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Posted: 10/29/2013 6:07:54 PM EDT
| I have a question on threading a barrel. I have a Chiappa M4-22 upper that I removed the set screw bird cage and threaded the barrel with 1/2 28 threads. I bought a DPMS sleeve moderator and attempted to screw it on, but it will not start the threads. What am I doing wrong? |
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You don't have another flash hider you can try do ya? Was it a split die? If it is, you can try cranking it down in the holder a little bit more to make it cut a little more.
Have you checked the nominal diameter? If it's more than .500 you might have a problem. I'm not sure if a die will fix that or not. |
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Besides what's already been mentioned, you didn't chamfer the end, which means the thread starts cold and sharp, and even if it's the correct dimensions will be a bitch to find the right spot to get it started until you wear it in some.
Better yet, the paper-thin leaf at the leading edge may have been folded over some when you tried to install the new muzzle device, effectively closing off the end of the thread, which would need to be touched up with a needle file or similar tool. |
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Thanks guys for making me feel better. I already tried all of these. Measured it, but not with a mic before I started. I bought a second moderator from another company. Same issue. The dye is split, so I cranked it smaller to cut deeper threads. No help. Before I started I rounded the tip of the barrel with a half cut file to make it easier to start the dye. I also reversed screwed the moderator on a quarter thread before going the right way to try to catch the first thread. No help.
I know things like this normally come down to something stupid that I think I did right or believe I checked twice, but did it wrong twice. This one currently has me stumped... |
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Quoted:
Thanks guys for making me feel better. I already tried all of these. Measured it, but not with a mic before I started. I bought a second moderator from another company. Same issue. The dye is split, so I cranked it smaller to cut deeper threads. No help. Before I started I rounded the tip of the barrel with a half cut file to make it easier to start the dye. I also reversed screwed the moderator on a quarter thread before going the right way to try to catch the first thread. No help. I know things like this normally come down to something stupid that I think I did right or believe I checked twice, but did it wrong twice. This one currently has me stumped... Sounds like your OD (outside diameter) is oversized measure over the threads it should be close to .500 |
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DON'T PANIC. Take your die. There should be a screw on it to set the die, Screw the screw in to expand the die just 1/8 turn at a time. Use the side with the lead down. Slowly thread it on your barrel. Won't go on? open it up a little more, but don't go nuts here.
Once it will thread on your barrel. Make sure you are not cross threaded. Spin it all the way down. Now turn it over and use it that way. Oh YOU are doing this with your hand, and not in your Die handle. Turn your Die back to where the lead is down again See if your brake will fit. If not back the screw out a little. Rethread the barrel this time using your die handle, and the screw on the handle will close up the die. Go slow here, you want a good fit. Once you have a good fit turn the die over with the side non lead side down, then go all the way down. Should give you a flatter shoulder. T&D Maker, 30 years 
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I'm a machinist and I have one of the M4-22 upper and threaded the day I got it before a single shot.
The OD is .495 I threaded it on a lathe then chased it with a Die Make sure your die is 1/2-28 and that the muzzle device is too. Make sure one or the other is not LH Too me about 10mins to do the job including crowning the barrel and is so much nicer than the crappy set screwed break. |
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Ok, I got it installed. It measured .497 on the barrel end. I re-cut the threads by hand slowly backing the screw all the way out of the die. Then I used the screw on the handle to tighten it just a little more. At that point, the moderator screwed on. It is tight and does not screw on easily by hand. A wrench with light pressure is needed. I backed it off and checked for cross threading, there is none.
Thanks for everyone's help. I have threaded many items over the years and have never run into this type of issue. I would have expected this to take ten minutes also, but in the end it was about an hour. |
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