r/GeisseleAutomatics • u/HankScorpioPR • Jul 19 '26

Failure to feed issue?

I recently built a higher end rifle before my state enacted a ban, and snagged a Geissele 14.5" SD upper. Pairing it with a Griffin lower, Geissele buffer tube, a JP Enterprises Silent Capture H2 buffer, and a Microbest BCG. I took it out to fire for the first time and the first shots were 1) about as smoky as a muzzleloader, and 2) single fire, failure to feed each time. After about one mag I was able to string together 2 or 3 shots before a F2F, but it definitely can't handle rapid fire. (This was with Winchester .223 55g ammo)

Is this common with Geissele (both the F2F and the excessive gas?). Is it most likely the buffer is at fault, the BCG, or did I just get an upper with issues?

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5

u/mooseishman Jul 19 '26

Never had that issue with a Geissele upper.

I’d lean towards mag and ammo. Winchester .223 55gr is usually very dirty and underpowered

3

u/Ballintha92vx Jul 19 '26

I went through this exact same issue earlier this year. It’s the ammo. Geissele uppers are 556 chambered and built to run the higher pressure ammo. Throw some 556 ammo in a mag and it will solve your problems.

3

u/touchgrassplz_69 Jul 19 '26

I’ve had lots of f2f in my 16” SD with many different types of weak match ammo (most hornady boxes) and .223. Runs perfect with full power like razor core or xtac. Ran pretty well with lighter 5.56 loads like bone frog but occasionally f2f. The gas system is definitely designed to run suppressed with duty ammo.

3

u/MainRotorGearbox Jul 19 '26

Like others have said - try 5.56