Well, I have had my Rock River lower for two years and finaly got the rest. I used a M&A carbine kit. It went pritty well but I have two problems. The take down pins are hard to move past the detents and my magazines (used) stick in the mag well. So the question is what do I do about these problems.

Welcome to the board (sooner or later you had to post)!

The take down pins will loosen up over time and as it gets fired.  Don't worry about that.

There is no requirement for magazines to drop free, and magazines are easily bent, dented or outright damaged.  Its possible that the magazines you are using need to be tweeked a bit, but its also possible that the magwell is a bit tight.  There really is no way of knowing with what is posted.  Do they drop free from other AR15s?

I haven't tested them with other ar's yet. I thought  I might go buy a brand new one. I seem to remember that I liked the 20 round mags for bench shooting way back when I was in the army. A brand new colt mag should be right, right?

Also if I did want them to drop free what should I do?

go shoot the rifle!



eventually it will "break-in" and you will be posting why your rifle is soo loose.

Quoted: I haven't tested them with other ar's yet. I thought  I might go buy a brand new one. I seem to remember that I liked the 20 round mags for bench shooting way back when I was in the army. A brand new colt mag should be right, right? Also if I did want them to drop free what should I do?

Find out where they are sticking, and if it is a magazine issue, than bend it back into alignment.  There is a difference between mags not dropping free, and a magazine sticking in the magwell and having to be forced out.