New Single Shot JRA Breech for QB78 Family Air Rifles

Many of you will have heard of “JRA”, Jay Joyner’s venture into making custom airgun parts. Jay’s first product was the QB78 family rotary indexing magazine system (which you can find in our store).

Jay’s next move is to manufacture replacement breeches for the QB78 family. This post covers the single shot JRA breech - in fact of a prototype that Jay sent me for review. Archer Airguns will be selling these breeches very soon - once we receive stock available from production.

The main benefit is the increased height and clearance provided by this breech compared to the factory breech. The rise is 4.5mm greater than for the factory breech. This allows much greater clearance for 9oz tanks used on a QB79 or AR2079A, or for use with custom shrouded barrels. The breech also provides a precision mounting base for scope rings and accepts the factory rear peep sights, too.


My first thought was “wow this is heavy!” The JRA breech weighs 21 ounces - that’s 14.6 oz (yes, nearly a pound) - heavier than the stock factory breech. It’s precision CNC-milled from solid steel and is supplied with replacement hammer and cocking pins, breech locking screw and barrel setscrews. This is clearly a high quality product. It functioned faultlessly.

This single shot breech works with standard factory barrels and bolts in either .177 cal. or .22 cal. from any QB78 family model. Installation is very simple - almost exactly the same as for fitting a factory breech. A material difference is that barrels are a tighter fit than most factory breeches and they are retained with two setscrews instead of one. This provides a very solid fixing for the barrel in the breech, useful as factory front bands can no longer be used with this breech due to the increased rise.

You can see a comparison of the JRA and factory breeches in the photograph below.

Archer Airguns will be offering the JRA single shot breech as a parts kit, or we will install it on new QB79 family air rifles ordered from us if you wish.