Steyr LP10: adjusting muzzle velocity

Alexey931 · Post by **Alexey931** » Wed May 18, 2005 12:15 pm

Hi, everybody,

After three years of medium usage I observed a decrease in compressed air consumption. At first the green sector served 90 shots, now it's rather 130 shots. I purchased a muzzle velocity gauge and tried it. Got 120 m/s (160 m/s is supposed to be normal). Tried the screw in the breech which is supposed to be the velocity adjustment screw. It works in it's own way, but it is actually useless. Even turned 0.25, it does something to the trigger pull and trigger feel, turned 1.0 it does to the trigger something definitely nasty, turned 1.25 it blocks cocking. Still I can get nowhere near 160 m/s and am forced back to the initial setting. I suspect that actually some spring is no longer serviceable and has to be replaced. Any comments?

Best regards, Alexey

PS Mr. Pilkington's opinion is welcome :)

KrizakCz · Post by **KrizakCz** » Wed May 18, 2005 12:56 pm

Don't know if this is the case,but for most compressed air guns, a replacement of all sealings is reccomended after 3 years.Just a thought...

Honza

Post by **pilkguns** » Wed May 18, 2005 2:03 pm

Alexey,

Not sure what screw you are turning, but there is no way that it should effect the trigger. The velocity adjustment screw is at the very back, under the rear sight, probably the biggest slot screw on the entire gun. You first must loosen a setscrew (allen head type) on the right side of the gun before you can turn the rear one.

regards
Scott

Alexey931 · Post by **Alexey931** » Fri May 20, 2005 2:43 am

I was fooling with just one screw: the big one facing aft. I just descirbed my experience precisely as it happened and for what it is worth. And yes, it does affect trigger very much.

Best regards, Alexey

ben · Post by **ben** » Fri May 20, 2005 4:15 am

alexey
there does not appear to be a cross-section around of the LP10, but both the LP1 and LP5 will produce your symptoms if the hammer spring (under the velocity adjusting screw) has failed and become coil-bound
hope this helps
ben

ruig · Post by **ruig** » Sat May 21, 2005 12:07 am

It's good idea to meet with Gontcharov, for example... if you're from Petersburg. Or take a train and visit russian championship in Moscow 30 May-5 June. There're many Steyrs and few gunsmiths.

Everytime I played with velocity turnin' that screw - i had no problems.
http://pilkguns.com/tenp/spstlp10p.htm

Here you can see that big screw.

Alexey931 · Post by **Alexey931** » Sat May 21, 2005 11:58 am

With all due respect, Gontcharov only knows which end of the gun the pellet comes out of. He knows that pretty well, though. As to the Championship, that's what I have in mind endeed.

You were playing with the screw, whereas I tried to remedy a problem with it, which, probably, makes the difference.

If you are from St.-Petersburg we couldn't help being acquainted :)

Best regards, Alexey

Post by **pilkguns** » Sat May 21, 2005 1:26 pm

I have not seen this relationship, but if its happening, then something is broke, the striker spring as was mentioned above. remove the screw and then the spring and see what it looks like.

Alexey931 · Post by **Alexey931** » Sun May 22, 2005 12:27 am

Bingo! The hammer spring, part number 52. Broke in two, to say nothing of the nasty little shards, or something looking very much like that. Thanks, gentlemen. And you all seem to be suspiciously familiar with the problem. European quality...

Best regards, Alexey

ruig · Post by **ruig** » Sun May 22, 2005 1:11 am

Alexey931 wrote:European quality...

Nothing lasts forever... and russian quality too.

Contact with Steyr via e-mail... and you'll get your spring... just for about 10-15 Euro... I suppose...

Alexey931 · Post by **Alexey931** » Tue May 31, 2005 3:36 am

Putting in the new hammer spring, should I lubricate the parts involved, or should I, on the contrary, wipe them dry?

Best regards, Alexey

ben · Post by **ben** » Tue May 31, 2005 4:01 am

alexey
recommend lightly lubricate with thin oil, but without additives (PTFE), as these can make the trigger pull erratic. NONE of this oil in areas with high pressure air.
glad to see my diagnosis had been correct. This was not based on previous experience with Steyr products, but was a straight forward deduction.
with best wishes
ben

Alexey931 · Post by **Alexey931** » Tue May 31, 2005 12:08 pm

Thanks, Ben,

NONE of this oil in areas with high pressure air.

It's just as I suspected, but then that hammer thing contacts with high pressure air, or does it not? There is not much else to lubricate/wipe dry in the area.

Best regards, Alexey

ben · Post by **ben** » Tue May 31, 2005 3:33 pm

alexey
There does not appear to be a proper cross section of the LP10. I had assumed that the hammer was sealed from high pressure air as in the LP5. Looking at the exploded diagram - I hate 'em - it seems that the valve operating rod (hit by the hammer) is NOT actually sealed so that oil could migrate into the high pressure end. In that case I would follow the Steyr recommendation of using silicone oil, though I am not enthusiastic about silicone oil on the trigger mechanism.
My LP5 manual has a proper engineering cross section so that one can see what does what. Maybe your LP10 manual has a cross section to resolve the point finally? I presume your strip for repair has not needed to explore the high pressure end?
Thank you indeed for raising the alert!
yours
ben

Alexey931 · Post by **Alexey931** » Wed Jun 01, 2005 1:37 am

It seems that we could use some official opinion on the subject. Mr. Pilkington's would do... :)

Best regards, Alexey

Alexey931 · Post by **Alexey931** » Sat Jun 04, 2005 4:49 am

Any more opinions on lubrication?

Best regards, Alexey

LP5 owner · Post by **LP5 owner** » Mon Jun 06, 2005 4:23 am

I have a LP 5 that has always had a nasty habit of doubling occasionally. The frequency of doubling was reduced when I adjusted the muzzle velocity down a bit.
One sunny day i lengthen the 1. stage ("take up") of the trigger a bit, and the doubling vanished!
I was then able to increase the velocity by 1/3 of a turn of the crew untill the doubling started to show up again.

Alexey931 · Post by **Alexey931** » Tue Jun 14, 2005 8:23 am

Yes, there is a lot to trigger adjustment in Steyr pistols. A science unto itself.

There is still no reply on whether or not I should lubricate or else wipe dry the hammer thing. :)

Best regards, Alexey

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