Page 1 of 1

LP10 Erratic Velocity

Posted: Sun Jan 03, 2021 3:14 pm
by brent375hh
My LP10 whacked out for a while. It shot from 610-58 feet per second. I initially thought that my chronograph was bad, but the report and the 58 fps that bounced back out confirmed my readings.
My I Z H shot its normal velocity too.
Now my LP is back to a steady low 540 with R10 pistol like nothing happened. Anyone else have this happen, and did it go away, or is it the beginning of a problem?

Re: LP10 Erratic velocity?

Posted: Mon Jan 04, 2021 12:19 pm
by spektr
Airguns are reasonably simple devices that are susceptible to "stiction".
Look it up, its a condition where a mechanical device with lots of connected parts sticks a little bit
after it has been sitting around a while. Its normal in a lot of devices, and our air pistols all do this to some degree or another.
My P44 gets 5 rounds thru it before I even worry about where its shooting. I never see stiction issues because I know what it is and
just let the gun be itself and limber up before shooting for score. Does it need 5 rounds? who knows, but I run 5, never see an issue, so
what the heck, It works for me. My 777 is the same way, the pump needs to move the lube around to seal perfectly.
Anyhow, Im overcomplicating things by describing it, so stop worrying, its normal.......

Re: LP10 Erratic velocity?

Posted: Mon Jan 04, 2021 7:32 pm
by brent375hh
It seems to working again, but it hasn't sat for more than 3 days. I don't don't think 58 or 610 fps is ever normal.

Re: LP10 Erratic Velocity? Fixed!

Posted: Tue Jan 19, 2021 8:42 am
by brent375hh
After I had wild variations, as above, I cycled my regulator by taking the cylinder on and off. It finally calmed down and ran with an 13 fps variance. Good enough to get by.

I did notice that whenever I put a cylinder on, I was hearing a squeaky sound. My suspicion was that the o- rings in the regulator piston where very dry. I ordered new o-rings and a complete spare regulator from our host. I had it all in two days. Jennifer is a very efficient at what she does.

This morning I pulled off my regulator, and took it apart. BTW the barrel does not have to come off to do this, as is shown on the Steyr service video. I slid all the washers onto a hex key for orientation. There is a small hole in the regulator to then put a pin through and push out the regulator piston. It took quite a bit of effort. Sure enough, the o-rings were very dried out looking. Without even changing them, I put a very light coat of Super Lube grease on them and reinstalled the piston and washers, and the two screws that hold it all together. While I was in there, I cleaned my firing valve and seat, and gave it the lightest coat of Super Lube and reinstalled everything. When I screwed my cylinder on, the squeak was gone, just a light click.

Upon testing post assembly, my velocity had dropped down in the 490s. I have noticed that my velocity had been climbing over time, and that I had been backing out the adjustment screw to get it to adjust back down. Today I screwed it back down in to obtain my desired velocity.

It is now shooting between 528-531 feet per second for a 12 shot sample. I consider this a successful 35 minutes spent, and I still have spares for any possible problems down the road.

After seeing how all the seals work, I can totally agree with Scott's recommendation of removing the cylinder when not in use, especially to keep the valve o-ring from compressing over time.

Re: LP10 Erratic Velocity

Posted: Wed Jan 20, 2021 5:16 pm
by spektr
Postedin theotber tbread
I do not understand why people allow the regulators and orings to dry out. I do not directly oil the gun, but I periodically apply a touch of silicone based oil to the tank threads, it makes it far easier to put the tank on and odd AND the oil slowly migrates into my regulator and it shoots very consistantly....... The issues I see you describe along with my previous crusty tank valve problem reinforces 2 things in mind. First, we must gently lube these creatures.
Second, Extended periods of storage, like a few weeks or longer, should have the tank unscrewed to unload the regulator and drainiing the tank is probably a great idea. Unscrewing the tank also means unseperaring the threads completely to protect the threads from excessive cam out forces if its case is bumped or dropped...

Re: LP10 Erratic Velocity

Posted: Thu Jan 21, 2021 5:59 am
by brent375hh
For what its worth, I too have been lubricating my fill tank threads, and often. My seals were dry.
I think unless you are putting oil directly into the 2 inlet holes, you may not be getting as much lube on your regulator piston seals as you would hope for.