Let me start again. somehow deleted my post. First of all, if it wasn't for family and friends I'd be out of this looney bin. It is getting super crowded here and I hate the hassle, but I'd rather be married than have high cap mags and the house is paid for.
I screwed up and put a new 9mm hammer from Brownells in the DD lower just because I had it. Trouble is, the bolt charges when the hammer is cock but when the hammer is in the fired position, the bolt is locked in place. SO. Home from the range, change to the old hammer and off to the range again. Must have been in the cocked position when I initially checked for function. Annoying.
At the range, I had a couple FTEs with Amer Eagle 115 ammo but then it settled down and no more happened. My old black follower and new orange follower C products mags worked great. Fiocci ammo also worked great, operating the gun with authority. The gun likes most 115 in the 1150 Fps range but really likes 1200 plus ammo and 123 grains bullets. I bought a light recoil spring from Brownells which I will clip to carbine length and try in the gun to see if it improves 115 round functioning.
The RRA mag ($45!) continued to pop last loaded round out and up into the top of the receiver jamming the gun. The Promag mags did the same to a mildly lesser degree. these will be sold along with the hammer and the Hahn mag block.
Next stop will be to bob some Metalforms and see how they function.
Overall, I like the lower. Obviously high quality. They had it in stock and shipped immediately, function is excellent and I wish I'd got one of these to begin with.
I also noticed that because of the short ten round mags, I tend to rest my hand under the mag well and mag which pushes up on the mag. I think pushing the mag up like that contributes to malfunctions. I now just grab the forend. jp