9mm mag latching problems

[carcass]

Guys, I and a friend have been having problems with 9mm mags not staying latched in to our AR15s/M16s.

Here's the deal:

I have a Hahn mag block that loads from the bottom. He has the top-loading Hahn block. We both have C-products mags and some Promag glass filled poly mags.

The c-products mags tend to not latch reliably or fall out when jiggled. The promags seem to stay in OK most of the tike but have fallen out occasionally and tend to not drop free when empty. We both prefer the durability of the stainless c-products mags.

We have tried all possible combinations of different mag blocks, mags, and lower receivers. The lowers we have tried are Sendra RR M16, 2 different Rock River semi lowers. We have tried a total of about 20 different magazines; all with similar results.

Any thoughts or similar experiences? Before we started modifying mag catches or mags I thought I'd ask here.

 

[amphibian]

First of all, I assume you have already adjusted the mag catch by pushing the mag release far into the receiver like w/ a punch and advancing it so that it pretty much bottoms out as much as it can go.

I've got a bottom loading Hahn block and I was having the same problem but I noticed that when I tightened into position, the block would shift to the right of magwell on its own. Could probably get some shim stock and stick it the right side of the magwell to make it go more to the left side but since I have an MGI modular lower, I just bolted the block on the left side which sucks the block over to the left side. I drilled and tapped it to go through the ejector also since the Hahn block I have, the ejector wiggles a lot unlike a factory Colt which is solid. So the bolt serves three functions, keeps the ejector solid and pulls the mag block to the left so that the mag catch is exposed more and lastly there is no way the block is going to fall out.

I know it doesn't help much for a RR but my help out for a non-NFA lower. Another thing you can do is relieve some material from the receiver where the mag catch bottoms out, that will also allow the catch to go deeper.

Kinda hard to make out in the pic but you can see the bolt below the ejector on the 9mm magwell.

 

[Elkrock777]

I had some issues with som mags i just got. They didnt work well until i loaded them then they stayed put.

 

[AZ Doug]

On my Oly RR I had to bend a mag catch inward to reliably engage 9mm mags. I change to an unaltered mag catch when I revert back to .223.

 

[Swede15]

Stupid thought... buy, borrow, or steal a Colt 32 rd 9mm mag and see if that works. At $50 each, pricey, but maybe it'll help identify the problem.