I got a new Bushmaster M4 that's had about 400 rounds.  Last few times i've handled the rifle it's made me feel like crap about buying the brand. It is interimittently not loading the first round of a fresh mag after reloading from a spent mag. Happens when i release the bolt either using the charging handle or the bolt release lever.    The bolt slaps home, but no round in the chamber is the biggest problem. I slap the mag each time i reload and as stated it happens even when releaseing the bolt using the bolt catch lever. I at first thought I was riding the charging handle or weak buffer spring, but that doesn't explain the bolt completely missing or not loading the first round at all even using the bolt erlease lever manually.

I have checked the troubleshooting posts and see no obvious burrs, dents or anything out of the ordinary. Gas tube is clean. Happens with the factory BM mag and a new USGI mag and regardless of ammo.

It has also jammed twice on me since i bought it causing a big dent in the round casing but not sure if it is related since the jams have been a while. Any help would be greatly appreciated!

Try to get you hands on quality mags. Sounds like a mag issue.

b

Really? I would figure a new factory BM M4 wouldn't have any issues with it's own factory or a new USGI mag. Both in excellent condition and they don't appear to be riding low.
If it does have issues with certain mags, well that just sucks big time. Now i got that itch in my ass that it will fail at the wrong time regardless of which mag i use.  Any other suggestions?

I just found some stuff related to tightening/ loosening the magazine release lever on the BM manual, would that fix this type of problem? I don't want to mess with it if it's not related.

Quoted: I just found some stuff related to tightening/ loosening the magazine release lever on the BM manual, would that fix this type of problem? I don't want to mess with it if it's not related.

As long as the magazine catch is working (mag not dropping out unexpectedly), then adjusting it will have no bearing on your problem.