Gunsmithing Can this be recrowned?

[nikonNUT]

Alright guys,
I done fucked up. I have a Tippmann M4-22 with a 7" barrel and running a DA mask on it tucked in a 9" handguard. Looks cool and the long handguard lets me run a clip on for hunting egg suckers and the like around the house at night. Downside is it is a PITA to get the suppressor off. Gotta pull the handguard and that screws up the colimnation of the thermal so normal post shooting procedure was to lock the bolt back and let it breathe for a couple hours before putting it in the safe (Several Eva-Drys in there but I digress). Pulled it apart for a deep clean and saw a bad thing...

So yeah... I fucked up! Question is this. I'm going to put a Wojtek .22 QD on it so I can pull the suppressor at will and to do this I need to whack about .030" off an inch off the crown as per Wojtek if the threads are more than .400" long I'll need a spacer (I'm at .4155") so I figger I'd have it shortened to .385". Do y'all think that is enough to clean it up or should I spring for a new barrel (cheap enough at $150.00) and a spacer ($12.00) and not look back? I have a good gunsmith that I think would do it for about $75.00 so I'm torn. The inside of the barrel looks ok so I am guessing that with the rifle sitting at an angle the moisture pooled to one side and didn't get in the barrel to add another data point (Should have stored it muzzle down but too late now). What say y'all? Lop and re-crown or new barrel. Not like it's a Vudoo or anything. I just want it to be minute of squirrel. Thanks in advance!

 

[Hecouldgoalltheway]

So....... how does it shoot? I'm not just busting your balls, I'm curious. Does that have any effect on accuracy?

 

[Trigger Monkey]

If you have some basic tools you can clean that up with a file, a brass screw, some valve lapping compound, and cold blue. If not then the gunsmith option might be your best bet but I think a whole new barrel is a bit extreme unless you just really want a new barrel for piece of mind.

 

[nikonNUT]

So....... how does it shoot? I'm not just busting your balls, I'm curious. Does that have any effect on accuracy

Seems ok. I'm going to throw it back together, test it sans suppressor, and report back. I want to say that new without a suppressor my best was .625" at 50 yards. At least I have a baseline.

 

[nikonNUT]

Just go back from the range. 26 degrees and a 6 mph left to right steady wind with some gusts. Ammo was CCI SV and it was giving me fits but that was due to my dumb ass . Anyways…

Obviously POA is off because I pulled the scope off but 7 of the shots seeem OK-ish. Drop the 2 that went wide ( I know. Cheater! I don't get to pick and choose) and it’s .721" wide x .872" high at 50 yards with a 7” barrel and cheap ammo aka minute of squirrel but What say y’all? Let it eat?

 

[BR7.62]

i dont see why it couldnt be cleaned up by crowning or even counterbored.

 

[Trigger Monkey]

Is that about what it was doing before?

 

[nikonNUT]

Is that about what it was doing before?

Best I can recall was .649” at 50. Dead calm and 90 degrees. That was MANY rounds ago.

 

[Trigger Monkey]

Ok, I'd go at it with a brass screw and valve lapping compound to clean up the muzzle and see if it improves. There's a ton of YT videos on it but it's pretty painless and leaves a decent looking crown for something like this.

 

[AllenOne1]

For $75 drop it at the gunsmith, have him cut it down and clean up the crown. Done! Assuming he can turn it around in a reasonable time frame that works for you.

If you start buying a brass screw, lapping compound, spacer and your time and labor you'll end up not that far from $75 for a fair job. Just pay the man. lol

 

[Trigger Monkey]

If you start buying a brass screw, lapping compound, spacer and your time and labor you'll end up

a little more knowledgeable than you were before. The screw, lapping compound, and spacer will run about $30 and take about 10 minutes to do but can you really put a price on gaining a new skill set...

 

[Sum Ting Wong]

If you’re going to put it in a lathe, just cut a new crown.

 

[nikonNUT]

If you’re going to put it in a lathe, just cut a new crown.

Any run-out concerns I should be aware off. We run Shar's 3-jaw scrolls so I'm thinking .003" is the best I'm going to get.

 

[Sum Ting Wong]

Indicating it in a four jaw to the bore would be ideal, but I think you’ll be just fine with the three in this case.

 

[prebancolt]

Take it back to 0.400" then put an 11 degree taper crown on it. You should be back to good bore.

 

[nikonNUT]

So my crown issue resolved itself. Tippmann (Legit customer service!) is sending me a new barrel under warranty and then I can play with crowning the old one.

 

[B y r o n]

So you pulled it apart for a deep clean but the photo is what you found. What does it look like after that deep clean?

 

[nikonNUT]

So you pulled it apart for a deep clean but the photo is what you found. What does it look like after that deep clean?

That photo is post scrubbing with a nylon brush and Hoppes No.9. It is not pretty.

 

[iceng]

i dont see why it couldnt be cleaned up by crowning or even counterbored.

This guy nailed it. Do that. Easy.

 

[nikonNUT]

Well, the new barrel is in and currently marinating in SOTARacha (Mobile1 synthetic grease cut with Mobile1 0w20 synthetic oil) to "help" with my previous issue. Taking the suppressor off will help more but I digress. The old barrel is a 3/4" straight taper so I'm going to take it to our other shop (has a lathe with a collet closer and a DRO) and face it then throw an 11 degree crown on it. Always good to have a spare, right?