I had, what I would consider, a pretty good day at the range with this yesterday. I just used it at my club's 50' indoor range, so I could get used to the brand new gun, see how the conversion kit worked and to sight in the new red/green dot. Although they recommend shooting 36 grain plated ammo (Federal CPHP is the recommended ammo), the closest thing I had was 40 grain CCI Mini Mags. They also recommend a round hammer versus a notched hammer, for reliability reasons, but since my Colt came with a notched hammer, I wasn't going to swap it out just for this kit. I shot 100 rounds of the Mini Mags and everything worked flawlessly; and after getting it sighted in, it was very accurate, as you would expect at this distance.
For the last 20 rounds of the day, I figured I'd try some cheaper ammo, and went with Federal 40 grain non-plated blue box ammo. I only put 10 rounds into the mag at a time. With the first shot out of both mags, I experienced a slam fire, but it ran fine with the remainder of each of the mags. So I'm not sure what would have caused the slam fire, but I'm thinking I'll stick with the Mini Mags going forward, unless I'm able to find some 36 grain plated ammo. I suppose that the notched hammer might have had something to do with the slam fire, or the cheaper ammo...or possibly the magazines themselves, which are not a tight fit in the AR.
And speaking of the mags not being a tight fit, when researching the potential cause of the slam fire, I came across a lot of discussion about the loose fitting CMMG mags, with many people saying not to use them. A lot of people recommended these mags, so I ordered a couple of them last night (these are 25 round mags, so not available to those in MA, of course...although they do come in 10 round versions as well):
Black Dog Machine Sonic X Conversion Mag Nylon Feed Lips AR-15 CMMG
In the next day or two, I hope to get out again and try this conversion kit in my new AR pistol, although I know that there's very mixed feelings about how well this kit works in a pistol. But it should be fun trying it out anyway. At least the pistol has a round hammer, so that should eliminate that as a possible cause of any reliability problems.
I'll keep you posted with any additional developments!
Frank