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Trimming the cartridge length to the proper OAL

komifornian

Sergeant
Full Member
Minuteman
Feb 12, 2011
419
8
55
Peoples Republic of Kalifornia
I've been reloading for a while now and have thus far been super picky about everything. However, does it really matter if case length is short by a few thousandths even though when complete the over all cartridge length is exactly correct? I guess what I'm asking is how much if at all does this effect accuracy?
 
Re: Trimming the cartridge length to the proper OAL

Well from my tests that i have run i accidentally trimmed a 308 case 4 thousands under min and it still shot just as well as the ones that i trimmed correctly. But on that note i have trimmed 300 win mag slightley short and it did have an affect on accuracy of about 1/4 MOA but i assumed this is probably due to the short neck already. I dont think it affects it as much as them being different lengths does or as much as being close to max length. As long as its not overly short i think it will be ok on a standard size neck.
 
Re: Trimming the cartridge length to the proper OAL

So I'm going to assume that if the length fluctuates a few thousandths on the short side I shouldn't see any noticeable accuracy changes.

I've also been super meticulous about everything else as well and because of this it takes a really long time to load 20 rounds. Everything is exactly the same in every way. So if I can have just a little lead way it would save me a bunch of time. The most time consuming thing is getting exactly the same powder grain count. I throw it then weigh it (digitally) and remove or add to make sure it's perfect. For example if the recipe requires 38 grains, every load is exactly 38.000 grains. If I could just have a variance it would be so much faster. So one would be 38.0, the next might be 37.8 and the next 38.1.... Anybody live with these tolerances?
 
Re: Trimming the cartridge length to the proper OAL

Buy the RCBS chargemaster and be forever done with the weighing BS ! Lifes short and there's better things to be doing....let the damn machine weigh and meter while you prep brass or sort bullets or clean a rifle.
 
Re: Trimming the cartridge length to the proper OAL

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Exhogflyer</div><div class="ubbcode-body">Buy the RCBS chargemaster and be forever done with the weighing BS ! Lifes short and there's better things to be doing....let the damn machine weigh and meter while you prep brass or sort bullets or clean a rifle.</div></div>

Great advice! Unless you're shooting a benchrest match, life's too short to worry about a few thousandths or even tenths when it comes to powder charge, trimming etc. Spend a some bucks and get a Chargemaster or good powder measure along with a Giurard (sp?) trimmer and spend your time doing something more productive.

Group size fluctuations are far more likely to be a result of the shooter doing something wrong vs your brass being a few thousandths too long or short. As long as they're pretty close to the same you'll be fine.