Possible improved muzzle gas trap design - revolver or autoloader...

J

Jim March

New member
I wonder what others will think of this type of gas trap?

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I haven't shown any uses of the gas but there's all kinds of options. I'm planning to alter the gas trap on Maurice to match this design and at that point I should have enough gas for shell ejection and a compensator.

Might actually have enough for hammer cocking if it wasn't for that pesky Hughes Amendment thingie...
 

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I have the same issue, what would you use it for?? I could see a muzzle brake for a revolver, but a semi-auto pistol will not have enough clearance for the front of the slide unless you have the barrel extended a half inch. That would push up the cost of the pistol. It would seem cheaper just to port the barrel.

Jim
 
You don't know about Maurice yet?

I'm doing something similar right now and tapping muzzle gasses to blow empty shells right out the back of my revolver, on the right side (via a modified loading gate on a single action). The firing chamber gas-ejects the previous fired shell in the cycle. And then once an empty chamber passes in front of the magazine on the left side, a spring-loaded tube crams a round into the back of the cylinder one position away from hammerfall.

I can get up to 14 rounds capacity by stacking a 9rd mag on top of 5 in the chamber.

http://thefiringline.com/forums/showthread.php?t=511297

With a more efficient gas trap I can do shell ejection plus have enough energy left over for a very effective compensator :). In theory, instead of a comp I could set up gas-powered hammer cocking but I'd better not on an SA wheelgun unless I wanted to violate the rules on full auto. Which I have no intention of doing until the Hughes Amendment is repealed...so I'll test this gas trap by doing a comp with it so I won't have enough gas pressure to build an auto-cocker...

Now, gas traps of this sort are already used in some designs of comps on semi-autos. So a more efficient gas trap that grabs more of the muzzle gasses has a lot of potential to improve comps.
 
I could see a muzzle brake for a revolver, but a semi-auto pistol will not have enough clearance for the front of the slide unless you have the barrel extended a half inch. That would push up the cost of the pistol. It would seem cheaper just to port the barrel.
Click to expand...

Lots of handguns are available with a factory "silencer ready" option - this "mega-efficient-comp" could be added instead of a silencer and with no tax forms needed, cash'n'carry because esp. if used as a compensator it will be louder than stock, not quieter!

http://www.impactguns.com/hk-usp-sd...-sights-15rd-mags-m709001sd-642230237483.aspx

http://www.thetruthaboutguns.com/2012/12/robert-farago/new-from-fnh-usa-fnx-45-fnx-45-tactical/ - note second set of pics...
 
Semi-auto bolt action and lever action

Several years ago I saw patent drawings for a semi-auto lever action rifle. A spoon-shaped arm (with a hole in the center of it) used muzzle blast to pull a rod attached to the lever of the rifle. Instant semi-auto on a lever action.

There were also plans to use the same sort of external mechanism to operate a bolt-action rifle in semi-auto mode that date back to WWII. I understand there were some prototypes built in the Philippines.

No internal modifications were involved, I think.

Lost Sheep
 
Where do you find those patent papers? Online? I wanna read!

I really like your design. It does leave a wide variety of options open. Makes me think about all the possibility left in the world of firearms.
 
John Browning came up with the idea while watching a rifle shooter shooting over some tall grass. He noticed the muzzle blast made the grass sway back and forth - just like a lever. This caused a ding in his incredibly fertile brain. He went to his shop, fabricated what he called a flapper out of sheet steel with a hole drilled in it and a jury rigged linkage to the lever of a Winchester 92. A little sear filing and... a functioning pre prototype firing about 7-800 rpm. Imagine going from concept to prototype in 1 day. When he whipped up a prototype to show to Colt, they showed him their gattling gun and told him about the Maxim. He had never seen or heard of either. That prototype became the 1898 'potato digger'. A few years later John went to gas guns, some of witch are still in use today.
You may be able to tell from my call name that I am a big fan of John.
 
Barrel is a section of Douglas Premium .355". Cylinder throats are hand-reamed to .3555" with a chucking reamer after being chamber-reamed with a Dave Manson 9mm finish reamer, by hand, in a Bowen chromoly cylinder blank.

Ask me if I'm worried about keyholing much.
 
Plumb amazing.
A wonderful and wonderment accomplishment, for sure.
But I just gotta' ask -
With all the inexpensive 9mm auto loaders available, what was the motivation for doing this?
Other than exercising one's fertile mind and a providing a reason for staying off the streets and out of the bars at night.
 
Well I like SA revolvers. Accurate, feel great in the hand, ergonomics rock, but the sights and firepower and reload speed kinda stink.

So I upgraded the sights first, then set about doing something about the firepower...and I'm now up to 14rds (9rd mag on top of a 5rd cylinder) with no reload, quick-change 9rd mags...ummm...yeah. :)
 
The insert would have to have a forcing cone because a lead bullet would expand into the gap and have to be squeezed back down. A jacketed bullet probably would work OK, though.

As for a magazine feeding a cylinder from the rear, not too new an idea. Check with a fellow named Rollin White, who had the same idea. (His patent has expired, though.)

Jim
 
No, the insert will be larger than the bullet diameter by a safe margin. That's what I'm doing right now...I have a gas trap somewhat like this but not with the sort of internal "air channeling" that I'm picturing here. Shot it plenty of times, no problem, and my gas pressure right now is well sufficient enough to drive 9mm standard pressure shells into my right cheek with stinging force! That's why I added a hammer-mounted shell deflector after the first six test shots in 9mmPara.

This is the feed cycle for a late WW2 Nazi prototype 20mm autocannon, the Mauser MG 213:

217211d1354087406t-revolver-cannon-design-canon_revolver_mauser_mg_213_ani-1.gif


The US "Pontiac" M39 autocannon used in the F86 Sabrejet and other early fighter jets was derived from that captured Mauser, and I am told other western allies cloned it as well. I was told about this critter here on TFL about halfway through my build process so it's a case of separate invention rather than copying...I'm doing some things differently but this is the same basic feed cycle as Maurice, more or less.

The M39 had a good rep for reliability and I can see why: the shells don't have to make any sort of "turn" to go up a feed ramp. Maurice will feed empty shells just fine and I would guess it will eat Keith-style SWCs, full wadcutters seated case-depth or further out or even CCI shotshells in 9mm.
 
The Dardick was even faster, since there was no reciprocating part at all. Of course, it had other problems.

And IIRC, someone came up with a 20mm cannon that had two cylinders, with six or eight cuts of half the cartridge case shape and belt cut into the outside. The two cylinders were geared to roll against each other, pulling the belt through and squeezing the round between them, forming the chamber. The round was fired when the cylinders mated as the round passed the end of the barrel. I thought that was really neat. Kept things tidy, too, as the cases were never taken out of the belt.

Jim
 
How is this arrangement any different than the cone shaped baffles used in some silencer designs?

Considering that your interest is tapping gas flow for energy, rather than diverting it to decrease noise, I'm not sure if having a canted surface will actually yield that much extra energy or not with a fluid. The extra surface area the gas has to flow over may actually decrease its energy due to drag and cooling.

You might compare it to an oar - would an oar angled at 40 degrees more efficiently interact with the water, or does keeping the oar's surface perpendicular to the flow increase efficiency despite how the water can flow off the bottom?


It's a fluid dynamics question that I don't pretend to know the answer to. I'm just saying that a cone may not be better than a flat surface when you're talking about hot expanding gas for reasons that aren't immediately obvious.

I imagine the volume of the system and it's ability to capture pressure efficiently instead of just creating back pressure is going to be the real measure of efficiency, rather than the shape of the tap.
 
Could be. At the very least the lip would give you some material to erode through before you start losing pressure.

There may be a "right" to this design, or it may be that the shape differences are such a small percent of the energy capture that it is unimportant. I imagine production cost and longevity wins over efficiency.
 
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