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Have rotozip, will attempt.
Unless you need to reshape or remove serious imperfections I stay away from any power tools. Dowel/casing wrapped with wet dry sandpaper, for more agressive polishing, or just cotton tip sticks suits me just fine.

It kind of depends on the ramp, but you can do more harm with a rotary action than you will with a back and forward polishing movement. If there are side to side machining markes, a soft rotary pad can tend to simply make them worse... as an example. Examine first to determine how you plan to approach the job at hand and it's not always a "one size fits all" process.

It doesn't take much to alter the geometry with a power tool so I avoid it unless I am intentionally trying to alter/expand it or correct a receiver/ramp transition.
 
Actually, the problem is the feed ramp sucks when inspected closely. There's a small gap bw the feed ramp and the chamber, and relatively soft .22 lr ammo hits the edge of the chamber and grabs. The only fix I can imagine working is taking a 1/16th to a 1/32 off of the back side of the barrel collar. Reminds me sone used deals aren't good deals.

I guess I might splurge and grab barrel / collar combo if I can find one on sale for the holidays. Honestly, the Spikes Govt profile barrel I have seems heaver than necessary for the round.


Thanks for the tip on polishing and not going overboard. I knew I kept those 1200 grit sheets of sandpaper for a reason. Next project.
 
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I was having the same problem with my dedicated 22LR upper, and yah the problem was the feed ramp had a little lip and rounds kept getting hung up. I used a jeweler's file from harbor freight and a bit of 800 grit emory cloth and that fixed all my issues, except for duds in cheap 22 ammo!
 
Actually, the problem is the feed ramp sucks when inspected closely. There's a small gap bw the feed ramp and the chamber, and relatively soft .22 lr ammo hits the edge of the chamber and grabs. The only fix I can imagine working is taking a 1/16th to a 1/32 off of the back side of the barrel collar. Reminds me sone used deals aren't good deals.

I guess I might splurge and grab barrel / collar combo if I can find one on sale for the holidays. Honestly, the Spikes Govt profile barrel I have seems heaver than necessary for the round.


Thanks for the tip on polishing and not going overboard. I knew I kept those 1200 grit sheets of sandpaper for a reason. Next project.
RTB has pretty decent sales fairly regularly. They almost always have a "sale" price on shtuff, but that's more their every day price than a "sale". Watch for the 15%/20% off codes on the main page. CMMG kit rebranded "RTB" kit at a slight savings over "CMMG". I've never seen the casings/collar sets (is that what you meant by barrel/collar?) before and likely have to purchase seperately. It's nice having the option to flip to dedicated or drop in though.

 
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I went the CMMG route with just the conversion kit and then later with a dedicated barrel. After a bunch of parts as mentioned above and trial and error, I gave up on it and bought a S&W 15-22 and never looked back. While the CMMG ran ok, I could never get it to the level of reliability I needed.

I like the idea of having a kit to run in a standard AR, but everything is so overkill for what is needed for a .22. Kinda like putting Geo Metro 3 cylinder engine in a Suburban. It's not to scale. Anyway, I've enjoyed reading all the replies in this thread.
I hope the OP gets it all sorted out. :)
 
I went the CMMG route with just the conversion kit and then later with a dedicated barrel. After a bunch of parts as mentioned above and trial and error, I gave up on it and bought a S&W 15-22 and never looked back. While the CMMG ran ok, I could never get it to the level of reliability I needed.

I like the idea of having a kit to run in a standard AR, but everything is so overkill for what is needed for a .22. Kinda like putting Geo Metro 3 cylinder engine in a Suburban. It's not to scale. Anyway, I've enjoyed reading all the replies in this thread.
I hope the OP gets it all sorted out. :)
We started with drops in's too, but mainly use them in the "kicker" rifles. Good enough for training and plinking and have always been satisfied with them. Ammo type plays a big part, I think.

The dedicated is a more recent build and couldn't be happier with it. About a brick and a half in and it's a highly reliable tack driver... but I know plenty of folks have reported theirs haven't been up to what they expected. I'm not entirely sure why that is, but... it is what it is.

I'm a bit particular with parts and with any rifle, the first thing on the menu is tearing them down completely for a physical and fine tuning during reassembly. Maybe that helps resolve a lot of those simple issues that could affect reliability(?) I dunno, but I would certainly do another over some of the prepackaged (and some proprietary) options. I really like the feel and function of a true AR platform with the dedicated.

Any rifle assembled from components I think likely has those issues. Yeah... they "should" work, but then again... they aren't legos. There always seems to be a bit of fine tuning/fitting involved and some components just don't play well together no matter how much they "should". YMMV
 
The S&W 15-22 is fine for the kids when they're small as it's light weight. But, as they grow, they should get used to the weight of the real thing. The 15-22 is great for training and plinking, but few parts are interchangeable with an AR15. :(
 
I was having the same problem with my dedicated 22LR upper, and yah the problem was the feed ramp had a little lip and rounds kept getting hung up. I used a jeweler's file from harbor freight and a bit of 800 grit emory cloth and that fixed all my issues, except for duds in cheap 22 ammo!
Hey man, hope that thing works well for you!
 
The S&W 15-22 is fine for the kids when they're small as it's light weight. But, as they grow, they should get used to the weight of the real thing. The 15-22 is great for training and plinking, but few parts are interchangeable with an AR15. :(
They make a fine gun for speed steel matches too. I've used my highly modded 15-22 to great effect in said matches.
 
Did you get the black rubber bolt assist from cmmg? It does assist in reliability. Also may look into the redi mag adapter to use m&p 22 mags they are the best .22lr out there.

 
Did you get the black rubber bolt assist from cmmg? It does assist in reliability. Also may look into the redi mag adapter to use m&p 22 mags they are the best .22lr out there.
That's very subjective. Kind of the difference in saying, "my mag works flawlessly" and "my mag works MORE flawlessly.... if you buy the $50 adapter for it". KWIM?

The more parts involved increases the potential points of failure, IMHO. For someone that wants to share mags between platforms I think it's a no brainer, but I don't really see the point into running a conversion on a conversion to use an adapater to run mags that were not intended to run on that platform.

Just sayin..... :s0155:
 
I've never used one, but I hear great things about the quiet collar. From my experience... bolt bounce seems be the core of a lot of the reliability issues, especially when rapid firing. The bolt weight resolves that, but from what I hear... the quiet collar not only works to quiet and reduce wear, but does nearly as well eliminating bolt bounce... without requiring a weight.

I've considered it for the drop ins (already have weights for the dedicated). It's pretty spendy, but cheaper than the weights. Maybe still worth it, but I don't know if, overall, it's all that necessary on the drop ins. For me, I don't require the same amount of reliability from the drop in's as a dedicated and so far... bolt bounce hasn't been an issue for me. I don't rapid fire much and the drop in seems to like and runs well on what I'm feeding it.

I'm aware the drop ins take more abuse, but so far, I haven't had the need for any replacement parts and haven't noticed excessive wear. IOW, I'm still waiting for the recoil shock to break the back plate weld and fall off. 🤪

Food for thought though on an alternate path to resolve FTE/FTC/double feed issues... if present.
 
Re 15-22 it's a reliable option but note that it feels like a plastic toy which I really don't like. You can put a binary trigger on it though which is the only reason I keep mine. Rate of fire is a little over an m-60.
 
Actually, the problem is the feed ramp sucks when inspected closely. There's a small gap bw the feed ramp and the chamber, and relatively soft .22 lr ammo hits the edge of the chamber and grabs. The only fix I can imagine working is taking a 1/16th to a 1/32 off of the back side of the barrel collar. Reminds me sone used deals aren't good deals.

I guess I might splurge and grab barrel / collar combo if I can find one on sale for the holidays. Honestly, the Spikes Govt profile barrel I have seems heaver than necessary for the round.


Thanks for the tip on polishing and not going overboard. I knew I kept those 1200 grit sheets of sandpaper for a reason. Next project.
Flitz is a great polishing compound. Jewler /mechanic grade
 
No more FTF. A few duds but it was cheap mixed ammo. Accuracy seems pretty good but information on that is limited bc I test fired at an indoor 50' range. Once I got scope zeroed made a ragged hole except when I wasn't doing my job.
 

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