New dsa stg fal. Cases are bulging approximate 0.25 from case rim, more prominate one one side rather than all the way around. Ammo is brass sa or radway and Russian steel case. Problem occurs with each ammo.
I think it is a us made dsa bbl, I think that's what dsa is using on all builds these days. Long story short, had a problem with my 2yr old stg which was mostly import parts & bbl and they sent me a complete replacement. Looks like this one is going back to be looked at.
So were you able to keep the original barrel?
How many rounds have you fired thru the rifle before this problem started OR has this been an issue from the beginning?
I would have it checked locally or by someone that knows these rifles, Yes DSA builds them and sells great parts BUT their smiths are something to be desired!
out of round chamber or excess headspace. A cerrosafe casting and a micrometer will tell you for sure about the roundness of the chamber, a set of headspace guages will tell you the headspace. Also you can try loading a round with a mark on it with a sharpie oriented to the top of the chamber. Fire the rifle and inspect the bulge relative to the mark. That should tell you where the out of round may be.