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FN SCAR - Lower rail screw torque?
9/17/2011 3:43:49 PM
I couldn't find the torque spec for the lower rail screw that holds the rail to the barrel. Does anyone know the correct value? It is a similar T-25 Torx screw as the 6 that hold the barrel to the receiver, and it also bolts into the barrel extension (same as the 4 rear barrel screws) but FN used some threadlocker.
I had to remove the flash suppressor to check something and my lined barrel vise jaws wouldn't hold the pencil barrel properly, so I took off the lower rail to grip the thicker portion of the barrel in that area.
I had to remove the flash suppressor to check something and my lined barrel vise jaws wouldn't hold the pencil barrel properly, so I took off the lower rail to grip the thicker portion of the barrel in that area.
9/17/2011 7:31:33 PM
It appears to be a 10-32 Torx flat-head screw, probably stainless steel due to the lack of attraction to a magnet. Just snooping around Google, 32 in-lb seems to be like a recommended torque value. I guess I could use blue threadlocker, torque to 32 in-lb, and see if it comes loose. I have a Tangodown SCAR panel to hold it in case it backs out.
9/18/2011 1:26:13 PM
You took the entire barrel off to remove the muzzle brake?
That's like taking off the front axle to change the brake pads.
That's like taking off the front axle to change the brake pads.
9/18/2011 3:19:55 PM
Originally Posted By detacbob:
You took the entire barrel off to remove the muzzle brake?
That's like taking off the front axle to change the brake pads.
You took the entire barrel off to remove the muzzle brake?
That's like taking off the front axle to change the brake pads.
I couldn't find a set of barrel vise jaws that would hold the pencil barrel. The barrel and lower rail was already removed for me to torch out the stuck case
9/24/2011 4:46:25 PM
I started at 32 in-lb and thought it was rather loose. I decided to go to 62 in-lb just like the other barrel screws. I have to say that the quick-change barrel design isn't perfect, but it sure beats having to use a bench vise and armorer's block to remove the barrel.
9/25/2011 7:06:21 PM
Originally Posted By metroplex:
I started at 32 in-lb and thought it was rather loose. I decided to go to 62 in-lb just like the other barrel screws. I have to say that the quick-change barrel design isn't perfect, but it sure beats having to use a bench vise and armorer's block to remove the barrel.
I started at 32 in-lb and thought it was rather loose. I decided to go to 62 in-lb just like the other barrel screws. I have to say that the quick-change barrel design isn't perfect, but it sure beats having to use a bench vise and armorer's block to remove the barrel.
Metroplex, what isn't perfect about the quick change design? Just would like to know what you have found......
