Promag AR15/M16 9mm Magazine Quick Change Adapter Block - Black Polymer

I tried the promag block first trying to save a few dollars. The feed ramp was too short and the cartridge jammed into the receiver just below the chamber 50% of the time. It pushed the bullet into the case and ruined the round on most jams. This problem happened with Federal and Winchester (only tried these two). I also tried Metalform and ASC magazines and had equal trouble. I will say promag support was fast to reply to my request for help and offered to send me another. I opted to return it and bought different magazines adapter from JSE. The other block ran great and was only slightly more expensive.

This product is very good for the money. I have the Promag drop in as well as the CMMG full 9mm lower. CMMG 9mm lower functions at 99% with the Promag functions at 90%. I thought I had problems with the Promag product early on but the feeding problems were actually a result of the barrel. I had a early edition Ballistic Advantage 9mm barrel and the ramps were too steep to chamber a round. Clint Hanson at Ballistic Advantage was great and sent me out a new barrel with new ramp angle once we figured out that was the problem to the feeding issues. If you look at the cost of this product in comparison to others. It is a no brainer especially if you are doing a budget build. If you have the extra ducks to throw at your build then a designated 9mm lower is always best in my humble opinion.

I used one of these for several years. It worked fine. When you install it, you must install from the top of the receiver. You also must pull the bolt catch off and reinstall after the block is in place. Promag is not the only one who uses this way to install. Other higher cost adapters install from the bottom and then secure with a screw on the top of the adapter block. This is quicker to swap out, but functions just the same. So, if you have a dedicated lower for 9mm then it really not much different. The "Block" is poly/glass like many magazines. One advantage is it is lighter than the aluminum blocks on the market. As for durability, the promag might suffer at the ejector, but mine has lasted several 1000's of rounds. Another tip with any 9mm block is that to seat the mag, lock the bolt back first. Second is that if you have feeding problems, then try RN bullets. Some longer cone/ HP bullets may have a longer OAL and hang on the mag lips when feeding causing a jam. It is normal that the block feeding ram is not flush with the barrel ramps. I did get a bottom install type for my SBR because I swap between 9mm and 5.56 uppers. I moved my Promag adapter to a dedicated lower I just run my 16" upper on. At least this is more easy than the old 2 piece Colt pin in blocks.

I can't get this adapter to feed from any magazine I put in it. 4 different mags of different brands. The front of the bullets will not feed and ram into the ramp and/or the barrel breech. Trying to decide the best way to get out of this poor investment. *** added by JSE 10/15/17 *** Have you spoken to Promag? We have probably sold 100 or more of these in the past 2 months and have had no complaints. We use them in our test fire lowers as well, so we run different mags and different uppers on the lowers without issue. I'm sure they will help out. Sorry for the issue.