Hi Y'all,
Last summer, I received an Air Arms S510 Ultimate Sporter in .25. Being a field target and springer guy since I've started shooting, this was my first rifle over 20 FPE, and it was also my first modern high-end PCP, with the previous go to guns being a .22 AA S400 (that I still compete with) and and a Custom Shop Marauder with an LW barrel and Huma Reg.
I was immediately hooked on this S510. The quality was unreal, it was smooth as silk, had a GREAT factory tune that was extremely consistent with a wonderful shot cycle, and the stock was superb. It shot pretty well too - I took it to RMAC a month after I got the rifle and placed 5th in the Marksmanship Challenge, despite shooting only 42 FPE.
(Running the S510 at EBR)
Which brings me to the subject of this thread - increasing energy output of the S510. At RMAC, it became apparent to me that I needed to shoot heavier pellets. The 25.4 AA/JSB/FX pellets are great, but in terms of ballistics, they are inferior to the H&N Barracudas or the JSB Heavies. The goal was to get 50-55 FPE out of the rifle. I had contacted several tuners about having the gun worked on, but several of them seemed hesitant that it could be done and still maintain a decent shot count and shot cycle.
Being a stubborn 20-something, rather than listen to those who are wiser than me I figured I'd give it a go anyway. My goal was at least 30 shots at 50+ FPE. This translates to about 815 with JSB heavies or 850 with Barracudas.
Stock, the S510 was shooting the 25.4's at 860. Here is a sample shot string. I was getting ~49 shots with the factory tune.
Like I said, extremely consistent tune, but too weak for what I'm after.
34gr JSB's shot around 770, or 44 FPE for reference.
My first try at increasing the power involved increasing the reg from 150 to 160 BAR and installing a longer hammer spring with the same .063" wire diameter as the factory spring. This resulted in the power I wanted, 830 FPS with JSB heavies (~53 FPE), but only 25 shots. The shot cycle was also very harsh.
I ran this tune for a while, and I wasn't happy with it. Long story short, I noticed that there was significant preload (about 1") run on this hammer spring. I am almost certain that this new hammer spring was generating significant hammer bounce, causing a lower shot count and therefore excessive turbulence that wasn't conducive to accuracy. To solve this, I ended up going with an SSS, or Shorter Stiffer Spring with the theory being that this shorter spring will create a quasi-free flight hammer since the hammer is no longer being forced against the valve during the entire shot cycle. The ideal spring length to give me a "hammer-gap" of 1/3 of the valve lift was 1.9". I ordered a bunch of compression springs and the winner was a spring with a wire diameter of .086" and a length of 1.91" (ID of ~.7" for those who are curious).
This generated the same power, and upped shot count to 33 BUT the cocking effort was a little much. Since I plan to use this as my speed challenge rig, this was a deal breaker.
To remedy this, I replaced the stock valve spring (wire diamter .04", ID .145", length .375") with one that is much softer (WD .016", ID .12" length .59"). With that same hammer spring, I was now getting about 900 FPS with JSB heavies, but only 20 shots or so. Ended up with a 2" hammer spring with .072" wire diameter, same ID. Hammer gap is smaller, only about .05".
After fiddling with the reg, I ended with a pressure of 152 BAR. This results in 36 shots at 856 with Barracudas and 825 with JSB heavies or 50.5 and 52.5 FPE respectively. I can get 4 additional shots after falling off the reg before velocity falls below 840 with the H&N's. The barracudas shoot significantly better in my barrel, so I will be running those. Here is a shot string:
Very happy with this tune. It is VERY consistent, with a .25% SD and .875% ES. Most importantly, the shot cycle is sublime with only slightly more muzzle flip than the stock setting. Accuracy is A-OK as well. These are groups shot with HN barracudas - both sub MOA.
50 yards (International Rimfire Benchrest Target, 10 ring is ~.25"):
100 yards (Black circle is ~1.5" for reference).
44 FPE with JSB heavies prior to the tune, and 52.5 after equates to a 20% increase in muzzle energy. 49 shots to 36 shots equates to a 24% decrease in shot count. That seems like a pretty good "efficiency" trade off. Needless to say, the ballistics in the wind are much improved shooting these heavier pellets at this higher velocity. JSB getting a full 33% (ish) less wind drift than the stock tune running 25'4s, and the HN's are getting approximately 25% less wind drift at 100 yards. Wind profile is 10mph and 90 degrees.
Keep in mind, these numbers are with a ~280cc cylinder, rather than a 400, 480, or 580 cc bottle. With that sort of air capacity, shot count would be much closer to, or exceed that of other rifles in this class.
Just thought I'd throw this out there for any AA S510 owners to show that this can be done without extensive modifications to the rifle. I will be shooting the gun in the Speed Challenge and BR event at RMAC this year and I am hoping to showcase what it can do
I am still strongly considering getting this gun ported/radiused/polished so I can run the reg at a lower pressure and/or gain a little more speed with the 34 gr JSB's, which might improve their precision since I suspect they will do extremely well in the 840-850 range. But, given that RMAC is a month away, that is a project for another day...
Next up...my Galahad Slug tune for NRL events!
Last summer, I received an Air Arms S510 Ultimate Sporter in .25. Being a field target and springer guy since I've started shooting, this was my first rifle over 20 FPE, and it was also my first modern high-end PCP, with the previous go to guns being a .22 AA S400 (that I still compete with) and and a Custom Shop Marauder with an LW barrel and Huma Reg.
I was immediately hooked on this S510. The quality was unreal, it was smooth as silk, had a GREAT factory tune that was extremely consistent with a wonderful shot cycle, and the stock was superb. It shot pretty well too - I took it to RMAC a month after I got the rifle and placed 5th in the Marksmanship Challenge, despite shooting only 42 FPE.
(Running the S510 at EBR)
Which brings me to the subject of this thread - increasing energy output of the S510. At RMAC, it became apparent to me that I needed to shoot heavier pellets. The 25.4 AA/JSB/FX pellets are great, but in terms of ballistics, they are inferior to the H&N Barracudas or the JSB Heavies. The goal was to get 50-55 FPE out of the rifle. I had contacted several tuners about having the gun worked on, but several of them seemed hesitant that it could be done and still maintain a decent shot count and shot cycle.
Being a stubborn 20-something, rather than listen to those who are wiser than me I figured I'd give it a go anyway. My goal was at least 30 shots at 50+ FPE. This translates to about 815 with JSB heavies or 850 with Barracudas.
Stock, the S510 was shooting the 25.4's at 860. Here is a sample shot string. I was getting ~49 shots with the factory tune.
Like I said, extremely consistent tune, but too weak for what I'm after.
34gr JSB's shot around 770, or 44 FPE for reference.
My first try at increasing the power involved increasing the reg from 150 to 160 BAR and installing a longer hammer spring with the same .063" wire diameter as the factory spring. This resulted in the power I wanted, 830 FPS with JSB heavies (~53 FPE), but only 25 shots. The shot cycle was also very harsh.
I ran this tune for a while, and I wasn't happy with it. Long story short, I noticed that there was significant preload (about 1") run on this hammer spring. I am almost certain that this new hammer spring was generating significant hammer bounce, causing a lower shot count and therefore excessive turbulence that wasn't conducive to accuracy. To solve this, I ended up going with an SSS, or Shorter Stiffer Spring with the theory being that this shorter spring will create a quasi-free flight hammer since the hammer is no longer being forced against the valve during the entire shot cycle. The ideal spring length to give me a "hammer-gap" of 1/3 of the valve lift was 1.9". I ordered a bunch of compression springs and the winner was a spring with a wire diameter of .086" and a length of 1.91" (ID of ~.7" for those who are curious).
This generated the same power, and upped shot count to 33 BUT the cocking effort was a little much. Since I plan to use this as my speed challenge rig, this was a deal breaker.
To remedy this, I replaced the stock valve spring (wire diamter .04", ID .145", length .375") with one that is much softer (WD .016", ID .12" length .59"). With that same hammer spring, I was now getting about 900 FPS with JSB heavies, but only 20 shots or so. Ended up with a 2" hammer spring with .072" wire diameter, same ID. Hammer gap is smaller, only about .05".
After fiddling with the reg, I ended with a pressure of 152 BAR. This results in 36 shots at 856 with Barracudas and 825 with JSB heavies or 50.5 and 52.5 FPE respectively. I can get 4 additional shots after falling off the reg before velocity falls below 840 with the H&N's. The barracudas shoot significantly better in my barrel, so I will be running those. Here is a shot string:
Very happy with this tune. It is VERY consistent, with a .25% SD and .875% ES. Most importantly, the shot cycle is sublime with only slightly more muzzle flip than the stock setting. Accuracy is A-OK as well. These are groups shot with HN barracudas - both sub MOA.
50 yards (International Rimfire Benchrest Target, 10 ring is ~.25"):
100 yards (Black circle is ~1.5" for reference).
44 FPE with JSB heavies prior to the tune, and 52.5 after equates to a 20% increase in muzzle energy. 49 shots to 36 shots equates to a 24% decrease in shot count. That seems like a pretty good "efficiency" trade off. Needless to say, the ballistics in the wind are much improved shooting these heavier pellets at this higher velocity. JSB getting a full 33% (ish) less wind drift than the stock tune running 25'4s, and the HN's are getting approximately 25% less wind drift at 100 yards. Wind profile is 10mph and 90 degrees.
Keep in mind, these numbers are with a ~280cc cylinder, rather than a 400, 480, or 580 cc bottle. With that sort of air capacity, shot count would be much closer to, or exceed that of other rifles in this class.
Just thought I'd throw this out there for any AA S510 owners to show that this can be done without extensive modifications to the rifle. I will be shooting the gun in the Speed Challenge and BR event at RMAC this year and I am hoping to showcase what it can do
I am still strongly considering getting this gun ported/radiused/polished so I can run the reg at a lower pressure and/or gain a little more speed with the 34 gr JSB's, which might improve their precision since I suspect they will do extremely well in the 840-850 range. But, given that RMAC is a month away, that is a project for another day...
Next up...my Galahad Slug tune for NRL events!
