Ok did some tests sans bolt catch. I backed the bolt catch pin far enough out to remove the bolt catch:
I noticed a wear mark on the top rear of the mag well that looked odd. I don't know if this is a normal wear spot so I snapped a picture. I can feel a slight dip where the mark is so it isn't just surface finish removal:
I then fully loaded 3 PMAGs and 3 BCM mags. I made sure the rifle was plenty wet with slip2000. I loaded the first 30rd pmag, made sure it was fully seated by striking the bottom a couple times and tugging. I pulled the CH to the rear, paused, let go, round fed fine. Also note I had the rifle angled down pointing towards the ground (about 45degrees). I did this with other two pmags and switched to holding the gun parallel with the ground, they all fed fine. I then used the first BCM mag and holding it parallel to the ground it fed fine. I tried the second BCM mag and help it upward at about a 45degree angle towards the ceiling (about the angle you hold the rifle when reloading), it hung up like it's been doing:
I used the last BCM mag again holding it upward and it hung up. I then went back to the PMAGS (topped them off) and did all three of them. 2 out of 3 PMAGS failed to feed when holding them upward toward the ceiling:
On a side note the PMAGS I used were previously lent to a friend who used them in a a VTAC class with a S&W M&P rifle. They worked fine and he didn't have any issues at all.
So is it safe to say that it isn't the bolt catch at this point? Does this indicate there is something "bigger" wrong with the rifle, like lower/upper tolerances, feed ramps, etc? Remember when at the class I used the instructors lower on my upper and it fed fine when I tried out a few different fully loaded mags.
I guess next thing to try is a stronger buffer spring. I don't have any spares, can someone advise a good choice for that?
Thanks for all the help guys.







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