Tuning Pros and Cons of SSGs ?

[Parrotculler]

I think I understand the pros of a Spring Stop Guide (SSG). It increases the accuracy of the hammer spring preload and stops the hammer from hitting the valve stem too hard. More important, it stops the hammer spring from bouncing, thus eliminating the ping-pong contest with the valve spring. Hammer bounce is thus avoided or at least greatly reduced. As a result, less air is wasted, shot count goes up and the burping (or "trrrrrrrttt") noise is a thing of the past. No need anymore either to increase the regulator set point or the valve spring pre-load merely to provide more "push-back" against that bouncy hammer. Less stress on the system and less noise.

Are there other benefits ?

And what are the downsides I wonder ? One SSG concept I have seen in a recent thread about the Kral Puncher Jumbo is very nifty. In this "external" SSG, the hammer spring is controlled on one end by a tapered pin, which also serves as the contact point with the hammer pushing it forward. The other end of this pin (which also serves as a hammer spring guide) is threaded and controlled by a bolt that slides out of a hole in the hammer spring adjuster screw when the rifle is being cocked. When fired, this contraption jumps forward until it hits the hammer spring adjuster screw, stopping it. I guess a variant would have the pin simply glued/epoxied/threaded in the inside of the hammer instead of being loose in it. This could be done by drilling further into the existing hole of the hammer, but with a smaller diameter to suit the SSG pin. This second concept may provide a more stable hammer spring guide than the first -- perhaps with less action noise as a result ? But then the pin also becomes part of the hammer, which then gains weight. And in this variant also, the pin is again halted by the hammer spring adjuster screw. That important screw therefore needs to be pierced to enable the pin to slide through it. Does this weaken the hammer spring adjuster screw or make it less stable ? Does the shock when the hammer spring is stopped move the position of the hammer adjuster screw ? Does the screw being hit make noise or create recoil ?

Other concepts / pros / cons ? Thanks !

 

[JimNM]

I think the Kral part you speak of is intended to keep the hammer oriented correctly in the slot, rather than reduce hammer bounce. The hammers on my Puncher Breaker and Knight did have an issue with hammer bounce. I installed a twin spring system on them both. Consistency and shot count improved markedly on both guns, and the shot cycle on the knight went from unpleasant (twangy) to almost undetectable.

 

[vmaxpro]

Cons - harder cocking for some. Side lever probably wouldnt even notice. I made one for my brocock and its awesome. Way more effecient and smooth shot cycle.

Another I suppose con would be it adds to manufacturing costs in something mass produced.

 

[Parrotculler]

Thanks JimNM! What dimensions (OD, ID, length) did you use for that second spring ? As I recall, the hammer spring on the PB has an OD of 10 mm and an ID of 8 mm. (Side bar: my PB hammer spring guide is only 6 mm in diameter for some reason, 2mm less than the spring ID. Due to the considerable wiggle room the spring is not properly guided, mine was crooked. I put a delrin sleeve over the guide to stabilize the spring.)

In other words, I guess the PB has a fairly large spring enabling insertion of another spring inside it. Note: the hammer spring of the Puncher Pro (and potentially also the Jumbo, not sure yet) is much thinner, OD = only 8mm, ID = 6mm. Unclear to me how a second spring could be inserted into such a relatively narrow spring.

Or am I getting the twin spring concept all wrong ?

 

[JimNM]

I bought turn-key solutions from Troy Hammer at Annihilator airguns. The new gen bottle guns (Pro, Knight, etc) have a different hammer that needs to be bored to size and cut down to length. That part is hardened steel and will take specialized tools to accomplish. Contact Troy (THAMMER here on AGN) to get your own.



https://www.airgunnation.com/members/thammer/

 

[thammer]

The twin spring does the sme thing as the ssg for the most part. It's much simpler to install and allows for a lighter hammer to be used (In the Kral guns) but keep the same power. No modification to the stock or exterior of the gun is required with these twin spring. The bottle guns use a longer, heavier hammer. That was the fix to lower cocking effort and get full power but really messed up the firing cycle. I modify the factory hammer by shortening it 3/8" and boring the hole to ½" then installing a twin spring. Pic should show the differences in the hammers. 

 

[Motorhead]

Every single PCP I own if possible to incorporate a SSG devise has one !!

Even my Field Target competition rifles use SSG's as well the high power guns using Balanced valves get SSG's



As a professional tuner having spent countless hours in the R&D and proof of concept of the devise, tuned with and without .... I'm sold the devise works !!!



If there is a down side ? ... and there is, Would be that you loose a wide power spread that some guns afford via radical changes in HST.

SSG's tuned to a specific power output in harmony with regulator settings simply can't be beat with any other configuration IMO for high efficiency, shot to shot consistency and lowest muzzle report. Another plus is,in most applications because you have more spring Pre-Load the action is fired quicker ( faster lock time ) aiding guns accuracy potential further.



Do they work in non regulated configurations ? Yes but no where as well as in regulated guns.





JMO,

Scott S

 

[Parrotculler]

Thanks Troy! The pre-mod hammer you show is the exact same one as in my Puncher Pro 6.35 (not the bottle version but the cylinder version with cocking bolt). After I regulated it, hammer bounce started reducing shot count - just like you said in one of your videos. I then lightened the hammer and increased the reg set point -- shot count doubled to 38 consistent 55 joule shots (ports opened all the way thru to 4.5mm). I would be grateful for your validation as to whether that's good shot count for my 330cc cylinder, or could still be improved upon? Note also that cocking remains smooth -- I wonder if double spring would not make it too hard on the bolt. My only real frustration: the JSB king heavies travel at only 223m/sec from the 58cm long barrel. Slightly underpowered IMHO -- presumably 100m accuracy could be better at higher speeds don't you think? I wonder how I can increase that speed though -- Open up the ports more ? (I would send this beauty over to you for some TLC but I live in Europe...). Advice in the above points appreciated!

 

[Parrotculler]

Much appreciated !

 

[Parrotculler]

Much appreciated Scott! I got lucky receiving this kind of feedback from you and the other airgun luminaries who have been kind enough to respond.

Which SSG do you prefer -- the one where the guide is attached to the hammer (epoxied in, or threaded) or the one where the system is loose inside the hammer? I would like to evaluate these options against the dual-spring method Troy has suggested.

I would think that the fixed variant makes for a more solid ensemble, perhaps causing less vibration and action noise than the other SSG option? But it might also make the hammer heavier again ... Wonder what the better approach would be for my new Kral Jumbo 6.35 that is presently making its way from Valencia, Spain, to the north where i live ...

Thanks again!!

 

[Vetmx]

The type of device you use to eliminate hammer bounce sometimes depends on your guns design. I use the design that sticks out the back of the gun if it’s hidden, semi hidden or a really clean design. On my Prod I had to use an internal SSG because I have the gun in a stock that I didn’t want something mechanical sticking out the back. The Prods hammer didn’t require me to drill a hole which we know is no fun with hardened steel. There was barely enough room in the Prod and the spring had to be heavy which made cocking no fun. I regulated the Prod and was able to then use a spring that made cocking almost as friendly as stock. Just remember, either of these designs requires a heavier spring because you are no longer trying to drive the hammer through the valve. The hammer is in free flight and has lost some of its ooomph. 

 

[Motorhead]

Exactly .... the "TYPE" SSG one can use is many times w/o choice based upon design of the gun & if or not Stock clearance for an external can be done ?



Myself ... MUCH prefer a free floated SSG that is NOT attached to the hammer. It can float independent or be attached to the end cap ... just not attached to hammer !!

Outside of my RAW / Theoben guns that allow a completely hidden design, all are external rod types, when cocked the stop rod becomes a COCKED indicator extending outward off the rear cap.

This one for a gen2 m-rod. It stays attached to end cap, tho when SSG stops spring expansion the hammer is free to continue forward striking poppet stem.

These types are the MOST CONSISTENT because the energy from the spring transferred to the hammer makes a clean break being just an instant disconnect.

* Unlike designs in M-rods where a bolt goes threw the hammer and when spring expansion stops THE BOLT / SPRING ASSEMBLY that was stationary is now brought into motion. This absorbs energy and hurts the consistency ... they still work, just not as well.



Scott S

 

[Vetmx]

I agree with Scott. Here is something else to consider. The one attached to the hammer is a nice hidden design but another drawback is just simple physics. When you pull the trigger, your hammer is propelled forward but the spring and guide are propelled rearward. Think of it as a tug of war. Fat guy is gonna win but the skinny guy will scrub off some of his speed. This can lead to some of the inconsistency Scott mentioned. But it is still better than having your hammer act like it’s in a pinball machine. 

 

[Parrotculler]

Thank you Gentlemen for sharing those valuable insights! They bring airgunning to the next level. Just like the choice and price/quality ratio of PCPs has expanded dramatically over the past few years, I wonder if more of them will start coming with SSGs in the near future. It seems like a natural evolution, especially since the parts really don't break the bank ... I picked up the necessary yesterday for just a few bucks ... 

By the way, in doing so in a German hardware store I came across those little Ballistol bottles (the original) for around 2.5 EUR apiece. Best price I had ever seen them at ... I came away with this gratifying feeling that authentic quality sometimes comes at a LOW price ! 

 

[Motorhead]

Sadly I don't think SSG's will ever become mainstream ... simply because they lack a broad adjustment range that is easily changed by the end user. 

Alternatives allready exist giving a similar effect while having a broad adjustment range a simple screw turn away.

These being FREE FLIGHT hammers systems using light hammers and heavy springs we are seeing more & more of in High leverage side lever cocking systems.

Many don't even free flight the hammer .. but still use Light hammers and heavy springs.

 

[Parrotculler]

I am starting to "dig" this topic based on the reactions received. Spring Stop Guides help cure hammer bounce, saving air and noise. Accuracy benefits as well. Here follows a (long-ish) summary of what I have learned.

- Consensus: a lighter hammer = typically key to reduced hammer bounce especially in formerly unregulated rifles that are thereafter fitted with a reg. Why? A regulator means >=25% less air pressure slamming the valve shut. That in turn means the valve stays open longer wasting air, unless a lighter hammer is used at the other end to restore the balance. That is certainly true in the heavy-hammer Kral Puncher Pro and Jumbo. Gregor Kamensek demonstrated the same with his Hatsan BT65 in the Altaros video. "Lighter hammer" may mean as much as 30% lighter. For that, turn out the hammer spring adjuster first to reduce the hammer spring preload. But often this will not be enough -- the heavy hammer itself also needs to lose weight. For that, shorten it at both ends and drill out the inside.

- Still, a combo of enough hammer weight and spring pressure continues to be needed to create sufficient kinetic energy to open up the valve. Make the hammer too light, and you will need to compensate with a longer or stiffer hammer spring -- unless you want less power. For high power with a lighter hammer, reduce the VALVE spring preload first. Unfortunately, though, this may actually increase hammer bounce -- we ain't done yet!

- A second ingredient (to be used in combination with a lighter hammer) on the road to a hammer bounce-less experience is reducing/removing the HAMMER spring preload. But even turning out the hammer spring adjuster in full often still leaves preload. Measure the length of the spring and compare it to the space from the uncocked hammer to the end of the breech block (minus adjuster). How then to "free the hammer -- let it float"? There are actually different ways. The simplest is to cut the stock spring so it stops pressing against the uncocked hammer. A more complicated way to "free" the uncocked hammer is to stop the spring expansion when the touchpoint with the uncocked hammer has been reached. This can be done with an SSG, i.e. an implement whereby the Spring slides on a Guide that is back Stopped so that the spring expansion ceases when the hammer touchpoint is being reached.

But in all cases a strong enough hammer spring is still needed -- at least if you want power. Simply cutting coils from the hammer spring may therefore be counterproductive. (Unless you are in a .22 Artemis pr900w. That underrated shooter lacks a hammer spring adjuster: the combination of a somewhat shorter hammer spring with a Lane reg worked wonders!)

More details about these options:

- First, cutting coils from the spring to remove the preload yet keeping it strong enough for power may be achieved with shorter twin springs, as explained by Troy as an alternative to SSG. Short springs enable a free floating hammer / hammer without undue preload. But for a dual twin system you need enough bore (diameter) inside the hammer. Whether that is available depends on the gun and your hammer drilling skills. In some cases , e.g. the stock Puncher Pro hammer with an 8mm bore, the inner spring would need to be tiny unless you drilled out the bore. In other cases, such as my P12 (12mm bore), the twin springs fit well. But I always wonder how both springs, the one sliding into the other, are gonna be stable. They might start "rubbing each other the wrong way". Is there another way to skin this parrot? Yes, the SSG option(s).

- SSG concepts to "stop the spring and free / float the hammer" are several. Consensus = do not fix the SSG spring guide to the hammer itself. Instead either [1] fix the spring guide to the hammer adjustment screw (Motorhead, Troy H) or [2] let it slide backwards out of that screw when cocking (Vetmx's external SSG). And let's not forget to also strengthen the spring as appropriate in the process, in particular if you want high power instead of tuning the gun down. You may need to replace the stock spring by a stronger one when putting the SSG together. Different possible SSG concepts:

--- The first ("internal") SSG concept has a clear downside for lovers of high power and easy cocking because it typically means a (much) shorter hammer spring than stock. The hammer bore is not available anymore for the spring to slide into it. Instead the SSG spring retention washer sits against the hammer so that the SSG guide (not the spring itself) can cock into the bore of the hammer. The spring itself is compressed in the remaining space between the hammer and the adjuster screw. In many guns that space is only a few centimeters. Coil bind then comes fast. It's rather obvious (even to neophyte parrot lovers) that such a short spring is likely to reduce power, adjustability and ease of cocking -- probably by a lot! The dilemma deepens ... Troy therefore stated that this internal SSG concept is far from optimal for higher power guns (especially bigger calibers).

--- The second ("external") SSG concept, whereby the cocking action causes the spring guide to slide out of the adjustment screw in the back, may offer solace -- at a (thankfully small) price. The good: it allows for a much longer hammer spring because the entire hammer bore length remains available for cocking. The hammer might even be drilled out more to enable lengthening& strengthening the hammer spring further. "A long spring is a comfortable spring", Jack the Parrot whispered before expiring. So now the hammer has been freed, the hammer spring remains powerful enough for decent power, and less cocking issues and more adjustability are the additional benefits. The bad? None, as long as you can live with the SSG protruding from the hammer adjuster screw when cocking, and potentially from the stock itself ... Vetmx highlighted a nifty stock boring solution for high-comb guns such as the Kral Jumbo. In that case the external SSG backs into the stock and is invisible.


This external SSG looks like a versatile solution, only requiring a high-carbon drill bit for stainless steel, a long bolt with nut -- AND skill to drill a smooth and straight guide hole thru that hammer adjuster screw

Hope this did some justice to the feedback received ...!

 

[Parrotculler]

Update:

I thought the unbecoming noise emanating from my Cometa Orion 6.36 (Lane regulated) was hammer bounce. (Listen to Creepy Dan's video if you wanna experience it ...) Was I going to be able to pleasure her with an SSG? Freshly educated thanks to all generous comments, especially Vetmx's that also cover Orion in another topic, I opened her up ...  

... only to find that the stock hammer spring, together with my previous tuning efforts, had already resulted in nearly 0 preload. I should have known this because my previous tuning had achieved its goal -- increase the previously poor shotcount yet retain 50J power and accuracy. Only what sounded like hammer bounce still stood in the way of total bliss.

Just to be sure that my enemy really was hammer bounce, I turned the adjuster out to reduce the tension to the point where the rather short&stiff spring was now entirely loose with room to spare. I cocked&fired in the expectation of not hearing any hammer bounce anymore ... but the unbecoming noise INCREASED!  

I learned that a little hammer spring preload in fact results in the least noisy set up, with good shot count and power preserved.

My conclusion: my Orion has action noise, probably little to do with hammer bounce. This noise will be hard to eliminate because of the design of the hammer and action. Also, the gun's build makes valve adjustment nearly impossible -- except for those in possession of a kind of giant flathead screwdriver to unscrew the valve block from the front of the cylinder. Nice looking and accurate gun though -- darn, the pellet probe o-ring just blew out! 

 

[Vetmx]

You can free flight a hammer all you want but if your hammer spring is soft, your hammer will free flight right back, hit the soft spring, then head right back and smack the valve again. Trust me, your Orion is going to hammer bounce until you kill the hammers momentum when it rebounds off the valve. When the hammer shoots back and hits twin springs, dead. When a hammer shoots back and hits a preloaded SSG, dead.

 

[Parrotculler]

Update:

Bob Sterne wrote an article about SSGs in Hardairmagazine. He describes the different setups. One of his points is about cocking, which is easier in SSG setups compared with twin springs. It in part depends on the available clearance for the spring movement.

Armed with all the knowledge & advise gained I made my first SSG (the external version) for my P12. Takeaways:

- it was easier than thought, despite my reluctance to saw off the spring guide from the hammer spring adjuster. Left 7.5mm in place to continue serving as a guide. I then drilled thru the adjuster from both ends, first with a thinner drill and then opening up to 6mm.

- I used the stock hammer spring, a 6mm diameter bolt (rounded off the hexagonal head), and metal + pvc washers. Two nuts to secure the setting. 

- cocking is noticeably easier than with the previous twin spring setup. There also is a slight risk of pinching ...

- adjustment is extremely sensitive. Only a tiny lightening (turning out) of the SSG nuts increases fps significantly. The hammer spring adjuster continues to play as well -- in the other direction. The right balance needs to be found. Once that is the case, consistency, accuracy, and shotcount are achieved. I ended up with a tiny bit of preload on the hammer, not a free floating one, to get the right amount of power&accuracy. Maybe this would be different with a lower regulator setpoint. But I want to stop messing for now, because this P12 .25 is finicky with unexpected impacts on accuracy. It is fine now at 60m, 260m/sec with the JSB Kings. 40+ shots.

 

[Vetmx]

Replace that black washer with a tight fitting oring.