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Posted: 12/30/2023 12:26:07 AM EDT
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I'm using ASC mags on an 80% lower with a Hahn block. my mags don't lock into the lower very well. If you pull on them hard they will come out. It's like the little nub is not long enough to go through the block and still have enough meat on it to lock the mag notch. Is there a custom mag catch out there? ETA: I purchased the RRA 9mm mag catch and it fixed the problem. Under close inspection I could not see any difference but it works. My mags will not come out when inserted. Attached File |
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I file my mag catch down slightly in the area on my ar9 Also on my dura mags which I think are the same as asc, I noticed the mag catch cutout is a bit smaller than my metalforms, and my lula loader doesn’t really work with them. When I load rounds, I have to hold in the mag catch on the Lula or else it will pop off |
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The problem you're experiencing is likely a tolerance stacking issue. Options: Try a different AR mag catch. A new one may be on the better end of the tolerances your setup needs. Yours may be out-of-spec. Make sure the mag catch is seating all the way into the receiver slot. Removing the coating around the outer edges of the mag catch usually fixes seating issues. Make sure the mag catch is fitting all the way through the adapter slot and isn't catching on the adapter, holding it back from fully engaging. The adapter may be sitting a little high/low and dragging on the mag catch. The magwell is a little wide, or the adapter is a little narrow. Shimming the right side either between the lower/adapter, or adapter/mag will push the mag toward the catch. Colt's AR-15 and 9mm SMG's use the same mag catch. They're identical. The RRA "9mm" catch's mag catch tab was supposedly longer, but I can't find any measurements or evidence this is true. If someone has measurements I'd love to see them. ETA: found one old post that said the RRA catch's mag catch pad was 0.020" longer, and another old post that said the STAG or DPMS would also work for the same issue. Without confirmation, it could just be a case of some catches being on the high end of the machining tolerances for the part, or they may actually have slightly longer catch pads on purpose. Not sure. |
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Sealed Brownell’s bag with Colt’s 9mm mag catch. I identified it as 9mm when I received it. Note it is stamped “9” on the back side. The 5.56 mag catch has a Brownell’s SKU # of 160-308-112. The one outside the bag is a Rock River’s. Don’t think either firm bothered to mark them with a 9 just for the hell of it. https://imgur.com/a/4u7YzJe https://www.brownells.com/gun-parts/rifle-parts/rifle-magazine-parts/ar-15m16-magazine-release/?sku=160308112 |
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Quoted: Sealed Brownell’s bag with Colt’s 9mm mag catch. I identified it as 9mm when I received it. Note it is stamped “9” on the back side. The 5.56 mag catch has a Brownell’s SKU # of 160-308-112. The one outside the bag is a Rock River’s. Don’t think either firm bothered to mark them with a 9 just for the hell of it. https://imgur.com/a/4u7YzJe https://www.brownells.com/gun-parts/rifle-parts/rifle-magazine-parts/ar-15m16-magazine-release/?sku=160308112 @swOHmatt Nice! This may solve the mystery! Can you measure the thickness of the part with a set of calipers at the mag pad and next to the threaded stud? One or both areas may be different for it to seat deeper in the mag. |
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Quoted: @Droppoint See 2 new photos at link below. I placed a white dot inside the Colt’s so they wouldn’t get mixed up. Looks like the RRA’s may be a little better, but only by 1/2 thousandths. https://imgur.com/a/8CJOsbw @swOHmatt Thank you! Very thorough - more than I expected. I'll pull out some standard catches I have installed and see how they compare. |
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Quoted: @Droppoint See 2 new photos at link below. I placed a white dot inside the Colt’s so they wouldn’t get mixed up. Looks like the RRA’s may be a little better, but only by 1/2 thousandths. https://imgur.com/a/8CJOsbw How do those numbers compare to a standard mil-spec mag catch? Edit; just saw @droppoint is going to do that. Thanks dude! |
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9mm Colt magazine magwell adapter "magazine retention fix" mag catch vs. standard AR-15 mag catch measurements. Edit: got rid of the HTML table and just put in an excel screenshot because of Arfcom software display glitches.  So it appears that the "9mm" designated mag catches made for a standard lower with a Colt 9mm magazine adapter insert are indeed different, BUT the difference is the height at the stud platform, not at the mag catch pad. This allows the mag catch to sit deeper in the lower, and by extension, the mag catch pad has more purchase on the mag though the magazine adapter's cutout. This is great information that confirms that there is a difference, but that the difference isn't where everyone seems to have thought it was. It also appears that RRA is the only one possibly still producing the deeper-sitting catch, since Colt lists the same part number for both the AR-15 and 9mm AR now. https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=1731 Now I just need to purchase a current production RRA "9mm" catch and see if they still have a different stud platform height for 9mm with adapters. Time to dig into the website budget. Thank you @swOHmatt for helping to put together a definitive answer so the entire community can benefit! |
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Quoted: 9mm Colt magazine magwell adapter "magazine retention fix" mag catch vs. standard AR-15 mag catch measurements. Sorry for the weird empty space below - I don't know what the ARFCOM software is doing...
So it appears that the "9mm" designated mag catches made for a standard lower with a Colt 9mm magazine adapter insert are indeed different, BUT the difference is the height at the stud platform, not at the mag catch pad. This allows the mag catch to sit deeper in the lower, and by extension, the mag catch pad has more purchase on the mag though the magazine adapter's cutout. This is great information that confirms that there is a difference, but that the difference isn't where everyone seems to have thought it was. It also appears that RRA is the only one possibly still producing the deeper-sitting catch, since Colt lists the same part number for both the AR-15 and 9mm AR now. https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=1731 Now I just need to purchase a current production RRA "9mm" catch and see if they still have a different stud platform height for 9mm with adapters. Time to dig into the website budget. Thank you @swOHmatt for helping to put together a definitive answer so the entire community can benefit! That’s awesome. I actually purchased 3 RRA’s for my 3 9mm lowers a few days ago (I have 2 H&R dedicated 9mm and 1 using a KAK insert) I can take measurements and provide the data once when they arrive. |
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Quoted: That’s awesome. I actually purchased 3 RRA’s for my 3 9mm lowers a few days ago (I have 2 H&R dedicated 9mm and 1 using a KAK insert) I can take measurements and provide the data once when they arrive. @seand1111 That would be great - thanks! I just ordered 3 as well, so together we'll be able to get a really good sample size average. |
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Quoted: RRA's 9mm mag catch is longer. Don't know why so much consternation over it. A whole $6.50 https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1731 That's the thing. It isn't longer. It's the same overall size. It reaches deeper into the receiver because the depth-limiting dimension is shorter. Although the effect is the same, the means of accomplishing it is different. It's an important distinction for troubleshooting a platform where there's so much bad information being passed around as true. Confirmation, not consternation. Trust but verify. |
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Why does it seem that some users use a milspec AR15 mag catch with no issues and some need this 9mm specific mag catch? The 9mm specific mag catch only solves the problem of retaining the adapter but nothing to do with the function of the mag release, right? EDIT: Nvrmind, I looked and saw the "tab" that sticks out that retains the mag. Since the adapter can take up a little bit of width, I can see how SOME mag catches would not be "long" or "deep" enough to retain the mag past the adapter. However, that has to be rare as that would be an extraordinarily short tab/ledge of a mag catch. I like the mention of using a punch or a pencil to push in the mag release button to get a few more rotations in - I didn't do that and was able to get 2 more rotations. (EDIT #2: I backed off a rotation as the threaded portion of the mag catch was no longer flush with the mag release and I did not have this issue at all to begin with) I'd say my mag catch sticks out generously past the adapter; it's just a milspec aero one. Can't imagine having one shorter than that - I would guess a crappy out of spec lower causing these problems? https://imgur.com/a/qcbNqU9 |
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Quoted: I like the mention of using a punch or a pencil to push in the mag release button to get a few more rotations in - This was the one piece of advice that made no sense to me. If the catch has seated as deep as it can against the lower, how will putting more spring tension on the catch improve how deep the catch engages the magazine? Since you‘re fighting the mag catch spring the moment you begin to screw on the button, it would have to be awfully loose for this to have any affect on engagement. May help if the top of the mag catch tab isn’t square, but then the problem is the catch, not how much spring preload you have on the catch. |
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Quoted: This was the one piece of advice that made no sense to me. If the catch has seated as deep as it can against the lower, how will putting more spring tension on the catch improve how deep the catch engages the magazine? Since you‘re fighting the mag catch spring the moment you begin to screw on the button, it would have to be awfully loose for this to have any affect on engagement. May help if the top of the mag catch tab isn’t square, but then the problem is the catch, not how much spring preload you have on the catch. Agreed. I stated in my edit the mag catch wasnt flsh w the release anymore. How common of this issue is this? Extra rare, I am guessing? |
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Quoted: Also have you tried a Metalform mag, or just those ASC ones? I’ve had nothing but problems with ASC and CProducts mags myself, I only use Metalform and converted Uzi mags now. I have a few of the ASC mags. I had a few problems with the followers on a couple of them. The flashing on the front of the follower was dragging causing the front of the follower to drag downward. I used a knife to trim the flashing from the molding process. They work just fine now. |
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Quoted: I received my 3 RRA "9" marked mag catches. post mag pad pad delta .141 .155 .014 .141 .155 .014 .141 .155 .014 @Droppoint Finally received mine and they are the exact same measurements as what you have posted here. I am impressed with their precision given they are likely mass produced. but.... They work great on my standard lower with a KAK magwell insert, better than a standard mag catch and the measurements show why. However, they do NOT work in my two H&R 635 9mm dedicated lowers. I couldn't figure this out as I could see that they had a slightly deeper insertion into the magwell, but they would not seat a mag. I took a mag apart and observed that when inserted, to the point of touching the bottom of the feed ramp, the mag catch was not seating at the top of the notch in the mag. Further inspection of the H&R provided mag catch and the RRA 9mm catch showed that the H&R has a notch milled into the top part of the pad. This notch makes the pad .017" more narrow, allowing the mags to seat. So, the measurements for the H&R are Post Pad - .158 Pad - .155 Pad Width - .228 for Reference, the Pad width on the RRA is .245" same as my other standard mag catches. H&R in the foreground and RRA behind it. The scratches on the RRA are me seeing how hard it would be file the notch (not gonna happen, need to mill it and I don't have the tool to do that.) 
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| I could machine .017” off the top of one for you, but I’m puzzled. From the Palmetto Arms site I’d think the H&R lower is standard AR spec, so why the f’d up mag catch? Do they use some proprietary magazine? Or have some screwy reason the mag needs to seat lower than your standard Colt style 9? |
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Quoted: I could machine .017” off the top of one for you, but I’m puzzled. From the Palmetto Arms site I’d think the H&R lower is standard AR spec, so why the f’d up mag catch? Do they use some proprietary magazine? Or have some screwy reason the mag needs to seat lower than your standard Colt style 9? They use standard Colt style mags, but the Magwell in the lowers is not standard AR spec. It’s basically only drilled out for the 9mm mag. No inserts, no ability to use 556 type mags, etc. I don’t know why they won’t seat, I have not taken the time to measure the lower and compare it to spec. I know at one time Mike (H&R CEO) mentioned he might redesign the mag catch. I assume this is it. BTW, I did try a standard AR mag catch in one of the H&R lowers, same result, it wouldn’t capture the mag. |
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I had the same issue with Colt mags not locking into the H&R 635 lower, unless you really slammed them in. The front lip of the magazine was restricted from inserting fully by the over insertion tab on the bottom of the feed ramp. I notice that the 635 lower used the same feed ramp as my PSA PA-9 lowers did (PA-9 lowers haven't been available for several years). The difference was that the PA-9 lower also had a PSA installed shim that raised the feed ramp enough for the Colt magazine to easily lock into the lower. I contacted Mike about the issue and he told me that from testing different configurations they decided the feed ramp without the shim gave them the optimal angle for feeding. I told him that if he had access to the shims from the PA-9 lower I would like to purchase one. Mike sent me the shim at no charge. It did correct the magazine insertion issue and I haven't had any issues feeding ammunition. I also replaced the H&R 635 magazine catch with a standard one. H&R 635 lower  PSA PA-9 lower with shim  |
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Quoted: I had the same issue with Colt mags not locking into the H&R 635 lower, unless you really slammed them in. The front lip of the magazine was restricted from inserting fully by the over insertion tab on the bottom of the feed ramp. I notice that the 635 lower used the same feed ramp as my PSA PA-9 lowers did (PA-9 lowers haven't been available for several years). The difference was that the PA-9 lower also had a PSA installed shim that raised the feed ramp enough for the Colt magazine to easily lock into the lower. I contacted Mike about the issue and he told me that from testing different configurations they decided the feed ramp without the shim gave them the optimal angle for feeding. I told him that if he had access to the shims from the PA-9 lower I would like to purchase one. Mike sent me the shim at no charge. It did correct the magazine insertion issue and I haven't had any issues feeding ammunition. I also replaced the H&R 635 magazine catch with a standard one. H&R 635 lower https://i.imgur.com/q4qxVEe.jpg PSA PA-9 lower with shim https://i.imgur.com/UkG0Wtm.jpg I had to file a bit off the bottom of that front lip on both of mine and even shim one a little, though not as much as that shim. looks to me that the position of the mag catch is actually out of spec slightly... hence the .017 reduced shelf on the catch.  pics of the lower for @swOHmatt  
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