Diagnosing a FTF with multiple variables.

[joelogic]

What is the order you would elimate possible variables with a given gun and a Failure to Feed?

Today my G19 ate my reloads without a hiccup.
Gun - Brand new G19.
Ammo - Reloads, Once fired brass, 4gr of 231, 125gr TMJ FP @ 1.050" OAL.
Everything ran fine, slow fire, rapid fire, mag changes.

However with my G34 it would fail to fully chamber a round every ~25 under shooting conditions. It would chamber the round fine when loading.
Gun - G34, unknown round count, 3 owner.
Ammo - same as above.

Buy some round nose ammo?
Up the charge weight?
Lengthen the round?

[buffybuster]

I'd try going up 0.5grs to 4.5grs. The 34's greater slide mass might be making it slightly short stroke (slide comes back to pick up a round but not far enough to fully compress the recoil spring). Also your OAL is 0.045" shorter than I usually run but that shouldn't make too much of a difference.

[ar15barrels]

What barrel is in the 34?

[joelogic]

Factory barrel.