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ProMag AR-15 / M16 9MM Magazine Adapter Block

MSRP Price: $59.75
Our Price: $35.00
You Save: $24.75 (41 %)
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Item Number: MAGPM237
Manufacturer: ProMag
Manufacturer Part No: PM237
ProMag AR-15 / M16 9MM Mag Adapter Block

 PM237 9mm Magazine Adaptor Block easily installs in AR-15 lower-receivers to allow the use of 9mm Colt* SMG in Colt* pattern 9mm upper-receivers. The block is constructed of high strength polymer with steel hardware, roller, ejector, and bolt stop.

Product Reviews

(17 Ratings, 8 Reviews) Average Rating:
Don't Buy this block
conchanfle (San Diego, CA) 6/27/2016 10:09 PM
This 9mm mag block adapter is useless. Don't waste your time and money buying this product. I love to make things work and 99.99% of the time I am successful. But the geometry of this product is all wrong. This is a product produced to sell to people on a budget and who don't realize that they are being sold a useless product. Sometimes if you are lucky this will actually work, but mechanically this product is all wrong and will only lead to failures. Buyer beware and good luck! *** Added by JSE 6/28/16 *** Since we don't have a name on this review we aren't able to contact the person to make an effort to correct his issue. But, since we post all reviews regardless of good or bad I want to add a bit of information. We have sold thousands of these mag blocks over the years. Many have been sold over multiple orders by the same person. So, even though this particular one was problematic for this customer, the general perception is they are a good budget minded block. In fact, we have used one in our test lower for the 9mm uppers we build for the past 3 years or more. We are still on our first one and I'm not sure how many thousand rounds we have fired through it.
mine worked with a little work
glenn gates (Maple Park, IL) 3/25/2016 11:09 PM
I had to file all the extra plastic flashing off before it would fit in correctly.mag drops out and bolt stays open on last round.out of 100rds i had 3 fail to feeds,not sure what caused them yet but nothing is broke in yet on this new build. I was very pleased ,the first 32 rds had no problems.maybe after i polish everything it will feed better. I had fun and didnt pay allot.i was happy
You get what you pay for. Thin, cheap, and possibly unusable.
Phil Brady (Dallas, TX) 3/7/2016 8:48 PM
For a plus the JSE order arrived on time and was packed well. It's the item from ProMag that was not quality. It's cheap plastic and was mis conformed. The sides we bent in and asque. It's low quality. Go with metal not polymer. This review will not let me post a photo. I orderd two, one for A-2 buttstocked lower and one for CAR lower. One I will try and hopefully be able to form fit with a colt mag left in it for some time. The other? Time will tell. Definitely makes me rethink ProMag's Q&A for magwell blocks.
Money well spent
Ray D. (Western, NY) 1/3/2016 7:24 PM
After reading a lot of negative reviews I wasn't sure I would have good luck with this mag block but after installing it I am pleasantly surprised and quite happy with my purchase. Yes it is more work to install a mag block from the top of your lower because you have to remove your bolt stop but once you do that the block drops right in and stays where you put it. The block feeds and ejects perfectly and holds the bolt open on the last shot which is something that some blocks and dedicated lowers won't do. The only reason this doesn't get 5 stars is because it is plastic and does cause some friction with the metal mags dropping freely. To me that is no big deal but to others it may be. I will be buying a second block when they are back in stock.
Paul Tannahill (Lebanon, OR) 12/7/2015 1:54 PM
I had read on a few different sites that I would likely need to dremel this block for a good fit, and I had no problem with that. I don't want to have to remove my bolt catch to install and uninstall this block, and was easily able to remove just enough material for a snug fit via a bottom insertion. I got it to sit in the exact location it would have been in as a top-install block, so I thought I was good to go for a test-fire. NOPE. The feed ramp was way too low to feed a single round into my JSE-purchased 9MM upper receiver. No problem, I thought. I would just disassemble the block and raise the feed ramp up about 1/8". NOPE. The upper wings on the feedramp scraped against the bolt, marring it. I realized this block would have never worked for me, even if I hadn't modified it, and now I have a block and an upper kit I can't return for refund. Ugh. I guess I'm left with purchasing a much more expensive block, or maybe even a dedicated 9MM lower receiver to even be able to use this upper.