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

[shorty]

What bullfrog and Bob says is one of the reasons why I am sticking with the short stiff spring for now on the marauder platform.

You just can't get the spring power from the SSG before it bottoms out (coil bind) with a reasonable design that doesn't stick far out of the gun. It works great for lower power, but a short stiff spring does the same (atleast for me).

I am not saying the SSG isn't good for the marauder platform. It has a specific job that is limited for power and power range. Now, if you go nearly full bore porting (which the marauder can not do) the SSG like Bob mentions in his grizzly at 100 fpe sounds good but isn't really apples to apples.

I made this video a year ago or so. Looks silly now Listen to shot signature and look at the power levels. This was with a nearly stock gen 2 marauder .22cal. Since then, I have opened everything up to as far possible. The power levels at 3000psi can now be made at 2000psi and the gun maxes out to 56 fpe with 25.39 grain. Sure good example of what porting can do. Most importantly, each shot was extremely efficient.


I think it was canniborrowsomeammo is running my short stiff spring in his 25 cal marauder with war valve. I think he hits in the high 90's FPE I just don't know what he can turn it down.

I look at it this way. Short stiff spring, cheap and simple with capabilities of 1.84 efficiency with extreme power ranges vs SSG elaborate/novel/expensive with the same efficiencies and with limited power capabilities.

It may sound like I am against the SSG but I am not. It has it place on the playground. There's a lot of people reading this thread and trying out the design along with selling them now. Its important (to me) that people know what they are building or buying and what it's capable of.

[mooseslayer]

I am still trying to get my disco .22  tuned with the available .040" spring I have and am ordering more springs. I couldn't get past 720fps with 15.89 JSB. I tried combining springs but would get coil bind. I needed to lengthen my endcap so I could use a longer SSG and spring. Then yesterday I got the bright idea to weld a 3/8 nut to my end cap and then i could use a longer spring. It worked and I am up over 800fps with a quick test.
I also noticed throughout this process, that if I dial it in so no gap it gets so much louder and I was over 910fps...basically like not having the SSG. Create that bit of gap and instantly much quieter, but I lose a lot of power.
I think I am on the right track. I made a 4" guide and threaded it for a long way and it sticks out and looks terrible but once I find the tune and power and shoot a string to confirm more shots and efficiency I will cut and clean it up, possibly make a shroud that will cover everything and prevent a pinched finger. Eventually I will probably move to the design that has less sticking out the back if possible.
Ordered .312 OD springs in .037, .041, .047 and .055 in 10" lengths for about $5 apiece so something should work.

[rsterne]

Just to clarify, my Grizzly is only 75% porting, and over 100 FPE in .30 cal.... The only reason I mentioned it is to point out that the SSG can be used in higher FPE applications, it is NOT limited to low power.... In fact, the first gun I converted in this thread to the SSG, basically a Disco with a 2260 air tube, is now turning out 57 FPE with JSB King Heavies.... When tuned with the 25.4 gr. Kings, it went from 5 shots to 7 with a narrower ES, at the very same 50 FPE, running on only 1880 psi.... That is NOT a low power output.... If the MRod isn't suited to maximum power with an SSG, you can hardly fault the SSG, can you?....

Bob

[shorty]

Bob you right. No fault of the SSG.

The thing is, what you are showing is extreme modified guns using the SSG. Most or everything I have read that people are using the SSG for is for stock to semi stock guns.

Put an SSG in a stock marauder 22 or 25 and you will not achieve the power levels you used to get. You will need to de-tune to a normal FPE to even cock the gun before coil bind or make a 1.5 inch extension out of the back of the HS adjuster cap.

This doesn't flaw the SSG either. I have plans for it's use too during my experiments with running an extremely low pressure regulated gun for max shot count at a normal plinking hunting gun.

Run a war valve with an SSG and a stock length barrel in a 25 and you will not be able to tune over 60 fpe (using it with negative pre-load) without coil bind, way too excessive cocking, or an extension out the back.

Calculated out, that would be 25 shots at 60 fpe with a 1.58 efficiency from 3000 psi to 1800 psi. The spring force needed to achieve this with a stock hammer is approximately 15 lbs per inch compressed on a SSG guide to allow for .02" negative preload. The guide would need to stick out of the back of the gun a minimum of 1" to allow the spring to be long enough to not go bind before full cock.

[oldpro]

 Shorty you didnt see my strings? They were all done with stock M-rods and I was able to shoot into the high 800s with out any spring bind you just have to mod the parts to allow for a longer spring to be used and it all fits inside the stock mrod. heres a bone stock mrod .25 and its easy tocock and the whole SSG is internal. I should have started this string 10 shots earlier but I was testing changes from spring to spring at a 2800psi fill.

Created: 01/18/16 06:14 PM
Description:
Notes 1: stock .25 cal marauder
Notes 2:
Distance to Chrono(FT): 1.50
Ballistic Coefficient: 1.000
Bullet Weight(gr): 25.40
Temp: N/A °F
BP: N/A inHg
#          FPS  FT-LBS      PF
29    ERROR 3
28    846      40.37    21.49
27    845      40.28    21.46
26    850      40.76    21.59
25    855      41.24    21.72
24    860      41.72    21.84
23    854      41.14    21.69
22    864      42.11    21.95
21    862      41.91    21.89
20    863      42.01    21.92
19    865      42.21    21.97
18    868      42.50    22.05
17    871      42.79    22.12
16    860      41.72    21.84
15    866      42.30    22.00
14    867      42.40    22.02
13    865      42.21    21.97
12    870      42.70    22.10
11    871      42.79    22.12
10    864      42.11    21.95
9    866      42.30    22.00
8    866      42.30    22.00
7    860      41.72    21.84
6    855      41.24    21.72
5    846      40.37    21.49
4    858      41.53    21.79
3    846      40.37    21.49
2    847      40.47    21.51
1    847      40.47    21.51
Average: 859.2 FPS
SD: 8.6 FPS
Min: 845 FPS
Max: 871 FPS
Spread: 26 FPS
Shot/sec: 0.1
True MV: 859 FPS
Group Size (in): 0.00

[Matt15]

It doesn't, it allows you to get the same power with a lower maximum cocking force by using more preload.... Three examples using 1" hammer travel.... same average force (10 lbs.).... giving same hammer energy....

No preload, 20 lb/in. spring.... maximum 20 lbs.
5 lbs. preload, 10 lb/in. spring.... maximum 15 lbs.
8 lbs preload, 4 lb/in. spring.... maximum 12 lbs.

If you used the exact same wire size and coil spacing, the 10 lb/in. spring would, however, be twice as long to start with as the 20 lb/in. spring.... You would start with it compressed 1/2", and it would be compressed 1.5" when cocked.... Then it would have to have enough room for all the coils (twice as many) on top of that.... so it needs more space behind the hammer....

Bob

Thanks Bob!! I understand now!!

[Sfttailrdr46]

Shorty you didnt see my strings? They were all done with stock M-rods and I was able to shoot into the high 800s with out any spring bind you just have to mod the parts to allow for a longer spring to be used and it all fits inside the stock mrod. heres a bone stock mrod .25 and its easy tocock and the whole SSG is internal. I should have started this string 10 shots earlier but I was testing changes from spring to spring at a 2800psi fill.

Notes 1:
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 0.00
Temp: N/A °F
BP: N/A inHg
#          FPS  FT-LBS      PF
24    851      0.00    0.00   
23    852      0.00    0.00   
22    854      0.00    0.00   
21    861      0.00    0.00   
20    858      0.00    0.00   
19    861      0.00    0.00   
18    867      0.00    0.00   
17    864      0.00    0.00   
16    868      0.00    0.00   
15    868      0.00    0.00   
14    871      0.00    0.00   
13    872      0.00    0.00   
12    874      0.00    0.00   
11    875      0.00    0.00   
10    873      0.00    0.00   
9    881      0.00    0.00   
8    882      0.00    0.00   
7    883      0.00    0.00   
6    872      0.00    0.00   
5    884      0.00    0.00   
4    879      0.00    0.00   
3    884      0.00    0.00   
2    874      0.00    0.00   
1    878      0.00    0.00   
Average: 870.2 FPS
SD: 10.1 FPS
Min: 851 FPS
Max: 884 FPS
Spread: 33 FPS
Shot/sec: 0.1
True MV: 870 FPS
Group Size (in): 0.00


Sent from my iPho

Are you going to fabricate and sell the M-Rod SSG ?

[oldpro]

On bottom of page.
http://wickedairrifles.com/store.html

[oldpro]

I can shave $10 off price if buyer wants to drill out their own hammer and use it. Also as a service for $50 send in your parts and I will machine and set up yours and include extra spring for tunning like with above. I can set them up fairly close so only small adjustments will be needed. 

[Sfttailrdr46]

On bottom of page.
http://wickedairrifles.com/store.html

Thanks just ordered next a nice wood stock 

[oldpro]

And another in .22 and all of these are internal SSG not getting anywhere near spring bind or hard to cock.
ated: 01/12/16 06:04 PM
Description:
Notes 1: bone stock marauder .22 with SSG
Notes 2:
Distance to Chrono(FT): 1.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 14.30
Temp: N/A °F
BP: N/A inHg
#          FPS  FT-LBS      PF
58    881      24.65    12.60
57    889      25.10    12.71
56    889      25.10    12.71
55    895      25.44    12.80
54    882      24.71    12.61
53    886      24.93    12.67
52    889      25.10    12.71
51    883      24.76    12.63
50    881      24.65    12.60
49    890      25.16    12.73
48    896      25.50    12.81
47    894      25.38    12.78
46    895      25.44    12.80
45    891      25.21    12.74
44    904      25.95    12.93
43    892      25.27    12.76
42    904      25.95    12.93
41    895      25.44    12.80
40    905      26.01    12.94
39    894      25.38    12.78
38    899      25.67    12.86
37    892      25.27    12.76
36    911      26.36    13.03
35    908      26.18    12.98
34    911      26.36    13.03
33    909      26.24    13.00
32    891      25.21    12.74
31    897      25.55    12.83
30    907      26.13    12.97
29    900      25.72    12.87
28    912      26.41    13.04
27    914      26.53    13.07
26    898      25.61    12.84
25    895      25.44    12.80
24    891      25.21    12.74
23    898      25.61    12.84
22    911      26.36    13.03
21    913      26.47    13.06
20    895      25.44    12.80
19    900      25.72    12.87
18    891      25.21    12.74
17    911      26.36    13.03
16    901      25.78    12.88
15    907      26.13    12.97
14    903      25.90    12.91
13    887      24.99    12.68
12    918      26.76    13.13
11    906      26.07    12.96
10    899      25.67    12.86
9    899      25.67    12.86
8    896      25.50    12.81
7    900      25.72    12.87
6    894      25.38    12.78
5    893      25.33    12.77
4    896      25.50    12.81
3    882      24.71    12.61
2    888      25.04    12.70
1    ERROR 10
Average: 897.5 FPS
SD: 9.2 FPS
Min: 881 FPS
Max: 918 FPS
Spread: 37 FPS
Shot/sec: 0.1
True MV: 898 FPS
Group Size (in): 0.00

[shorty]

Travis,
I did see your strings with the SSG. I'll be as honest as possible without trying to insult/disrespect/ or make it appear as if I am selling something. I think you made a great working SSG.

But,
I wish I was able to get one of those short stiff springs in your hands for some testing on the marauder platforms. It has the same efficiency as an SSG system. More of a power range. No modifications to the gun. Still have control over the throw. And will not cost your customers 100 bones. Heck it can take your war valve from 35 FPE up to 85 FPE with just adjusting the HS with efficiencies of 1.3 to 1.8.

Shoot me a PM and I will send you some for yourself to try out. I will even show you how they are made and with what material. All I ask you is to have an honest opinion of them.

[oldpro]

 I understand what your saying shorty BUT Ive already been down that short stiff spring road and the SSG for one cocks WAY easier and is far more adjustable across the spectrum. Your SSG wasnt made correctly or implemented well or you would see that yourself. I have far too much data that tells me the SSG is right now the best thing going. Easy to cock/spring changes easily/Beginners can tune/can be adjusted from-0 to max with ease etc etc. Maybe you should start a short stiff spring thread this doesnt seem to be the place for it in the SSG thread IMHO.  Shorty do you have some strings you can post of short stiff spring in 50fpe gun or around there I have never seen and effiecency of 1.8 using any type of spring alone in anything put a very low powered gun or high fill pressure gun with short shot count. Ive posted more strings then everyone combined. This is also not meant to call you out or doubt you but my personal experience says SSG wins hands down.

[shorty]

The table was from a long time ago with just TP and exit port matched at .141" using the short stiff spring.

Things are much different now. Remember when I converted this gun to .357 , http://www.gatewaytoairguns.org/GTA/index.php?topic=91575.20

Efficiency at 80 fpe was 1.37.

If you want me to post the strings I can. I keep them all stored on my PC. Just thought a table is a little more presentable. Lot's of it is old data from last year.

[rsterne]

shorty, I have to admit, those are great results.... I'm impressed.... You don't really have any before and after comparisons, but your results at 25 FPE are comparable to what Harry got with his Excalibre a decade ago.... and are very good for the power levels.... I do notice that as you push the power, the efficiency REALLY drops off, though, which is to be expected because the spring no longer has negative preload.... I've used lots of short stiff springs along the way, and I've never achieved those sorts of numbers, although as I said before the efficiency is definitely better than a conventional preloaded spring.... Perhaps the reason was that I have never really been interested in the lower end of the power range, which is where your numbers are particularly stunning.... I'd noticed how quiet the gun is when you back it off a ways, but never really explored that part of the power range.... What I didn't like was how hard the gun was to cock when you get up onto the knee of the curve, pushing the power like you did in the two right hand columns, where the efficiency is back to normal.... If you've solved all those problems, you are to be congratulated....

Bob

[shorty]

They have been solved with 75% matched porting and extra hammer travel.

I was asked to no longer post on the SSG thread.

[oldpro]

 I didnt ask you NOT to post in the SSG thread I said in writing that you should start another thread about the Spring. I think it will have a life of its own if you do.Otherwise well have to clump that in and oring buffers and regulators etc.  I have tested all kinds of short stiff springs ,Bob also and they require far to much cocking effort and bind very easily and If you have to match port the valve to get where the SSG is now then when you match port the SSG youll still be behind lets not forget how easy it is to tune and SSG compared to and conventional Spring/ guide arrangement. One only needs two get two things to set full curve. Fill pressure at crack and starting FPS wanted for curve the SSG will balance out the rest. Plus spring changes are all external. If making a simple spring change was all it took all the manufacturers would have done it and Many people, SMART PEOPLE would have done it by now. Your results are good and about what Ive seen doing what your doing maybe a little better but still not as good as the SSG

[rgb1]

Shorty, any chance you're an old FT shooter?  Those folks
were all using stiff springs with no preload back in the 80's.

                                                                         Ron

[rsterne]

I was curious what I could get for efficiency using the SSG.... so I took my 2260 HPA, which is regulated at 1600 psi, and started dialing back the power and recording the pressure drop for 20 or 30 shots, using 18.1 gr. JSBs.... Here is what I came up with....



This is the first time I have had an efficiency greater than 2.0 FPE/CI.... At just under 12 FPE, I got 2.12 FPE/CI, which is 7.7 barcc/FPE.... That would give me 250 shots per fill on the 13 CI tank.... Adjusted for 23 FPE, the efficiency would be 1.7 FPE/CI and 100 shots per fill.... The way the gun is normally tuned, at 37 FPE, I can actually shoot down to 1400 psi without velocity drop, and I get 60 shots (6 mags.)....

Bob

[Matt15]

Wow!!! 2.12 FPE/CI!!! That is awesome Bob.