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Gun Build Series II

Posted by Administrator on 2/3/2015

Click HERE to view or download brochure for the BHAK54 featured in this article.

This jig is versatile enough where it allows us to do other rivet patterns, like the second picture showing a rear trunnion that isn’t designed to accept a stock, which is how our BHAKR39 Krinkov is configured

Once the front and rear trunnions are riveted in the next step is to insert the barrel and do the head spacing. You will see in the following picture we have a manual horizontal press that moves the barrels in and out by turning a 60” wheel, which rotates a large ACME thread and moves the slide table.

The knurled knob you see has a rod going through the upside down “T” block that aligns the barrel vertically using the grove for the eccentric cam on the lower forearm bracket. With the barrel and receiver locked in, the horizontal movement of the slide table allows us to dial in the head space to within .001” - .002”.

The clam shell hold downs can be located in multiple locations and have changeable insert tooling to accommodate different barrels from as short as 8.5” long up to our 27” bull barrel. We don’t make our 8.5” barreled pistol chambered in 7.62 X 54R anymore as seen here, but this next picture shows just how versatile this press is.

We use multiple methods to determine head space; one are go / no-go pucks seen been held, another is an inert round. An experienced operator familiar with the feel of the tension on the bolt in the front trunnion, moves the slide table forward and back, using fingers to lock and unlock the bolt in the closed position on these two spacers until it's perfect.

Once the head space is set, the trigger guard is riveted on and you can see the rivet jig pictured. The rivets are placed in the gig pointing up and the trigger guard with the safety stop are added. This is placed in a hydraulic 20 ton vertical press and a mandrel is used to compress the back side of the rivets from the inside of the receiver.

The finished receiver is seen in this last picture. The next blog were going to post of this build we will show installing the barrel pin, front sight block, lower forearm bracket, bayonet lug and front sight.