This is not a bash on the Unimag, just outlining issues with the brand lower I am using.

Bought a RZE Unimag from Primary Arms for my 7.62x39 build. Had to beat the mag to get it to seat in my Anderson lower. Loaded 20 rds (all I had), and it fired all 20 without a hitch. Had one failure to fire I think is firing pin issue. Took two people to get mag out of magwell.

Mag seats ok in a Bushmaster and Ruger lower. Doesn't drop free but inserts and pulls out ok.

Today I squared the mag in my bench vice like I had to with my AR45 grease gun mags. Huge difference but still will not seat in my Anderson lower without a great deal of struggle. Held the lower with mag seated up to the sun light and identified where the mag is dragging on the lower. Spent about 15 minutes filing down the contact spots on the lower and now the mag goes into and out of my Anderson lower just slightly harder than my Bushmaster lower.

Combination of squeezing mag to reduce contact points and filing down of contact areas on lower worked. I would think the mag can me made narrower by a few hundred thousandths to fit better in most magwells, would not impact the follower working fine. I did all my mag squeezing with the follower installed to make sure it still slid up and down ok. I might try some dry lube on the magwell to see if it helps even more.

The filing on the lower was on the inside front left of the magwell and just a little on both sides of the inside rear. Filing actually makes my ASC 30rd mag seat much slicker. It doesn't drop free when empty but pulls out real easy.

The Unimag is two piece welded together. The front of the mag where the pieces overlap is where the mag is dragging on the lower. If the mag was one piece and only welded at the rear, the tight fit in some magwells would be eliminated. I am looking to see if the Unimag follower will fit into another brand mag body that doesn't have the fitment issues. The right and left rear of the mag has a sharper radius than the rear corners of my Anderson lower and did drag a little.

Overall, I am satisfied with my purchase and will buy more. I really don't like the exaggerated curve of the ASC mags. I post pictures as soon as find my camera. Bottom line, the Unimag mag works for 7.62x39.

Just saw this thread today. We are addressing this issue and I think I found out what cause the problem of this batch. Stay tuned.

Get it to drop free and you have a customer for life.

You can bet on it!

Really interested in these mags for 7.62x39 and Grendel.

I'm interested in it's performance with 5.45x39 (and yes, I saw the Youtube video RZE did, but am waiting on others' experiences before I buy).