Yesterday's Weapons Forums

A party in the sense of the old "G.I. Party."

Recently, I dug through my supplies of brass and took out all the cases that needed to be cleaned and sized. This included about 500 .30-06. Over the past week, I cleaned, sized, and cleaned them again.

A few nights ago, I went down and trimmed about 20 .30-06's and decided it was going to be a big project. Tonight, I went down intending to do some unspecified amount and got them all done. In addition, I also trimmed 50 Swiss 7.5x55 and a few .223 Rems; fortunately, most of the .223's had been done before the last loading and were still within specs.

So, I wound up trimming close to 600 cases. What a chore; probably my least favorite part of reloading. I told my wife it was no fun, and she said, "then why do you do it?" My reply was, "I don't like doing it, but it's satisfying when I am finished." The trimmed .30-06's will last me a while. I already have quite a stock of that caliber for shooting, so it will be a while before they are needed.

I know that many reloaders hate the Lee "Zip Trim" but after I started using this tool, I kind of fell in love with it. So much so that after having it attached to my bench with a small "C" clamp, recently I permanently mounted it with screws. It's just a little plastic toad, but it works very simply and well and after trimming thousands of cases, it has yet to break a string. One of the things that I like about it is it saves a little time in the case mouth champfering process. After you trim the case, there is a flash of metal left around the mouth of the case. This must be removed with a champfering tool. With the Lee Zip Trim, I can just leave the trimmed case in the little chuck and champfer it while its still there. With my old trimmer (Hornady/Pacific design), I had to take the trimmed cases out of the trimmer chuck and champfer them by hand as a separate process.

If you don't already have a trimmer, the Zip Trim is pretty inexpensive, too. The shell holders and mandrells come in sets by caliber, but they are dirt cheap. One Lee set costs less than one single Hornady pilot.

Once you get your cases in proper trim, you don't have to do it with every firing. Some cases stretch more than others with firing, but you should be able to get 2-5 firings out of them between trimmings. .30-30 cases seem to hardly stretch at all.

New brass usually needs trimming. I know, this seems like a pain in the neck (pun intended) but check the length on new brass. You will find that often it is overlength. Plus, before you trim new brass you will usually need to run an appropriate sizer ball through the mouth of the case (don't full-length size it). This is because so often new brass cases have mouths that are out of round from handling and shipping.

Many of the .30-06's that I trimmed tonight were once-fired factory loads. I noticed that the cases that tended to be the longest were Winchester where the manufacturing process includes the use of a "factory crimp." This is the step where they use a special die to kind of crush the case into the bullet for a good tight pull. Lee makes factory crimp dies so you can duplicate this in hand loads. There are reasons for using a factory crimp, which I will mention below. The downside is that this slight crushing process accellerates the growth of the brass in length.
Consequently, you will be trimming more often.

There are a couple of reasons for the use of a factory crimp. One, it gives a nice, tight crimp on the bullet. Two, with a factory crimp, you don't have to be quite as precise with your case trim length as you would with a roll crimp or a taper crimp. I suspect that is why some ammo manufacturers use this method; it eliminates a manufacturing step (trimming). Winchester brass has been the worst for case trimming, in my experience. Not only are they often overlength, but sometimes the case mouth isn't level all the way around; it might have a high side to it. With a roll or taper crimp, an untrimmed case like this would never work properly.

With bolt action milsurp calibers, I find that as often as not I don't apply any kind of crimp. With good brass that gives a nice, tight pull on the bullet, it really isn't necessary. When loading ammo for my M-1 rifle, I use bullets with a cannelure and give them a good crimp.