Did some more work on my SSP here's a 10 shot string,

Did some more work on my SSP here's a 10 shot string,

Joined: June 25th, 2002, 1:34 pm

July 21st, 2012, 8:25 pm #1

754.0,746.4,745.7,745.5,750.6,749.5,749.6,740.7,755.7,749.6 7.9cpl's avg.748.7 9.8fpe. Consistency is getting better, the pellets were just picked out of the box.
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Joined: June 30th, 2011, 11:13 pm

July 22nd, 2012, 12:55 pm #2

Impressive shot string, jp.
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Joined: June 25th, 2002, 1:34 pm

July 22nd, 2012, 1:50 pm #3

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

July 22nd, 2012, 2:03 pm #4

754.0,746.4,745.7,745.5,750.6,749.5,749.6,740.7,755.7,749.6 7.9cpl's avg.748.7 9.8fpe. Consistency is getting better, the pellets were just picked out of the box.
Avg FPS = 749, Stdev = 4.4fps, ES = 15fps, Avg FPE = 9.8

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

July 22nd, 2012, 4:08 pm #5

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: June 25th, 2002, 1:34 pm

July 22nd, 2012, 5:33 pm #6

754.0,746.4,745.7,745.5,750.6,749.5,749.6,740.7,755.7,749.6 7.9cpl's avg.748.7 9.8fpe. Consistency is getting better, the pellets were just picked out of the box.
n/t
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Joined: March 1st, 2002, 12:22 am

July 22nd, 2012, 8:07 pm #7

Avg FPS = 749, Stdev = 4.4fps, ES = 15fps, Avg FPE = 9.8

Looks perfect to me, just the way it is.

Steve
those are excellent numbers. What pellet did you say?


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Joined: June 25th, 2002, 1:34 pm

July 22nd, 2012, 8:39 pm #8

n/t
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Joined: July 4th, 2012, 7:51 pm

July 22nd, 2012, 10:00 pm #9

n/t
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.

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

July 22nd, 2012, 11:00 pm #10

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?
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.
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