I got a fever...and the only cure is a new rifle!

[Ian]

I worked out a simpler sketch on my lunch break, the hammer spring and strut attach to the cocking lever vertically just behind the bolt and pin to the lever. The strut passes through a hole in the hammer and has a tee-head or nut on top. The lever cocks the fired hammer and the strut passes back through the cocked hammer when closing the lever. One piece hammer, integral strut/cocking rod, and spring. Minimal parts, plenty of room for it all, very simple.

The challenge I'm working on right now is the firing pin mechanism. Still toying with the vertical transfer pin, thinking a long taper at the top and a radiused firing pin installed with a threaded breech face bushing and spring. Breech not bored through for either pin. Hammer drives a floating transfer pin upward in a drilled hole, it hits the firing pin and the wedge angle drives it forward into the primer cup. The advantages are safety (firing pin can't blow out the back of the bolt), the firing pin will be wedged into the primer mechanically, preventing primer cup blowout from rejecting the pin, there are no pivot pins to get beaten up from repeated shock loads in shear, and it requires a minimum of metal to be removed from the bolt. The DISadvantage is the lack of mechanical advantage and high frictional losses of transferring firing pin force 90 degrees by one angle-tipped pin driving into another. I'll try to work up some drawings.

I definitely want an over-centering toggle link between lever and bolt. Reasons are many. A plunger and spring in the lever can act against a notch in the bottom of the link to keep the lever closed, the bolt can't be pushed open unless the lever is pulled, and the lever can have a lobe on it that directly contacts the bottom of the bolt slot right at the end of closed travel to lock it upward and double with the link to hold the bolt locked. Also it is a sacrificial part of sorts, a piece that can be easily remade or adjusted over the lifetime of the rifle. Since the link is mounted on pins, there is no sliding part and hence very little friction compared to a pin in a slot.

 

[popper]

Hammer drives a floating transfer pin upward in a drilled hole, it hits the firing pin and the wedge angle drives it forward into the primer cup Nope. primer is set off by IMPULSE energy - you can't get enough velocity out of the wedge,even a double wedge. Proof by cocking your 30/30, thumb on hammer and pull trigger. let the hammer fall slow and it won't go off. OR just let hammer drop from half position. E=mv^2 but P=f*v and that is what makes the primer go off.

 

[fiver]

that's why I hate the rebounding hammer the model 94 started using in the 70's it needs more mass or more speed.
they just barely got it to work and there's no room for ''error''

 

[Ian]

Ruger New Vaquero is the same way. It BARELY sets the primers off and has a cap-pistol feel to it. Light hammer, transfer bar, then a pin, every piece soaks up energy. At least it's safe to load six and drop it on the hammer.

I dunno, I might make a mock-up with an aluminum bolt, barrel stub, and a block of maple for a receiver and see how much energy it takes whacking the transfer pin to get a primer to pop. I don't think it will work for the reasons Popper mentioned but I intend the hammer to follow the transfer pin all the way (not a true floating pin, like 1911s have) and that may work. Or it may not, either way I need to know for sure because what I'm imagining here will solve SO many other engineering challenges if it is workable.

 

[Ian]

All right, here's a rough drawing showing the arrangement I'm imagining. Haven't made a paper working model to get the geometry perfected but basically this is what I'm going to test.



Yesterday I made a crude test bolt and firing mechanism to test the perpendicular striker. It took three hits to set off the primer but the .092" firing pin was too big and I didn't dome the point nearly enough. Also the striker face angle was about 55⁰ instead of 45. This morning I steepened the face to 45⁰ and repolished it, and domed the firing pin tip. Voila! It works now with no lubrication and without having hardened the grade 8 striker or O-1 firing pin impact surfaces. The primer is popping the pin back enough to make witness marks on the striking surfaces, so I'll have to harden them and re-test.

 

[Ian]

If that doesn't work out, my contingency looks something like this:

 

[Ian]

I re-polished and hardened the striker surfaces and it's MUCH mo' betta'. I like it when Plan A works out, one fewer part to make.

The setup made to scale so I know it will work within the confines of the action size I chose:



The indent after hardening the impact surfaces:



It's so crazy it just might work! Gonna put that behind me and get on with refining the design to a blueprint from which I can build.

 

[fiver]

spring and slot with a pin for the firing pin.
I know it adds more parts,, but you'd have a captured pin with a way to hold the pin out of the way or help return it in case of a ruptured primer.

 

[Ian]

Been stewing on this for months. Last night and today I finally worked out something that might work and I might be able to build. I've had money set back for a mill for a long time but have decided I need a little bigger model and some upgrades so I'm working in saving up another thousand dollars and have fewer regrets.

In the meantime, this design actually ended up having the accidental benefit of being made with either separate tangs or with short enough tangs to be made on a 7" lathe. I made a paper cutout working model and altered just a few little things from this drawing to make the geometry right but basically here's what I have:

• Key features:
• Cylindrical breech bolt set at 5⁰ angle forward of vertical. Bolt and receiver similar to 1902 Webley 22 Hornet small-frame action
• 40⁰ lever travel, similar to Martin Hagn actions, bench-friendly
• Hammer is caught by rear sear and cocks on closing per Browning 1885 and Langenhan designs.
• Rotary thumb safety, also borrowed from Hagn
• Two-stage trigger (optional but I like them)
• Firing pin/breech face bushing
• Mainspring rod shares pivot with lever but is angled to keep the breech closed and cams over at about half travel to keep it open for extraction and loading
• Wedge link which lifts the hammer face off the firing pin prior to bolt movement, my only "original" contribution to falling block rifle design and only original in this configuration
• Reverse striker spring allows compact hammer necessary to be fully contained in a cylindrical breech bolt of reasonable size and also allows for a stronger action in that the receiver can have a web of metal left behind the bolt....essential for cylindrical bolt actions of any significant pressure capacity. I think this one will work with .30-30.

 

[Ian]

More photos.

Lever partly cocking hammer:



Action fully open:



Action closed and cocked:



I gotta tune the wedge link a little and get the triangle slot sorted out but basically the design seems to work. Next to make a working model out of hardwood.

 

[Joshua]

I like it!

 

[fiver]

to prove it out.
a wood model should do the trick, and it'd make changes to angles and such some easier.
it'd also provide a pattern.

 

[Ian]

Also, a model will prove the fixturing and tooling I'm planning to use.

 

[Spindrift]

Ok, this is way above my pay grade. But I’m following with great interest- fascinating!

 

[Joshua]

Does the main spring have a telescoping guide rod?

 

[Ian]

Guide rod and strut, I think. Will be pinned in at the lever pivot and probably just float in the hammer notch since it will be under near full compression at all times.

I haven't worked out the extractor fully yet either. I want an ejector but don't know how to make one yet....another research project.

 

[Ian]

Ok, this is way above my pay grade. But I’m following with great interest- fascinating!

It's way above mine too but a fellow has to start somewhere. I've already barreled and chambered several rifles and done one whole restoration/rework and numerous light overhauls so it's time to try making the whole thing. I've never made hammers and sears and such from scratch before so I have lots to learn.

I still need to get set up for color case hardening and learn how to engrave, but those are things for if I get bored later in life.

 

[Joshua]

I’ve been looking at your drawing. With the lever pivot so far forward it can’t really directly cam up an extractor finger. There will have to be a linkage bar(possibly two if they run on either side of the main spring), pushing back twords the bolt, it will need to be pinned just above the main action lever pivot point, to the lever. The linkage bar would need to be slotted and move front to back on a pin. A wedge on the other end of the linkage could lift the extractor finger. The top of the bolt would have to be releaved at the same angle the extractor finger is traveling in, for clearance. The extractor would need to be captivated in a track somehow, and sprung so that it would retract. As far as timing goes the bar and wedge could be any length so that by adjusting that length you could get it timed right. The bottom of the finger would be rounded where it engaged the wedge.

Well I’ve rambled on quite enough. I’m sure you will devise a more eloquent solution that what I just came up with. Fun stuff.

 

[Ian]

Joshua, scroll up to post #65 and look at the extractor I drew there. It's essentially a Darcy-type floating extractor but I didn't show the flat spring that keeps the extractor in position. I drew the extractor in the latest illustrations but did not complete the front of it where it contacts the lever. If you'll examine the paper working model with the action open, the angle on the front of the breech block lines up with the extractor angle and the amount of travel available at the cartridge rim about equals the availabe stroke of the lever tip where it contacts the extractor. I just need to figure out how to load the extractor under spring pressure, make a small primary extraction movement, and then release the spring pressure at the end of the lever travel to pop the spent case free of the feed channel.

 

[fiver]

the Remington 870 just uses a stud as an ejector.
the extractor pulls on one side of the case and angles it the direction the hull will be flung.
then it's drawn back until it hits that stud, flipping the hull out of the extractors grasp.
super simple.
the 340's use something similar but the ejector is a blade that rotates on a pin, it just catches the case and rotates until the other edge of the blade hits the receiver and the bolt moving backward proves the impetus flipping the case out sideways.