I had an issue with the MPX not going into battery, the bolt would stay about 1/4" open when charging or when using the bolt release. I cleaned and lubed the gun and fixed the issue, however now the bolt is getting "stuck" on something as it passes the back edge of the magazine if a loaded mag is in. Of no magazine is in, the bolt moves smoothly.

Hoping someone may have experienced this before and may know what I should try next to resolve the malfunction.

Thanks for the input!

Have you shot it?

Is your cam pin installed correctly?

If you put it in backwards (with the arrow going the wrong way) it can get the entire BCG stuck inside the receiver.

Remove the black rubber stud within the extractor spring to help with that going into battery issue. Worked for me.

Mine's going back to SIG for FTE issues so fingers crossed for ya.

It functioned flawlessly once in battery with the first issue. Since the issue of the bolt locking up and requiring a lot of effort to move it past the magazine came up, I have not shot it. Hoping to next week but also hoping to get it fixed by then of possible. Thanks for the tips so far, I'll give those a go and see what results I get.