The process for reloading rifle brass goes like this: shoot, clean, size, measure for potential for trimming, trim, reload. You must size before deciding whether you need to trim or not.
Brass as it comes from the factory is smaller in diameter than any chamber for a production gun. When you fire the cartridge it acts as a gasket for the 30,000 to 60,000 psi pressures that rifle cartridges creates. It stretches to fill the loose chamber. In that process it expands in diameter and shortens in overall length. When you resize it you force the diameter back down to the correct size and push the shoulder of the case back. This process makes the overall length of the case longer as the case walls thin ever so slightly. Eventually the case walls get brittle from the working of the brass and thinner as well and the case neck develops splits. Most cases can be reloaded 5 or more times (belted magnum cartridges are lucky to get three reloads) but neck sizing only can make it more than that as the case body is not changed by neck sizing (still may need occassional trimming, though). But this neck sized brass may only fit the gun it came out of. Eventually the neck sized only brass case MAY have to be full length resized as they may no longer fit even the gun they came out of.
So size the brass then determine if it needs trimming (and it will after maybe as many as three reloads or maybe even after the first reload). Once trimmed it is good for two or three reload before trimming again. Pistol cases should never need trimming, in my experience.
RCBS has a relatively new die set (X-Dies) that is suppose to minimise or actually eliminate trimming after the first trim. The brass is suppose to last longer as well (more reloads). One tester got upwards of 12 reloads before he got a measurable change in trim length and half of his test lot went all the way to 20 reloads before he deemed them unsafe to use anymore. It was 308 in a semi-auto rifle and his previous regular die resizing was good for no more than 5 reloads before he was forced to discard the brass. This guy shoots alot!!!
Doubling the life of the brass is a big savings to any reloader. I just started testing my own 308 brass for my FAL rifle using these X-Dies, so I have no personal experience with them but we'll see if it works for my gun/brass combo as well. It will probably take me years to make this determination as I have lots of rifles and pistols all clamoring to get shot and only one of me with only so much time to shoot. But I like the theory behind the X-Dies.
Last edited by LDBennett; 08-07-2008 at 09:07 AM..
I just wanted you to know that LDBennett hit the nail on the head and not that he needs any codification from me but rather to provide you a second concuring opinion from someone who also does a lot of reloading sharing his knowledge.
The 30-30 tends to need less trimming because of the lower pressure it opperates at. You shouldn't need to think about trimming once fired 30-30 cases but checking their length would be safe.
One load manual I have documents the author loading a 30-06 case 100 times with mid-range loads & minimal trimming needed. The case was ready for more re-loads but by then he was bored. It was Lake City case if I remember. Good old tough brass.
In the good old days Scheutzen rifles were often shot their entire service life with only one case that was re-loaded at the range.