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I am trying to figure out the best way to obtain a 22lr AR style pistol build. Options include cmmg bravo conversion kit, dedicated upper, complete 22lr (e.g. Tippman M4-22).

I have a complete lower with SBA3 brace ideal for an AR pistol build. I also have the following parts:

CMMG BCG
CMMG Mags
BoreBuddy buffer plug
12" Slant M-Lok MOE rail
What additional parts would I need to just finish an upper build? I would prefer a barrel 10.5" or less. I could get a different rail if necessary.

I would just use the CMMG conversion kit with my 223 barrel but it is 1/7 twist and I have read that running 22 through it can mess up the barrel and the gas tube.
 

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Well if you have a dedicated CMMG Bolt and your railed handguard has a barrel nut..Sounds like you need a upper Receiver of your choice, Charging handle, maybe a muzzle device, barrel, sights..

If you have a drop in conversion with the chamber adapter..You will have to buy a dedicated collar to swap that out..
 

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I have two CMMG B units on dedicated CMMG barrels, nominally in the 10-11" range....both are for a registered SBR lower (with RRA NM trigger) that I use for Steel Challenge... one is cut down from a 16" barrel, and the other is threaded with a flange for the flash hider (the three prong does not lead as badly as a standard bird cage).... if your collar unit is older, measure the front to rear distance of the collar... if you use a newer barrel a .700" collar should be used
 

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when changing barrels on an AR9 or dedicated .22lr, you don't have to worry about a gas block or gas tube to align... I use a couple of hardwood blocks in a good vise and clamp the upper on it's side, across the top and bottom flats, no action rod or saddle block needed... if you get a full float style fore end that clamps to the barrel nut it makes a barrel installation a 5 minute job...lube the threads and tighten with a crescent wrench...
 

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I'm going to suggest you focus more on the BoreBuddy weight than the buffer plug.

My opinion only.
The weight does nothing to keep the bolt assembly from slamming into the lower receiver. The pressure plug does and it also keeps forward pressure on the assembly to hold it in place. The weight is nice though. Get them both us my recommendation, along with the BoreBuddy firing pin and extractor.
 

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I'm going to suggest you focus more on the BoreBuddy weight than the buffer plug.

My opinion only.
I'd share that opinion. Bore Buddy pieces address specific problems, and you want to know which problem you are having before you fix it.

The Plug remedies the condition in which the cycling of the bolt pulls a chamber insert or collar off the barrel shank. That's a potential problem if hammer energy gets absorbed shoving the insert or collar back into place. Before the commercially offered plugs, one of the tips for getting a conversion unit to "run" was to tape some coins to the face of the buffer. Along with using a full power GI hammer, this was supposed to leave enough energy to light off the rimfire round. The Bore Buddy verson of the plug has some enhancements that make it more effective and easier to use.

It probably doesn't keep the BCG from hitting the lower; as we all know the buffer spring is compressible. If your BCG is already compressed by the closing of the rifle, the back plate rests against the lower and can't actually hit it.

The bolt weight is important for regulating bolt speed and keeping the bolt closed until most of the dirt has blown out the muzzle end of the barrel. The difference in how quickly my lowers look like someone dumped volcanic sand into them is easy to see. The slower bolt speed also gives bolt hold open devices like the Catch22 and Better Mag Adapter time to do their work. I don't fire fully automatically, but I could see the premium bolt weight with the tungsten inserts acting as a true buffer and reducing or stopping bolt bounce nd reducing the rate of fire.

You won't be hurting anything by throwing every aftermarket part at your rifle, but if you are fixing something that didn't need fixing, you are just adding parts.

My two cents.
 

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Right To Bear has a really nice upper for rimfire/9mm applications
HERE

Chris
Do you use and like those? There have been reports that some of them are out of spec.

I also see that they have a gas tube hole. Exactly once over tens of thousands of rounds, I had a spent casing lodge itself in that hole. Not what you'd fairly call a recurring problem, but there are uppers made for PCCs that don't have that hole.
 

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I do use a slick side upper for my dedicated uppers but I haven't used the Right to Bear. I think the shell deflector and forward assist are useless in a rimfire conversion. On my precision M 261 based AR 22, I am using one of the DPMS extruded uppers. It is quite thick and has no assist, deflector, or door. FWIW, the slick side upper I have in my CMMG was out of spec, I had to lap the barrel seating surface square and glue in the barrel because the opening for the barrel was loose. Just more opportunity for tuning/tinkering.
Chris
 

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I've mostly used Anderson lightweight upper that have no FA or port door, but do have the shell deflector. I've eyed the DPMS, but never found one at a low enough price.

I've never glued a barrel in, but over the winter am going about shimming the barrels on each of my existing rifles. I don't know that it will help, but I don't see how it can hurt.
 

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Shimming? How does that work?
Chris
Stainless steel shim material is wrapped around the barrel extension so it doesn't quite fit into the upper. The upper is heated and the shimmed barrel inserted before it cools. I've been using .003 inch material, but I've seen video in which .005 is used and as thin as .001.

The idea is to achieve a thermal interference fit with the upper and barrel you already have.
 

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The weight does nothing to keep the bolt assembly from slamming into the lower receiver. The pressure plug does and it also keeps forward pressure on the assembly to hold it in place. The weight is nice though. Get them both us my recommendation, along with the BoreBuddy firing pin and extractor.
I guess I am confused about the need for a plug as I have not experienced this slamming you and others have talked about. Maybe due to spring and buffer weight already installed? Could it out of tolerance bolt carrier, i.e. shorter than it should be? Maybe there is a larger gap between the rear of the upper receiver and the lower receiver in that area? All my upper/lowers, are pretty snug in this area.

I don't know. What I do know, having a couple of conversion kits installed in different rifles, I didn't need the buffer plug as much as I needed that weight.
 

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Buffer plug

On my RTB upper I had a bit of front-back play in my bcg, didn't feel like much but first trip out did have occasional light strikes. Popped a garden hose washer between the BCG & buffer and it stopped. Ordered up the BoreBuddy pressure plug and firing pin, haven't come across any ammo it won't touch off now.

I'm no expert, but I think putting a bit of forward pressure on the BCG is it's only function. There's another thread somewhere about someone who basically beveled the front of their buffer to mimic a pressure plug and that seemed to work fine.

I run an A2 buffer tube on a dedicated lower, and once I got the pressure plug, I removed my A2 buffer and just run the plug with the spring.
 

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Stainless steel shim material is wrapped around the barrel extension so it doesn't quite fit into the upper. The upper is heated and the shimmed barrel inserted before it cools. I've been using .003 inch material, but I've seen video in which .005 is used and as thin as .001.

The idea is to achieve a thermal interference fit with the upper and barrel you already have.
That should really put a barrel in tight! I'm thinking it would take me 3 hands to do that. Glue in, while not as tight, does establish 100% contact to barrel extension and upper receiver, and is much easier.
Chris
 
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