I was able to get mine loose by sitting on the couch with the rifle between my knees, butt plate on the floor and loosen the flash hider with a 3/4" end wrench.
...you should not ever use a vice unless you can grip the reciever by the trunion area "only"...ie ...up front...you can easily deform the reciever otherwise...Oregonian said:Putting the receiver in the vice seems like it could put too much pressure on the base of the barrel.
...take a foot long (or longer) steel rod and run it through the vents of the flash suppressor to give you some leverage...use something like Breakfree CLP as a penetrant and lubricant and apply heat...don't burn off the CLP...ullie said:...you should not ever use a vice unless you can grip the reciever by the trunion area "only"...ie ...up front...you can easily deform the reciever otherwise...Oregonian said:Putting the receiver in the vice seems like it could put too much pressure on the base of the barrel.
...if your flash suppressor is stubborn... use some penetrant like WD 40...or even Breakfree CLP...let soak into the treads and then heat it up a little...it should come off...if not...use two tight fitting wrenches...one on the suppressor flats and the other on the barrel flats to counteract the force applied to the flash suppressor flats...
...torque down the new flash suppressor to about 15-20 foot pounds...nice and snug and then about another 1/8 to a 1/4 of a turn if using a crush washer...