Steyr LP10 weak cylinders after 6 year break

[nc513]

Well, it's been a while, for sure ... :)

Yesterday, I took my Steyr LP10 to the range, after a 6.5 year break. All this time, the LP10 has been hiding in its case, with a cylinder attached.

First off, I filled 4 cylinders to slightly below 200 bar. Then I simply just started to shoot. However, I immediately noticed that the first shot sounded ridiculously weak, as did the next one, and the next ... After a while, I switched cylinders, but there was no improvement. After about 30 shots, the mean point of impact was in the 4-ring, right below the ten ring.

Switching to a third cylinder actually made a difference, though. The LP10 sounded a lot more efficient, and the shots immediately started landing in the black.

Unfortunately I had to leave shortly after switching to the third cylinder, so I have not yet been able to convince myself that the LP10 is operating correctly and consistently. I did not have time to test the suspicious cylinders with another LP10, either (I'm sure the club would happily have lent me one for testing).

So, now I'm looking for some facts and/or opinions. :)

1. Does the LP10 or its cylinders typically require some sort of maintenance/service after sitting idle for a long time?

2. Do these problems sound familiar? Does it seem likely that the cause of the problems are the cylinders, the pistol or both?

[David M]

Cylinder pressure has little to do with velocity as long as the pressure is above that needed to work the regulator.
Velocity is dictated by two things.
1 The pressure in the pre charge chamber, controller by the pressure regulator.
2 The energy of the striker opening the poppet valve.
If the pistol was left with the tank screwed on and under pressure, the pressure regulator spring/s may have weakened and
then the precharge pressure will be low.
The striker may be dirty and gummy which will slow down the valve opening, also if left cocked the spring will have weakened.
The slight improvement may be the striker freeing up a little but needs checking.
Either way your pistol will need a strip/clean/service by a good pistolsmith.

[spektr]

Agreed. almost.
I have had a cylinder issue once caused by me leaving a cylinder charged and not discharging it.
What happened was that the valve got "crusty" and didn't open fully when the can was screwed onto the gun.
I had never heard of this being an issue on my P44 let alone any pcp pistol;
I took a very small amount of a good silicone oil and lubed the valve, exercised it with a toothpick and freed it up.
After that the can shot at full velocity instead of partial pressure low and slow shots. If it isn't this, send the gun off for service......

[stephen_maly]

I ran into the same symptoms with my LP10 about two years ago. In retrospect it appears that the culprit was the pin and valve. Store your pistol with the cylinder completely removed for a few days and try shooting it again. Also, store it in the uncocked position. What happened with mine was the power was not enough to push the pellet out of the barrel. I thought it might be the regulator, but it was not. I think it had something to do with the high pressure and warm temperature of where I live and perhaps humidity in the air. The seat of the release valve "sticks", and residual air remained inside the regulator even when the cylinder was removed, as the gun could still be fired several times. On any case, removing the cylinder when not in use seems to solve the problem for my gun.

[nc513]

Thank you David, Spektr and Stephen, very interesting comments!

There's not been much progress yet, but I did happen to notice something presumably abnormal: While unscrewing the cylinder, some air will leak, as usual. But about a second after I had completely removed the cylinder, there suddenly was another small burst of air (from the gun, not from the cylinder). That's not normal, is it?

I'm going to let the gun sit uncocked with the cylinder removed until Thursday. On Thursday I'll try to confirm that all my cylinders are in fact good, by borrowing another LP10 to test with. If the cylinders are good, I'll just try to see how my own LP10 decides to behave this time. Hopefully, there's magically been a significant improvement. :P

I think I saw a couple of new MegaLink 3D-Score electronic targets at the club and it seems they have some sort of chronograph feature built in. Might be useful for testing if my LP10 is powerful enough and performs consistently.

[nc513]

Today I started with one of the cylinders that seemingly made the pistol perform badly last week. I completely emptied the cylinder and then filled it to about 190 bar.

My ~10 warmup shots felt ok and the scores seemed logical. Then I was allowed to try one of the new MegaLink 3D-Score electronic targets for a few minutes while the juniors were on a short break.

According to the MegaLink, my pellets were traveling at the following speeds (when hitting the target?):

138.6 m/s
147.1 m/s
147.6 m/s
147.x m/s
146.9 m/s
146.9 m/s
143.8 m/s
152.9 m/s
150.6 m/s
148.1 m/s

That looks relatively normal, doesn't it? Not a consistent 155 m/s, but that could hardly be expected, either.

I guess I could repeat the experiment next week, maybe also with a borrowed LP10, for comparison.

[nc513]

Maybe I should add that the LP10 has been stored indoors, untouched for 6.5 years, in temperatures varying between 23 and 32 Celsius (73 to 89 Fahrenheit).

Here's the quick MegaLink speed test I did (shooting free hand):

[spektr]

Obviously the gun has decayed to the point of unusability.


LOL

Well done

[nc513]

Haha :D Yeah, hopeless case, I'm afraid.

Well, it does seem the gun is suddenly working reasonably well indeed. Regarding shot placement, it's definitely giving me exactly what I order. For instance looking at the three worst shots above, they were very obvious triggering errors that I immediately called myself as well.

Maybe a thorough checkup could be good though, for peace of mind.

[nc513]

Well, I'm not sure what to believe. After a dry firing session last Tuesday, I left the pistol alone for two days. On Thursday at the shooting range, I noticed the pistol had once again lost most of its power. I believe the first shot actually hit the wall instead of the target.

I did not fire a live shot at the end of that dry firing session and I didn't remove the air cylinder, either.

The LP10 did quickly regain (most of?) its power on Thursday, after this procedure: 1 live shot that missed the target. Unscrew and reattach cylinder. 1 shot in the 4 ring. Unscrew and reattach cylinder. 1 shot in the 8 ring. Unscrew and reattach cylinder.

The first two times I unscrewed the cylinder, there suddenly was another small burst of air (from the gun, not from the cylinder), a couple of seconds after I had completely removed the cylinder from the gun.

So something in the gun seems to be sticking, until it gets "warmed up" ... ? Pretty much like David and Stephen commented above.

I think I'll just shoot my Morini CM162EA instead, until I can get this problem sorted. It actually surprised me a bit, how pleasant the Morini was to shoot, after not having touched it for probably about 9 years.

[David M]

Really sounds like the regulator is sticking, that is giving variable output on discharge.
Strip, clean, lube are the order of the day by someone who know what they are doing.
Service.......