300WM case length

[AndrewS]

I am new to reloading this year. I'm still learning a lot. I am using Norma brass and Berger VLDs. Berger book says full length 2.620 and trim length 2.610. SAAMI spec on it says full length 2.620-.020. So I assume that means they can go down to 2.600. Is that correct? So my questions, what length do I trim to and when do I do it? Once it exceeds 2.620? Thanks all!

 

[ksthomas]

Your call. Anything over the SAAMI Maximum is (potentially) a problem. This is a safety issue, and not much of an accuracy issue. So long as you're under that Max dimension, you won't be having any problems. The "trim to" figure is actually somewhat random, and is just a nominal figure of .010" under the SAAMI Max. If you want to take it down below that by a bit, you'll just increase the time between trimmings. Max length for a 308 Win is 2.015", with the trim to length given as 2.005". I've always trimmed (like most HP competitors) to 2.000" even, just to avoid having to trim quite so often. Nothing to sweat over, I promise.

 

[AndrewS]

Your call. Anything over the SAAMI Maximum is (potentially) a problem. This is a safety issue, and not much of an accuracy issue. So long as you're under that Max dimension, you won't be having any problems. The "trim to" figure is actually somewhat random, and is just a nominal figure of .010" under the SAAMI Max. If you want to take it down below that by a bit, you'll just increase the time between trimmings. Max length for a 308 Win is 2.015", with the trim to length given as 2.005". I've always trimmed (like most HP competitors) to 2.000" even, just to avoid having to trim quite so often. Nothing to sweat over, I promise.

Thanks for the detailed explanation. So is it ok to trim all to 2.600? And would I trim after the first fire if they are over that to begin with? Then just watch that they don't go over 2.620 and then trim again at that point?

 

[ksthomas]

Won't hurt a thing. Yes, the max length is the issue. Anything beyond this, and you run into the risk of the end of the chamber starting to "crimp" the bullet in the neck. Very poor accuracy, pressure spikes blown primers, case heads, etc., and some other very bad Ju-Ju. Wanna stay away from that kinda stuff.

 

[Victor N TN]

Look in Sinclair's catalog and get their case gauge plug,

Sinclair Chamber Length Gage | Sinclair Intl

Follow the directions and trim your cases to what the chamber length is -.010" No matter what the books say. If it doesn't work in your rifle, what good is it?

Good luck.
Victor

 

[AndrewS]

Ok, so just to make sure...too short is ok, too long is not. So SAAMI says 2.600. These are the last I trimmed. They are all ok to stuff? I just want to make sure due to obvious danger factors. Thanks!

 

[Shoottothrill]

This is a great read on case prep and talks about trimming. http://www.snipershide.com/shooting...and-loading-long-range-1-brass-case-prep.html. This is a sticky at the top of the forum, there are 4 others as well. If your trying to load really accurate ammo I would read them all. If your just looking for plinking ammo then you can just trim to book specs.

 

[AndrewS]

This is a great read on case prep and talks about trimming. http://www.snipershide.com/shooting...and-loading-long-range-1-brass-case-prep.html. This is a sticky at the top of the forum, there are 4 others as well. If your trying to load really accurate ammo I would read them all. If your just looking for plinking ammo then you can just trim to book specs.

I'll take a look, thank you! I started the the reloading process sticky. It was great. I am sure this one will be as well.

 

[Powermac]

Listen to Victors advice it is a good one.
Having the correct brass length and knowing how long your chamber is, is worth the 5 $ for sure.
It will at least reduce carbon ring buildup, as the closer the neck is the chambers neck the faster the brass will seal the chamber, and reduce any backflow. Shooting a large case with slow powders it is more likely too occur too.
And it may positively affect your SD a tiny bit.

I trim mine closer then 0.10 but i also trim every firing and monitor case growth, so doing so is at your own risk.
Using the gauge you also know how long a case can be before it starts to get dangerous.