CMMG Bravo for training

[Near miss]

Has anyone here experience on the CMMG Bravo 22LR conversion kit?

Here is my recent exploration into kits as I just loaned one from my friend. He was able to shoot it very accurately from his DD but in my gun (MR223, LW barrel, Wylde, 16", 7"tw) the results were not quite that good.

The goal here is to get me more 22LR time on this particular gun so I can keep blasting my favourite gun without burning out my barrel again. And preferably do also more precision-oriented excercises also.

I tested mine at 165m with SK Biathlon, Norma Tac, CCI Std and RWS match.

Surprisingly, the CCI fared the best with near 1mrad cone of fire. From this we can conclude that there is possibility for optimization to be done as in an optimized setup, the SK ammo would show the best.

The RWS was done afterwards and while I marked down results, I did not take another picture. But it was quite near to Norma Tac.

Here are photos of the gun and the kit itself after shooting around 150 rounds. I did use a suppressor but I doubt it had much to do with this, maybe some. Most likely the adapters loose fitting was mostly at fault.

It strongly looks like the kits 223 adapter only touched partially my chamber from the shoulders and was loose enough for a lot of debris to escape to my chamber and the adapter itself.

After this inspection I wiped the upper and lower a bit. I also cleaned the chamber clean.

The bore I checked with a borescope and noticed that it was doing great, just filled with water droplets. I did not do anything to it, just put it to rest for the night.

The next day I tested shooting 223 out of the gun and it had absolutely no problems with accuracy. This was my main concern for the testing.

Would silicone tape maybe be a good way to test how improving the seal between the adapter and chamber would change precision? This seems like a no-brainer to do, if it works (gets me close to 2moa 10 shot group with SK or CCI) I can even make a new adapter that fits my chamber perfectly so the changes would be permanent as silicone will definitely be tricky over time.

What have you done to improve how the kit performs?

Any other ideas worth trying?

 

[Mark_Dorman]

I had the same kit and had a very similar experience as you initially. Accuracy was pretty garbage by most standards. My receiver would get pretty gummed up from all the crap. I do think the kit was made with 5.56 barrels in mind and I have a 223 Wylde barrel. I never went back to my 5.56 barrel to test, but I think that is part of it. I've also found it likes CCI ammo the best. It'll do fine with CCI SV, but seems to really like Mini Mag and AR Tactical.

Personally I just decided to build a dedicated upper and converted the CMMG bolt using the collar. It runs a lot better and cleaner, but now I don't have to worry about my main receiver getting as dirty. A lot of that is because there is no gas port letting the gas blow back into the receiver. In terms of accuracy, the CMMG barrel I picked up was decent, but not great. The barrel was only $136, so I shouldn't have expected much, but 2 MOA is about as good as it'll do at 50 yards. I have not done a lot of testing for accuracy as I mainly build it for CQB training since rifle rounds aren't allowed on most of our action ranges (also way cheaper).

CMMG #22D7C0A
Barrel Sub-Assm, 16.1" M4 4140CM SBN, 22LR

Barrel Collar - Just pops in place to replace the insert that goes into your normal AR barrel.

I would like to eventually try a different barrel. I went with this one because of price and similar weight to my normal 14.5" 223 Wylde. I'm using my spare handguard and such on my dedicated upper, but will eventually make it identical to my main AR.

I think reliability wise you'll be hard pressed to beat a dedicated upper for it. I'd definitely recommend the BoreBuddy reliability parts. Also check your magazines. The Bravo Mags can be a bit finicky with feedback because of how they seat in the lower. I added very small shim to the front of my mags which helps they stay stable and snug in the lower and helps a lot with feeding.

Basically what my current setup looks like:

 

[renaissanceman]

A 2 moa 10 shot group is a big ask for a conversion kit. My conversions generally run about 6-8moa with a 50 shot group of CCI SV...with around 30ish of those shots falling into a 4moa group. Feeding a conversion premium ammo is pearls to swine.

A dedicated upper is the only way to fly if you want to do anything other than mag dump trash ammo. BoreBuddy makes quality barrels, (but I'm biased since I designed the barrel line). The match barrels should do less than 2moa 10 shot groups at 50 yards easily without needing to buy expensive ammo.

 

[Mark_Dorman]

A 2 moa 10 shot group is a big ask for a conversion kit. My conversions generally run about 6-8moa with a 50 shot group of CCI SV...with around 30ish of those shots falling into a 4moa group. Feeding a conversion premium ammo is pearls to swine.

A dedicated upper is the only way to fly if you want to do anything other than mag dump trash ammo. BoreBuddy makes quality barrels, (but I'm biased since I designed the barrel line). The match barrels should do less than 2moa 10 shot groups at 50 yards easily without needing to buy expensive ammo.

That's actually the barrel I want to try next. I've heard good things about them and wouldn't mind some better accuracy out of my AR22. That's awesome that you helped design them.

 

[renaissanceman]

That's actually the barrel I want to try next. I've heard good things about them and wouldn't mind some better accuracy out of my AR22. That's awesome that you helped design them.

The 16" will be a Gen 2 when it restocks towards the end of February. Minor updates, but updates nonetheless. Standard Apogee barrels are getting a Bentz chamber as well for Gen 2, so there should be a good bump in accuracy on those.

 

[Near miss]

Thanks for the info, too bad that over here there is not much supply in addition to the regular kit. I found there are some parts available made by Borebuddy but nothing to help with the current situation.

I was thinking that the custom barrel adapter could easily have bentz chamber to help with accuracy, but as long as it is wobbling about, there is not much to gain. I really would not want second upper to do the job since I most like the simplicity of the drop-in bolt.

I will try to fit the adapter better and see if I get cleaner chamber and better precision but for now the current groupings will just have to do it, and for the most of it, it already does.

 

[Mark_Dorman]

Thanks for the info, too bad that over here there is not much supply in addition to the regular kit. I found there are some parts available made by Borebuddy but nothing to help with the current situation.

I was thinking that the custom barrel adapter could easily have bentz chamber to help with accuracy, but as long as it is wobbling about, there is not much to gain. I really would not want second upper to do the job since I most like the simplicity of the drop-in bolt.

I will try to fit the adapter better and see if I get cleaner chamber and better precision but for now the current groupings will just have to do it, and for the most of it, it already does.

I'm sorry, didn't realize you were in Finland so some parts might not be as easy to get. If you don't want to go with a full upper there one thing you can try. The bore buddy Buffer Pressure Plug is one of them. The slop of the drop in conversion bolt is a source of problems for many. The plug that just pops over your buffer spring helps keep it from moving backwards.

I don't know what else you could do about the chamber issue, but this would be worth a try.

 

[renaissanceman]

Thanks for the info, too bad that over here there is not much supply in addition to the regular kit. I found there are some parts available made by Borebuddy but nothing to help with the current situation.

I was thinking that the custom barrel adapter could easily have bentz chamber to help with accuracy, but as long as it is wobbling about, there is not much to gain. I really would not want second upper to do the job since I most like the simplicity of the drop-in bolt.

I will try to fit the adapter better and see if I get cleaner chamber and better precision but for now the current groupings will just have to do it, and for the most of it, it already does.

Try these guys if you can order from Sweden:

https://thearmourysports.se/search/?q=borebuddy