Bolt action rifle muzzle brake installation: Installing a Surefire MB762SSAL/RE

May 27, 2013 Bill Marr Accessories, Gunsmithing 0

The business end of a Surefire brake on our 308 rifle.
The business end of a Surefire MB762SSAL/RE brake on our 308 rifle.

Bolt action rifle muzzle brake installation: Installing a Surefire MB762SSAL/RE

We decided to add a Surefire muzzle brake to our custom 308 Remington 700 lightweight tactical rifle we built in a previous article.  The Surefire MB762SSAL/RE muzzle brake  provides excellent reduction in muzzle flip as well as the ability to mount one of their suppressors.  The design of the brake requires that 2.15″ of the barrel behind the threads to be no more then .775″ in diameter to fit under the device.   For many bolt action rifles, this requires that the muzzle be turned down behind the threads.

We ensure our rifle is safe and empty and removed the barrel from the action.  The following documents the process we used to install our brake and is intended for information purposes only.

We ordered the following parts from Brownells:

All lathe work is conducted on a Grizzly gunsmith’s lathe.

The barrel is mounted into our lathe's spider. A crown saver protects the end of the live center from damaging the crown.
The barrel is mounted in our lathe’s spider. A crown saver protects the end of the live center from damaging the crown. Note: our barrel wasn’t long enough to use the outboard spider.
The machine set up gauge is used to level the high speed steel cutter to the centerline of the barrel.
The machine set up gauge is used to level the high speed steel cutter to the center line of the barrel.
The cut is made from the left to right. Since the barrel is tapered, cutting towards the headstock can possibly put the barrel out of alignment.
The cut is made from the left to right. Since the barrel is tapered, cutting towards the headstock can possibly push the barrel out of alignment.  The threaded portion of the muzzle will be .625″ long and .616″-.623″ in diameter.  The tenon behind it will be 2.145″ x .775″.
The finished cuts for the brake. The long tenon allows the brake to slide into postion, the short tenon will be threaded.
The finished cuts for the brake. The long tenon allows the brake to slide into position, the short tenon will be threaded.

NOTE: On this installation we did not cut the threads on the lathe- which would have been a better method.  Instead, we used the die and tail stock method.  This was done to show various methods one can use to accomplish the same results.  Current best practices would suggest single pointing the threads on the lathe.

A 5/8-24 die is held in a die holder in the tail stock and the lathe ways are lubricated with oil.
A 5/8-24 die is held in a die holder in the tail stock and the lathe’s ways are lubricated with oil.

 

The tail stock is pushed against the muzzle. The tailstock will not be locked in place. With light pressure applied to the tailstock, the "inching" button is pressed on the lathe and the cut is made.
The tail stock is pushed against the muzzle. The tail stock will not be locked in place. With light pressure applied to the tail stock, the “inching” button is pressed on the lathe and the cut is made.

 

The lathe is revered and the die removed. The threads are now aligned with the bore. Note: oil is on the camer lens.
The lathe is reversed and the die removed. The threads are now aligned with the bore. Note: please ignore the oil on the camera lens.

 

The threads were stopped short of the shoulder on the lathe. The die is removed from the tailstock die holder and placed in a die stock. The threads are completed to the shoulder.
The threads were stopped short of the shoulder on the lathe. The die is removed from the tail stock die holder and placed in a die stock. The threads are completed to the shoulder by hand.

 

The brake is test fitted.
The brake is test fitted. Critical: the bore must be checked to ensure that a fired projectile will not contact the brake.

 

Final indexing of the brake is accomplished with the supplied shims and thread locker. Alternatively, the shoulder can be cut to provie indexing.
Final indexing of the brake is accomplished with the supplied shims (.003″- .020″) and thread locker. Alternatively, the shoulder can be cut back to provide indexing.
The business end of a Surefire brake on our 308 rifle.
The business end of a Surefire brake on our 308 rifle after installation is complete.  Our barreled action was coated in Cerakote prior to final installation.

 

 

 

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