The basic QB breech is something that I have always wanted to tackle as an improvement upgrade project. Some recent posts and conversations finally gave me the push to get on with it.
I had a number of things I wanted to accomplish.This is what I came up with
- Complete compatibility with all existing QB parts
- Much more positive registration on the tube
- A longer barrel socket with three points of contact to get rid of the notorious wiggle
- A real dovetail with a flat top
- The same OD as the tube to give the rifle a better visual balance
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The OD of the breech is 7/8" giving it the same OD as the tube.
The length is 3/4" longer giving a total of 2" of barrel socket. The QBD and AR barrels simply slide into a bored recess and the thinner QB barrel has a sleeve which slides onto the barrel and into the socket.
The registration of the breech to the tube is almost 3 times wider giving a very stable mounting.
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Of course the transfer port is milled for a positive sealing face.
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There are two additional setscrews placed discreetly at 120 and 240 deg to provide the three points of contact for barrel stability
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A true 11mm dovetail runs the full length of the breech and is .075" higher to provide clearance for the objective of an AO scope. On all of my QB's the AO ring bumps the barrel on medium rings. And the loading port is just a fraction bigger and beveled both ends to provide just a bit more finger room.
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Overall I think I hit all the major improvements that could be made on a QB breech
Any thoughts?
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