I picked up a like new Colt SP1 upper recently (slab side, now forward assist) that was neutered during the ban years by cutting off the bayo lug and cutting the barrel behind the threads and FH shoulder. Can this be threaded without having the barrel turned? or is the diamete too large for the die?

Currently it has a Smith brake on it with 4 set screws, nice unit but incredibly LOUD

Jeff

The diameter is around 0.550", IIRC and you need the diameter to be 0.498", so some lathe turning is required.

Would it be better to have the threads lathe turned as long as the diameter requires turning? Or should I just have a Cav Comp. reamed to the barrel diameter and install with set screws? Or maybe I should have it cut to 16" for an SP1 Dissy and have the Cav Comp permanently installed?

Jeff

Quoted: Would it be better to have the threads lathe turned as long as the diameter requires turning? Or should I just have a Cav Comp. reamed to the barrel diameter and install with set screws? Or maybe I should have it cut to 16" for an SP1 Dissy and have the Cav Comp permanently installed? Jeff

If the machine is capable of cutting those threads, I'd cut them on the machine.  My lathe isn't thread capable, so I made a threading adapter to keep the die square to the bore and use a die.  I turn them down to 0.498", then spin on the die by hand.  I have all the components to make my machine thread capable, but it means a total tear down - a good winter project.

Do you do this work for other people? I saw a thread recently with some SP1 Dissy's and really liked the idea, being that this barrel has lost some length to begin with I wouldnt feel bad about having it whacked.

Jeff

Quoted: Do you do this work for other people?

Nope.  First, my machine isn't tight enough to trust it on anybody else's equipment.

Second - liablility.  That should speak for itself.

fair enough Mr. Mongo, I wasnt sure if you were strictly a hobbyist or did side work smithing for people.

We had a great machine shop here in little Cuba, NY but the guy couldnt make it (NY taxes suck), he knew gunsmithing quite well, had some kick ass CNC equipment, was very reasonable and one hell of a nice guy. I think he moved backl to PA, never could figure out why he moved here in the first place

Jeff

Send it to these guys-->   www.adcofirearms.com/

They can cut/thread/install muzzle devices  , whatever.
Their prices are very reasonable too.

I do threading on lightweight barrels as well.
I came up with a slick step-up spacer that threads on to the barrel to give a more finished look and better support the muzzle device that you tighten against it.

Pictured is a BM lightweight that is about 0.550" before threading:



Fresh parkerizing makes every barrel look this good...

Randall Rausch
www.ar15barrels.com

This one's threaded without any additional shoulder.  A crush washer grabs the barrel shoulder nicely and makes for a smooth transition to the FH.

Send it to joeblack, or adco.  Joe is a couple hr closer, and we also have Johnny McEldoo here also that does threads on the side, he work in Tool & Die also.  All 3 are here in Ohio.

Mongo,

You read my mind I was thinking of the crush washer in my parts box as opposed to the additional threaded shoulder.

I do have a friend that chambers and threads his own benchrest barrels, what are the dimensions you used for the dissy? If he can chamber and thread bolt guns barrels he can probably do this.

Jeff

Quoted: This one's threaded without any additional shoulder.  A crush washer grabs the barrel shoulder nicely and makes for a smooth transition to the FH.

Don't I get a brownie point for cool factor?
How about 'Doing it right'???

Randall

Quoted: Quoted: This one's threaded without any additional shoulder.  A crush washer grabs the barrel shoulder nicely and makes for a smooth transition to the FH. Don't I get a brownie point for cool factor? How about 'Doing it right'??? Randall

i'll give ya +1, atta boy. i like what you have going for the skinny barrels. i may send you one of mine.

Quoted: Quoted: This one's threaded without any additional shoulder.  A crush washer grabs the barrel shoulder nicely and makes for a smooth transition to the FH. Don't I get a brownie point for cool factor? How about 'Doing it right'??? Randall

Yours is a good concept and I like it.  I'm just showing what is possible, for the minimalists out there.  Is there a "right way"?  

Randall,

You get 2 brownie points That really is a great idea and beautiful work, I certainly dont minimize your effort.

As mongo ststes, I am exploring options and would like to have work done locally if I can and the crush washer would seem to work emminently well for this application.

I have to see what my benchrest buddy has to say about it, if he's not comfortable with the project (which I cant imagine, he designs his own chamber reamers and builds up all of his barrels from blanks and took 2nd place 2 years ago at super shoot so he knows what hes about with a latthe), if he says yes then here it stays, if not I'll farm it out.

I have to say though, I was shooting this upper last night and kind of like the bare muzzle on the pencil barrel, it certainly doesnt suffer from extreme muzzle climb so a muzzle device is not a necessary item, more cosmetic than anything, if there werent 4 dimples for the Smith brake I would be tempted to leave it bare and crowned.

Thanks for your imput guys, always a pleasure

Jeff

Quoted: I have to see what my benchrest buddy has to say about it, if he's not comfortable with the project (which I cant imagine, he designs his own chamber reamers and builds up all of his barrels from blanks

If he can fit a barrel to an action, muzzle threading is child's play.
Tell your buddy to make the major diameter about 0.497" before he single point threads.
If he has thread micrometers, stop at 0.474" and he will be right where you want to be on thread fit.
Thread length from crown to the torque shoulder is about 0.6" to 0.625" max.

Randall

Quoted: I do threading on lightweight barrels as well. I came up with a slick step-up spacer that threads on to the barrel to give a more finished look and better support the muzzle device that you tighten against it.

And it works REALLY well.  I had Randall do this for my LW barrel and it came out fantastic.  It even shoots better (thanks to the new crown) than it did prior to the threading.

Quoted: And it works REALLY well.  I had Randall do this for my LW barrel and it came out fantastic.  It even shoots better (thanks to the new crown) than it did prior to the threading.

Forest-

That might actually be YOUR barrel in the picture above.
Most of these that I have done do NOT have the flats machined.
I remember you wanting a way to easily dis-assemble.
Maybe it was someone elses though... I have worked on too many barrels to try and remember every one.

Randall