A New Method for Increasing the Efficiency of a PCP - the SSG

[rsterne]

For the tune you have in your AT-44 you can probably get the SSG to work just fine.... It just wasn't up to the 72 FPE I'm after I mine....

Bob

[Rallyshark]

If I didn't have two separate air cylinders that are meant for different purposes, I'd be all over it.  I don't see the feasibility of taking the gun apart to adjust it for one cylinder or the other.  I don't think the same settings would work between the two cylinders very well, and I'd just end up compromising on one or the other.  That is why I've been trying (unsuccessfully) to come up with an SSG like solution that is still adjustable without dis-assembly.  The only way I can think to make the SSG work for both cylinders would be to set it for the high power cylinder, and turn my reg down and hope for the best with my other cylinder?  I'm certainly open to suggestions, if I'm wrong on this though  

[Motorhead]

Scott, it's interesting you are now hearing things you could not hear before because of the air not being blown out of the muzzle after Elvis has left the building, isn't it....

Bob

Lol ... been that way a couple years now as operational racket and blast gets tamed.  Whats most impressive with the SSG device is that bounce is now so negated you can hear hammer making valve strike, valves air pulse within the action. 
Pay attention to what those noises origins are perhaps correcting a minor air leak as transfer port, maybe a striker pip to quiet valve strike & you get a PCP to really be quite stealth 

[oldpro]

 Scott I found a very simple way of getting rid of the spring Twang without messing with the tune. I put a 80D urethane oring between the spring and adjustment body it works like a charm my friend, same thing i do with NBH and spring.

[oldpro]

 Method #7 potentially http://airgunguild.com/index.php/topic,11.msg140.html#msg140

[rkr]

Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload.  Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming.  Need to engineer a fix for that cause it is annoying !

Hey, some photos or it didn't happen. I've been considering a SSG for my BR Scorpion so it would be nice to see how you did it. Do you reckon it would be enough to push pellets at 55+ fpe in .25 caliber Scorpion?

[Motorhead]

Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload.  Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming.  Need to engineer a fix for that cause it is annoying !

Hey, some photos or it didn't happen. I've been considering a SSG for my BR Scorpion so it would be nice to see how you did it. Do you reckon it would be enough to push pellets at 55+ fpe in .25 caliber Scorpion?

Same deal as previous ....
Machined a HAT just a bit smaller than diameter of hammer cavity, small shoulder to center spring having a short shank threaded for screw.
OEM marauder 6# hammer spring.  Made a delrin spring guide that rests in rear cap to counter spring cant & kill buzz.  * It fitting spring I.D. and at a length just shorter than compressed length required when cocking gun.  Head of screw resting on adjuster dust cap w/ o-ring.

Did try it with hat against hammer core, then again keeping the Red rubber buffer in place between Hat and hammer finding operation quieter with it being there. Running a gap of @ .040" or so.
Cut a clearance slot in stock and were done.

[rkr]

Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload.  Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming.  Need to engineer a fix for that cause it is annoying !

Hey, some photos or it didn't happen. I've been considering a SSG for my BR Scorpion so it would be nice to see how you did it. Do you reckon it would be enough to push pellets at 55+ fpe in .25 caliber Scorpion?

Same deal as previous ....
Machined a HAT just a bit smaller than diameter of hammer cavity, small shoulder to center spring having a short shank threaded for screw.
OEM marauder 6# hammer spring.  Made a delrin spring guide that rests in rear cap to counter spring cant & kill buzz.  * It fitting spring I.D. and at a length just shorter than compressed length required when cocking gun.  Head of screw resting on adjuster dust cap w/ o-ring.

Did try it with hat against hammer core, then again keeping the Red rubber buffer in place between Hat and hammer finding operation quieter with it being there. Running a gap of @ .040" or so.
Cut a clearance slot in stock and were done.

Did you notice any improvements in shot-to-shot consistency?

[benzy2]

I decided to give this a try on the cheap.  All I have invested is a 1/4"x2 1/2"x20 bolt, a nyloc nut, a plastic washer, an oring for an oring kit and a shorter spring.  I'm looking for mild/modest power out of my .177 Gen 1 Marauder but with efficiency.  I have a tube extension so I'm guessing I'm somewhere around 285cc of volume or 17.4 ci.

First run was with the factory spring, just tightened one full turn of the 20tpi nut from touching the hammer (roughly 0.05" gap).  CPHP were shooting 1150 from a 2800psi fill.  First time I've heard a pellet go super sonic in the basement.  I wasn't looking to push those pellets that hard so I swapped a spring from Menards in place.

Second try resulted in 80-85 shots within 4% of the 1001FPS max I saw (didn't write them all down, just took an average of three every 10 shots to keep things moving) from 2200psi to 1525psi peaking at 2000psi-1800psi with 30-35 shots holding under 2% ES.

I've got a few more springs to try out.  I don't dislike the power but I'd like some heavier pellets to drop velocity a bit.  I have a feeling these are still moving a little too hot.  I have the striker all the way in to the hammer so that could be extended to cut velocity a little.  The preload is about as minimal as this spring will take to get off the hammer.  What I can see is I'm somewhere around 1.65-1.70 fpe/ci and its at a point that is very SCUBA tank friendly.  I may try a slightly shorter/softer spring but cocking effort is very manageable so maybe the striker is a better adjustment at this point.

I no longer hear the hammer bouncing off the valve.  I tried the Bstaley mod but still thought it sounded like it was bouncing a bit.  This is as dead as it gets after the initial opening of the valve.  Not pretty how she sits but I'm happy with how efficient she has become.

[Motorhead]

Just finished up an SSG devise for the BSA Scorpion .... same design as M-rods previously.
Utilized a longer 6# spring with heavy preload.  Power easily adjusted to get the JSB 8.4's at 900 fps.
Stupid quiet operation with most noise from hammer spring vibration / strumming.  Need to engineer a fix for that cause it is annoying !

Hey, some photos or it didn't happen. I've been considering a SSG for my BR Scorpion so it would be nice to see how you did it. Do you reckon it would be enough to push pellets at 55+ fpe in .25 caliber Scorpion?

Same deal as previous ....
Machined a HAT just a bit smaller than diameter of hammer cavity, small shoulder to center spring having a short shank threaded for screw.
OEM marauder 6# hammer spring.  Made a delrin spring guide that rests in rear cap to counter spring cant & kill buzz.  * It fitting spring I.D. and at a length just shorter than compressed length required when cocking gun.  Head of screw resting on adjuster dust cap w/ o-ring.

Did try it with hat against hammer core, then again keeping the Red rubber buffer in place between Hat and hammer finding operation quieter with it being there. Running a gap of @ .040" or so.
Cut a clearance slot in stock and were done.

Did you notice any improvements in shot-to-shot consistency?

I did ... rifle had a self done blast tamer in place.  Rifle shot well enough but was still using more air than i thought it should.
BT removed and SSG in place the SOUND of shot now much less telling me valves getting closed much faster ( Reduced dwell )
The ES figures are comparable or a tad better.  Efficiency of air use appears to be the greatest attribute. 

[rsterne]

Method #7 potentially

Isn't that just the original with different materials?.... I meant 6 different modes of operation, as to fixed guide, guide on hammer, floating guides in both directions, etc.etc....

Bob

[oldpro]

I agree just different ways to skin the same cat. #7 though prevents almost all the rod from extending out the rear of the gun.

[rsterne]

#7 though prevents almost all the rod from extending out the rear of the gun

.
HUH?.... Looks like the end of the guide and stop nut you can see in the photo, and it's uncocked.... How does it do that?....

Bob

[oldpro]

Yea bad picture(drawing) Ill cad something up so it makes more since.  But basically the plunger on the hammer slides in and out a orifice on the hammer, the other end is just like before just shorter.

[rsterne]

So the washer on the front of the guide (against the nut) hits the back of the hammer (like in Gippeto's idea) and the guide and nut slide down into the center hole of the hammer?....

Bob

[shorty]

All I can say is wow.

Lots of you guys are getting excellent results. It's taking me more time than I wanted but, I am almost there for testing. I need to find a sleeve for the guide. The system is a little too "crunchy" still.

I went with Travis direction a little with the cassette style.Drilled and taped the end plug all the way for 1/2 X 20 so I can remove the entire SSG without taking the gun apart. This also allows for a longer spring. it's nice but just not smooth yet to try out. I also do not like the guide sticking out so I may counter sink it into the knurled part of the preload adjuster.

I am really curious to know if it will out perform the short stiff spring. I saved an old doc file from testing with the dual wire spring at 1.8" long and 20lbs/inch. According to Travis's .22 numbers at 24 fpe the short stiff spring got a little more at 70 shots under 5% last year.

After reading so much I am starting to wonder if it's not the "bounce" and it's the "preload" that is causing the extra dwell. Since the SSG and the short stiff spring do not use preload it appears as it is starting to boil down to at what is the lowest pressure you can run without a bounce that causes a re-opening of the valve.

[aPpYe]

Hi All, newbie here.  I finally figured out what was the cause of some pretty extreme sudden hammer bounce I have been experiencing, but the experience had me rethinking the idea of a hammer debounce device.  Somewhere along the way, I found this thread.  Awesome idea, and I would like to implement it and see what more efficiency I might gain ...  I am wondering, can this all be done with hardware store parts and a drill press?  I don't have nearly the experience many of you have, and while I can get access to a lathe, it is about an hour and a half from home.  I have a small tap and die set...

Currently, I have a 2400kt that has been converted to air, with a challenger RVA installed at the back.  It seems to me that I can get one of those long bolts that is only threaded at the end to act as the spring guide, another to act as the adjusting knob, and I can use the original end cap from the gun.  Does this sound right?  Since I am seeing that this works best with a longer, weaker spring, would the original hammer spring from the gun suffice? Likely I am oversimplifying things.

This is for a 24" barrelled 2400kt in .177 that has been converted to HPA.  It has an unmodified disco valve and spring and is currently at 1200psi.  I am gonna see what I can get with lower pressure, but it is currently launching 10.3 grain jsb heavies at about 910fps, well into the knee of the curve, as Bob puts it...

... so can this be done with my caveman tools?

[Motorhead]

Hi All, newbie here.  I finally figured out what was the cause of some pretty extreme sudden hammer bounce I have been experiencing, but the experience had me rethinking the idea of a hammer debounce device.  Somewhere along the way, I found this thread.  Awesome idea, and I would like to implement it and see what more efficiency I might gain ... 

... so can this be done with my caveman tools?

Just read the thread and pick up on the earlier thoughts shared on WEIGHT that hammer spring must move tho have no effect on actual strike energy, and the need for enough strength of the stop rod being able to tolerate repeated impacts of decelerating the stop rod components.  ( Think small jack hammer ) and build accordingly.

Have fun !!

[bnowlin]

I guess I have a dumb question, but why couldn't you just put say a 15/16 od by about an inch long medium light spring in front of the hammer kinda like a bstayley mod or the gen 2 NBH with the small spring and pointer Travis had.  The spring shall be light enough to touch the hammer and valve at the same time lightly holding the hammer back until fired and push the hammer back instantly.  only adjustment would be the striker.  Just crazy thinking.
Bob

[rsterne]

The spring as you describe, aided by the closing of the valve, would throw the hammer back even harder, to store even more energy in the hammer spring.... Whether or not it could prevent a re-strike would be a matter of getting the rates perfect.... The stronger you have to make the return spring to prevent the hammer re-opening the valve.... the harder you would have to launch the hammer on the firing stroke to get the dwell you need.... It may or may not work as intended.... but for sure you will need more hammer energy, making the gun harder to cock....

Bob