I seem to recall that while the earlier Mk1 type flash hiders appeared to be longer, the overall length of the guns remained the same. The overhanging butt plates did affect the chest and as a result there was a miscellaneous instruction to peel back the horsehair felt packing and add a tapered chamfer at the point where the overhand went into the chest. The lead-in chamfer would compress the gun buffer sufficient to allow the gun to be inserted tightly into the chest.

I have the exact wording somewhere............ just a minute............. Here goes

A minor problem presented itself with the introduction of the Mk2 gun in that the gun, being 1” longer due to the additional overhang of the butt plate, would not fit into the chest! The answer was that after May 1941 Bren chests were manufactured with a 1” wide x 1 ½” long (measurements vary somewhat… …) tapered/chamfered recess cut into the inside of the right hand end of the chest, opposite to where the butt is positioned. This chamfer is quite difficult to see as it is usually covered with horsehair matting. The overhang of the butt plate, which is itself chamfered, acts on the chamfer cut into the chest and the action of one on the other forces the butt slide to compress the piston buffer spring. With the gun now slightly compressed, it fits snugly into the chest. There it is, a slight manufacturing modification that will help to date a ‘true’ chest. This slight manufacturing variation was notified in ACI’s and described thus; ‘… …these modified guns should be inserted muzzle first into the left side of the chest. The gun should then be seated into the two crutches in the normal manner and in so doing, the rear butt strap will meet against the chamfer… … This will compress the recoil spring (Authors note: No it won’t, it’ll compress the SPRING, buffer, piston!) to afford the gun its correct seating position within the chest… …’

To date only three UKicon manufacturers of Bren chests have been identified. These are; Papworth Industries from Cambridgeshire, Bolton and Paul from Essex (the same parent company who manufactured the Defiant fighter) and Elliots of Newbury, bespoke furniture manufacturers who also manufactured Horsa gliders.