I made and installed an SSG in my Daystate Air Ranger

[AlanMcD]

I have been wanting to try an SSG in my .22 cal Daystate Air Ranger for some time.  The gun is reasonably efficient, but does seem to have a fair amount of post shot hammer and spring noise, and some definite burps of air on the downside of the shot curve.  Reading ShakySarge’s posts on the .25 Marauder builds with an SSG got me back to it – especially the links to all the illustrations that Bob had put up on the different kinds of SSGs.  There are lots of different flavors of Air Rangers, and this one started life as a 50 FPE one, so there is no slingshot hammer in it.  I have tuned it up and down in power levels, and like it at about the 30 FPE level best (it stacks AA 16 grain pellets all day long), but seems to be a bit compromised in the hammer system with the big 108 gram hammer and not much energy on it, so an SSG seems like a good option.

I don’t have access to good tools for fabricating accurate parts, but I have been able to make many different spring bushings to tune this Air Ranger at many different power levels out of acetyl rod, using a hand drill and a table saw, so I have been inside the gun before.  I decide to take it apart and to measure everything relevant, then I sketched it up and played around with it in my mind.  Before long I realized I could make an SSG that would be completely internal to the gun, using a modified approach to the spring bushings Daystate used.  The first picture attached is of two of the bushings – the one on the left is the stock “50 FPE” one from the factory (the gun shoots 34 grain pellets at about 48 FPE with this bush, and the one on the right is a lower power one that I made and had in the gun as I was using it (AA 16 grain pellets at 28 FPE).

So with a little work, I decided on the dimensions that I would have to drill and shape the acetyl rod into to work in this case (I had to fabricate a few jigs to hold stuff well enough for hand tools to do the job).  The second picture is what that new  part looked like when done, compared to the prior bushings, followed by the full SSG assembled and ready to install (the end cap of the gun had a space that could accommodate the nylock nut, once I ground it down a bit) and that is shown in the last picture).

There was a lot of trial and error, getting it to work right and back to the power level I wanted, but in the end I got it to where I wanted it with a quieter shot cycle.  It really is no more efficient on the upside of the shot curve, but it is definitely better on the down side.  I am not sure if this SSG will hold up long term, but it at least proved to be a good proof of concept that it can work.  But in this application, it clearly reduced the peak power available, so I may have to tweak things on a final design (I think I Can gain a bit more pre-compression of the spring).  I expect if I am going to keep this in there long term, I will need to switch to something more robust than acetyl, as the load is probably pretty high when it slams to a stop on firing.  So far it has held up for several hundred shots, but time will tell.  As on now, there is only 1mm of free flight in it, but it does seem to be enough to stop any hammer bounce.

Any thoughts or ideas for improvements?  I expect if I want to keep this, I will probably need to have an aluminum part made to replace my acetyl one, but this at least let me prove out the concept.

[rsterne]

Nicely done, Alan.... glad it worked out for you....

Bob

[Motorhead]

That is one platform i never built an SSG to fit.  So from here, looks great !
proof will be in the shooting and getting at what ever target speed your after ... from there just enjoy the air savings !

[oldpro]

 Very nice Alan!!! Good work my man!

[AlanMcD]

I have it tuned pretty much where I want it - it is making a bit more power than before, and is a bit more efficient.  Most of the benefit is clearly on the back side of the shot curve.  Here is the data showing the comparisons of two 60 shot strings four ways, first isolating the best 30 shots in the strings, then the rest of the data in total and split into the first half and last half of the strings.  You can clearly see that most of the benefit is on the back half . . .

[rsterne]

Yep, lower pressures are where any hammer bounce increases.... A properly tuned PCP should have little bounce on the front half of the string.... Nice numbers to show how your SSG is working, for sure....

Bob

[ranchibi]

Alan, great work! Do you think delrin would be a viable option for the bushing?

[Motorhead]

Alan, great work! Do you think delrin would be a viable option for the bushing?

FYI ... Delrin is a "Brand" name of Acetal ... there pretty much one in the same outside of specialty blends.

[AlanMcD]

Randall,

As Scott said, it is basically the same stuff.  So far it is working well, but I don't know how it will hold up under the repeated tensile impact of lots of shots.  I may end up having to get a part made from something stronger, as I do think I want to keep this in there.  It works really well so far.

This is the rod I made it from:


Scott,

Do you think the Acetal / Delrin will hold up in this use?  I tried to keep all of it at least 2mm thick, and I have an o-ring under the screw head in the bushing to help absorb some of the impact when the SSG does its thing and stops the spring sending the hammer into free flight . . . . and that still has to be quite a load.

I just was shooting offhand at paper with it (indoors at 21 yards in my basement) and the shot cycle is amazing - I just kept shooting without refilling, and the sound never changed.  As it is tuned now I filled to 1900 psi for a tight 30 shot string that in the past would normally end ~300 psi lower with a very different shot cycle sound.  But I kept on shooting and finally stopped down when the gun gauge was entering the "red band", and when I refilled the valve opened at 1150 psi!  All I can say is "wow" (yes, it was obviously shooting much slower there, but at 21 yards offhand the difference in drop is negligible - at least for me  ).

[ranchibi]

Scott and Alan, thank you for that info! I’m trying to learn more about PCP’s and all the materials and language. I think it would be awesome for someone like Scott or you Alan to organize local PCP workshops where you could go through, take apart different manufacturers air rifles and explain all the parts (plenum, etc.) tuning, similarities and such...I’d be happy to pay for such an insightful class!

[triggertreat]

The thing about an SSG is that if your gun is already well tuned and getting good efficiency,  the SSG doesn't do to much more for you.  However, if the gun is not tuned for optimum efficiency,  the SSG can really make it a lot more efficient.   It looks like you gained a little in efficiency utilizing an SSG and had a pretty well tuned gun to start with.


The same holds true for similar mods like the NBH, TSS, SSS and even the LW hammer that similarly prevent hammer bounce or wasted air per shot.

[Motorhead]

In SSG parts such as spring containment end caps/spools/washers ... I like to use PEEK. if not generally Nylon 66 over Acetal.
Because when the spring finally hits full containment there can be quite the strain on the threads of center rod holding it all together.  While the threads likely won't strip so long as an @ 4 to 1 rule is followed. That is 4X the threads length of engagement to the diameter of fastener.

The design of SSG and whats springs diameter is also has a bearing on the degree of flex the parts will have.  Peek being the stiffest, toughest and hardest of the typical plastics we machine.

[mobilemail]

Well done Alan!  I have a .25/50fpe Air Ranger, and at 50 it is really an air pig!!  I turned mine down to about 43fpe by replacing the preload spacer with a thinner stack of nylon washers. Right now it will produce 45 shots within 3%, but that still doesn't seem very efficient given the humongous air reservoir.  It is the one downside to an otherwise outstanding rifle.

[rsterne]

I know nothing about the Air Ranger.... but an "air hog" generally means the gun is being pushed nearly to its limit with the pressure, barrel length and porting it has to work with.... This is because the valve is being held open until the pellet is exiting the muzzle, or nearly so.... The only way to determine that is to continue to increase the hammer strike until you get no further velocity increase.... If you are already there at 50 FPE, then you must back off on the power to get reasonable air use....

Bob

[AlanMcD]

Bob,

The 50 FPE Air Rangers have 17" long barrels, and a 100+ gram hammer with a fairly strong hammer spring (1.5mm wire diameter, about 8 coils, and a 55mm free length pre-loaded by about 15mm or so, plus or minus a bit).  For what they are, I do thin they are pretty efficient and not a true air hog.

Pre-SSG, staying in the sweet spot of about 1.5% ES, mine (a .22 call) mine shot the following pellets at the approximate FPE and Efficiency listed below (tuned to the different power levels by changing the pre-load on the sticker and/or the length of hammer flow as the only adjustments):

34 grain JSB Beasts at 48 FPE and 1.13 efficiency,
21 grain Baracuda at 43 FPE and 1.08 efficiency,
18.1 grain JSB at 35.5 FPE and 1.22 efficiency,
18.1 grain JSB at 30 FPE and 1.41 efficiency,
16 grain AA at 27 FPE and 1.41 efficiency

All in all not bad for a conventional high power gun with a fairly short barrel.

[AlanMcD]

Mark,

I really never thought of the gun as an air hog - mine seems similar to yours.  It certainly would do better with a longer barrel, but for the 17" one on it 45 shots at these power levels is not bad for a conventionally valved gun, at least in my opinion.  I know I could never get even close to a proportional number of shots out of of my .22 Marauder at these power levels at the same ES (before I regulated it and put in higher tech valves), relative to the reservoir size, and that is with a 20" barrel instead of the 17" one.

Yours could probably benefit from the SSG too - as noted, it really did not gain me many shots within a given ES, at least so far.  I think that this is the case in part because the SSG seems to raise the shot to shot variability in the system compared to the base, which was so darned consistent - most shots in the sweet spot were always within 3-4 fps of the prior shot, but this is higher with my SSG.  I will probably make up a new central bolt rod that has a polished shaft, as opposed to the ground off threads of my current one, and that might help some.

The big benefit is the quiet shots on the down side of the curve, which is great if just plinking or shooting at close targets.

[mobilemail]

The other thing I noticed on mine is that when I lowered the power, the sweet spot in pressure also lowered. When I got my gun it was set for max power - about 55fpe    If I filled to 3300psi it gave me about 20 shots within 3%ES.   So I took the preload spacer out completely and then it was shooting about 60 shots @ 39ish fpe, between 2500 and 1700 psi.  Going for the happy middle at 43fpe, my 40 good shots run south of 2800psi.  So it's friendlier when my air tank gets low.

But back to Alan's success, it looks like you did fine work making that SSG. Well done!  It's great to see your success. 

[rsterne]

Yep, when you back off the hammer strike the fill and refill pressures both decrease, as well as the top of the bell curve....

Bob

[AlanMcD]

Mark,

Good data there to consider: I had thought the basic hardware of the .25 and .22 50 FPE guns were the same, but apparently they are not - there must be something different in them.  I never ran mine with the spacer/bushing completely removed, but I did make one that was very thin at just under 1 mm of spacing.  That one gave me 26 FPE with the JSB 18.1 pellets, and 24.6 with the AA 16 grain ones.

The lowering of the pressure range is what happens as the hammer energy drops.  The approximate range I had for a 3% ES was 3300 to 2500 PSI for my max power tests, and 1950 to 1350 psi for the 26 FPE configuration, so we had very different results.

I do find the results odd, as your .25 should be more efficient than my .22 just due to caliber, so if the only difference was the hammer spring, I would have thought yours would get by with a lighter one . . . . maybe the valves are different too, as you clearly don't get to as a low a pressure range as my .22 does.

[rsterne]

For the same FPE, a larger caliber should be, and usually is, more efficient.... There is more base area for the pressure to push on, so more force available to accelerate the pellet down the bore....

Bob