Threading Shotgun Barrel for Chokes

G

Gregory Gauvin

New member
Years back I purchased a Remington 870 Express, 18.5" barrel 12ga pump. This was long before they came around with their tactical lines of shotguns. The price was right.

I have my clay guns. This shotgun was strictly meant for home defense purposes, in which, when my grandmother's house was being routinely burglarized, came with me to spend several nights there. It is also the only gun in my gun room with 5 rounds of 00 Buck shots on the stock and an ammo belt of shells. I.E., aside from my carry pistol that is loaded, the shotgun is my go to gun.

It is a fixed cylinder bore barrel, had a 4 shot magazine tube. I added a 2 shot extension (yes, I had to dremel down those dimples), barrel clamp with front sling swivel and an ATI heat-shield.

Obviously, I essentially created Remington's later 870 Tactical line shotgun, only, they can't accommodate a heat-shield :) but do come threaded for Rem Chokes. Or at least, whatever their extended Rem choke is with the prongs.

I wanted to make this shotgun more versatile. Sure it breaks clays at 20 yards but is no good for any real clay shooting. I run a modified choke in my other shotguns for clays.

I just spoke with my gunsmith about having my cylinder bore barrel threaded for chokes. My smith has been around and knows guns like you know the sun is going to rise the next day. He had just finished unitizing my gas cylinder on my M14 and some trigger work...sighted in my Leupold Mk IV....3 rounds 1 hole. He's made firing pins for Type 14 Nambu pistols...he's a retired master gunsmith from Kimber.

Anyhow, despite what I read on the internet about shotgun barrels being able to be threaded for chokes, he told me this can not be done. Because the barrel is cylinder bore, it opens near the end, and couldn't be done. I would imagine remington's tactical shotguns with extended chokes are thin walled because they have to be reamed to be threaded thus having the choke extended. Nonetheless, has anyone ever attempted to thread a 18.5" 870 barrel for rem chokes? Can it be done?

I know I could just buy an aftermarket barrel. But, I'm not spending half the price of the shotgun on a barrel and have a barrel I never use sit and collect dust.
 
Brownell's sells a is special tool with which you can measure the thickness of the barrel. I think we were supposed to measure it at four points.
 
For Win-chokes it has to be .850 outside and you can do a Rem-choke at that but .875 is better . If you are .900 it wont be a problem. I have done a Rem-choke at .840 but it was paper thin at the muzzle and needed the choke installed at all times to keep from denting the edge.
 
I have the reamer, tap, and pilots from Brownells for Rem Choke.

My brother borrowed them because his 870 will not shoot straight.

But rather than put the barrel in his lathe, he clicked on a replacement barrel. I think a Hastings. Now it shoots straight.

Last month he sent a picture of him with the new barrel.

He still has my Remchoke reamer.
 

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I'm pretty sure it could be done. I picked up a brand new 870 probably 20 years ago with a 28" barrel dirt cheap. Walmart had lost the box and had a Wingmaster priced $50 less than the Express, but without the box. I had it cut down to 24", that would have been cylinder too, and threaded for Remington tubes. I've read of others doing it to the same barrel you have.

FWIW, I don't really think it is cost effective. For about the same money or less you can buy a 20 or 21" barrel that is already threaded from the factory. I would just as soon have the extra 1.5-2.5".

By choosing shells carefully you can do more with the cylinder tube than you may think. Shoot some patterns and you might be surprised.
 
There are thinwall chokes that can be installed. Briley in Houston is the 800# gorilla for that work. They've threaded some very thin barrels on some friends' old English double guns.
Otherwise, if there is enough material, Mike Orlen in MA can do the barrel work. You might call him; he gets great reviews on other sites and is fast and very reasonable on pricing.
 
With an 870 barrel cut back to 18.5 inches, I'd venture to say it is now thicker, at the muzzle, than it was before it was cut. Just measure the muzzle's bore, with a caliper, both inside and out. Subtract the ID from the OD, then divide by two to get the thickness, or if the calipers have a good knife edge to them, just measure the thickness, and it ought to be within a thou. That barrel ought to be pretty thick back at that length, due to the taper of the OD.
 
I measured my OD at .900" ID measured .725".

I gunsmith on ebay who does this work says it can be done, and has done several of them with no problems. I'm thinking...perhaps, my gunsmith doesn't own the reamer to do the job. It's an expensive tool and not something done frequently I suppose.
 
Doing the math there .900 - .725 = .0875".

That's about what I measured the wall thickness with my calipers. I got a reading of .0875 to .09". Kinda tricky to get precise measurement as the slightest angle of the calipers not perpendicular with the barrel with throw the reading off a few thous. Also, I'm inclined to believe the measurement differs the further you take the measurement in the bore. I tried my best to take the reading at the muzzle. I would imagine the walls thicken further back.

The finish on the barrel probably adds a thousandth or two, and most likely isn't uniform.
 
Is there anyone out there that will thread a 10 gauge for browning chokes? Every place I called directed me to briley, but they only do true chokes
 
I'm not knowledgeable enough to quote the necessary thickness for this job but I know someone who is and does a heck of a job.

Mike Orlen (a member of this forum) did a great job threading the barrel on my Franchi AL-48 which was cylinder bore to start. His work was quick, quality, and very reasonable on the price. My suggestion is to "Ask Mike".:)
 
Had my barrel threaded and plus 3 chokes for less than your ///// poly choke /// option and don't have a muzzle heavy shotgun like you get with a poly choke.

FWIW, the first shotgun I ever owned was a Mossberg bolt action with a poly choke from the factory.
 
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