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- Joined: June 30th, 2011, 11:13 pm
Impressive shot string, jp.
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- Joined: June 25th, 2002, 1:34 pm
I made the valve stem a pretty tight fit in the valve body to prevent pressure loss past the stem, I'll lapp the stem in a bit and soften the seal angle a couple of degrees so it's a bit more flexible. I'm using Larry Durhams toilet plunger seal and micro stem design. One other thing that could be effecting consistency is sludge build up in the valve, I thought being a single stroke that I wouldn't have the condensation problem of an MSP but that isn't the case and I'm thinking that the volume of the firing chamber being so small that sludge build up has a bigger effect. But SSP's are typically very consistent so I'm at a bit of a loss to fully grasp what's going on?
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- Joined: November 28th, 2002, 6:26 pm
Avg FPS = 749, Stdev = 4.4fps, ES = 15fps, Avg FPE = 9.8754.0,746.4,745.7,745.5,750.6,749.5,749.6,740.7,755.7,749.6 7.9cpl's avg.748.7 9.8fpe. Consistency is getting better, the pellets were just picked out of the box.
Looks perfect to me, just the way it is.
Steve
Last edited by pneuguy on July 22nd, 2012, 2:08 pm, edited 1 time in total.
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- Joined: June 25th, 2002, 1:34 pm
hear though is a good bit of excess air at the muzzle, current barrel length is 19" I think with a 24" barrel it would break 10fpe. which you predicted a few years back when I first told you about this design. Also a few days ago it was making it's best power with a slightly larger transfer port than I'm using now.
Last edited by jpsaxnc on July 22nd, 2012, 4:10 pm, edited 1 time in total.
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- Joined: March 1st, 2002, 12:22 am
those are excellent numbers. What pellet did you say?Avg FPS = 749, Stdev = 4.4fps, ES = 15fps, Avg FPE = 9.8
Looks perfect to me, just the way it is.
Steve
dr_subsonic's pneumatic research lab
the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic
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- Joined: July 4th, 2012, 7:51 pm
the 0.6 FPE increase with the 10.5's is probably due to less energy loss from a slower moving pellet - drag from the atmosphere and bore increase with velocity squared.n/t
BTW, I've been following your project - extremely impressive!!
WyoMan
[Pistol Pete went to the Brothel]
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- Joined: April 12th, 2002, 5:26 am
I noticed my 2004 hotrod pistols gave the best numbers with a freshly cleaned port. The oil/water emulsion built up there within a dozen shots, and numbers drifted down a few fps.I made the valve stem a pretty tight fit in the valve body to prevent pressure loss past the stem, I'll lapp the stem in a bit and soften the seal angle a couple of degrees so it's a bit more flexible. I'm using Larry Durhams toilet plunger seal and micro stem design. One other thing that could be effecting consistency is sludge build up in the valve, I thought being a single stroke that I wouldn't have the condensation problem of an MSP but that isn't the case and I'm thinking that the volume of the firing chamber being so small that sludge build up has a bigger effect. But SSP's are typically very consistent so I'm at a bit of a loss to fully grasp what's going on?
