Yes, I bought a complete Gen I upper with the BCG...(have since done the Gen II upgrade...love it). I agree a lot of the reviews on BCA in general aren't stellar. Many of them are from years ago, and I think in the last year or 2, they've made strides forward to make their products either better or the quality more consistent. Just keep your expectations in check...it's a budget upper and priced as such. I can, have and will recommend them. I can also say, from experience, their customer service is excellent.
Honestly, I have no idea what weight buffer I have. When I built my first AR lower, I told the gunshop guy that I was going to build it in 7.62x39...he just handed me a buffer kit and said this will work, so i'm thinking it was just a standard ar-15 kit?...I can tell you it was an Anderson pre-packaged buffer tube kit.
Anyway, the only issue I had (and I sent it back for it...turned out I could have fixed it) was that it would jam when feeding. There was a shim in the extractor (?) that didn't need to be there, so there wasn't enough movement for it to fully snap over the rim...something like that. Anyway, they took it out, test fired it 12x and sent it back, no issues since. I did buy my upper before they started shipping them with enhanced firing pins, so I added one and a power spring to mine even before firing.
I shoot steel case...cheapest stuff I can find, out of it (wolf/tula/some old Chinese stuff/random branded/etc.). I haven't had any issues since getting it back. It's a fun plinker and i'm sure with good ammo it would drill them in. I usually shoot at 50 yards and i'd say 1"+ is what i'm getting...but that's the nature of the crappy cheap 7.62x39 ammo...it's just not that accurate.
As for mags I went with what BCA recommended...ASC. I've got 2 each of 5 & 10 rounders...no issues. My only 2 gripes with them, is that they aren't marked for caliber, and the only visible difference between the 5 & 10 is a "SS' mark...on the 10's. I am curious to check out some other brands of mags.
For the price of the BCA uppers, I don't think you can go wrong.
Back to the BCA 22lr uppers...just ordered mine today :t
DW
p.s. I should clarify something...The second 7.62x39 upper I got I never fired. It was their rear charging carbine upper. I ordered it in April 2021. Opened the box, took a quick glance, thought it looked great and put it back in the box. I took it out again a couple weeks ago and noticed when it was assembled, the punch slipped off the forward assist pin, and there was a dent. The area also looked to have been ground and coated in black. Anyway, I sent it back asking for store credit, expecting the 15% restocking fee. They ended up refunding the whole amount. Instead of just getting a replacement, I opted for the 22 upper. I just bought a mini 30 and have no need for another 7.62x39 rifle