g34 going to slidlock w/rnds in mag?

[newcc]

shot idpa match yesterday and had my g34 go to slidelock with rnd's in magazine (twice). What would cause this & how do I correct it. When I released the slidlock the round chambered and fired. previous rnd ejected (no jam) My handloads, 600 + rnd's tru gun, No problems ever till these (same load 4.0 Titegroup, 124 gr Fmj, 1.140 OAL) ManyThanks

[JR]

Did you install a extended slide stop recently? If so, I am willing to bet your thumb is engaging it under recoil. Get your thumbs straight up and you will avoid activating the slide stop.

[newcc]

OK, I will watch what I'm doing, Its a New gun to me, (The G34 comes with an Extended Slide Stop) Many thanks and Good day Sir.