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forever4
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Posted: 2/12/2011 2:50:50 PM
[Last Edit: 2/28/2011 8:15:17 PM by forever4]
If you are like me, you want your firearm to be 100%. Sure, we can get a dud round with .22, but I want the gun to feed and eject like it should. My rifle seemed to be running pretty good but then every mag one or two rounds would fail to feel properly. These would jam at an angle as they lifted up off the magazine and tried to swing into the chamber. You know the routine, drop the mag, clear the round, re-insert the mag, chamber the next round, start shooting again. Lets be honest here, we shoot .22 ARs to BURN ammo, not do the single shot rifle thing. That is for bolt guns!

Two common complaints with all firearms and especially .22 AR's are failure to feed ( Here called FTF) and failure to extract (Here called FTE) We could break these down further into sub-categories but lets keep this quick and easy today. Also, both of these conditions do have some overlapping causes too, so I will just go over the steps to deal with both. I won't get into magazines here. Let's face it, with the mags we are currently using on .22 AR's we aren't going to be dealing with making adjustments to feed lips, etc.

On your new dedicated upper you want smooth parts. I am talking smooth like shiny and slick. We want that round to have an easy, unobstructed pathway up from the magazine (at a slanted angle), up against the feed ramp and then up and around into the chamber. Next, its going to fire, the brass will expand and then contract, and then its going to be pulled out and pitched aside. Our firearm was designed to do this and do it very quickly. Its like a beautiful dancer doing all these moves in perfect time. If we add any excessive friction to this we are going to have problems. Stop and think about this process in slow motion, one step at a time and picture this round rubbing against all these un-lubricated parts

Here are some simple, DIY steps you can do that will make any firearm run better.

Lets do the chamber first. This area has a lot of metal moving across it and oiling it is out of the question. So, make it slick. Slick here does NOT mean it has to look like chrome. What we are looking for is a smoother surface. All machined areas will have marks where the metal was cut. Small marks are NOT a problem as long as the area is smooth. We don't want to remove metal here as it could make the chamber too large. But, we do want it clean and smooth. On their site CMMG will tell you to take a chamber brush and chuck it in a cordless drill. Then, spin that brush in that chamber until the brush gets warm. I do with with a little Hoppe's #9 to clean things up after a big day at the range. As I spin the brush I am moving it in and out and letting it smooth out the area. I don't want any ridges or rough spots that can grip on the casing or the nose of the bullet. I once had a .22 Brand "X" conversion that had a plated finish that got into the chamber. I actually had to take some 400 and 600 grit emery cloth (sand paper) with a touch of thin oil on it and lightly spin that in the chamber until it was smooth. It worked great and saved a good unit from being sold due to its unreliable operation. This is NOT something you would normally do as you can enlarge the chamber and cause other problems. This was an extreme case.

Tools for cleaning the chamber: Note a brass bore bush mounted to a cordless drill motor. I dip this in Hoppe's 9 to clean the chamber. A little light oil if you are smoothing it up. CMMG says run the brush until its warm on their forum. As you are "buzzing" the chamber I like to move that brush in and out as it spins. Many recommend you do this after every other, or every, range session. It really depends on how much you shoot and the ammo. There are days when my rifle shoots many hundreds of rounds. I definitely want to buzz her out after that.



Brush in chamber. Remember, its only the chamber area that needs the polishing job. Some machining marks are normal from the reamer that cut the chamber. We just want to smooth off the rough edges. We don't need to go in so far as to hit the rifling. That will be taken care of during normal cleaning.



Once the chamber is nice and smooth lets work on the next common feeding area, the feed ramp. That is the sloped part where the round coming out of the magazine first contacts and gets pushed up into the chamber. Any roughness here will results in FTF, jamming, etc. Its amazing how little roughness here can really screw up the dance. Here we will use a Dremel type tool. Do NOT use a grinding wheel or sanding wheel! The angle on the feed ram is critical and any changes to it can give some nasty bad results. What we are trying to do is make is slick and smooth. We are going to use one of those little white soft polishing wheels on this. To do this you need some polishing compound that is made to polish steel. This will be listed on the compound. Pay attention to this as there are four to six different compounds you can buy, each for a different material. You can get these many places. Sears, Tractor Supply, etc.

Polishing supplies:




Put on your safety glasses ! (OK lawyers, there you are!) Chuck up your white cloth polishing wheel. Spin 'er up and apply some compound to the wheel until the wheel is the same color as the compound. Now, using a light back-and-forth motion proceed to polish the feed ramp. After a bit of work is will begin to look like its chrome plated. GOOD! This is what we are looking for. Keep polishing until that thing looks like a chrome piece off a show car. It may have a few smooth ridges or lumps on it from the manufacturing process. Don't worry, its the surface we are concerned with. As long as you can put a shine on it you should be OK. We do NOT want to try to use a grinder to take those out. Doing so may well change the angle on the ramp. This will cause a new set of problems that will be difficult if not impossible for you to fix.

So, make is smooth and shiny and it will run better. I have had to do this on many firearms over the years. It has saved me many headaches and solved many feeding and extracting problems. There is a lot more to know in these areas but for simple .22 these two things will solve a majority of our issues. You could send it back in, or you could try doing these things yourself first. I think its a fun hobby to "master" your firearm and fix it yourself.

CMMG recommends you DON'T take the sleeve and bolt apart as they can be damaged. As you can see in the pictures its a simple matter to use a plastic tie wrap (or other method) to hold the bolt to the rear out of the way.

Bolt tied back with a plastic tie:



Now, using the proper polishing compound make it shine. Here again, a few machining marks may still be left, that is OK, but make it shine:



Several others have added some compounds they use. Just remember you want to POLISH the parts. Don't use an abrasive compound made to clean up rusty metal or you will take material off that could damage the parts. We want to polish them, not change their size or shape.

On various firearms I have used the same tools and techniques to smooth any parts that were rougher than I thought they should be. Hammers, guide rails, any parts that rub together. In a .22 firearm that uses blow-back action friction is your enemy as it will keep the bolt from fully cycling and cocking the hammer. Ammo does also matter and low power ammo can also cause this, but this is only dealing with making everything smooth and slick.

If you have any questions, just ask. Several have added tips and suggested products. Just remember, smoother is better!





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shadowcop
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Posted: 2/12/2011 3:25:48 PM
Nice tips and write up.
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Posted: 2/13/2011 10:07:01 AM
[Last Edit: 9/15/2011 5:23:13 PM by SpecOps-13]
forever4: I know the effort that you put into the work and this thread, Thank You. With what you've done,
this upper will be around for a long, long time. It's a Riot to shoot it now, isn't it ??? The work you did is
the kind of stuff you'd expect if the factory had a custom shop. It's great that you could do it yourself...
There's gotta be somebody here that would appreciated a tutorial some day you have time...
John edited in the tutorial and it's quite a fine job too.
Dave in Florida
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forever4
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Posted: 2/13/2011 10:48:29 AM
Back in the old days the factory would do all this hand work. Problem is increasing labor costs it made things so expensive that people could not afford them. So, the factory does the best it can to maintain a price that people can afford. This means lots of people can afford things that would have been out of their reach not too many years back.

Look at the CMMG .22 uppers. It amazes me that they can produce such a nice product and still be able to price it where we can all afford one. But, the other side of that is they can't put a ton of custom hand work into each and every one at that price. So a manufacturer has to walk a fine line between making it as good as possible while keeping the price affordable. It takes some great engineering to design a product that is massed produced yet still can function well. Look at Compass Lake Engineering for example. They produce wonderful, beautiful products but how many of us can afford $1k or more for just a range plinking upper? CMMG on the other hand can sell us a complete upper for $350. Its not fair to try to directly compare the two, they are in two different classes, and price ranges!. But, if a shooter is willing to take some time and learn a few things they can do work in their home shop to make their firearms much better. They can save hundreds of dollars plus have the satisfaction of doing it themselves. Personally I enjoy the challenge and take some pride in what I can do. I think many people might be surprised by just how much they can do themselves with not much expense or effort.

As I read threads here and on other sites I see a lot of fine work being done at home by some gifted and skillful shooters. People making their own stocks, magazines, and more. Many people may think they need a lot of expensive machinery and skills. That is not always the case. A lot of what is being done doesn't require a big investment at all. What it does require is an interest, some time, and some basic tools. Its a great hobby and rewards us with the personal satisfaction of what we can accomplish. After all, sitting around in the work shop in the evening with the dog and the History channel while we polish or sand our latest creation is a pretty nice way to spend an evening. Heck, we might even pop open our favorite chilled beverage while we are at it. Life is good!
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scavenger16
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Posted: 2/13/2011 12:15:52 PM
I did exactly what forever4 said and then took 7 mags out in my backyard and every one of them fired flawlessly. I would like to thank you for saving me money and headaches, as I was going to order the stainless biolt and collar on Mon.

I thought that is what would be needed to solve my problems, so again thank you.
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forever4
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Posted: 2/13/2011 12:22:00 PM
Originally Posted By scavenger16:
I did exactly what forever4 said and then took 7 mags out in my backyard and every one of them fired flawlessly. I would like to thank you for saving me money and headaches, as I was going to order the stainless biolt and collar on Mon.

I thought that is what would be needed to solve my problems, so again thank you.
scavenger16


Thanks for sharing. Isn't it nice when we can solve our own problems, and save money doing it!
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ImpacTT
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Posted: 2/13/2011 12:24:25 PM
[Last Edit: 2/13/2011 12:24:54 PM by ImpacTT]
good stuff, yes please add some pictures and step by step ( especially the chamber part). thanks !
GlockA-Molee
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Posted: 2/13/2011 4:51:08 PM
Sticky!
SecondAmend
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Posted: 2/13/2011 6:52:59 PM
Thanks for the compilation.

There's also an extensive list of suggestions directed to mainly full auto operation issues (anti-bounce weight, ball detent, and such) currently on the Subguns.com website, NFA discussion forum. I would think that some of the suggestions apply to semi auto operation as well.

Not legal advice, MHO, YMMV, etc.
CMMG
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Posted: 2/13/2011 7:18:55 PM
Thanks for the great write up! You nailed it. The chamber, and it being smooth, is key to proper feed and proper ejection. Mass production brings its challenges as you have pointed out. We do spend a significant amount of time on the ramp angle, radius to chamber and actual chamber to make feeding as reliable as possible. There are limitations to what we are able to do and still crank out the volume at an affordable price.

What you have written is spot on. One point I would like to add, if working with a CMMG kit, do not remove chamber adapter from frame when polishing surfaces. It is possible to do everything you have described without removing the adapter. Nearly all returned kits have deformed, out of spec frames. This is especially the case with parkerized kits. The SST are much stronger and are not bent near as easily.

Again, fantastic write up. This is my favorite forum on ARF go figure. These kinds of threads make my day.
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rman43
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Posted: 2/13/2011 7:54:13 PM
Great write-up forever4! Thanks for sharing the info with us. Pictures would be nice. Some of are somewhat "technically challenged".
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sanman28
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Posted: 2/13/2011 9:08:59 PM
So.....ive been suffering from this problem for a while now. Ive trimmed about a 1/2 inch off my recoil spring and changed the lower springs to low power units. It seems to feed everything but CCI subsonic ammo fine.......but CCI subsonic is the only ammo I want to shoot. Its a suppressed 5.5" SBR and anything other than subs make some noise. So, have you run into issues with different ammos or are you just shooting the bulk stuff all the time?
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Posted: 2/13/2011 9:41:06 PM
[Last Edit: 2/13/2011 9:42:08 PM by forever4]
I am glad this can help people. I will post this step-by-step with pictures, hopefully tomorrow. After weeks of snow, ice, and much below normal temperatures we had warm weather show up today and I had to get busy and get some work down here at the house. I cleaned up my to-do list so tomorrow when I get back from the range enjoying my perfect CMMG .22 AR I will get out the camera and get this posted.

I understand the frustration of having any machine that doesn't work just right. I spent my working career solving problems and trying to make things work right. Its nice to be able to apply some of those lessons to our favorite hobby. I am happy if I can help anybody here in any way. I have learned a lot here myself and really enjoy the sharing of ideas here, its a great asset to us all.
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itchytriggerfinger
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Posted: 2/13/2011 9:45:52 PM
pics please

i would love to get a little more reliability out of my 22
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forever4
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Posted: 2/13/2011 9:58:35 PM
Originally Posted By sanman28:
So.....ive been suffering from this problem for a while now. Ive trimmed about a 1/2 inch off my recoil spring and changed the lower springs to low power units. It seems to feed everything but CCI subsonic ammo fine.......but CCI subsonic is the only ammo I want to shoot. Its a suppressed 5.5" SBR and anything other than subs make some noise. So, have you run into issues with different ammos or are you just shooting the bulk stuff all the time?


I run about eight different ammo brands in my .22 uppers, but not any subsonic stuff. In the past I have tried it just to see what it would do but its low power and didn't like to cycle the action fully. Due to cost concerns I mostly shoot Federal Bulk in this type rifle. Due to this I never spent much time trying to make it work with the subs. Other people have posted about their suppressed firearms and they will know more about those and the ammo to use than I would.

Whatever you are shooting polishing up all the parts will help as it reduces friction. I had a "Brand S" conversion that gave me fits because it drug across the hammer as the bolt came back. The fix for that was careful shaping and polishing of the hammer and the bottom of the bolt. That may, or may not, help with the lower power ammo as it will help reduce the effort that is needed to push the bolt back and fully cycle the hammer back. It certainly wouldn't hurt anything to try it.
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shadowcop
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Posted: 2/13/2011 10:15:40 PM
Originally Posted By sanman28:
So.....ive been suffering from this problem for a while now. Ive trimmed about a 1/2 inch off my recoil spring and changed the lower springs to low power units. It seems to feed everything but CCI subsonic ammo fine.......but CCI subsonic is the only ammo I want to shoot. Its a suppressed 5.5" SBR and anything other than subs make some noise. So, have you run into issues with different ammos or are you just shooting the bulk stuff all the time?


I've not had to change anything on my 5.5" It will even run Remington Subs until the ramp gets gummed up.
Something else is going on. I run the same CMMG kit in the 5.5" as I do in the 16".

It is a CMMG Kit?
Dave

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Posted: 2/13/2011 10:30:06 PM
[Last Edit: 9/15/2011 5:24:31 PM by SpecOps-13]
This is One Hot Thread...If it doesn't get sticky'd we need to preserve the information somehow.
It'll help people out for years to come... Especially with what forever4 and others will add to it...
You've already missed what just happened, Forever...... The Green has become Red, it's running down your face and into your eyes and the Green Laser is now shining out the back of your head.....
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kdoggy
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Posted: 2/14/2011 8:59:17 AM
I'm about to head to the store now to get some polishing compound so I can give this a try.

I've had a bit of feeding issues but I haven't really had time to iron out the issues with my CMMG upper.
happyal
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Posted: 2/14/2011 9:03:19 AM
Hello,

I have already done this on my Spikes and it's running great, just one quick question, do you need to polish up the feed ramp every so often or is it a do once thing?
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Posted: 2/14/2011 9:42:49 AM
Yep, nice tips.

I want pics too!
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forever4
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Posted: 2/14/2011 9:57:30 AM
Originally Posted By happyal:
Hello,

I have already done this on my Spikes and it's running great, just one quick question, do you need to polish up the feed ramp every so often or is it a do once thing?


The answer is: It never hurts. Depending on ammo and use you can get a little buildup on some. It varies from firearm to firearm depending on how smooth the ramp and the chamber were machined, the ammo, how clean you keep it, etc. So, since it only takes a couple of minutes its not a bad idea to just touch them up once in awhile. Just keep an eye on these parts and see how they are doing.

I have had some ammo that started leading up the firearm after only 400 rounds. There are days at the range, especially when I am out with friends who also like to shoot my firearms, that I have lead build-up while we were shooting. I am not one of those people who will tell you not to clean your gun each time its out. The chamber area in particular needs attention on blow-back firearms.
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shadowcop
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Posted: 2/14/2011 10:05:56 AM
I usually buzz my chambers every other range trip. The lead and gunk will build up. The chamber will just get smoother.
Dave N.
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forever4
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Posted: 2/14/2011 10:14:01 AM
Originally Posted By shadowcop:
I usually buzz my chambers every other range trip. The lead and gunk will build up. The chamber will just get smoother.
Dave N.


+1

You are exactly right when you say, "The chamber will just get smoother". This is part of the reason that a good firearm will actually improve with age. Its part of the "breaking in" process that all firearms and machines need. Parts will wear off the rough edges and work better. But, we do need to get the bad stuff out. Look at all that gunk your .22 ammo leaves behind. That and the lead build up needs to be cleaned out.
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kdoggy
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Posted: 2/14/2011 1:21:23 PM
[Last Edit: 2/14/2011 1:22:50 PM by kdoggy]
I just buzzed my chamber and polished my feed ramp until it looked like a mirror.

I live in the city so I can't exact test my gun here but I loaded some of my magazines and make sure my rifle was on safety, went down in my basement and aimed into my plate carrier (it's got plates) and cycled threw 4 fully loaded magazines, manually with my charging handle and had ZERO failers to fully feed and extract.

Granted this is not live fire BUT I was unable to do this before following the above tips. I knew about chamber buzzing but I never thought to polish the ramp which makes me feel stupid because we have been doing this to our aluminum framed 1911's for years to fix the very same problem!

Heading to the range around 6:00 p.m. to give it a try!
sanman28
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Posted: 2/14/2011 3:30:13 PM
Ive trimmed almost a 1/2" off my spring and went to the low power JP springs. It feeds plated and bulk ammo fine. CCI sub are another story. Still does not like those.....and they are super quiet so I really like em. Im going to re-buzz my chamber and polish my ramp and see what happenes.
adam731432
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Posted: 2/14/2011 5:35:14 PM
[Last Edit: 2/14/2011 5:35:58 PM by adam731432]
I don't feel safe using 400 grit sandpaper in my CMMG chamber as it is already in spec and rounds easily drop in and out . You could easily take away another thousandth (.001) very quickly. Some chambers may need it but this could cause excess blow by and dirty cases in others.

I might try some Remington 40x bore cleaner/JB bore paste the next time I buzz my chamber or some mothers/flitz polish on a .22 bore more with patch around it for a tighter fit.
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