Build Thread Dedicated 22 upper

[2gr8dgs]

So I got the itch to get a 22/ar15 the other day. I went to look at the S&W M&P 15/22. I am certain it's a fine running gun, Just a little too much plastic for me.
Went home & did a little research on what it takes to build one. I ordered a cmmg conversion kit w/3 25rnd mags, A cmmg dedicated 16" bbl, & a bbl collar from Primary Arms.
It all showed up in the mail yesterday.
I had a long bbl target style AR project that wasn't getting used , so I tore into that for the upper & lower parts.
going to try it out today, I think it might be hoot. It's all new to me, so, feel free to share your tips & insights on your similar builds!

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[powermad]

Looks good, looks like it should be a solid runner.
Nice to see .22 stuff coming around again.

 

[2gr8dgs]

OK, just got back from the first shoot.& the accuracy is great. For me. About a fist sized group of 25 rnds @ 50yrds with the red dot.
However, I had plenty of Jams. Most, if not all, were FTE.
1st mag was minimag 36gr hp's. 2nd was federal bulk blue box (I think) 3rd mag really smoothed out with of all things, Rem. golden bullet.
I still have the buffer & spring in it... I don't remember what trigger it has, but it is light.
Also, I never cleaned anything, just hit the bolt group with some Remoil & went for it!
I think I'll give everything a good scrub & try again.


EDIT: so it looks like some of my jams are from a spent case getting into the hollow of my charging handle. working on a wecsog fix right now.
EDIT#2 scrubbed it clean & light oil & not much changed, then I put a spacer in the hollow of the charging handle, & it ran a little better. Finally, I put a bone stock trigger/hammer group in it & ripped off a mostly full mag of Federal American Eagle. Which had failed miserably before.

 

[spookshack]

RTB Polymer Charging Handle - 22LR

This Right To Bear .22 LR charging handle is designed to prevent spent casings from becoming stuck between the bolt and charging handle.

www.righttobear.com

 

[osprey]

Light after market triggers don't work well and you need a plastic buffer/spacer replacement as well. You can run a lighter springs on a alg trigger but that s as good as it gets. Some ammo is still suspect but cci standard velocity and mini mags run all but 100% in mine.

 

[2gr8dgs]

I just got back from another shoot. 100% function. CCI minimag HP. I think putting in a stock hammer, trigger & spring set was the fix. So far so good!

 

[PiratePast40]

Broken firing pins are common so might want to have an extra or two on hand. If you can find hardened ones, they'll most likely last longer. Doesn't hurt to have extra springs on hand as well. Google AR-22 and you'll find several aftermarket parts suppliers. Keep in mind that dry fire isn't recommended since the firing pin can hit the breech face. For decocking, just pull the bolt back a half inch or so and pull the trigger.

ETA: noticed your comment about the trigger. I run a Larue MBT-2 and don't have any issues with it. My go to ammo is Federal Auto Match. Very few misfires with it. The RTB charging handle or insert also works well. I went with a latchless charging handle and the insert.

 

[MichaelH]

I built one using a used spikes 22lr barrel and collar with a cmmg bolt and accuracy was fine, but I also had a ton of FTE's. I think it was suspect ammo more than anything, but if it doesn't work with ccis then I'm going to drop in a bolt buffer and charging handle insert into mine. I didn't want a poly charging handle since I'm clumsy and can envision breaking it. I was running a mil spec aero trigger.

My hope is that the problem isn't an unhappy marriage bw the spikes and cmmg parts. Time will tell I guess. Still a blast, even if a bit heavier than a 10/22 and finicky.

 

[Yarome]

I did a dedicated not too long ago and really love mine too. One thing on the FTE's that might help is tightening up the bolt to buffer face gap. There is just a bit of bolt slop with the recoil and going back into battery. The back shifting can reduce the blowback pressure on the bolt face and lead to FTE's.

There's a buffer plug available for that. RTB carries them as well as Borebuddy. Borebuddy also has a ton of other goodies for a dedicated build. One tip on the plug though, add just a drop of oil on the faces of the plug . There is a tendancy for the plug to rotate and breaking the friction seems to resolve that.

(Side note, I bought a 3D printed buffer plug off a guy on ebay for 3 bucks.. compared to the 12-13 + shipping RTB and BB wanted. Works just fine so far.)

If you rapid fire, FTE's and such can also occur due to bolt bounce. I had that issue.

I'm running a bolt weight and it's been humming along like a kitten. I also run an enhanced firing pin and ejector. Not that they were particularly needed at the moment, but figured, why not while I was buying the weights and it leaves me with the OEM's as backups.

 

[MichaelH]

Yeah. I have the bore buddy fixes in mind.

Thanks

 

[Yarome]

Yeah. I have the bore buddy fixes in mind.

Thanks

BB certainly ain't cheap. My son and I run drop in's as well, but BB gear is too spendy to use for diminished returns on a drop in, IMHO. The dedicated though is well worth it. It shoots night and day different than the dropins. Just like a real live 22lr rifle should.

If you go with a weight... I haven't worked up the weights loads for subsonic yet, but MM I've been using 2 large SS and the 2 smaller tungsten (with 4lb recoil spring). Velocitors I'm running all tungsten (with 6lb recoil spring), and it could probably still use just a bit more, but that's as heavy as she goes and runs flawless.

Just for future reference.

BB doesn't give you much guidance other than, start with all aluminum and work your way up until you have the right weight.

 

[MichaelH]

Thanks for the tips!

 

[MichaelH]

So bore buddy standard weight, bolt buffer and charging handle insert fixed my FTE problems, but now I'm getting more FTF issues. I think my older-purchaesed- used barrel collar is the problem bc it's parkerized and I think the feed ramp is causing some unnecesary friction while feeding. Though I could learn to polish gun parts, I think I'm gonna get a cmmg stainless barrel collar to see if that fixes the problem. It could also be the underpowered cmmg magazine springs, but they get the rounds up there so that's the second fix.

 

[Nwcid]

Interesting thread.

I also built a dedicated AR vs buying an AR style .22. I wanted all of the parts to be compatible (minus bolt and barrel of course) with any other standard AR. Mine is at least 15 years old.

I originally purchased aCMMG upper that I have used throughly with only the occasional failure to fire issue but I blame that on the ammo. If I put the round back in and try again they have always fired. I am typically shooting Federal 550 bulk pack (under $15/brick). If I have had FTF or FTE they have been so rare I do not recall. I have a standard lower with the buffer spring in place, so I can swap to another upper if I ever needed or wanted to. The buffer should make no difference since it has nothing to do with the function of the .22 kit.

Along the way I have added the last round bolt hold open feature and the forward assist adapter. I use the FA from time to time when the gun is real dirty or if I am trying to get a loaded round to eject.

I have not heard about frequent fire pin failures, and I probably have at least 5k rounds though mine.

I also recently picked up a drop in conversion (on sale) for my wife to use with her left handed AR for cheap practice time. We only have a couple hundred round though it, but no issues that I can think of.

 

[Yarome]

So bore buddy standard weight, bolt buffer and charging handle insert fixed my FTE problems, but now I'm getting more FTF issues. I think my older-purchaesed- used barrel collar is the problem bc it's parkerized and I think the feed ramp is causing some unnecesary friction while feeding. Though I could learn to polish gun parts, I think I'm gonna get a cmmg stainless barrel collar to see if that fixes the problem. It could also be the underpowered cmmg magazine springs, but they get the rounds up there so that's the second fix.

That could be. 3 other areas to consider would be using a bolt buffer plug to reduce back and forward play in the bolt, the mag fit and mag follower.

Some magwells there may be a lot of slop in the fitting. Adding a bit of material to the back side of the mag can help tighten it up at the proper angle for better feeding. I've seen folks use layers of electrical tape, a strip of self adhesive moleskin, the fabric side of self adhesive velcro strip, layers of clear fingernail polish, epoxy... to name a few.

The other common issue with CMMG mags is the follower itself. The angle of the top edge being too aggressive so levelling the front angle down to almost level the full length with a dremel (or other method) seems to work well. I would consider the non-invasive fixes first.

As mentioned... ammo flavor can matter too.

All that said... a parkerized feed ramp would certainly seem a likely candidate for friction. Checking the mag fit can't hurt and I'm a true believer in the buffer plug. YMMV

 

[MichaelH]

This upper shares a lower with my AR upper and my buffer is a silent capture system buffer that has a thick rubber washer on the end that molds itself around the buffer retaining pin and keeps the bolt pretty snug in the upper. I'll try the magazine fixes first—thanks for the suggestions—before dropping dough on a barrel collar. Thanks!

 

[Yarome]

This upper shares a lower with my AR upper and my buffer is a silent capture system buffer that has a thick rubber washer on the end that molds itself around the buffer retaining pin and keeps the bolt pretty snug in the upper. I'll try the magazine fixes first—thanks for the suggestions—before dropping dough on a barrel collar. Thanks!

That'll work! (buffer issue)

Ya know though... if buying a new collar is on the table, you might as well try your hand at polishing up the one you have. Worst case.... you bugger it and need to buy a new one. Best case, you add a highly valuable skill to your "toolbox" and might end up saving yourself a 50.

It's really not at all difficult. I think many that bugger them just get too aggressive or try and speed/power though the process.

 

[Yarome]

Side note... I polish SS ramps too. Some stick cotton tips, a couple different grit pastes from amazon or the craft store and finish up with some mothers mag and aluminum polish. Sometimes just the mother's and a bit of elbow juice is enough.

Like bubblegum through a goose.....

 

[MichaelH]

Have rotozip, will attempt.

Honestly, I'm pretty into the DIY thing at least as to the AR platform. Given cost savings if one wants more than a budget starter rifle, it's almost a no brainer to learn how to put them together, and how they work. My gen X upbringing makes me dislike posers, so the things I do get into I want a bit more than least common denominator knowledge. Honestly, the process took me from questioning why people wanted ARs at all to thinking "hey, these things work pretty great, and almost everything about them is designed to maximize the ergonomics for successful shooting. No wonder people don't want their access to them limited!"

Except for the buffer-tube system. It works well, probably made production of them cheaper, and field repair a little easier than having the recoil system in the receiver, but that damn tube off the back seems like it wasn't Stoner's best idea.

 

[Capn Jack]

Personally I use ATF in my AR's and I found that my DPMS .22lr upper needs to run wet.

* Note do not use bore cleaners, Like Hoppe's #9 on any of your plastic magazines.
It eats up the plastic and the feed lips will break.