I went back to the first page and found that you already did some darn good velocity tests from the 8" barrel. I thought that you had posted the water volume of the 22Uzi but couldn't find it. QL says the 5.7X28 water volume is 12.24gr and some place in here I believe you posted the 22Uzi had around 13gr of water volume so you're better than the FN round and I don't really like the FN brass -- kind of soft. If you load the FN round up hot you start getting loose primers. The 22TCM is in a different world since it won't fit in a 9mm magazine and it has a water volume per QL of 16.80gr. The 22TCM 9r is just too ugly for me and the choice of bullets is like zero. I guess I'm a 30gr Varmint Grenade fan but I will go with the 40gr bullets in the small cases because they are easy to find. I guess I'll just have to sit back and wait till you get the time to test the 22Uzi in a carbine version and maybe DI operated.
Just called Manson about reamer status and Dave is out for the week and will give me a call next week.... Ran some numbers in QL: I need updated bullet tables so contacting QL about those. I think my capacity is a bit high so I'll have to measure again and verify. My QL shows I can run up to 12 gr of H110 but my real world pressures don't match that in the AR. I do know that I can run hotter DI than BB so we'll have to solve that issue (which we are working on) My velocity measurements do come close tho so adjusting for a carbine length barrel we should be in the 22 - 2300 fps range safely in blow back.
No reamer yet, They are supposed to call back tomorrow with status. I ordered some tool steel today just in case..... One issue with the blow back actions is the added stress on hammer pins and extra reciprocating weight. I've been playing around with some delay tactics, other than the gas operated kind, so we can safely ramp up the power using stock blow back parts. Did the initial test on one today and going to start ramping up loads to see if it truly makes a difference.
Dave says reamer should be here Monday. Problem now is I'm wheels up Saturday.... Good news is our Delay Device appears to be working! 8.5 gr was our "stout" load in the blow back AR. As we have been ramping up the Glock we've been testing in the BB AR. Up to 9.2 gr and still have room to go
Fit in a couple of range sessions with the 22 in both the Glok and the AR. The Glok starts to stick in the chamber at 9.3 gr of H110 and velocity from the 5" barrel was just under 1800 fps at 1798. Not too shabby. The same loads in the 8" AR clocked out at 1885 fps. The 9.5 gr loads ranged from 1882 - 2015 fps. I'm back at the shop for a couple of weeks and our new reamers came in last week. I'll cut new chambers or barrels and send some cases out for die sets. I've got a 16" AR thats been sitting on the bench waiting..... Sorry 22, moved you back again... Lee, Hornady, and CH4D all offer the die set service so I think I might try Hornady this time as the price is all about the same.
Test fired barrel today and don't know if the blow back will give me the case definition we need for a die set. That means we either do a DI version or just have the dies built to a print which Hornady and CH4D both offer. Test cases were my 3 gr Bullseye loads so now I'll try some of the 2400 loads.
Had a couple of light primer strikes, which I figured because the formed cases have more headspace than fired cases. Then I got three in a row so I pulled the carrier apart and the firing pin was def beat up.
The pin on the top was chewed up a bit. It came with the PSA unramped bolt assembly they had on sale a while back. I cleaned it up and stuck it back in and have had no problems since.
Loaded up two loads, 7gr and 7.5 gr of 2400 under the 40gr spire point. Velocity avg 2140 and 2280 fps from the 16" carbine AR. Have some issues with the new barrel / load: necks split excessively and cases took a big beating during chambering. We'll pull it apart tomorrow and see what it looks like.
Finally, got barrel off and polishing up the chamber. Going to take some measurements and see where we are for body taper. We don't have much because I wanted to max powder capacity but I need to find out why we are beating up cases so bad compared with the other chamber. I also built a new pistol.
The black one on the bottom. Been in the works for a while and finally "just build the dang thing" I've got some tweaking to do on it and some testing but so far its doing everything I need. Once I get some dims taken on the new 22 UZ and find out what's going on with that, we'll get some reloading dies made. In the mean time I'll run some more reloads.
Polished up the chamber in the carbine barrel and "sized" the 8" pistol barrel with the new Manson reamer. Loading up some 2400 loads for testing. My notes are hit and miss on the 2400 loads, but we'll try it again because QL is showing it as about the slowest powder available to get close to 100% burn in a 16" barrel. Tested 7.0 grs of 2400 under the 40 gr JFP 22TCM bullet. The carbine is set up with stock carbine buffer and spring in a Calvary Arms lower and the 8" pistol in our new pistol upper. The pistol barely moved the carrier with the current weight set up I have in it, but that's a good thing. We are still blowing the shoulders forward a bit so I guess that means we need to build a DI version to get good cases for dies unless I lock the blow back carrier down......