Making some adjustment on dies to make sure we don't have any headspace issues with the blow back and the new chambers. They are a shade deeper than my original reamer. Adjusted buffer weights on the pistol and got it cycling, what a blast! New load is 9.0 gr of Lil Gun because I can't find my can of H110..... Going to tune on it a bit then do a 9mm for a comparison.
Pulling things apart for a good cleaning today and inspection. I still have some inconsistency between by chamber and reloading dies so our goal is to get that worked out and get a standard set. This round is just too much fun to not develop. Our last outing put us over the 2000 fps mark from our pistol blow back uppers and that was our goal, to get a safe, reliable 2000 fps .22 cal round that fits a 9mm magazine. Now to get it all matched together.
Just for some kicks, I cut down some .223 brass to .905" yesterday and going to run them through the 30 Luger then my cut down 22 RE dies to see how they form into 22 UZ brass. My cut down dies would swage the base of Tok and 9x23 brass so maybe the .223 stuff will be different. We'll give it a try.
Mocked up some .223 cases in the cut down 22. RE dies today, only a couple but they might work. Looking at an alternative path to the 22 UZ because the TCM and RE both have small bases on the brass. In the process of setting up big blue with the 4th axis to help with reamer development but this (.223 brass) might work by short chambering the 22 RE......... 22B, what do you think?
Got the 22 Uzi carbine together running the "new" brass and had some thick necks so had to turn a few down. Starting load is 8 gr of Lil Gun and 34gr Dogtowns = 2300 fps from the straight blow back carbine set up. Recoil is a bit stiffer than I would like running a stock blow back system so next run will go on a new pistol set up with our MOD RAB and see how it works. Cases were all once fired 38 Super stuff I've been reloading and I didn't try any of the newly formed 9x23 cases yet.
I did an extra barrel set up for a Tok port location for the 22 Uzi, just to see what would happen in the "gas mode". What? Am I waiting for gas blocks? Why, yes I am, how did you guess? If its any consolation, my box of BCG came in yesterday!
Holy September Batman! Time is just flying by as the road has me very busy. Great day at the range this weekend goofing off and I had brought my 22 Uzi stuff from the shop last trip. One thing I wanted to do is use our Glock AR lower with glock mags for testing. I've got the carbine set up with the Manson chamber and using a combination of 38 Super and 9x23 brass. The necks definitely need to be turned with both types of brass. An interesting note, using the same loads, only difference is brass, the neck turned rounds are almost 300 fps slower and show no sign of expanding the brass or blowing the shoulder forward. The in-turned rounds are harder to chamber, blow the shoulders forward and are faster. Another issue we are having is OAL. The Armscor 40gr TCM bullets come in at 1.150" and work fine in Glock mags. The Dogtowns can get shoved in the case farther than the others and come in at 1.195" oal and barely fit the glock mags. All other bullets are 1.20"+ and won't fit the glock mags. Cases are holding length at .900" max so that's not the issue. The Uzi mags will hold a bit longer rounds. Now the decision of dropping case length to .850 so a larger selection of bullets can be used.... That puts us right at 30 Luger length! Without access to the shop, its all going to have to wait....
Post by squirrelslayer on Feb 14, 2020 21:02:25 GMT -5
How is it going Tim. Noticed you mentioned a .850" case I'm currently playing with a wildcat of a wildcat with a .860" case formed from .223 brass.
So far it's looking pretty promising getting 2230 ft/sec with the 34gr dogtowns from a 5.2" barrel in an actual glock. Case capacity comes in at 11gr on the nose mine has minimal body taper and 30' shoulder with a .150" neck. I call it the 22 Adder which was actually derived from my 22 Mamba (1.125" case 17.3gr h2o PDW cartridge i've been toying with. which does 2700 ft/sec with 40's from a 6" barrel and 2550 from a 5")
We put the 22 Uzi back on the workbench last month and made a new sizing die and getting it polished up. Our goal was a direct conversion from the 9mm AR blow back users.
The major issue is that when you start necking down the 9mm, you create more force acting backwards than forwards. This is the issue that the 357 Sig conversions faced and everyone stopped making blow back sigs when rounds started to blow up.
We went through the same thing with the TCM and blown cases.....
Without a locked breach / delayed blow back design, getting the rounds to function AND have any power over the 22LR is the challenge for the AR platform.
Post by squirrelslayer on Feb 18, 2020 17:04:20 GMT -5
Yeah i'm not a huge fan of blow back but do understand the appeal.
I'm running the Adder on a glock so tilting barrel delayed and the Mamba is locking bolt DI operated (2.5" gas on sub 5" and 3.2" on 5" and up. did do a 20.5" barrel and tried carbine gas and it's working quite well.
So I'm assuming that the cases are wanting to do like the FN 5.7 and telescope rearward and this is allowing to much case to be unsupported during firing and ultimately leading to case failure?
I have a friend who was asking me if something like these cartridges would work in his keltec sub 2k.
Is it a bolt mass issue? Now in my limited research I read that tapered cases will cause more bolt thrust vs a case with minimal to no taper as the case holds onto the chamber better. 5.7 has zero taper so maybe there's some validity to that?
Also I just got to thinking this afternoon that in my example where i'm using formed .223 brass my case walls are very thick which may translate into less expansion/grip? I know when I had a WSSM rifle these were plagued with hard bolt lift as brass was crazy thick. You'd think you were over pressure but no other signs. I annealed a batch of cases and the problem went away.
Anyway just bouncing around idea's. I've enjoyed reading some of your crazy builds. Wildcatting is an illness
Our 22 Uzi has zero taper to help that issue. It (IMHO) comes down to pure physics. I have 35,000 psi of pressure with a .224 dia hole on one end and a .394 dia hole on the other. Bigger hole gets the force. We've done buffers up to 22 oz just to test, but that's unrealistic. That's when we started playing with various delay devises.