Tried some new extractor geometry today and still not getting the operation I would like. I'm getting about 50% ejection rate. The groove on the 10mm is cut very deep and it really grabs the AR extractor so I thinned it out today to let the fired case roll off the claw, but its just not working out the way I would like. My next move is to add a deflector bump or thin the claw out some more.
10mm is running good and I have to admit, it just feels like it has power. The 357 ARMag is ok, but the 10 feels "heavier" We definitely need to work on mag geometry to get it feeding smooth like the 357 ARMag does.
But, to kick the 10mm to the curb..... Tested the 10mm Mag today. Used some std load data and stretched OAL to 1.67 to take advantage of the M1 mag space. With 200gr JFP it was just into the lands and way too much pressure.....
Pulled the remaining test loads and dropped the charge down and will test tomorrow. Modified a std 6.8 extractor to a new profile and had ejection so we'll keep going on this thing. Way cool.
Did some more testing and did some R&D on the new mag set ups. Hopefully will make some universal adjustments that will make all the mags feed better.... Time will tell, but its hard to get enough spare time to make all this happen
10mm, 10mm Magnum, 10mm Maximum, 10 Max w/180gr JHP
We use 6.8 SPC cases to do the 30 / 357 Herrett stuff. At one time I estimated that the 30 Herrett (Rimless Tactical per Marty) was one of the best 30 cal AR rounds out there. I bumped some cases up to 357/8 and one up to .400"
Finally made a couple expanders today and opened up some cases. I figure to trim them back to 1.600" just to give the case mouth a good square cut and "standardize" it at the Maximum length.
QL predicts 2400 fps+ from 16" brl w/180gr bullet at 50ksi pressure.
I'll order a couple blanks and get some new brass and see what happens..... in my spare time of course....
Got a couple blanks in with this last order. Now I need to get a reamer together to get the Maximum length. Got a couple of 10mm Mags to build so will get them out of the way and do some more mag testing with the M1C-AR set up. In the meantime, I'll work on the new reamer geometry and send it off to Dave at Manson.
Building another 10mm and working on Mag geometry. The larger dia case requires different feed ramps so we'll put one together for testing and then see if the smaller dia rounds will feed with the 10mm set up.
Worked on the 10mm Mag Large Pistol Mag and both versions feed 100%. The larger dia rounds need some different geometry, but they are working and its nice to have a BHO! No time at the shop so getting them when I can.....
Milled out two 80% lowers from New Frontier using their jig. Not a bad set up, everything worked as it should.
Don't have any glok 10mm mags so I used our modified PSA 9mm glok / TCM lower for the 10mm to test it out. We modified the last couple 357 Sig gas systems and they are much better so did the same mod for the 10mm with the same good results.
Feeding was ok, but the barrel was set up for our Tok mag feeding which is a bit lower than the glok style, but it still fed. Next one we'll set up for glok feed.
Ran a new load of 8.2 gr of Power Pistol w/200g FMJ (plated) bulk bullets. QL est at 1350 fps from an 8" brl