I recently bought my first AR, a RRA Elite CAR A4. (I know, I know. My next will be a builder.) I've also got a variety of mags -- AR-Stoner, CProducts, and a bunch of PMAGs.

Reloading on an open bolt is not a problem; however, even with 30rd mags (including PMAGs) downloaded to 28, or 20s downloaded to 18, it's extremely difficult to get the mag to seat when the bolt is closed. I am using a "beer can" hold on the mags, FWIW.

I basically have to do one of two things:

a. Release my firing grip and push the mag into the well, with great force, while applying counter pressure on the top of the receiver with my firing hand;

or

b. slam the mag into the well at high speed and with great force.

Method "A" takes about all the force I can muster and is very slow, and method "B" is still not reliable, 30-40% of the time the mag still does not seat and I have to keep slamming it home or banging on the baseplate until it locks in. (This probably isn't doing the top round any favors either.)

Is there a better technique to this, or could there be something wrong? I'm paranoid about having an out-of-spec lower receiver, for example. I knew this would be difficult but didn't expect this much trouble with downloaded mags. I am perfectly willing to accept that maybe I am just too wimpy but am hoping that I am just missing something. I don't see why I should have to exhaust myself slamming in a few downloaded mags.

The "bang on baseplate" method seems to work most of the time, but I can't count on the mag to not fall out of the magwell when I remove my hand to wind up for the slam. (And this will only get worse as the mags and magwell wear.)

Thanks.