Snowpeak Interesting P35-25 tune

[JaceSpace1369]

I couldn't leave it alone with a first shot so much below the rest of the string. When it's done this before it was because I needed more hammer spring. But the hammer spring is at maximum and was with a 1mm thick washer as a spacer to increase the HS force. So I added another washer and the difference dropped to about 20 fps and velocity went up to 780-795 fps after the first shot. So I went up another 0.5mm on the shim. Total of about 2.5mm. I shot that today after church and lunch in two strings. First was at about 1:40p when the temperature was 89 degrees F. Just 5 shots starting at about 185 bar and ending at about 175 bar; 783, 795, 790, 795, 799 fps. I then let the gun sit because I wanted to see what it would do at the peak temperature today, 92 degrees. I had a problem this summer with a tune that shot fine in the winter but the velocity dropped into the 600s in the summer. So starting about 4:10p and 92 degrees I shot a string 795, 784,790, 784, 785, 793, 785, 791, 792, 790, 795, 789, 791, 782, 788, 795, 787, 785, 786, 792, 782, 780, 772, 760, 757. I was at 105 bar at the end. So my ES was 17 for the first 26 shots. I can't tell when I went off reg but it pretty much doesn't matter.

I was shooting 5 shots groups at 30 yards to see if the point of impact changed and whether it was grouping reasonably well. I was using the Primary Arms 4-14 scope I normally have on this gun. That scope has a nice thick reticle which is good for hunting/pesting but not so good for target shooting. But except for one shot on the right hand target in cell 1 my groups were 1/2 inch or smaller. I think that is plenty good enough for this gun. The right hand target in cell 3 has the last five shots where the velocity got significantly lower but was still a decent group.

I'd like to call this my 50/50 tune but it doesn't really get to 50 fpe, more like 47. I think it will do 50 shots on a full fill but I haven't proven that yet. ~50 shots at >45 fpe on a little gun with a 450mm barrel and storing only 265cc of air at no more than 250 bar seems pretty good. Especially when they are pretty accurate shots.

View attachment 498433

Interesting, not sure how different the p35 snd the bullshark is, but I did some full fill shots and some shots around 150b down to about 135b and at full fill the .25 polymags were going 785-795 for the first 8-10 shots, and towards the end of the fill my shots were around 823 and 836fps

 

[JimD]

The bullshark barrel is 40 mm longer than the P35 (490 versus 450mm). Polymags are about 25.4 grains while the JSB heavies I am shooting are about 34 grains. So your bullshark seems to be tuned to a lower regulator pressure. I don't know if pushing things up would produce a shot string like mine but if you gun will shoot the heavies accurately you could try it. You should get 10-20 fps more at the same regulator setting due to your longer barrel and I shoot 25.4s about 850 fps at my regulator setting. My guess is you would have to turn your regulator screw at least 1/4 turn and probably more like 1/2 a turn counter clockwise to get to the regulator setting I am at. If you turn it up like this you may need to shim the spring with a washer or two too. Just turning up the hammer spring all the way may not open the valve well.

I should also mention that my gun is not a stock P35. The biggest change is a bigger plenum from South Africa. I also drilled out the barrel port and passage between the valve and the barrel port from about 75% of the bore size to about 85%. The plenum made the most difference. So maybe your regulator is not lower but my guess is that it is. I think the plenum makes a bigger difference than the extra 40mm barrel length. Drilling out the passage makes less difference though, I think.

 

[JimD]

I've shot a couple more fairly long strings with this tune. The first tune started at 200 bar. It was 12 shots sighting in my 32X scope for shooting targets and then 24 shots on a 30 yard challenge target. I ended at 100 bar. If I ignore the last 4 shots I think the ES was 22 fps. The final two shots were Xs, however, with a velocity of 756 and 751. I scored the target at 189 with 10Xs. The best I've done with this gun is a 194.

Today I shot 40 shots starting at 220 bar and ending at 110 bar. The first 24 were on a 30 yard challenge target and the final 16 were sighting in the 4-14 scope I put back on the gun and messing around a little. The ES was 26 without the final two shots (765 and 759fps). The Average velocity of the same 38 shots was 785 fps. The first 25 shots (the ones I think were on the reg) averaged 788 fps. 13 of the final 15 averaged 779 fps. Fpe ran from 45 to 48 fpe. Todays target was a 190 with 10Xs.

The ES is a little higher than I would like but it doesn't change by incorporating the final few shots. It might have been made worse by my chronograph shifting a little while I'm shooting. There is enough of a muzzle blast it twists the chronograph sometimes. I changed the way it is mounted before shooting the last 16 shots and the ES dropped to 10. So maybe part of the 20s ES is measurement. I am not seeing point of impact changes.