AR 9 Colt Mag Variations- Beware!

[calicojack]

I want to share something with you guys. I was having problems with my 32 round Colt 9mm mag. The 10 round Duramag mag ran fine, but the 32 round ASC mag caused FTF issues. Found out why. Look at the pics below. I have a KAK magwell insert on the table and the two mags (I ended up getting a Hahn Precision insert instead). They mags appear to have identical followers. But the slot for the mag release is cut higher on the 32 round ASC. If you look at each mag inserted in the magwell insert, the ASC sits a little higher. This causes the following chain of events:
1. In order to seat the 32 round mag, you have to bang it on the table.
2. When you do that, the magwell slips upward.
3. This causes the mag release to bind.
4. But worse, the mag sits too high and feeding is unreliable at best.

The 10 round mag runs fine. Interestingly enough, the 32 round mag seems to run in the CMMG Banshee clone I built, but the 10 rounder is easier to insert.

 

[TheOriginalMexicanBob]

My Colt marked mags and Brownell's mags run perfectly. No idea who made them for Colt and Brownell's. Actually...the Brownell's mags seem better made...at least heavier and far less expensive.

 

[jimbobborg]

I've not run into that issue with ASC mags, but I use a dedicated 9mm lower, not an insert.

 

[smdub]

I've found follower differences too. The ASCs I have (I think it was the ASCs), I've filed the followers a little to make them reliable. Ususally just knocking the burr/edge off here and there so they don't hang.

 

[calicojack]

I use a dedicated 9mm lower, not an insert.

I like the flexibility of an insert, but a dedicated is probably a bit more reliable.

[EDIT] I will say the Hahn Precision insert is VERY solid, it mounts from the top (have to remove the bolt hold open lever, inert it, and then replace) and does not move once in place.

 

[Rockzilla]

Interesting, was thinking about adapter long ago, but ....
Colt mags, ASC mags 32 rd run perfectly in my Colt 9mm mag lowers, even the 80% AR-9
"Colt" lowers work great, SMF Tact upper, ToolCraft gen-2 bolt, Macron Armory Guaranteed
to feed barrels, Macron Armory Dead blow buffer, all is good. Unfortunately I don't run adapters.
so..can not comment otherwise on the adapters.

-Rock