Help with 7.5 in AR pistol

[Los Tacos Bueno]

I bought a complete pistol lower and upper from Karri's Guns, and took it out for the first time the other day. When I shot it, it was firing two rounds with one trigger pull (I have the pistol disassembled for now) and then it would double feed. I took it apart when I got home, examined the hammer and disconnector and didnt see any chips or any backwards springs. I put it back together and did a function test, and everything works out fine.

I took out the buffer and buffer spring, and the spring measures in at 11 1/4 inches (my M&P15 has a 10 1/2 inch spring for a 16 inch barrel). Is this too long for a 7.5 inch pistol? Would this make the bolt slam forward so fast that it would cause a double feed or a slamfire?

[CK_32]

It's possible it was a slam fire, I would contact the company a let them know and see if they will let you send it in and inspect it assuming it's under a waranty.

But I would suspect as you did it's somehing to do with the FCG. Smart move taking it apart as well. Again I'd contact the company and see what they say about the issue. Maybe they will make it right for you.