I purchased a used AI AT308 on the exchange here that included a 6.5 Creedmor barrel. I can’t find the exact specifications in the owner’s manual. In searching the forums, it seems people quote the retaining screw for the muzzle brake in saying it’s a 4mm hex key and to tighten to 36in/lbs. I can’t find any mention of specs for the barrel retaining screw. I know people have lost a lot of accuracy without the proper torque. Thanks all.
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AI AT308 Barrel Change
- Thread starter mr2143
- Start date
Page 32 in your owners manual
10. QUICKLOC BARREL REMOVAL AND REPLACEMENT The AT308 Rifle features the Accuracy International QuickLoc® barrel system as standard. WARNING DO NOT REMOVE THE QUICKLOC BARREL SCREW. DO NOT TIGHTEN THE QUICKLOC BARREL SCREW WITH THE BARREL REMOVED.
To Remove the barrel:
Ensure weapon is safe to handle and unloaded.
Loosen the QuickLoc® barrel screw 2-3 turns - do not unscrew any further.
The barrel can now be unscrewed in a anti-clockwise direction. If the barrel will not unscrew by hand, a 3/4” or 19mm AF spanner can be used on the two flats machined into the barrel near the muzzle.
To Refit the barrel:
Ensure that the threads and mating surfaces of the barrel and action are clean, undamaged and free of debris. Screw the barrel into the action until the action mating face is securely in contact with the barrel flange - no gap should be visible.
Tighten the QuickLoc® barrel screw to 5.5Nm (49in/lbs).
Verify that the barrel is tight by trying to unscrew the barrel by hand, using no more than reasonable force. Headspace should always be checked after refitting barrels, see section 1.7.
WARNING - IF THE BARREL CAN BE ROTATED BY HAND AFTER TIGHTENING THE CLAMPING SCREW, RETIGHTEN THE BARREL AND BARREL CLAMPING SCREW AS DESCRIBED ABOVE. IF THIS DOES NOT PROPERLY SECURE THE BARREL, THE RIFLE MUST BE INSPECTED BY AN ACCURACY INTERNATIONAL QUALIFIED GUNSMITH OR ARMOURER. ENSURE THE LOCK RING IS IN PLACE AND IS SECURE. THIS CAN BE INSPECTED THROUGH THE EJECTION PORT. QUICKLOC BARREL SCREW (4mm AF HEX KEY) BARREL FLANGE ACTION MATING FACE N7 30.0 PRELIMINARY NOT CHECKED NOT RELEASED 1 2 20 50 100 1 1 3 TITLE DIM'N IN ORIGINAL (UNLESS (FOLDING) 4 (6) UNLESS OTHERWISE STATED, ALL TAPPED HOLE THREAD FORMS ARE (2) A RADIUS OR CHAMFER OF 0.2 (MAX) IS PERMITTED IN THE STATED) ESTIMATED 2:1 g mm AT, GENERAL ASSY AI-26677 OF 5 6 7 INTERNATIONAL LIMITED. The recipient acknowledges that the copyright NATO STOCK No: FINISH SPECIFIC
10. QUICKLOC BARREL REMOVAL AND REPLACEMENT The AT308 Rifle features the Accuracy International QuickLoc® barrel system as standard. WARNING DO NOT REMOVE THE QUICKLOC BARREL SCREW. DO NOT TIGHTEN THE QUICKLOC BARREL SCREW WITH THE BARREL REMOVED.
To Remove the barrel:
Ensure weapon is safe to handle and unloaded.
Loosen the QuickLoc® barrel screw 2-3 turns - do not unscrew any further.
The barrel can now be unscrewed in a anti-clockwise direction. If the barrel will not unscrew by hand, a 3/4” or 19mm AF spanner can be used on the two flats machined into the barrel near the muzzle.
To Refit the barrel:
Ensure that the threads and mating surfaces of the barrel and action are clean, undamaged and free of debris. Screw the barrel into the action until the action mating face is securely in contact with the barrel flange - no gap should be visible.
Tighten the QuickLoc® barrel screw to 5.5Nm (49in/lbs).
Verify that the barrel is tight by trying to unscrew the barrel by hand, using no more than reasonable force. Headspace should always be checked after refitting barrels, see section 1.7.
WARNING - IF THE BARREL CAN BE ROTATED BY HAND AFTER TIGHTENING THE CLAMPING SCREW, RETIGHTEN THE BARREL AND BARREL CLAMPING SCREW AS DESCRIBED ABOVE. IF THIS DOES NOT PROPERLY SECURE THE BARREL, THE RIFLE MUST BE INSPECTED BY AN ACCURACY INTERNATIONAL QUALIFIED GUNSMITH OR ARMOURER. ENSURE THE LOCK RING IS IN PLACE AND IS SECURE. THIS CAN BE INSPECTED THROUGH THE EJECTION PORT. QUICKLOC BARREL SCREW (4mm AF HEX KEY) BARREL FLANGE ACTION MATING FACE N7 30.0 PRELIMINARY NOT CHECKED NOT RELEASED 1 2 20 50 100 1 1 3 TITLE DIM'N IN ORIGINAL (UNLESS (FOLDING) 4 (6) UNLESS OTHERWISE STATED, ALL TAPPED HOLE THREAD FORMS ARE (2) A RADIUS OR CHAMFER OF 0.2 (MAX) IS PERMITTED IN THE STATED) ESTIMATED 2:1 g mm AT, GENERAL ASSY AI-26677 OF 5 6 7 INTERNATIONAL LIMITED. The recipient acknowledges that the copyright NATO STOCK No: FINISH SPECIFIC
I always torqued mine to 55in pounds. I think AI calls for 49 but I had better repeatability with the 55
Yes. Nothing happened, but I did hold my breath and watch out the window.
I've used a preset limiter at 49 in/lb for a few years without issue. Some step up to 55/60 in/lb and exhibit increased consistency when switching barrels. I've tried it with without noticing a significant difference.
Now I put a witness mark on the torqued screw, and simply use the wrench stored in the butt stock to tighten back to line up the marks.
Now I put a witness mark on the torqued screw, and simply use the wrench stored in the butt stock to tighten back to line up the marks.
I picked up my AT from some looney that goes by @jwood1284 
. It came with all kind of goodies including the manual and a 49IP tool just for tightening the Quicklock screw. I've only changed the original barrel once. After the 6BR barrel went on I decided to wear it out first.
. It came with all kind of goodies including the manual and a 49IP tool just for tightening the Quicklock screw. I've only changed the original barrel once. After the 6BR barrel went on I decided to wear it out first.I have the AXMC and switched between the 300 win mag and 6.5 every so often. I loosen the screw 2 turns and unscrew the barrel by hand. I then screw the other barrel on hand tight. I then torque down the lock screw as tight as I can by hand with the supplies Allen key. Never had any issues and POI shifts are repeatable. The manual says 49 inch lbs I believe but I discovered that it’s about hand tight when comparing the two
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