Need a bit of advice on the following. Picked up a NIB USP9c v1, dropped in a Rim Country Manufacturing threaded barrel and had some initial feeding problems with AE9FP. Chalked it up to any number of things. New gun / RSA, new gun / hammer spring, dirty mags, dirty / unlubed piston, weak ammo. So I swap the barrel into my v7 that has 7446 rounds through it, and immediately have the same issues. Below is a representation of the issues. Note that this is after cleaning and lubing the piston, cleaning the mag, and a gun with 7400rds through it. Temperature is 25 degrees but gear just came from inside, and did not reach ambient temperature, so no frozen lube or piston o-ring.
On occasion, a fired case will be ejected, along with a live round, and the gun will chamber.
7th rd
10th rd. The top round is just sitting there, the 11th round is trapped by the slide and mag body
13th and final rd. This one is actually just sitting in there and the gun is at slide lock
These type of issues have presented themselves over 1 brand new gun, and one with 7446 rounds through it. A thought I just had, is using new mags in the used gun. I don't recall if the new mags from the v1 were used with the new gun. I doubt it as they have the finger rest, and it does nothing for me. Amy other thoughts or input would be greatly appreciated.