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Old 08-24-2018, 04:04 PM
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AR 15 22lr last round bolt hold open solutions: Catch-22 and Better Mag Adapter



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I’ve posted enough about both of these that I thought there might be enough useful material for a thread on the topic. Both solutions employee Smith & Wesson 15 – 22 magazines, hold the bolt open on the last round and release the bolt with the same operation as a stock AR. This function may be important to the durability of the firing pin and the barrel breach face.

The BMA is a well conceived and precisely produced solution. In my rifle it does not work reliably with high velocity ammunition and the magazine well adapter can involve getting the magazine past a new hump in the magazine well that regular AR 15 users will not expect.

The Catch 22 is a simpler more direct solution that gave me more reliable function.


Redi-mag Better Mag Adapter (BMA)


The Gizmo
This device requires no modification of a standard AR lower. This was the draw for me; if my experiment with a dedicated 22 LR barrel was going to be a failure, I did not want to modify a lower only to have to reverse the modification later.

An aluminum magazine well sleeve holds a very small bowl to catch that operates off the spring pressure of a stock AR bolt catch. On my Anderson lower, this device was so tight that I could hear the scraping of the anodizing as I pushed it in with an empty magazine.

Its Virtues
Over the course of nearly 10,000 rounds, I operated this device in conjunction with a Rock River two-stage trigger with a full power hammer spring, a Larue two-stage trigger with a full power hammer spring, and each with various reduced power hammer springs. At times I have run Lakeside heavy-duty recoil springs. While I had read about these rifles requiring high-speed ammunition in order to function reliably, my experience, all of it with 16 inch barrels, has been the contrary. My best function has been with standard velocity or subsonic ammunition, and by best I mean flawless.

Problems and Limits
The problem I did encounter with the BMA was a failure to hold the bolt back on the last round of Remington Golden Bullet, Thunderbolt or CCI mini mag. My theory was that the bolt speed was too great and did not permit the chain of bolt catch spring, AR bolt catch and BMA bolt catch enough time to rise and block the returning bolt. This inability to use the really hot stuff was not a great loss to me because the accuracy with high velocity ammunition was much reduced.

In a second build, I re-examined whether I had made the right choice with the BMA. I removed it from the rifle, cleaned it and put it away. It came out looking as if it had been dipped in motor oil and dropped on a beach. The catch itself showed no sign of wear.

The Catch-22 (C22) bolt catch and magazine well adapter

The Gizmo
The C 22 is a bolt catch with a dogleg that allows it to grab the face of the ubiquitous Ceiner/CMMG bolt. The magazine well adapter is a self retaining piece of polymer that looks as if it may have been 3-D printed.

My First Thousand Rounds

I installed the C 22. Over the course of the first 50 rounds (10 magazines) of Aguila SV, I had several failures to hold open. I switched to the worst, most abusive round I had, Remington Golden Bullet, for several magazines and was rewarded with reliable function. I congratulated myself for having found the solution to the limits of the BMA. I switched back to standard velocity and the bolt now held open every time. I can only guess that there may have been some part-to-part polishing happening. My next session of 300+ rounds was failure free.

The C 22 swings through a greater range of motion than the stock bolt catch, so you may notice the release tab sticking out farther. The extended dogleg also means that the release button has less leverage; it feels like a grittier trigger with longer travel compared to a stock bolt catch release tab. That is not a problem in operation, but you may notice it. The C 22 also has a larger hole through the middle of it than a stock catch. IlHondo noted that and made a shim for his. I wonder whether that larger hole was intended as part of the design to confer some benefit.

My third session had a few failures to keep the bolt open, but worse the bolt dropped every time I dropped a magazine, sometimes immediately after I pressed the magazine release, and sometimes just a moment after the magazine dropped. I assumed this was a problem with the C 22, the only new element.

Customer Service Squared
That Saturday, I left an email for customer service at the Catch 22 website asking whether this was a known issue and whether there were any recognized fixes for this condition. My hope was that someone would see the note and give me some guidance when they got into the office the following week. Instead, I received a reply from Alex in less than one hour. He had read and understood my email (I do not consider this a trivial accomplishment given the difficulties so many have with online communication) and had questions about the operation of my rifle and the appearance of the bolt catch.

You might imagine that the bottom of a CMMG bolt is a simple 90 turn with a sharp edge. It isn’t. Instead, there is a very small bevel between the bottom of the bolt and the bolt face. That tiny bevel had its mirror image impressed at the top of the C 22 bolt catch. When I was dropping my magazine, the bolt catch was dropping like a too aggressive trigger job and releasing the bolt. I tried it with each of my magazines with the same result; if I could get the bolt to hold back after the magazine dropped, the bolt would drop as soon as the rifle was bumped. If I engage the catch manually, I could easily push it in far enough that it would hold the bolt safely.

Alex asked me a number of questions over the course of a couple of emails. This was not only a person who understood the bolt system and how the C 22 interacted with it, but who was reading the responses and thinking about them before he responded. He posed a basic question, “have you tried it with other magazines?”. Of course I had! I tried it with the other magazines I always use. Only then did it dawn on me that the first diagnostic step of trying a different magazine isn’t satisfied by trying a different magazine with exactly the same wear.

I thanked Alex for spurring this epiphany and let him know that I would buy a new magazine to test the Catch 22. At this point I was genuinely thankful to have someone who understands this system take the time to understand the problem and suggest a solution, and over a weekend no less. Alex wrote back that he would send a replacement Catch 22 so that I would have that to test as well. I made mild protest that I am not owed a new part where the original part may not even be the problem, but he assured me that that isn’t a problem and that he would be sending the part anyway.

The new Catch 22 and new magazine came on the same day. The new magazine pushed the catch up to solidly hold the bolt. I compared the new magazine to the old magazines, specifically the little orange leg that pushes the bolt catch upward. I detected no difference in the length of the old and new leg. I disassembled an old magazine and the new magazine and reassembled the parts with the following results:
1. Old magazine body + new spring + old follower = failure
2. New magazine body+ new spring+ old follower= failure
3. New magazine body+ old spring+ new follower= good function
4. Old magazine body+ old spring+ new follower= good function

Despite the appearance of the old follower, it must have have been the problem. I used a pair of fingernail clippers and clipped a bit of weed wacker cord to glue to the follower leg. This gave correct function with all of the old components.

I was able to get all of this to the range today for testing. Almost immediately, the little piece of weed wacker cord I had super glued to one of the legs came off, but the others held. The only failure to hold the bolt back on the last round with the new or fixed magazines was with one of six magazines of Remington Golden Bullet. This also happened when the Catch 22 was new. The CMMG bolt has many virtues, but I believe that one of its vices is excessive bolt velocity that makes it difficult for any bolt catch to do its job. The Catch 22 was again uniformly holding open on the last round with CCI standard velocity, Aguila standard velocity, Aguila high velocity, Seller & Bellot subsonic, Federal match and Remington subsonic.

What exactly did this test anyway?

Aside from my analytical failure to function check not just with a different magazine, but a materially different magazine, this tested two things, 1) the durability of Smith & Wesson magazines and 2) Catch 22’s customer service. Smith & Wesson 15 – 22 magazines are very good, but they are not immune to age and wear. More importantly, this episode reveals Alex’s focus on seeing that people are happy with this product.

Last edited by zukiphile; 08-24-2018 at 04:07 PM.
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  #2  
Old 08-24-2018, 09:49 PM
9x19

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Good info, thanks for taking the time to post that.
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Old 08-25-2018, 11:49 AM
octanejunkie

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Thank you for taking the time to post this thread

I've been following the other threads and we've discussed this all before; good to see it all in one place with this much detail.

I opted for the BMA over the Catch-22 for a few reasons, mostly the larger pin hole, and yes the BMA was a tight af fit in my LRB lower too, but I faced the outside of the forward lug (the ramp side towards the front of the rifle) on 600 grit until it was reasonable in my opinion; I also did not want to strip the finish off the inside of my magwell.

My experiences with the BMA were different than yours, so far, in that all my mags are new 15-22 mags, and I've only shot HV ammo - no failures of the catch at all.
FWIW, I am also running a Pressure Plug - not sure if that has anything to do with my experiences to date, but it's worth a mention.

Thanks again for posting and please keep this thread updated with any pertinent insights or experiences moving forward

Last edited by octanejunkie; 08-25-2018 at 11:53 AM.
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  #4  
Old 08-26-2018, 10:02 PM
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Hey everyone, Alex from Catch22 here. As you know, .22lr can be finnicky but we're completely committed to making sure that we make it work with your setup!
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  #5  
Old 08-27-2018, 08:16 AM
Triggershoe
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Originally Posted by octanejunkie View Post
Thank you for taking the time to post this thread

I've been following the other threads and we've discussed this all before; good to see it all in one place with this much detail.

I opted for the BMA over the Catch-22 for a few reasons, mostly the larger pin hole, and yes the BMA was a tight af fit in my LRB lower too, but I faced the outside of the forward lug (the ramp side towards the front of the rifle) on 600 grit until it was reasonable in my opinion; I also did not want to strip the finish off the inside of my magwell.

My experiences with the BMA were different than yours, so far, in that all my mags are new 15-22 mags, and I've only shot HV ammo - no failures of the catch at all.
FWIW, I am also running a Pressure Plug - not sure if that has anything to do with my experiences to date, but it's worth a mention.

Thanks again for posting and please keep this thread updated with any pertinent insights or experiences moving forward
Guys, it looks like this is the place to post my experiences with both the BMA and the Catch22, to hopefully add something of value to the discussion. Regarding the BMA, I think this is the easiest and best solution (no offense meant to Alex) to obtain reliable last round bolt hold-open and NOT have to essentially "dedicate" any particular lower to rimfire only use. Regarding the fit of the BMA to the lower receiver, I have seen them go in extremely tight in one lower and also somewhat loose in another. I believe this is due to a stack-up of machining tolerances and may require the BMA to be "massaged" slightly for the best fit. I will say that the BMA's that I have work perfectly EVERY time, at least in my lowers. One caveat, and that is the BMA's I have are the earlier versions, the ones that were made with extended "legs". The "newer" and currently produced BMA's have much shorter legs on them, presumably to save material and decrease the machining time required to produce them. I doubt if this makes any functional difference at all, but the longer legs of the older units seem to better stabilize the S&W magazines (less "play"). I will add that I really LIKE the BMA solution to the BHO issue.

Regarding the Catch 22, these obviously do work and are a good choice for someone that is dedicating a lower to rimfire use only. I still have and use an Armalite lower for rimfire only, and I have the Catch22 installed in this one. The BMA was not available yet at the time, and the C22 was the only game in town to obtain "normal" BHO. I did have some problems with the C22 in that it was not 100% reliable at first. In my case, the problem was that the upper leg of the C22 that engages the bolt was not rising high enough to get a good "purchase" on the CMMG bolt. What I did to fix this problem was to affix a shim to the BOTTOM of the C22 using JB Weld. I think the shim was about .035" thick. After I did this, the operation of the C22 was 100%. This shim causes the C22's upper leg to rise a bit further to more fully engage the bolt (Alex, are you listening?). I performed this modification/fix to several more of the C22's that my friends were running at the time and they ran perfectly as well. The JB Weld must be some good stuff because none of the shims have fell off the C22's yet! One final point about the C22 is worth mentioning, and that is the S&W mags need to be shimmed to really work reliably with the C22 (Alex sells really nice stick-on ones, I use them!) and that is it's only other "downside". Once modified, the mags can only be used with the C22 (without removing that shim, of course). Of course the "shimmed" mags can still be used in a lower that is running neither the BMA or the C22, but that is not what we are discussing here.. I hope this info is useful to someone, and I want to state that either option (the BMA or C22 using S&W mags) can be made to run 100% reliable and are good solutions to the BHO "problem". For me, if I were doing this for the first time, I would go with the BMA. This is just my personal preference. The BMA does cost a bit more than the C22, but it really IS the simpler way to go.
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Old 08-27-2018, 08:56 AM
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Quote:
Originally Posted by Triggershoe View Post
Regarding the BMA, I think this is the easiest and best solution (no offense meant to Alex) to obtain reliable last round bolt hold-open and NOT have to essentially "dedicate" any particular lower to rimfire only use.
That's why I bought the BMA first. I didn't want to "waste" a lower.

Then I experimented with AR buffers and springs, substitutes for both, using nothing in the tube, internal buffers for the BCG and different triggers and hammer springs. I gradually had dedicated a lower to my 22lr disease.

I modified the magazine follower leg on the principle that one should modify the less expensive part first, but your idea of sticking a shim to the bottom of the C22 seems quite smart.

1. Did you have to remove the catch to do that work?

2. Was your shim just JB Weld, or did you use it to glue something harder to the C22?
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Old 08-27-2018, 03:13 PM
Triggershoe
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Originally Posted by zukiphile View Post
That's why I bought the BMA first. I didn't want to "waste" a lower.

Then I experimented with AR buffers and springs, substitutes for both, using nothing in the tube, internal buffers for the BCG and different triggers and hammer springs. I gradually had dedicated a lower to my 22lr disease.

I modified the magazine follower leg on the principle that one should modify the less expensive part first, but your idea of sticking a shim to the bottom of the C22 seems quite smart.

1. Did you have to remove the catch to do that work?

2. Was your shim just JB Weld, or did you use it to glue something harder to the C22?
Zuk--- you were on the right track with your mod to the follower, but the "shim on the bottom" is MUCH more reliable and durable. You do need to remove the C22 to attach the shim. I made several at the time I was tinkering with this (for myself and a few friends) out of some brass sheet stock I had lying around. I THINK it was about .035" thick, I'm not positive. Be aware you can make it too thick, so be careful there... Anyway, I shaped it to fit nicely on the underside of the C22 where the S&W follower leg would make contact. I roughened up both surfaces, degreased thoroughly, and applied the JB Weld to cement things together. After cure, a quick "touch up" filing to get things perfectly aligned and remove any excess JB/shim material, and that's it. All of the ones I modified in this fashion still have that shim attached. JB is definitely good stuff! Regarding the shim, I GUESS you could just place a gob of JB in that location, and file/massage it to suit. I found it easier to shape the brass shim and then glue it, though... And, that brass is nice and smooth so the S&W follower can slide across the surface easily. Hope this helps....
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Old 08-27-2018, 07:09 PM
zukiphile is online now
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Originally Posted by Triggershoe View Post
Zuk--- you were on the right track with your mod to the follower, but the "shim on the bottom" is MUCH more reliable and durable.
More reliable and durable than a nugget of weedwacker superglued to the follower leg? Unpossible!

Quote:
Originally Posted by Triggershoe View Post
I found it easier to shape the brass shim and then glue it, though... And, that brass is nice and smooth so the S&W follower can slide across the surface easily. Hope this helps....
It does. I like the idea of a hard smooth surface glued to the catch. I'll wait for my weedwacker bits to fail while I scout for shim material.

Thanks.
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Old 08-28-2018, 12:16 AM
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One final point about the C22 is worth mentioning, and that is the S&W mags need to be shimmed to really work reliably with the C22 (Alex sells really nice stick-on ones, I use them!) and that is it's only other "downside". Once modified, the mags can only be used with the C22 (without removing that shim, of course). Of course the "shimmed" mags can still be used in a lower that is running neither the BMA or the C22, but that is not what we are discussing here.. I hope this info is useful to someone, and I want to state that either option (the BMA or C22 using S&W mags) can be made to run 100% reliable and are good solutions to the BHO "problem". For me, if I were doing this for the first time, I would go with the BMA. This is just my personal preference. The BMA does cost a bit more than the C22, but it really IS the simpler way to go.
Thanks a bunch for the feedback. I definitely recognize that the BMA is stiff competition but thankfully there's enough shooters out there for both of us to exist side by side!

One thing to note is that relatively recently we came out with a shim that clips on to the lower instead of sticking onto the mag. This way you only need one and don't need to modify your 15-22 mags to only work in standard ARs.
Here's a quick vid on how it works: https://www.youtube.com/watch?v=JgU50Ky8nsw
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Old 08-28-2018, 09:19 AM
9x19

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One more point in the Catch 22's favor, for me, it works with TacSol uppers, the Redi-mag does not.
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Old 08-28-2018, 09:38 AM
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Originally Posted by ARCatch22 View Post
One thing to note is that relatively recently we came out with a shim that clips on to the lower instead of sticking onto the mag.
FWIW, that is what prompted me to buy your catch.

Quote:
Originally Posted by 9x19 View Post
One more point in the Catch 22's favor, for me, it works with TacSol uppers, the Redi-mag does not.
Do you know why?

All bolts seem to work with the BDM/CMMG pattern magazines. We know the CMMG bolt works with S&W magazines and a BMA. Yet Tacsol doesn't work with a BMA, and 2A Armament doesn't recommend it. Nordic has two different kinds of uppers - who knows what works with either of them.

Then there are a couple of different collar sizes. I could understand why someone would avoid building his own 22lr upper.

Last edited by zukiphile; 08-28-2018 at 10:36 AM.
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Old 08-31-2018, 03:09 PM
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At the range this morning and over the course of 30 magazines, of which 20 were Remington Golden bullet, the bolt was firmly caught by the Catch 22 every single time. So, my inner dialogue is back to congratulating myself on my wisdom in having installed this.
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Old 08-31-2018, 05:48 PM
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My Catch22 has worked flawlessly after hundreds of last shots. Always wondered about the slop because of the large hole but as long as it works.....
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Old 09-12-2018, 10:19 AM
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Minding my own business a week or so back when PSA smacked me in the face with an offer for a 7.5" .22LR upper that I couldn't (OK, didn't want to) refuse.

It appears to be a CMMG pattern bolt, etc. Stainless steel. What do I need to know to make its first trip to the range a good experience?
I've only ever owned TacSol and Spikes .222LR uppers in the past. I have a PSA lower with SBA3 brace to mate with it, and I got a Better Mag Adapter as well so I can use my S&W mags.

The BMA installed without issues, no slop but no real force required to slide it into place. Function check went fine with a brand new mag.

I also have a 9" TacSol upper on a similar lower, and bought the Catch 22 (with the clip on mag well spacer) for it, but haven't installed it yet as the BDM mags still work fine and LRBHO hasn't been a show stopper for me yet. After all these years, I'm still wishing S&W made a 15 round mag similar in length to BDMs.

Last edited by 9x19; 09-12-2018 at 10:22 AM.
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Old 09-12-2018, 10:54 AM
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After all these years, I'm still wishing S&W made a 15 round mag similar in length to BDMs.
Me too. They make the 25 round magazine to mimick the profile of the 30 round magazine, why not a rimfire magazine that matches the profile of a 20 round centerfire?

Quote:
Originally Posted by 9x19 View Post
Minding my own business a week or so back when PSA smacked me in the face with an offer for a 7.5" .22LR upper that I couldn't (OK, didn't want to) refuse.

It appears to be a CMMG pattern bolt, etc. Stainless steel. What do I need to know to make its first trip to the range a good experience?
Every different kind of ammunition you can find.

Some people are getting terrible accuracy from these. At least one fellow has a barrel set so far forward that his hammer hits the bolt catch before the firing pin. I can't tell whether some of these people are just using ammunition those barrels don't like. A couple of years ago, there was a Truth about Guns article about the 9.5 inch CMMGs that noted really bad accuracy.

The AR15.com thread about problems. https://www.ar15.com/forums/AR-15/PS...nce/15-731204/

I look forward to your post about perfect function and great accuracy.
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