LP10 getting 75 shots

[seamaster]

My LP10 is getting about 75 shots from red line to yellow line of compression.

According to Steyr, I should be getting about 180 shots per charged compression.

Chronoed, getting speed 490 which is the max velocity adjustment for this LP10. Screw in the velocity screw any more, it becomes dangerous. It fires when catch lever is compressed down.

What might be the most likely culprit at this point? All the O-rings have been changed, including the ones in cylinder. Did not change the piston valve or the spring. What is the size of the O-ring embedded in the pistol valve? Is that O-ring on piston valve replaceable?

Any other likely culprit for this low velocity?

[Rover]

I would change the spring before trying anything else.

[seamaster]

http://www.pilkguns.com/wp-content/uplo ... 10_man.pdf

Spring coil #51 on diagram is such a short and strong coil.

IF it lose its springiness, that would allow piston valve #18 to stay open LONGER; therefore, increase air outlet and increase velocity, not decreasing velocity. No?


There are two springs #51, and #52.

Are you talking about #51 Valve assembly spring or #52 hammer spring?

A bad #51 would increase velocity and a bad #52 would decrease velocity, no?

[Rover]

The striker spring should increase velocity, but you're apparently not getting enough. Going to a light 7 grain pellet should increase your velocity by about 45 f.p.s. My LP1 with a max+ fill only gets me about 110 shots. I think 180 shots is completely unrealistic.

As I said, go to a NEW spring before messing with anything else.

[Rover]

The striker spring should increase velocity, but you're apparently not getting enough. Going to a light 7 grain pellet should increase your velocity by about 45 f.p.s. My LP1 with a max+ fill only gets me about 110 shots. I think 180 shots is completely unrealistic.

As I said, go to a NEW spring before messing with anything else.

[Gwhite]

If you aren't getting enough shots, you are using too much air. If you aren't getting enough velocity, you aren't getting enough of that air behind the pellet. That sounds like a leak someplace after the firing valve. I think the only candidate is the breech seal. Drape a tissue over the pistol and fire it. If the tissue goes flying, you've got a leak.

[northpaw]

My LP10 is getting about 75 shots from red line to yellow line of compression.

My LP10 does a little better, roughly 90 shots at 153 m/s (503 f/s). Bolt to barrel adjustment is critical, see instruction video from Steyr for this topic. My LP10 has correct bolt to barrel (head)pace, and my LP10 is definitely not leaking.

According to Steyr, I should be getting about 180 shots per charged compression.

You may get the adverticed 180 shots pr. fill if you adjust pellet velocity down to 400 f/s, or less, I guess.
At the from Steyr recomended velocity of 500 f/s + , pellet # 180 would barely make it out of the barrel, I think.

Steyr used the formula: "up to 180 shots" from a full cylinder. "up to"... :-). Velocity not stated, though.

[rmca]

Steyr used the formula: "up to 180 shots" from a full cylinder. "up to"... :-). Velocity not stated, though.

And you have to use most of the yellow area to get "up to" those 180...

[KH250]

My LP1 years ago lost velocity, the problem ended up being the valve was binding. It was replaced and the problem went away.
parts #51 #52 #18 #19 all interact with each other. If #19 hammer does not move freely when the sears release #18 Valve will not be struck with enough force. If #18 valve is sticking, same problem.
If the Belleville washers in the regulator have corroded with age and moisture. The regulator might be running at the wrong pressure. Winding up the hammer spring to get the velocity up might be causing the valve to bounce. This in rifles is uses lots of air.
Start simple check the hammer is not binding, replace the springs and the valve.
My LP10 from 150bar to velocity drop gets 120 shots. It was set to 150m/s on a 8 gr pellet at the time.

[seamaster]

Put my hand over breech and fire.

I did notice a small whiff of air coming out around catch lever.

Is that normal?

[KH250]

So does mine.

[Rover]

My LP1 doesn't.

[seamaster]

LP-1 does not have catch lever/ stabilizer.

Wondering the whiff of air around LP-10 catch lever is expected?

[KH250]

My lp50hp just about blows your hat off, but it still gets 750 fps. Firing my LP10 without a pellet does not leak any noticeable air around the catch. But put a pellet in and it does. It is good for a match plus the finals with air to spare.
A whiff of air? Hardly enough to explain 75 shots a tank and 490 fps. You are getting half the normal amount of shots.
If your regulator is running at to low a pressure and you are compensating by winding up the hammer spring to try and get the velocity. You may still be using a lot of air and getting no speed. Unfortunately you may need to borrow another regulator assy to eliminate it as the cause. I certainly would not buy one unless I was sure it would fix it. Giving it to an Steyr trained person may be the best way to fix it.
I am most probably on the other side of the world and cannot see or operate your pistol, so the best I can do is make a guess as to the fault.

[KH250]

One question no one answered is, the valve assy does not have a separate seal. It is one piece. One thing you failed to mention, is it a compact Steyr. In Australia you do not see too many compact ones. I just assumed the one you have is the full length one. We have the choice to get whatever Steyr we want. 75 shots in a compact, not as bad as 75 on a full length one.

[seamaster]

Changed all o-rings again. Measured from redline to yellow line how many shots I got. Total about 110.

1st shot chrono 470 Ft /sec, last shot 430 ft/sec.

Maxed out on velocity screw, any more screw in on velocity screw, push lever down gun fires dangerously.

So at this point, the hammer spring is probably the most likely culprit.

Very tempting to just pull/ lengthen the hammer spring by 10% manually, and see what happens.

Stupid idea or nothing to lose idea?

[Silvershooter]

Very tempting to just pull/ lengthen the hammer spring by 10% manually, and see what happens.

Stupid idea or nothing to lose idea?

That will ruin the spring imo. Order a new spring and replace. In the meantime I would change the cylinder before it gets to the yellow line. (Latest cylinders only have a red and green band.)

[northpaw]

My LP10 is getting about 75 shots from red line to yellow line of compression.

My LP10 does a little better, roughly 90 shots at 153 m/s (503 f/s). Bolt to barrel adjustment is critical, see instruction video from Steyr for this topic. My LP10 has correct bolt to barrel (head)space, and my LP10 is definitely not leaking.

At the from Steyr recomended velocity of 500 f/s + , pellet # 180 would barely make it out of the barrel

We have the choice to get whatever Steyr we want. 75 shots in a compact, not as bad as 75 on a full length one.

My LP10 is a full-lenght, and I get roughly 90 shots of uniform velocity.

[seamaster]

I am getting 120 shots with 330 FPS. It is punching paper still cleanly.

So I assume the low velocity is probably soften hammer spring.

Is there any replacement spring that I can order from McMaster.com? Anyone knows the specs of that LP10 hammer spring?

If spec unknown, I will just order hammer spring from Pilkguns, and order all other replacement O-rings from McMaster.com

[seamaster]

Come to think about it, can't I just use the old PCP rifle trick of adding one or two small washers to increase hammer spring strength?