Making Wildcat Brass

Kodiak99317

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The 22 MR (Mohn/Rempel) is a case designed by the late Clive Mohn and is basically a .243" NK 22 BR reamer run in deeper by 3/10's of an inch. To make this brass using regular dies (sort of) you have to first shorten a parent die (I have ones in 308 and 22-250) so it will set the existing parent case shoulder back without collapsing the case, then run it that thru a 22 BR FL die set long. This would usually form shoulders with small folds in them if you forced the brass into either of the dies with any speed. Yes, using smaller "pushes" until you get full stroke, sometimes, not all the time, make cases without the folds, but not many, and depending on how bad the folds were after the 1st fireform, many cases were tossed.

So I got busy here one stormy day and started to make up some new 22 MR brass for myself. I had some (I know, bad choice) RP 22-250 NP (Nickel plated) cases and no 22-250 so I got busy and made up some 20 cases with the above dies. Then I got to thinking, this case, being some small could really benefit by making up some small primer cases, and I just happened to have some 500 Lapua Palma cases weight sorted sitting there too, so... I got started swapping the dies all out again and stopped myself.

I though, might as well get a set of form dies, so I ordered the last set of Butch Lambert Form dies. Butch took this up after Skip passed I think, and the original idea came from Skip Otto and John Bunch. I talked to Butch via email and he sent me to Russ Haydon, were Butch sent his last 3 sets he had, and I called Marsha at Haydon's and she said I got the very last set she had!!! I got the very last one made :)

Man, I glad I got them! They make this task soooo much easier! It has 9 case hardened and polished bushings range in diameter from .404, .386, .348, .323, .302, .272, .250, .223, and .205. I set the up form die up and did 22-250 and seven 308 Lapua Palma cases at the same time, with no lost cases, using a fireformed 22 MR case to set the die up with each bushing and cycling thru the bushings until I got down to 22 cal. I only did up 7 of the Palma cases for now since they were the lightest of the 500 cases I sorted, just to try it... as a small group compare for ES over the chrony vs the large rifle cases. I slid out on the weekend and fired 5 cases of the 22-250 NP brass, 2 from the old multi die method, and 3 from the Lambert die. All firmed nicely in the -20c temps. This form die will come in very handy, since I have 3 wildcats in my stable now that I shot alot. A 30x47 HBR, a shortened 6mm-250 Savage 30 degree and the 22 MR, plus a 6BR, all of which are tight necked chambers and required neck turning. These 22 MR's have a .0084" thick neck after outside turning with my Pumpkin turner.

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Form die and inserts/bushings

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4 cases formed with form dies (1 of which is a Palma case), 4 cases with multi dies, 308 case, 22-250 case, 6 BR Lapua and 6 PPC Sako USA NP (1 of maybe 10000 that Wally Hart originally got done up special for his select friends, I got mine from Al Murdock, when the very first Sako USA PPC cases came into the US)
 
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Looks like a cool caliber. What does she perform like velocity wise? Post up some range reports please!

Any good range testing will have to wait for warmer weather. It is -32C out there now. When I test fired the 5 cases, the 3 form die brass cycled nicer loading (less rifle upset) and after firing test was a nice close with the firing pin removed so you can feel the effort required without the pin spring pressure. The 2 shortened multi die way had firmer bolt close before firing and nice after. Nice to me means, with the firing pin out of the bolt and a case in the chamber, when you close the bolt you feel a slight resistence on the down stroke starting about 1/4 of your bolt fall. With the pin out and no case in the chamber, the bolt will drop closed with no assistance. I can also tell you at 600 yds, 52g FB bullets out of her holds a great waterline on the target, but you can use most of the 6 foot wide target due to winds if it is changing fast, bin der, du it. Now this case with a fast twist and 80 or 90g VLDs would be a different story at 600 yds and beyond.

Velocity wise, 52g bullet over 38g RP3 does 3727 fps and 32g of N135 does 3713 fps. I have driven these 52 and 55g bullets well over 4000 fps but few make the target. Group wise, first time out, she did around 1/2" for a 5 shot at 385 M. I've only shot around 500 rounds thru her so far. The case holds 46.4g of H2O max., to the very top of the neck, almost as much as my 1000 yd rifle's 6-250 (think 6XC) which holds 49.7g of H2O. The 22MR is for varmints so it has a 1:13.5 twist factory barrel re-chambered into 22MR and shoots 52-55g bullets really well. For comparison, my 6BR holds 39.0g of H2O and since the 22MR is just a 22BR run in deep, the extra .300" of cylinder nets 7.4g more H2O capacity or 2.5g for each 1/10" of body.

Here's my competition and wildcat cases I use... (6BR .269 NK is missing in this line up)
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