Need help

[Bullshop]

Bull Shop
asked me to ask this here - hoping for some help

*How do I go about opening up 22 cal jackets for 6mm / 243 bullets?*

Thanks BS Mom

[Artful]

You need a die set that will stretch the brass around a mandrel.

If he's wanting 22LR or 22 mag case - same answer just different dies.
http://www.corbins.com/rfjm.htm

http://www.corbins.com/images/kit224r.jpg


This is probably the ONE product most shooters have heard about, because the process of using fired .22 cases as jackets for centerfire .224 and .243 rifle bullets launched so many of the giants of reloading, such as R.C.B.S., Speer, Hornaday, and others.

Corbin has offered the RFJM-22R, RFJM-22M, RFJM-6MR, and RFJM-6MM die sets for decades. Shooters use them to turn fired, empty .22 Short, Long, or Long Rifle cases into excellent thin-jacketed, explosive .224 centerfire rifle jackets or 6mm (.243) centerfire rifle jackets. The RFJM- stands for Rim Fire Jacket Maker. The -22 or -6M designates whether the die set is for making 224 or 243 caliber bullet jackets (the only difference is the punch and extractor mechanism). The final R or M determines whether the punch is for a standard slotted ram reloading press, or for the 5/8-24 TPI threaded ram of a Corbin Silver Press or Corbin Series II press.

The quality of bullet jacket you can make with free .22 cases is excellent. It has no more problem with bore fouling than a normal jacket, perhaps less. It has less friction in the barrel than a normal factory bullet, so it is actually easier on the bore than firing factory bullets. You cannot load these thin jacketed bullets as fast as a factory bullet, so this forces you to use less powder, and wears the bore even less! The bullets act like they impact at 4,000 fps even when you fire them at less than 3,200 fps (which you should, to keep them from coming apart due to high rotational force on the .010 to .015 thick jacket walls). Rimfire Case Bullets

Fired .22 cases make the very best varmint bullets, and probably the worst big game jackets (certainly not recommended or ethical from a hunters point of view to use such thin explosive bullets on big game). As target bullets, they can be extremely good, beating even some benchrest bullets. We do NOT recommend them for serious benchrest use, though, because when you pick up spent cases you run the chance of different lots, different firing pin dents, and thus differences in the final jacket temper or hardness that might cause the groups to become wider than they should. If you are looking for groups in the half-inch to one-inch range at 100 yards, fired .22 cases will do a great job. If you are looking at groups of .20 to .30 inches, they can do it if you sort every case by lot and make sure the original firing pin dents are the same, and use a lot of care in forming the bullet. But for record setting groups, use commercial or drawn jackets.

These are the ultimate plinker bullet because they are so very accurate, easy on the bore, and cheap! (as in FREE). The process is quite simple: gather up fired .22 cases, toss out the flattened ones and the ones that have firing pin dents torn all the way through, wash them in boiling water and detergent, spread them out to dry on a towel. Then use Corbin Swage Lube on your fingers as you pick up the cases, slip them over the punch, and push them into the die. I like to push them in just far enough so the head is ironed out as the end of the stroke is reached, only about 3/16 inch or so into the die. That makes it easy. You use full press leverage to unfold and iron the head back into a straight wall section (as it was originally, when the case was built).

Then I lower the ram, eject the jacket, and process another one. When I have done about 500 of them, I lower the ram slightly and push each one through all the way in a longer, but easier, stroke. Having unfolded the head, the rest of the draw is easy now. Doing it all at once is possible, but takes more effort and a perfect adjustment of the die so you get exactly the maximum leverage at a point where the jacket just disappears into the die. Doing it in two strokes is a lot more flexible and easier on your arm.

After about an hour, I have processed 500 of the little jackets. I put them on a little tray made out of fire bricks stacked side by side, and heat them with a propane torch using a fan-tail spreader nozzle until they just barely get visible red in a dark room. Let them cool, or scoop them into a pail of water if you are in a hurry (has no effect on the temper of the brass). Dry them, and use them as you would any other jacket (but use a .204-inch diameter core seating punch, since they are thinner than the commercial jacket which uses a smaller punch, normally about .198 to .201 inch).

You can make 45-50 grain bullets with .22 short cases, 50-60 grain with a .22 LR case, 55-65 grain with a .22 Stinger or other longer .22 case, and in the .243 caliber you can get a nice lead tip 65 grain bullet with a .22 LR case. You can also use the .22 Magnum but not in these dies: that case is thicker and requires a different, special die set which Corbin makes. The .22 Mag produces a 105 grain 6mm and can also be expanded to .257 caliber. There are good illustrations of .22 RF case bullets in the new Corbin Handbook No.8 and detailed discussion of the old myths and misconceptions regarding the use of such materials.

(One example: during the early years from 1930-1950 the priming mix in 22 cases was corrosive, which made the cases brittle. When used as a jacket in those days, the brittle cases flaked apart in the bore and caused fouling. Word got out the using fired .22 cases was bad for your bore. Well, sure it was, back then. But manufacturers don't use corrosive priming mix any more, and have not done so for decades. That was the whole problem, and it doesn't exist any more, but the myth still continues in some people's minds. Part of the reason is that shooters love to read old gun books, but many of the stories in them deal with problems that don't exist today. If you don't know the reason behind some of the statements, then you can easily become fooled into thinking the problems of the early days still exist.)

[Nickle]

Well, my understanding is they don't fully open up the case, but give it a big "belling out" when derimming it, which requires the case to come back the way it came, instead of push through.

I'd say they're relying on the core seating and point forming dies to bring it up to 243.

Like I said, I haven't done it yet. Soon, though, just haven't tooled up for 243 bullets yet.

[Cane_man]

corbins have some nice drawings of the process on their site, if you can find it, that site is a maze LOL

[teddyblu]

http://www.corbins.com/rfjm.htm

[BT Sniper]

As I understand it you use a short derim punch that has a beveled, fatter base to it that will derim and expand the jacket at the same time. It doesn't push the case all the way threw the die. It bells the mouth of the 22lr jacket. It is then up to the core seat die to expand the rest of the jacket while seating the core.

Somewhere on this forum is a pic!

BT

[Bullshop]

OK I understand what is being said about the punch belling the mouth of the case for 6mm use. I have that punch but still have a problem getting clean sharp bases in 6mm. Seating the core is not completely filling out the base. The finished bullets have slightly rounded edges at the base and seem not to be uniform for the entire circumference.
I bought some commercial 6mm jackets from an auction on this site some time back and the bullets made from them had perfectly sharp well filled bases. That made me a bit disappointed with the 22 rf jackets in 6mm.
Even so they seemed to shoot well within their pressure limits which makes me wonder if perhaps the bases are squaring up in the barrel under the pressure of powder ignition.
I wonder if and intend to try a harder than pure lead core to see if that may help to fill the base while seating the core. With the pure lead cores I have been using I adjust the core seating die so that the core just barely begins to show the tiniest bit of bleed past the core seat punch tip. An alloyed core slightly harder than pure lead may resist bleeding past the punch tip and allow just enough more pressure to better fill the base.
This is not a case of my jackets being too hard because I anneal them to be soft enough to easily crush between thumb and finger so lets not bother going there as I feel it will be a waist of everyone's time.
Many thanks for the help.