Captain1201
Plastic
- Joined
- Apr 18, 2020
I used a pipe thread cutter to remove a 1/2" long barrel shroud from in front of the front sight post of a Saiga 7.62 x 39mm Rifle barrel, in order to thread the end of the barrel for a muzzle device. The Saiga Rifles don't come with muzzle devices, and mine didn’t have threads pre-installed, so you have to thread the end of the barrel yourself.
The muzzle device calls for a 14 x 1LH thread. When I removed the barrel shroud, the tube cutter wheel did cut into the OD of the barrel slightly deeper than the depth of the shroud itself. The groove around the OD of the barrel is probably about the width of a dime.
The barrel diameter mics out as follows:
Barrel diameter =.565”
Diameter of the Tube Cutter Groove = .489”
I assume the pressures at the end of the barrel would be significantly less by the time the gases are expelled through the piston mechanism, etc. I also assume the muzzle device itself will provide quite a bit of additional strength when screwed down and completely covering the tube cutter groove. I’ll be using some Rockset to secure the muzzle device to the threads so the muzzle device doesn’t move.
But, in an effort to reinforce the barrel at the groove, I decided to fill the groove with an steel epoxy filler. I used JB Weld, "High Strength," which provides 5000 psi when cured, to fill the groove created by the tube cutter. With regard to a tube cutter causing any deformation of the ID of the barrel, the barrel has been slugged, and there was no deformation. In addition, the arbor used as a concentricity guide in the barrel when using the 14mm x 1mm die, rotated freely inside the barrel as the threads were being cut in the OD of the barrel.
The temperature range of the JB Weld is supposed to be around 500 degrees F, but if the barrel reaches that temperature in the groove area where the JB Weld is deposited, there will be a muzzle device that will be covering over the groove, and also reinforcing the barrel strength. The muzzle break is a pretty thick and a pretty substanstial piece of steel, around 2 ounces, and it seems that the combination of the JB Weld, and the addition of a muzzle break, should also reinforce the barrel in the area of the groove. Plus the gas pressures at the last .500" of the barrel should be relatively low by the time the remaining pressure in the barrel after the rifle is fired reaches the muzzle break area, since most of the pressure has been expelled or absorbed by the piston cycling.
Once the groove has been filled-in, the muzzle break is threaded onto the end of the barrel, and tightened down. I'm using Rocksett as a thread locker to keep the muzzle break from becoming loose from the concussion associated with repeatedly firing the rifle over time.
A photo of the unfilled groove and a photo of the groove filled with JB WELD "High Strength" are attached to this thread.
I realize it isn't desireable to have a .076" grrove around the periphery of the barrel, but it is what it is.
My question is, would I be better off not using the JB Weld, and just relying on the muzzle break to reinforce the end of the barrel, since it will be over the top of the groove. Or, does the addition of JB WELD help the integrity of the barrel where the groove exists by supporting the additional strength of the muzzle break.
The muzzle device calls for a 14 x 1LH thread. When I removed the barrel shroud, the tube cutter wheel did cut into the OD of the barrel slightly deeper than the depth of the shroud itself. The groove around the OD of the barrel is probably about the width of a dime.
The barrel diameter mics out as follows:
Barrel diameter =.565”
Diameter of the Tube Cutter Groove = .489”
I assume the pressures at the end of the barrel would be significantly less by the time the gases are expelled through the piston mechanism, etc. I also assume the muzzle device itself will provide quite a bit of additional strength when screwed down and completely covering the tube cutter groove. I’ll be using some Rockset to secure the muzzle device to the threads so the muzzle device doesn’t move.
But, in an effort to reinforce the barrel at the groove, I decided to fill the groove with an steel epoxy filler. I used JB Weld, "High Strength," which provides 5000 psi when cured, to fill the groove created by the tube cutter. With regard to a tube cutter causing any deformation of the ID of the barrel, the barrel has been slugged, and there was no deformation. In addition, the arbor used as a concentricity guide in the barrel when using the 14mm x 1mm die, rotated freely inside the barrel as the threads were being cut in the OD of the barrel.
The temperature range of the JB Weld is supposed to be around 500 degrees F, but if the barrel reaches that temperature in the groove area where the JB Weld is deposited, there will be a muzzle device that will be covering over the groove, and also reinforcing the barrel strength. The muzzle break is a pretty thick and a pretty substanstial piece of steel, around 2 ounces, and it seems that the combination of the JB Weld, and the addition of a muzzle break, should also reinforce the barrel in the area of the groove. Plus the gas pressures at the last .500" of the barrel should be relatively low by the time the remaining pressure in the barrel after the rifle is fired reaches the muzzle break area, since most of the pressure has been expelled or absorbed by the piston cycling.
Once the groove has been filled-in, the muzzle break is threaded onto the end of the barrel, and tightened down. I'm using Rocksett as a thread locker to keep the muzzle break from becoming loose from the concussion associated with repeatedly firing the rifle over time.
A photo of the unfilled groove and a photo of the groove filled with JB WELD "High Strength" are attached to this thread.
I realize it isn't desireable to have a .076" grrove around the periphery of the barrel, but it is what it is.
My question is, would I be better off not using the JB Weld, and just relying on the muzzle break to reinforce the end of the barrel, since it will be over the top of the groove. Or, does the addition of JB WELD help the integrity of the barrel where the groove exists by supporting the additional strength of the muzzle break.