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PostPosted: Wed Jan 06, 2016 8:47 pm 
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Joined: Wed Sep 10, 2014 2:42 pm
Posts: 147
Location: Ontario
Done mine. Just need to try it out. Need daylight for my chronograph to test.

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PostPosted: Wed Jan 06, 2016 9:40 pm 
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Location: Mississauga, ON
Does this device have to be made unique on a per gun basis, or would one design work for specific guns? I guess what I have in mind is - could someone make some that would fit say all 2240 pistols? Say all with stock hammer weights? Would barrel length require some change?

To get to the point - I would buy one for my 2240 but don't want to make one.

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Daisy 953 * QB78D * Walther 1894 * Beretta CX4 & PX4 * Zoraki HP01 * Beeman P17 * Walther CP88 Comp. * Crosman 1377/2240/SA6/357-8
Swiss Arms P92 * Colt Commander 1911 * Walther PPK * P08 * Colt Python 357 * TW 1911/Limited * S&W M&P R8


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PostPosted: Wed Jan 06, 2016 10:04 pm 
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Posts: 87
Fascinating.

Would this work equally well at lower pressures and velocities?


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PostPosted: Wed Jan 06, 2016 10:16 pm 
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Joined: Mon Oct 04, 2010 4:20 pm
Posts: 191
Location: GTA
Here's mine for a Disco:

Image

Image

Spring is just under 2 inches and diameter is .033"

Bolt is 3 inches (3/16 drill rod)

3/8 hex nut is 1 inch drilled out to 13/64 my next size up from 3/16 to accomodate the drill rod bolt

Set up as Bob specified with bolt just stopping before touching the hammer (unchocked) I'm shooting in the mid 600s using JSB 18.1 so I guess I need a thicker spring to get up into the 700-800s...

What do you think Bob?

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1377c
2289g
Disco


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PostPosted: Thu Jan 07, 2016 8:21 am 
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Joined: Mon Aug 24, 2015 4:56 pm
Posts: 462
Location: Tecumseh, Ontario in South Western Ontario
74% really is amazing especially for us hand pumpers.
I'm wondering though if it's as effective in different guns.
For instance my at44 has a wishbone shape lever to prevent hammer bounce I believe.

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PostPosted: Thu Jan 07, 2016 11:28 am 
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Location: Coalmont BC
You certainly have the concept correct, joed66.... It would have been better to start with a longer spring.... Most of my first attempts have resulted in low velocity, and I have to find a longer spring where I can use more preload to get that back.... Providing you have enough travel without hitting coil bind, you can use a stiffer spring, but your cocking effort will increase.... That may not be an issue in a stock Disco....

There is no reason this won't work in a 22XX, in fact it may result in a big increase in shot count when done properly with CO2.... Guns operating at low pressure are more prone to hammer bounce, so the potential savings are certainly there....

There are already small shops in the USA (eg. W.A.R.) who are setting up to produce the SSG, with the concept of having units pre-adjusted for stock guns like the MRod and PRod.... I have given them persmission to do this, free of charge.... I see no reason one cannot be made for a stock Disco, for example, and possibly a stock 2240.... For the most part, if a gun has been modded, then you would need to change the preload, or possibly the spring.... I think Travis at W.A.R. plans on having a few SSG "Cartridges" available soon....

I plan on pulling my AT-44 apart to see if it is possible to fit an SSG into that.... I realize it already has a hammer anti-bounce device, but it seems to me that if that was working as it should, the efficiency of that gun should be higher.... Certainly if a gun has no hammer bounce, the SSG won't help.... but so far everyone who has tried one, once they get it adjusted correctly, has found an improvement.... My guns are typically running 20-50% higher shot count....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Thu Jan 07, 2016 12:13 pm 
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Location: GTA
joed66 wrote:
Here's mine for a Disco:

Image

Image

Spring is just under 2 inches and diameter is .033"

Bolt is 3 inches (3/16 drill rod)

3/8 hex nut is 1 inch drilled out to 13/64 my next size up from 3/16 to accomodate the drill rod bolt

Set up as Bob specified with bolt just stopping before touching the hammer (unchocked) I'm shooting in the mid 600s using JSB 18.1 so I guess I need a thicker spring to get up into the 700-800s...

What do you think Bob?


I was wrong in stating that I was hitting mid 600s with the bolt stopping before touching the hammer (unchocked). Its actually low 500s.

I have tried playing around with the various springs I have (all under 2 inches) with out being able to improve velocity.

The only way I can achive the velocities I am looking for (ave 750 fps) is by turning in the 3/8s bolt in to the point where the bolt preloads the hammer (not a ton) see below.

Image

I've done some preliminary shooting through the Chrony and although this setup will waste air (as explained by Bob earlier) I am seeing a moderate improvement in shot count and consistent POI I'll have to do more testing later to confirm this. Start pressure is 1800 psi down to about 1000 ave 749fps.

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PostPosted: Thu Jan 07, 2016 6:36 pm 
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Location: Coalmont BC
I'm VERY familiar with your situation.... Check to make sure the guide is loose enough in the adjusting bolt, you need a few thou clearance, drag is BAD there.... Also make sure there is a loose fit between the end of the guide and the spring and the ID of the hammer, any drag there will kill velocity.... Then increase the preload on the spring until your velocity comes up.... as you shorten the guide, you will have to move it closer to the hammer by screwing in the adjusting bolt the same amount.... If you run out of adjustment, you need a longer spring.... You can use two springs (or 1.5 springs) on the same guide, just make sure they have closed ends so they can wind into each other....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Thu Jan 07, 2016 8:41 pm 
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Joined: Tue Oct 13, 2009 1:27 am
Posts: 2514
Location: Vancouver
Been playing with springs having wire thicknesses of 0.025", 0.032", 0.035", total lengths ranging from just over 2" up to 3.35", preloads ranging from 20% to 45%, but at the very best I'm able to come close to matching the shot count of my previous spring with RVA. That spring measured 0.035" x 1.4", with the spring loaded to the tune of 2-1/4 turns in from full slack, making for light preload on the hammer. My valve poppet stem protruded 0.475" from the valve, but this was not a problem, as I got a nice long shot string with a modest noise level. Still, owing to a concern that perhaps the valve might be dumping air with a too-deep hammer impact with this SSG setup I added a delrin spacer with an O-ring between that and the valve leaving just 0.80" of stem exposed, which should be short enough travel to avoid dumping excess air, especially with the Lane regulator set at just 800psi. My best effort with an SSG so far has resulted in a 2% power drop and 1 to 2 shots fewer per fill. Here's the spring combination which delivered that almost-as-good-as string, using a 1.25" long 0.035" together with a 1.1" long 0.025" and a shorter section of 0.025" spring added, though I also tried without that extra few coils:

Image

Today I went to Rona and looked around for spring sources, found a sliding guide for a folding door with two springs in it having 0.025" wire and total length of 3.35". Compressed onto my guide, with 0.080" clear from the end of the stop to the end of the hammer hole, the length is about 1.75" and adjustable down to about 1.65" before coil bind prevents cocking. Cocking effort is a lot easier than most of the springs I've been trying so far, but with some fussing on the outer bolt adjuster and stop length to match I was able to arrive at 100% of my original power level. Pumped the HiPAC with single extension up to 3,000psi and shot a Chrony string. At 75% of my previous string duration velocity started dropping off rapidly. Here's that insert assembled, with a floating delrin spacer inserted for better spring end alignment:

Image

So going to softer springs seems to be going in the wrong direction somehow. As much as I like the easier cocking effort, a 25% drop in efficiency (strange, because my sound meter is saying it's consistently at least 2dB quieter this way) isn't great, so I'll have to go back to firmer springs. Might even just go back to an RVA. This is getting really frustrating and taking a lot of time and pellets while seemingly going backwards. Perhaps Bob or someone else can spot something I'm doing horribly wrong/backwards which might explain this reversal of the incredible results he and others are getting? I lightened my hammer from the previously lightened 48 grams down to 42 grams (stock 2240 hammer is 60 grams) in case that might help, but it hasn't. Cleaning carefully (all surfaces are polished inside) and lubricating with a hint of dry graphite powder hasn't helped. Increasing the gap between guide end and hammer hole end to as much as 0.25" hasn't helped. Mostly any adjustment away from what's in the second picture results in dramatic velocity drops.


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PostPosted: Thu Jan 07, 2016 10:52 pm 
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Joined: Tue Oct 13, 2009 1:27 am
Posts: 2514
Location: Vancouver
And a slight update; though frustrated I persisted, and swapping out one of the new springs for the middle one from the first picture (also 0.025" wire and with wider spacing, but significantly more resistant to compression - it's a bit less than half of a Glock 17 firing pin spring I picked up from Reliable so I guess made of better steel?), I was able to get 36 shots at 98% of my former velocity, which setup was giving me 41 shots. Firmer definitely equals an improvement in this case. Still not overly difficult to cock. Slightly quieter still, no trace of the tell-tale burp.


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PostPosted: Fri Jan 08, 2016 12:05 am 
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Joined: Sat Nov 03, 2007 4:19 pm
Posts: 8972
Location: Coalmont BC
Hope you can get it sorted.... I have no more suggestions....

Bob

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Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Fri Jan 08, 2016 12:26 am 
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Joined: Tue Oct 13, 2009 1:27 am
Posts: 2514
Location: Vancouver
As I find other springs I'll try other settings... Perhaps a different length of rod and outer bolt giving a bit more room to adjust. Meantime I'm not too worried. The ES with this latest string is about 1.3% and that ain't bad.


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PostPosted: Fri Jan 08, 2016 11:20 am 
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Joined: Sat Nov 03, 2007 4:19 pm
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Location: Coalmont BC
Most installations require moving the adjusting bolt (RVA) back somewhat, which means a longer end cap.... to accommodate the longer spring.... It certainly isn't a given that you can do the SSG without increasing the length.... in fact you should probably count on it....

Bob

_________________
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal;
Too many! Springers, Pumpers, CO2, but I love my PCPs and developing them!
Proud Member of the 2000+fps Club!


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PostPosted: Fri Jan 08, 2016 12:35 pm 
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Joined: Tue Oct 13, 2009 1:27 am
Posts: 2514
Location: Vancouver
In my installation I'm using a 1" aluminum tube as an adapter between the new end plug and my old 3/4" pipe stock. The 1" tube slips firmly onto a very slightly tapered delrin plug to set firmly up against the steel breech's back end with a notch cut out for that to prevent rotation. I needed at least 0.7" beyond the main tube for that, so that's what I cut it to. If necessary I can go as long as 1.125" behind the main tube with another delrin plug before running into the the 3/4" tube and its delrin adapter sleeve which are a hard pressed fit. But considering examples shared by a number of other members in your GTA forum thread on the SSG it doesn't really seem likely to be necessary, as mine is within average range for the extended portion.

Image

I've drawn on the position of the hammer's back end when fully forward against the valve stem, giving a total distance of 2.4" from the back of the delrin plug to the inside end of the hole in the hammer. Anything shy of that in SSG cartridge spacing leaves a gap, so knowing my total SSG stem length is 2.9" it's easy to ensure at least 0.5" is sticking out the back end of the delrin and adjust as necessary with the larger bolt/guide.


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PostPosted: Fri Jan 08, 2016 6:20 pm 
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Joined: Tue Oct 13, 2009 1:27 am
Posts: 2514
Location: Vancouver
Went a bit further today, tapping out the delrin end cap to 7/16-14NC as that's what I had handy for the next bigger bolt and tap in my shop. This bolt left just enough room to hollow it out for the spring, something I hadn't been able to do with the first try, so I bored it out leaving just the last 0.20" at the slightly loose SSG rod fit. This left considerably more room for spring length. I also made a 0.7" longer SSG rod and threaded the ends 10-32, installed a nut at the far end and peened that and ground it and polished it to an easy fit into the hammer. Put a leather washer on this time to absorb a bit of the impact, then set about testing various spring combinations.

Results seem to point to my needing a very long (3" or perhaps longer?) spring with 0.030" wire, something I've not been able to find around here so I'll have to order one. Bought a tire pressure gauge yesterday hoping there'd be something like that in it... but alas, though the spring was of very high quality finish and over 4" long with 0.035" wire, the OD is just a bit large at 0.335" so it won't fit into the Crosman striker. Perhaps I could grind it down in OD.... but that's tedious and probably doomed to inconsistency. Anyway, I thoroughly established that even with the counter-bored adjusting bolt and longer spring total and longer bolt, weak (0.025") springs are useless for both consistency and efficiency in my setup. 35 shots or less with too wide an ES. Best result was a 4% power increase over 35 shots, after I gave up on the longer rod and went back to the first one I'd made at 74mm long. No way with the SSG and my existing spring combinations to get my 40 shots back at the same power. Dropping preload with that best setup just got me 35 shots at weaker power then dropping off sharply at shot 36. These 35 shots are fairly consistent, though the odd one outside 2% ES range. Still, I'll settle for this string until I can access more springs to test.


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