As the title suggests, I have a Remington R-15 in 30 Rem AR and am very pleased with it.  The only thing I dislike is the 4 rd mags.  DPMS has mags that supposedly hold 10 rds but requires fingers of steel to go beyond 7 rounds.

Someone on this forum said Magpul Pmags work.  I just got one today and while the large diameter of the rounds means the mag won't hold nearly as many 30s as 5.56mms, mine would swallow 15 rds.  I didn't try to put more in, it was close to completely full.  So, haven't gone to the range but gently slapping a loaded mag against my palm didn't cause issues and the rifle cycled rounds through the chamber.

Assuming it will work at the range, thanks to whomever suggested this approach.  Don

You might try sig mags too.

That was probably me. Have you had a chance to go out and shoot it yet? I've yet to have any failure with mine.

By the way, just got off the phone with Redding because I was having problems with dented shoulders when FL resizing my cases. I thought it was because they don't put a vent hole in the die and air pressure was building up and denting the case. It wasn't excess lube because I am very light with that. Well, long story short... I was screwing the die in too far. I would have never thought that. He had me back the die out until it was just touching the case holder (no cam-over at all), just lightly touching. Just ran 50 cases through and not a single dent. So, if you are using the Redding dies and are having dented shoulders like a lot of us then try backing the die out a little. Basically if you cam-over you are over sizing.