Post by blurrededge on Apr 4, 2014 4:55:09 GMT -5
I've been collecting parts to build a tokarev upper for a few years now, and am finally getting around to doing it. Glad I stocked up on a few cases of surplus when I did, or I would not even bother at this point.
I started with a stainless .300 winmag factory takeoff barrel that I bought off gunbroker a few years ago for about $45. I've got it turned down to a 16.25" profile, and just got the barrel extension in the mail today. (.223 raw barrel on top that I used as a guide for the length and tennon threading).
I originally planned to thread the muzzle end 5/8x24tpi, so it's currently turned down to .625". I am planning on installing an FSB at the mid-length position with magpul handguards, and have been toying with the idea of either adding a slip over XM177 style muzzle device, or cutting the barrel to 12.5" and permanently installing one. I've read that due to the nature of the pistol/smg round that the surplus is, it doesn't bennefit a whole lot from an extra 4" of barrel past 13", and velocity kind of plateau's. Is that true? and would the shorter barrel length have a dramatic impact on the functioning of the short gas system? I'm hoping someone can chime in with experience or other thoughts before I decide to just chop solely because my wife wants a neo retro look to it. (I received clearance to fund this project out of the tax return because she thinks it's for her )
Close up of the tennon threads. It was my first time cutting threads on my lathe (not counting to practice run on some round stock) which I finished with a die just to make sure it was right. Extension threads on snug by hand.
Because the barrel was a light weight sporter profile, I left as much meat as possible at the chamber end, so the barrel was cut just after the original chambers shoulder, leaving the neck. I figured the reamer will still have plenty of bore to keep it centered and the end result will deffinetly cut past that anyway.
Chamber reamer rental and guages are on order, and I'll have a 3 day window to get it chambered. I plan to follow standard 5.56 ar barrel chambering protocol with regard to final fitting of the barrel extension and finishing the chamber to match the bolt, any extra advice would be appreciated.
Bolt is 5.45x39 from Ballistic Advantage, both it and the barrel extension are FailZero* NiB coated. Might be overkill since I'm paranoid about cleaning after corrosive ammo, but I figure I can use all the help I can get. Gas block is 17-4ph clamp on from VLTOR.
Areas where I can use some advice. Gas tube length, research here reveals:
So, when cutting a gas tube, I am assuming that you leave the flared end that goes into the gas key alone, and cut the other end to length, reusing the plug from the gas block end, crimping it back into the tube, (maybe with a dull pipe cutter?) and redrilling the gas hole and retaining pin hole...?
I may have to trim alittle more off the barrel to slide the gas block back further after comparing to this photo from here,
I haven't tackled the mag block options yet, I'd prefer the muscle memory of the standard AR mag release and have no problem milling the side of my PPs43 mags, but I may have to settle for one of the HeavyMetalGroup blocks with the side release... I don't see the flush mount adapter listed on the new site anywhere.
I started with a stainless .300 winmag factory takeoff barrel that I bought off gunbroker a few years ago for about $45. I've got it turned down to a 16.25" profile, and just got the barrel extension in the mail today. (.223 raw barrel on top that I used as a guide for the length and tennon threading).
I originally planned to thread the muzzle end 5/8x24tpi, so it's currently turned down to .625". I am planning on installing an FSB at the mid-length position with magpul handguards, and have been toying with the idea of either adding a slip over XM177 style muzzle device, or cutting the barrel to 12.5" and permanently installing one. I've read that due to the nature of the pistol/smg round that the surplus is, it doesn't bennefit a whole lot from an extra 4" of barrel past 13", and velocity kind of plateau's. Is that true? and would the shorter barrel length have a dramatic impact on the functioning of the short gas system? I'm hoping someone can chime in with experience or other thoughts before I decide to just chop solely because my wife wants a neo retro look to it. (I received clearance to fund this project out of the tax return because she thinks it's for her )
Close up of the tennon threads. It was my first time cutting threads on my lathe (not counting to practice run on some round stock) which I finished with a die just to make sure it was right. Extension threads on snug by hand.
Because the barrel was a light weight sporter profile, I left as much meat as possible at the chamber end, so the barrel was cut just after the original chambers shoulder, leaving the neck. I figured the reamer will still have plenty of bore to keep it centered and the end result will deffinetly cut past that anyway.
Chamber reamer rental and guages are on order, and I'll have a 3 day window to get it chambered. I plan to follow standard 5.56 ar barrel chambering protocol with regard to final fitting of the barrel extension and finishing the chamber to match the bolt, any extra advice would be appreciated.
Bolt is 5.45x39 from Ballistic Advantage, both it and the barrel extension are FailZero* NiB coated. Might be overkill since I'm paranoid about cleaning after corrosive ammo, but I figure I can use all the help I can get. Gas block is 17-4ph clamp on from VLTOR.
Areas where I can use some advice. Gas tube length, research here reveals:
Welcome to the site, cut a pistol gas system in half and go from there.
So, when cutting a gas tube, I am assuming that you leave the flared end that goes into the gas key alone, and cut the other end to length, reusing the plug from the gas block end, crimping it back into the tube, (maybe with a dull pipe cutter?) and redrilling the gas hole and retaining pin hole...?
I may have to trim alittle more off the barrel to slide the gas block back further after comparing to this photo from here,
I haven't tackled the mag block options yet, I'd prefer the muscle memory of the standard AR mag release and have no problem milling the side of my PPs43 mags, but I may have to settle for one of the HeavyMetalGroup blocks with the side release... I don't see the flush mount adapter listed on the new site anywhere.