A little history from my personal experiences thus far.
Currently I have fired well over a 1200 rounds between 81 grain JSB's and 93 grain NSA's in the .357.
When I first started, the gun came from the factory firing JSB's at around 880 fps and the NSA' were 790 to 800 fps.
I began playing with various 1st and 2nd regulator pressures. In summary, what I discovered was:
-My gun has less regulator creep when the 1st and 2nd regulator are within 10 to 15 bar of each other. I believe it is recommended to have at least a 30 bar gap.
-My gun loses velocity if I up the 2nd regulator pressure above 135 + bar. I have tried numerous 1st and 2nd reg settings to confirm this. More on this to come.
-The fastest I could get 81 JSB's with the factory pellet probe was 894 fps.
-The fastest I could get 93 NSA's was around 820 fps with the factory pellet probe.
-With the NSA slug/pellet probe my velocities increased to a max of 905 fps for the JSB's and 835 for the NSA's.
-As I have shot my gun more and as the speed increased, the NSA's started grouping far better than initially. Initially they were around 2" groups at 50 yards. Now they are an inch or under at times.
I confirmed my hammer will not open enough at higher regulator pressures above 135 bar. This was with the valve adjuster two full turns out from line 4, the power wheel set on max, and the quick tune as far as the gun will let me while still engaging the sear (about setting 4.6). I then adjusted the first regulator to 170 bar and the 2nd to 155 bar. My goal was to see if the hammer would open the valve and add velocity or deduct velocity.
With 93 grain NSA's it shot 798 fps to 805 fps at 155 bar.
I also previously tried 155 bar on the first regulator and 145 bar on the second regulator, which showed a loss of velocity or around 795 fps to 805 fps.
When I set the first regulator back to around 145 bar and the second back to 135 bar, I get 825 fps to 835 fps. At the same setting the 81 grain JSB's go 900 fps to 905 fps.
What I discovered was anything past about 135 bar on the second regulator and the velocity drops. The hammer settings are maxed out, which leads me to believe the hammer isn't striking the C1 hard enough to open at higher pressures.
As for the C1, I have it set as far as it will screw on the valve rod, which measures 6.13mm off the frame. I also took the gun apart to make sure the opposite end of the valve rod wasn't un-screwing and it was fine. While apart, I checked for damage on the o-ring and valve sealer piece. Both were good to go and looked great. Afterwards, I relubed the O-rings and put the gun back together. I am getting really quick and good at that part now (lol).
While apart, I weighed the hammer pieces and washers too. Each washer was .43 grams with the main portion at 6.13 (part #C55) grams. Part # C54 was 18.13 grams. All combined I have a total weight of 25.12 grams.
The hammer spring (part # C56) measured 52mm long with 18 coils, if you count the very end ones on each end.
Currently I am seeing a peak power around 140 to 143 ft/lbs. I have read of people using the Mk2's and getting 870 to 900 fps with 93 grain NSA's, so I am bewildered. I have plenty of power for shooting JSB's but I would prefer to shoot slugs and a little faster. It has been grouping them quite nicely, which I think would even get better as the speed increases because it has so far.
My goal is to achieve at or above 155 ft/lbs with NSA's, so I can take advantage of the BC slugs have to offer. I am currently thinking I may need a heavier hammer to open the valve at a higher pressure. The JSB's shoot one ragged hole at 50 yards or around 860 fps, but that isn't my goal.
Currently I have fired well over a 1200 rounds between 81 grain JSB's and 93 grain NSA's in the .357.
When I first started, the gun came from the factory firing JSB's at around 880 fps and the NSA' were 790 to 800 fps.
I began playing with various 1st and 2nd regulator pressures. In summary, what I discovered was:
-My gun has less regulator creep when the 1st and 2nd regulator are within 10 to 15 bar of each other. I believe it is recommended to have at least a 30 bar gap.
-My gun loses velocity if I up the 2nd regulator pressure above 135 + bar. I have tried numerous 1st and 2nd reg settings to confirm this. More on this to come.
-The fastest I could get 81 JSB's with the factory pellet probe was 894 fps.
-The fastest I could get 93 NSA's was around 820 fps with the factory pellet probe.
-With the NSA slug/pellet probe my velocities increased to a max of 905 fps for the JSB's and 835 for the NSA's.
-As I have shot my gun more and as the speed increased, the NSA's started grouping far better than initially. Initially they were around 2" groups at 50 yards. Now they are an inch or under at times.
I confirmed my hammer will not open enough at higher regulator pressures above 135 bar. This was with the valve adjuster two full turns out from line 4, the power wheel set on max, and the quick tune as far as the gun will let me while still engaging the sear (about setting 4.6). I then adjusted the first regulator to 170 bar and the 2nd to 155 bar. My goal was to see if the hammer would open the valve and add velocity or deduct velocity.
With 93 grain NSA's it shot 798 fps to 805 fps at 155 bar.
I also previously tried 155 bar on the first regulator and 145 bar on the second regulator, which showed a loss of velocity or around 795 fps to 805 fps.
When I set the first regulator back to around 145 bar and the second back to 135 bar, I get 825 fps to 835 fps. At the same setting the 81 grain JSB's go 900 fps to 905 fps.
What I discovered was anything past about 135 bar on the second regulator and the velocity drops. The hammer settings are maxed out, which leads me to believe the hammer isn't striking the C1 hard enough to open at higher pressures.
As for the C1, I have it set as far as it will screw on the valve rod, which measures 6.13mm off the frame. I also took the gun apart to make sure the opposite end of the valve rod wasn't un-screwing and it was fine. While apart, I checked for damage on the o-ring and valve sealer piece. Both were good to go and looked great. Afterwards, I relubed the O-rings and put the gun back together. I am getting really quick and good at that part now (lol).
While apart, I weighed the hammer pieces and washers too. Each washer was .43 grams with the main portion at 6.13 (part #C55) grams. Part # C54 was 18.13 grams. All combined I have a total weight of 25.12 grams.
The hammer spring (part # C56) measured 52mm long with 18 coils, if you count the very end ones on each end.
Currently I am seeing a peak power around 140 to 143 ft/lbs. I have read of people using the Mk2's and getting 870 to 900 fps with 93 grain NSA's, so I am bewildered. I have plenty of power for shooting JSB's but I would prefer to shoot slugs and a little faster. It has been grouping them quite nicely, which I think would even get better as the speed increases because it has so far.
My goal is to achieve at or above 155 ft/lbs with NSA's, so I can take advantage of the BC slugs have to offer. I am currently thinking I may need a heavier hammer to open the valve at a higher pressure. The JSB's shoot one ragged hole at 50 yards or around 860 fps, but that isn't my goal.
