A dumb idea for a recoilless springer

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scotton

scotton

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Nov 2, 2016
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Alright, smart people, tell me why this idea is dumb. This isn't a trick question, I'm trying to figure out why this idea wouldn't work.

First, google the Park Rifles RH91/93. This air gun had two opposing pistons that sat in a tube under the breach/barrel. The pistons would compress air between them into a transfer port that would go up to the breach and send the pellet on it's way.

So here's my dumb idea.
Let's take a generic PCP. We'll use a Marauder because I know how they work and have had them apart many times.
What if you put a spring and piston into the air tube of a Marauder. I'm thinking you would put it in backwards from a traditional springer, so the piston would travel front to back. Put some sort of cocking mechanism in there (ideally side cocking).
So you would cock the piston, then release the piston. This would charge the plenum with air. Then you could cock the hammer and release a shot like normal.
My goal would be 12 fpe, so I think there would be plenty of room for a spring and piston along with the cocking mechanism. There even a good 6 inches between the end of the air tube and the end of the shroud to play with if needed.

So, ignoring the cocking mechanism (we'll just wave a magic wand at that for now), here are my first thoughts as far as potential problems.
1 - Let's assume a target of 800 PSI. Could the spring be powerful enough to generate 800 PSI and still be reasonable to cock? I suspect that the spring has to be powerful enough to overcome the big bubble of compressed air in front of it to continue it's forward travel. Otherwise it would sit there half cocked, and when the air was released by a shot the piston would slam home. Maybe there needs to be a valve in the piston so that once 800 PSI is achieved, the excess air would release through the valve and out the front of the air tube. So, essentially, the piston would be a regulator.
2- Would the piston seal (o-ring) be supple enough to travel in the air tube yet still be able to seal the 800 PSI in the plenum? I'm picturing something like a Marauder gauge block with the back o-ring removed. Add a rod and it becomes a big fat skirtless piston.
3- Remember how the FX Independence had all of those corrosion issues caused by condensation in the air tube? Would that be an issue here?
4- The cocking mechanism is going to need to be figured out with something other than magic. I'm thinking a side lever with the hinge at the end of the air tube. So you would cock it by pushing the lever away from you, re-seat the lever, then push a big button at the end of the air tube to "fire" the piston and charge the gun.
5- Would a gas ram be a better idea? I don't know a lot about gas rams, but I wonder if you could set the pressure in the ram to be slightly more than the pressure you are trying to generate in the plenum.

I assume the basic concept wouldn't work or someone would have already done this, but I'm trying to figure out WHY it wouldn't work.
Maybe if I find the time I'll thread an old Marauder gauge block and attach a threaded rod. Then I could ram the gauge block through the air tube and see what kind of pressure is created. I guess I would need to use a second gauge block to act as a, well, a gauge block. So basically take a stock Marauder and make a piston out of a second gauge block. I'll need to figure out how far back to start the piston, to simulate the space taken up by a compressed spring. Not sure if I'll be able to generate enough power by hand to make the experiment worth while, but you never know until you know.
 
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I'm not keen on technical things so I may have it wrong, but if you're saying you'd compress the spring (or piston) with something like a side lever. Why not just use a non pcp side lever gun? There are recoilless side lever guns that work sort of the way you described, having two springs that oppose each other to negate the recoil.
 
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I already wrote on this I think either here or at GTA.
I think your idea (my idea) is that instead of using a pump or a compressor or a tank to fill the marauder air tube. you cock a spring (either once twice or three times)...release the energy stored in the spring via a piston into a smaller volume (higher pressure)....then when you are ready to shoot...pull the trigger...release the air....

technically a springer? or is it a hybrid PCP? LOL (probably classified as a self-contained pumping p c p /spring assisted pumper)

Or Maybe I'm way off topic here...after having very quickly glance at your idea.

BTW I used to own a Park...supposed to be recoilless... But I couldn't get it to group. It could be just me.
 
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Not to be a party pooper but this design would not generate a lot of power with just one spring release. The reason being is that springers generate a huge amount of heat during a shot cycle, which aids in creating power, even at 12 FPE. If you store just the compressed air minus the heat you will need a much higher stored air pressure to get the same power level as a springer. So you would need multiple releases of the spring to charge your gun. It seems like a lot of effort to get the performance of a PCP or single stroke pneumatic, which is why the design never became popular.

-Marty
 
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skink said:
I'm not keen on technical things so I may have it wrong, but if you're saying you'd compress the spring (or piston) with something like a side lever. Why not just use a non pcp side lever gun? There are recoilless side lever guns that work sort of the way you described, having two springs that oppose each other to negate the recoil.
Click to expand...
The side lever is only a consideration because it helps to mount things to the gun, like bipods or hamsters. I'm not looking for a "recoilless" springer (and according to Park, Whiscombe and the TX200 SR, neither is anyone else, which is a bummer). I'm looking for a PCP without an outside air source.
 
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MartyMcFly said:
Not to be a party pooper but this design would not generate a lot of power with just one spring release. The reason being is that springers generate a huge amount of heat during a shot cycle, which aids in creating power, even at 12 FPE. If you store just the compressed air minus the heat you will need a much higher stored air pressure to get the same power level as a springer. So you would need multiple releases of the spring to charge your gun. It seems like a lot of effort to get the performance of a PCP or single stroke pneumatic, which is why the design never became popular.

-Marty
Click to expand...
Thanks. I think this is the info that I was missing. I guess that's the difference between a Sheridan multi-pump and a low powered SSP.

To go slightly off topic, I remember that there used to be someone making a valve that you could put into a Baikal IZH 46 that turned it into a multi-pump. I wonder how hard it would be to turn an older SSP into a multi-pump (and how many pumps it would take to get to 12 fpe). So now I've picked my rabbit hole for the day, see you in a few hours.
 
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ATI Nova Vista Freedom and the FX Independence were both outside air source free PCP's. Neither of them are made anymore although they pop up for sale now and then.
libertytreeguns.com

ATI NOVA VISTA FREEDOM .177CAL 1000FPS PUMP

<p>Available for the first time in the USA and exclusively imported by American Tactical the Nova Vista multi-stage pump pre-charged Nova Freedom Air Rifle! The Nova Freedom features a fully patented high effiency gas chamber design that allows the user to fire up to 17 shots at 1000 fps or...
libertytreeguns.com libertytreeguns.com
 
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scotton said:
Thanks. I think this is the info that I was missing. I guess that's the difference between a Sheridan multi-pump and a low powered SSP.

To go slightly off topic, I remember that there used to be someone making a valve that you could put into a Baikal IZH 46 that turned it into a multi-pump. I wonder how hard it would be to turn an older SSP into a multi-pump (and how many pumps it would take to get to 12 fpe). So now I've picked my rabbit hole for the day, see you in a few hours.
Click to expand...
I’m also curious to know what a converted SSP would be capable of. If it could get 12 FPE with 2 pumps I think that would be attractive.

That said, FX used to make a gun called the FX Indy. It was a multi-pump that got 30 FPE in .22 with 15-18 pumps. I didn’t own one but I heard that it required more than 15 pumps to first prime the air tank, after that it was 15 pumps after each shot to get the pressure back up. FX is pretty good at what they do but the rifle never gained wide acceptance, probably due to the large number of pumps. The Seneca Aspen rifle is today’s multi-pump equivalent to the FX Indy by the way…

-Marty
 
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Yeah, as I referenced earlier, I think condensation was the enemy of the Independence.

I think I found what I was looking for: https://forum.vintageairgunsgallery.com/titan/titan-mohawk/
Apparently they made a Titan Mohawk that would generate 12 fpe with two pumps. The lever traveled 180 degrees, so they must have used a big air cylinder to generate the pressure. It basically looks like an older PCP (Marauder) with a backwards SSP on the bottom. The power stroke was towards the body, unlike a traditional SSP.
This tells me that even if you could find the room to fit a valve in a 10M SSP to make it into a multi-pump, it would take a ton of pumps to create the kind of air pressure we are talking about. And most of the compression chambers on the 10M SSPs were very thin. So I don't think converting an inline SSP to multi-pump would be very viable.
So we are back to putting a multi-pump mechanism into the air tube of a PCP. And as you said, FX tried it and couldn't sell it.

For the record, I lusted after an FX Independence when they came out but the reality of needing so many pumps per shot turned me away. The price and condensation issues kept me away. But I would still jump on one if the price was right.

I just did a little dive on long term opinions on the Independence and it looks like the condensation issues may have been overblown. I assume the poor sales had more to do with marketing issues. Is it a 30 FPE survivalist gun that requires 15 pumps per shot? Is it a 12 FPE target gun that takes 1 pump per shot? Is it over-priced and over-complicated? Is it priced where it needs to be based on the amount of parts and precision required to make the gun? Probably yes to all of it.
 
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scotton said:
Alright, smart people, tell me why this idea is dumb. This isn't a trick question, I'm trying to figure out why this idea wouldn't work.

First, google the Park Rifles RH91/93. This air gun had two opposing pistons that sat in a tube under the breach/barrel. The pistons would compress air between them into a transfer port that would go up to the breach and send the pellet on it's way.

So here's my dumb idea.
Let's take a generic PCP. We'll use a Marauder because I know how they work and have had them apart many times.
What if you put a spring and piston into the air tube of a Marauder. I'm thinking you would put it in backwards from a traditional springer, so the piston would travel front to back. Put some sort of cocking mechanism in there (ideally side cocking).
So you would cock the piston, then release the piston. This would charge the plenum with air. Then you could cock the hammer and release a shot like normal.
My goal would be 12 fpe, so I think there would be plenty of room for a spring and piston along with the cocking mechanism. There even a good 6 inches between the end of the air tube and the end of the shroud to play with if needed.

So, ignoring the cocking mechanism (we'll just wave a magic wand at that for now), here are my first thoughts as far as potential problems.
1 - Let's assume a target of 800 PSI. Could the spring be powerful enough to generate 800 PSI and still be reasonable to cock? I suspect that the spring has to be powerful enough to overcome the big bubble of compressed air in front of it to continue it's forward travel. Otherwise it would sit there half cocked, and when the air was released by a shot the piston would slam home. Maybe there needs to be a valve in the piston so that once 800 PSI is achieved, the excess air would release through the valve and out the front of the air tube. So, essentially, the piston would be a regulator.
2- Would the piston seal (o-ring) be supple enough to travel in the air tube yet still be able to seal the 800 PSI in the plenum? I'm picturing something like a Marauder gauge block with the back o-ring removed. Add a rod and it becomes a big fat skirtless piston.
3- Remember how the FX Independence had all of those corrosion issues caused by condensation in the air tube? Would that be an issue here?
4- The cocking mechanism is going to need to be figured out with something other than magic. I'm thinking a side lever with the hinge at the end of the air tube. So you would cock it by pushing the lever away from you, re-seat the lever, then push a big button at the end of the air tube to "fire" the piston and charge the gun.
5- Would a gas ram be a better idea? I don't know a lot about gas rams, but I wonder if you could set the pressure in the ram to be slightly more than the pressure you are trying to generate in the plenum.

I assume the basic concept wouldn't work or someone would have already done this, but I'm trying to figure out WHY it wouldn't work.
Maybe if I find the time I'll thread an old Marauder gauge block and attach a threaded rod. Then I could ram the gauge block through the air tube and see what kind of pressure is created. I guess I would need to use a second gauge block to act as a, well, a gauge block. So basically take a stock Marauder and make a piston out of a second gauge block. I'll need to figure out how far back to start the piston, to simulate the space taken up by a compressed spring. Not sure if I'll be able to generate enough power by hand to make the experiment worth while, but you never know until you know.
Click to expand...
SO , i read your idea a few times and i think what your saying is fire the piston back to the butt end causing recoil to be rearward filling the plenum .
then later you shoot and it now acts like a pcp . possibly a two trigger setup might work . so Cock the rifle and "shoot" the first trigger charging the plenum . now the gun acts like a pcp with no recoil ? seems like a complicated way to achieve a pump up rifle ?
EDIT you could just add a plenum and second trigger to achieve the same effect from a normal springer ? Kind of a "pre recoil "springer rifle ?
 
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scotton said:
Alright, smart people, tell me why this idea is dumb. This isn't a trick question, I'm trying to figure out why this idea wouldn't work.

First, google the Park Rifles RH91/93. This air gun had two opposing pistons that sat in a tube under the breach/barrel. The pistons would compress air between them into a transfer port that would go up to the breach and send the pellet on it's way.

So here's my dumb idea.
Let's take a generic PCP. We'll use a Marauder because I know how they work and have had them apart many times.
What if you put a spring and piston into the air tube of a Marauder. I'm thinking you would put it in backwards from a traditional springer, so the piston would travel front to back. Put some sort of cocking mechanism in there (ideally side cocking).
So you would cock the piston, then release the piston. This would charge the plenum with air. Then you could cock the hammer and release a shot like normal.
My goal would be 12 fpe, so I think there would be plenty of room for a spring and piston along with the cocking mechanism. There even a good 6 inches between the end of the air tube and the end of the shroud to play with if needed.

So, ignoring the cocking mechanism (we'll just wave a magic wand at that for now), here are my first thoughts as far as potential problems.
1 - Let's assume a target of 800 PSI. Could the spring be powerful enough to generate 800 PSI and still be reasonable to cock? I suspect that the spring has to be powerful enough to overcome the big bubble of compressed air in front of it to continue it's forward travel. Otherwise it would sit there half cocked, and when the air was released by a shot the piston would slam home. Maybe there needs to be a valve in the piston so that once 800 PSI is achieved, the excess air would release through the valve and out the front of the air tube. So, essentially, the piston would be a regulator.
2- Would the piston seal (o-ring) be supple enough to travel in the air tube yet still be able to seal the 800 PSI in the plenum? I'm picturing something like a Marauder gauge block with the back o-ring removed. Add a rod and it becomes a big fat skirtless piston.
3- Remember how the FX Independence had all of those corrosion issues caused by condensation in the air tube? Would that be an issue here?
4- The cocking mechanism is going to need to be figured out with something other than magic. I'm thinking a side lever with the hinge at the end of the air tube. So you would cock it by pushing the lever away from you, re-seat the lever, then push a big button at the end of the air tube to "fire" the piston and charge the gun.
5- Would a gas ram be a better idea? I don't know a lot about gas rams, but I wonder if you could set the pressure in the ram to be slightly more than the pressure you are trying to generate in the plenum.

I assume the basic concept wouldn't work or someone would have already done this, but I'm trying to figure out WHY it wouldn't work.
Maybe if I find the time I'll thread an old Marauder gauge block and attach a threaded rod. Then I could ram the gauge block through the air tube and see what kind of pressure is created. I guess I would need to use a second gauge block to act as a, well, a gauge block. So basically take a stock Marauder and make a piston out of a second gauge block. I'll need to figure out how far back to start the piston, to simulate the space taken up by a compressed spring. Not sure if I'll be able to generate enough power by hand to make the experiment worth while, but you never know until you know.
Click to expand...

How about just a dummy piston in a second tube that is parallel but inverted from the compression tube. Think along the lines of those Discovery double tube conversions awhile back. If you can trigger them both at the same time, the recoil should still cancel out? You would still cock it twice like a wiscombe, but could maybe be assembled from a couple RWS 34's for a budget experiment?
 
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Cousin Vinny said:
Why use a spring piston to charge plenum space when the same volume of air can be compressed by the stroke of a lever in a 2stage cycle? Pull the lever back one time and you're at X psi, reset and crank it back so now a high pressure piston finishes the job and brings X up to Y psi.

Like a double-pump pcp.
Click to expand...
JOHN WISHICOMBE made the finest opposing piston high powered rifles ever built
 
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A springer creates an adiabatic transfer of energy; basically, the air is compressed and released so quickly that heat loss to the surrounding metal is not an issue. A mechanism such as you such suggest would lose that efficiency, plus be subject to losses from leaking seals, etc.

But the basic idea - an efficient way to pre-compress air without the need for separate pumps and tanks - is a good one. There are some good ways to do that already: guns needing just 2 or 3 pumps as Cousin Vinny suggested; the easy-effort multi-stroke pump mechanism on the new Dragonfly Mk 2; the lever/gear cocking mechanisms of SSP match rifles like the FWB 600 series, producing 6 FPE or so with a finger-light single motion.

I've often wondered if the last type of mechanism could be adapted to produce more power with still-reasonable effort. Imagine a gun with the size/weight/trigger/build quality of an R7, that could do a recoilless 8 or 10 FPE with a single charging stroke...I'd buy it!
 
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Here’s one already done…your post reminded me of how cool recoilless rifles are ….just made sure she still does her job.
71633245-CE2C-4876-8DD4-710B46E21DF7.jpeg
she does!
 
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c_m_shooter said:
How about just a dummy piston in a second tube that is parallel but inverted from the compression tube. Think along the lines of those Discovery double tube conversions awhile back. If you can trigger them both at the same time, the recoil should still cancel out? You would still cock it twice like a wiscombe, but could maybe be assembled from a couple RWS 34's for a budget experiment?
Click to expand...
I've been toying with the idea of using a dummy piston, maybe with mercury in it. It wouldn't be cocked, but would basically act as a buffer. It would need to have a hole in the center for the transfer port. Thinking a 5 mm, heavy piston with a short, stiff spring sitting in front of the TP. Then you would short stroke the active piston.
Now that I think about it, the dummy piston would actually increase recoil if it was just passively reacting to the active piston. The reason a Whiscombe works is because both pistons are actively cancelling each other out.

Instead of all this brain work, I think the easiest thing to do is for us to team up the next time Jeff or Chris bring their Whiscombes to the club. You distract them and I'll abscond with the goods.
 
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