.024 or so. Trimmed them all down to 2.005 with the lee setup attached to my cordless drill.

I was really nervous about getting it right, but it was really a non event. About 5 seconds per case and all is good to go

 

[454308]

Per Hodgen oading manual the overall max case length can be 2.015