I'm having a small annoyance with my new AR. It's a Bushmaster lower with an LMT M4 upper, standard LMT bolt and carrier and an H-buffer. After inserting a fresh mag and palming the bolt release the bolt/carrier travels forward, strips a round only about half way out of the mag and then stops. Upon inspection nothing seems to be out of the ordinary. The round is aligned with the feedramp and by simply pulling the charging handle all the way to the rear and then releasing the round is successfully chambered. This only occurs every so often (1 out of 5 mags) and it only happens with the bolt locked to the rear.
When inserting a fresh mag with the bolt closed and using the charging handle to charge the weapon everything goes as smooth as butter. I thought maybe it was a mag related issue but it has happened with various different USGI mags and Thermolds. My gun was generously lubed at the time so this shouldn’t be the problem either. So far I have just under 600 rounds thru it of mostly Q3131A and a few mags of Wolf. It has fed, fired, extracted and ejected 100% to date.
My guess is that for some reason the buffer spring isn't strong enough to accomplish the task at hand. Does Wolfe (sp?) make a stronger carbine buffer spring? I would like to get your guy’s opinions before I spend the money on a new spring though. I appreciate any and all help.