Saturday, July 12, 2008

Rifle case preparation for reloading, Part 2 of 3


In part one; we reviewed some basic case preparation work with 8x57mm fired cases.
The article left us with a basket full of nice, shiny, sized brass, all ready to proceed.

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Our next logical step, and one that’s required for accuracy in every case, and safety in some, is to trim the cases to proper length. I have found that, while having the case length set close to spec is important, having a matched set of brass with *matching* case length far more important. If each case neck is the same length and bullets are seated to the same depth, then neck grip on each bullet should be the same. That means each round will have a better chance of leaving the case in the same way, and each round will have a better chance at equal chamber pressure and powder burn rate.

Important? Yup, you better believe it!

There are many way to trim cases to length. Simple to complicated, both hand and powered are available. I have tried many of the usual methods and a few unusual ones, but years ago settled on a plain Hornady hand operated unit.

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It comes with a large number of pilots that center the case mouth against the cutter head and uses standard shell holders to grip the case. I mounted mine to a small board which can be clamped to the loading bench, or carried out to the back deck. There the sun shines, adult beverages are easily at hand. If confession is in order..... I have even trimmed cases while watching TV.

In use, with the proper pilot in place, a case is mounted in the trimmer and carefully trimmed a bit at a time till it’s the desired length.

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That leads us to a question that must be answered. Exactly how long should the case be?

That varies considerably. I’ll relate how I make my choice, but every hand loader has to decide on his own what’s best. In my case, since accuracy is a strong goal and I know every case must match to achieve this goal, I measure all the cases till I find the shortest one. If one or two are far shorter, they are tossed in the ‘spare’ pile.

The shortest one is then mounted in the trimmer and the case mouth is just squared off.

That case becomes the set up gauge for the trimmer, and every other case in this group will be trimmed to this same length.

There are many kinds of trimmers available, but be careful and give the choice some thought. One of the cheaper trimmers uses a long pilot that actually references the cut to the inside of the case at the primer flash hole. There is a danger in that course. Not every case is exactly the same at that point, as we’ll see later, and using that point as a reference means uneven case lengths.

Once all the cases are trimmed, we’ll need to chamfer the case mouths. The trimming process will leave the case mouths with a flashing both inside and out.

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Once again, there are many tools and gadgets out there for this. On smaller cases I have used a screwdriver, and old timers often swear by a sharp jack knife. Myself, I mostly swear at sharp jack knifes and prefer to use a Wilson case chamfering tool.

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This simple and inexpensive tool does an excellent job. It cuts quickly and with good control. A few twists of the case and tool will cut the flashing off and leave the case mouth with a smooth bevel that won’t snag while feeding or shave the bullet on seating.

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Now that the case has been trimmed to length and the mouth chamfering done correctly, it’s time to clean up the inside of the case neck. Once again... this job is a snap.

If there are only a few cases involved, a few twists with a case neck brush does a fine job.

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If there are more than a few cases, a decent cleaning brush chucked in a cordless drill will do a hundred cases in about four minutes flat. Just a short BZzzzzzz in each case mouth is all that’s needed.

Is this step required? Well....... I think so. Grab a flashlight and take a close look at the inside of the case neck. Now, clean it well and look again. Which case neck will do a better job of releasing the bullet in a regular manner?

At this stage of the case preparation process, I usually stop and clean my tools and work area. Good quality tools are worth buying, and certainly worth taking care of.

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So.... to recap......

We gave the cases a brief clean up, and then lubed them. The cases were then full length sized, wiped down, and examined. Then they went back to the polisher for long enough to become jewel like sparkling bits of joy. After this the cases were trimmed to length and the case necks were chamfered smooth. Then the inside case necks were well cleaned.

Still with us? Good...... lets move on!

What? You thought we were done and ready to load?

BWAHAhahahahahaha.......... Not by a long shot!

In part three we’ll look at the other end of the case. The primer pocket needs some care, and usually a small redesign job. The flash hole will also get some one-on-one counseling to repair leftover manufacturing flaws.

Stay tuned friends and neighbors..... There is more good stuff coming!

3 comments:

ExistingThing said...

Looking forward to the last installment, and more!

Thanks!

Carteach0 said...

You wish has been answered.... (g)

Tell your friends!

MP said...

On the Lee Case Trimmer, the pilot does not ride on inside of the flash hole, it goes through the flash hole and rides on the Lock Stud.