Experiences with Magwell Adapters (e.g. Stern, PSA, KAC, Hahn, Macon…)

[JRV]

I have finished all my pending projects and still have a spare standard lower that I would prefer to utilize in a 9mm PCC setup. Just a fun gun, maybe at an occasional Steel Challenge match, but not for any other purpose.

I have no strong preference in mag format—I can find Glock mags pretty readily, but non-ProMag Colt-pattern mags are out-of-stock where I have looked for them.

Cost is not an issue, except I’m not looking to buy another lower (i.e. a dedicated lower), because then J would still have to build out another AR.

Does anyone have any experiences, horror stories, praise for any mag blocks?

[DDTSGM]

Have you seen/thought about these:

https://www.meanarms.com/products/detail/endomag-9mm

I had the same idea as you, tried four of them before ending up building myself and my wife dedicated 9mm lowers for our PCC league.

I had one problematic mag insert that required some tinkering, but otherwise they work okay. The biggest issue I had with them was the fact that the ejector is on the magazine, so when you drop the mag and show clear, there would be a round held on the bolt face ready to be chambered when you let the bolt go forward.

The cure is a good thorough visual check - how many of those have you seen (NOT) at the end of a stage. You can also alter your clearing kata - lock bolt to rear, then drop magazine. This would serve to let the mag mounted ejector take care of the chambered round.

All in all, it was a good stop gap measure until the source for my 9mm lowers came back in stock. I've used two of these, both have worked flawlessly:

https://www.joeboboutfitters.com/Spartan-9mm-Glock-Magazine-Compatible-Billet-Lower-p/jb-spartan9.htm

The thing is, your going to have to get a barrel, a BCG, and in most cases a pistol caliber buffer and spring at a minimum. If you go with an magwell adapter you are going to spend:

Sylvan Arms - $95.00 ( https://www.masdefense.com/SYLVAN-GLOCK-CONVERSION-BLOCK-GCB100-p/gcb100.htm )

Gun-Tec - $78.71 ( https://tacticaltransition.com/product/ar-15-9mm-magwell-adapter-block/ )

PSA - $95.00 ( https://palmettostatearmory.com/psa-custom-9mm-glock-compatible-mag-well-conversion-block.html )

ATI - $150.00 ( https://www.opticsplanet.com/american-tactical-imports-9mm-glock-magazine-adapter-for-5-56-receiver.html )

Myself, I'd rather get the dedicated lower that doesn't have an inserted magwell adapter that could shift and cause problems and be done. Put that extra rifle lower on the shelf. You don't HAVE to use it right now.

[Spartan1980]

My Hahn toploader has been solid. Colt mags are hard as hell to load, get a Maglula, your thumbs will love you for it.

Keep your eye on Brownells, they offer a Colt pattern mag that's decent. Modified Uzi mags work too if modified properly.

[JRV]

Have you seen/thought about these:

https://www.meanarms.com/products/detail/endomag-9mm


Those are the one option I have definitively ruled out. The combination of a plastic ejector and not being able to rely on traditional manual of operations for clearing gives me the heebiejeebies.

[CleverNickname]

Over the years, I've used a VM-Hytech mag block for unmodified Uzimags, a Hahn bottom-loading mag block for Colt mags, and currently, a Stern Defense mag block for Glock mags. The VM-Hytech is only best if you have a large number of unmodified Uzi magazines (which I did). Otherwise it doesn't really have anything going for it. The Hahn bottom-loader worked ok, and used the normal magazine release, unlike the other two. The Stern Defense puts the mag release in a non-standard location, but it can still be actuated with your trigger finger. Also for competition, it'll be easier to find mag carriers for Glock magazines.

Honestly though, just figure out which magazine type you like the best and get a dedicated lower for that type. Barring a good reason like wanting to also use an SBRed 5.56mm lower in 9mm, a dedicated lower will always be the better choice over a mag block IMO.

[757_Magnum]

Those are the one option I have definitively ruled out. The combination of a plastic ejector and not being able to rely on traditional manual of operations for clearing gives me the heebiejeebies.

CMMG licensed the Mean Arms/Endomag for their RDB system, and it doesn't rely on the ejector built into the mag. I've read good things about the reliability. Look up posts by ARFCOM user Amphibian. I've had the barrel and bolt combo for about a year. I've just been too lazy to put it together.

[JRV]

Over the years, I've used a VM-Hytech mag block for unmodified Uzimags, a Hahn bottom-loading mag block for Colt mags, and currently, a Stern Defense mag block for Glock mags. The VM-Hytech is only best if you have a large number of unmodified Uzi magazines (which I did). Otherwise it doesn't really have anything going for it. The Hahn bottom-loader worked ok, and used the normal magazine release, unlike the other two. The Stern Defense puts the mag release in a non-standard location, but it can still be actuated with your trigger finger. Also for competition, it'll be easier to find mag carriers for Glock magazines.

Honestly though, just figure out which magazine type you like the best and get a dedicated lower for that type. Barring a good reason like wanting to also use an SBRed 5.56mm lower in 9mm, a dedicated lower will always be the better choice over a mag block IMO.

(1) How was reliability with the Stern? I’m eyeballing a kit from them with the complete upper and mag adapter.

(2) Going Form 1 on the lower is exactly why I am looking for an adapter on this last guy. Potentially moving in the next two months, so I am not starting that process until I know what the home address is going to be for the next year, but I don’t want to end up grabbing an extra lower that needs an additional tax stamp.

[CleverNickname]

(1) How was reliability with the Stern? I’m eyeballing a kit from them with the complete upper and mag adapter.
I haven't used it all that much, maybe 500-600 rounds, but I haven't had any problems yet either. I've got an SBRed CMMG MkG that I occasionally shoot in USPSA PCC, and I only use the Stern mag block when I put the CMMG upper on my M16.

[DDTSGM]

Going Form 1 on the lower is exactly why I am looking for an adapter on this last guy.

That would have saved me some time and effort in my quest to be helpful. :p

[CSW]

The only adapter that I ever got to work solid was one that came in a Rock River 9mm carbine. Fed Colt sticks.
I eventually sold it and purchased a dedicated lower from then DDLES, which feeds Colt sticks. This was just before Newtown [for a time reference] and thousands of rounds later it has never had an issue.


I believe DDLES became Quarter circle 10 brand.

https://www.quartercircle10.com/rider-clt9mm-lower-receiver.html