Craft Gunmaking, No compromises, No corners cut, EVER

Thursday, September 22, 2016

Rising-Bite Rifle from the Raw (#004)

This project is completely made from raw material, no rough forgings, no parts "pirated" from elsewhere and no CNC, EDM or castings.  Every part, screw, pin and spring was, and will, be made here, by hand with the assistance of manual machinery.  It's going to be a rising bite, bar-in-wood, self opening, leverless, single trigger double rifle with inboard mounted sidelocks.  The caliber is 7.62x51R (that's .30-30 Winchester on this side of  the pond).  The false outer lockplates will have hinged, spring-loaded "access panels" (or maybe crystal windows) so that the lockwork can be seen.

The blank frame and the block of 1020 from which I cut it.
The barrel lump was machined from a piece of 4140 hexagonal bar.

The vertical bolt that works in unison with the underbolt, and makes it a rising bite action.

The frame after further machining.  The right-side fence is rough chiseled to shape.

The top strap TIG welded in place.

The barrels contoured and fitted to the lump, and the top strap joint is refined.  Also shown is the underbolt, vertical bolt, link and pivot as they are assembled in the frame.  It's clear how the axial travel of the underbolt translates to the rising bolt's vertical travel via the link.

The right-side inboard mounted sidelock. The outside "lockplate" is simply a cover and obviously will be pinless. I'm going to incorporate a spring-loaded trapdoor in the outer lockplates to access the inner workings.
The cocking lever is also the mainspring. As the barrels open, the lever/spring rotates the tumbler to full cock where the sear will hold it. As the barrels are closed, the cam at the front will cramp the spring.
This also makes it a self-opener.
The lockplate, the bridle and the screws are 1020 (they will be case-hardened), the tumbler, sear, sear spring, mainspring and cocking cam are made of O1 (an oil hardening steel).

To give some idea of the amount of work involved, here is a photo of the lock bridle after machining the posts but before shaping it by hand.

I decided that the bridles should be pierced, in the interest of saving weight (not really).

After some more thought, I decided that since the locks will be readily accessible (and therefore visible), that they should be more visually appealing.  To that end, I redesigned the sear spring (it's now a single-leaf with a bridge supporting it), beveled the edges of the bridle and bridge and cut an ornamental pattern into the lockplates (which had to be remade).

With the locks sorted, it's time to make the triggerplate.  Here's a shot of it early on.

Here is the triggerplate almost finished.  Now I have to decide on a single trigger or double triggers.
I had originally planned on a single trigger but double triggers on a side-by-side do have a certain aesthetic appeal.  I also decided against the sidelever, which I had considered, in favor of direct operation of the bolt via a slide in the forward portion of the triggerguard.  This is similar in concept to what is used in the Ljutic Mono trap gun.  It also allows the action to be completely symmetrical and ambidextrous.

Now it's time to work on the pattern stock.

I made a new, more functionally and aesthetically pleasing bolt slide and fabricated and welded the tang to the triggerguard.

 Next was to make the left and right firing pin bushings, firing pins, springs and vent screws.

 The blank for the forend iron with a portion of the bar of 1020 from which it was machined.

With the barrel breeches brazed, the barrels blacked down and the bolts fit, and the assembly proof-fired, I rewarded myself with some fun work.  That work is chiseling the fences.

I've made a few changes to the original design brief.  The caliber was changed from the originally envisioned 7x57R to 7.62x51R (.30-30).  This was done for reasons of ammunition availability and performance.  Since the the selection of rimmed 7x57 is sparse here in the States (and considerably down loaded, at that) and Hornady's 160 grain FTX "LEVERevolution" offers ballistic performance that is simply amazing, it was the most logical choice.  The ability to use any other easily available .30-30 ammunition in a pinch is another advantage that couldn't be overlooked.  I'd originally thought of using a single trigger but went with double triggers for strictly aesthetic reasons.  A practical rationalization would be that a double rifle with double triggers is really two separate rifles in one, while a double with a single trigger is really a single, two-shot rifle that could possibly malfunction.  The self-opening lockwork was fully made but I abandoned it (maybe I'll mount and frame them) for two reasons which I'll detail below.

  The first is that having the outer (false) lockplates be removable simply to look at the lockwork seemed like less of a good idea the longer I pondered it.

The second is that I wasn't happy with the effort needed to close the self-opening design when the added weight of the barrels was taken with it. It wasn't difficult but it wasn't pleasing either and the spring opening combined with the weight of the barrels made for a rifle that felt like it was going to jump out of the hands when it was opened. The weight of the rifle barrels can be put to much better use in a conventional cock-on-opening design. So that is what I did, but in a way inspired by Westley Richards' hand-detachable boxlock. The locks are removable with no tools after the outer plates are removed. The lock frames are machined with integral sear and tumbler pivots,like the WR, but those pivots are also supported by the inboard lockplate, which also serves to locate the lock frame while the forward (scroll) portion of the lock frame engages the main frame, taking the stress off of the tumbler pin during cocking.

With the major design work finalized (and actually made), all that is left is to make the false lockplate retaining mechanism, the safety mechanism and forend latch mechanism and make and install the sights.  I will use use NECG's excellent trap grip cap since it would be foolish to make something that is readily available and of excellent quality.  The pattern stock and forend are made and it has been proof fired so, when time allows, I can begin the actual stocking.

Here are some photos.

The finished left lock assembly and the right-side, inner lockplate with the right lock frame (in its early state of manufacture).

The metalwork, assembled without the wood.

Here it is assembled into the pattern stock.

Here is the English walnut blank that the stock will be made from.
Well, metal and wood have finally met and are getting along swimmingly. 

In these photos, the wood is wet with mineral spirits to show the figure.

I wanted the old-school look of a wedge type forend retainer, but with the convenience of an Anson latch.  The design I came up with achieves both goals.

Here's a video of the forend latch.

The grip cap

Here are some almost finished shots.  After two and a half years of nights and weekends, the end is in sight.  The next agenda items are the four screws for the forend latch escutcheons, a safety mechanism, and to design and make the quick-detachable scope mount for the Leupold VX2 1-4X scope.  I have a few design ideas for the safety mechanism but almost all of them will spoil the smooth, continuous line of the top strap.  I will likely use a roller actuator since that would provide a much lower profile than any type of slide or lever, thus minimally impacting the rifle's profile.   I had designed and mocked up a grip safety earlier in the project but it spoiled the profile as well, so that idea was discarded.  Other than my name on the lock plates and rib, and the caliber, it will not be engraved. 

The final regulation target, shot at 75 yards (could not see it at 100).  I'll have to move the rear sight over a bit.

I finally found/made some time to make the screws for the forend escutcheons and scope bases, and mount the scope.  The scope is a 2007 vintage Leupold VXIII, 1.5-5 power, matte finish.
When time (and memory) allow, I'll send the scope off to Leupold for a post reticle.