Air rifle: when is V0 too low?

[JeroenH]

For air rifle, I'm used to having V0 somewhere around 170 m/s. (I don't know why, come to think of it...)

When is V0 so low that you'd need to have it looked after? (even when the grouping is still OK?)

With the rifle of a fellow shooter, we measured a V0 of about 140 m/s. This sounds pretty slow to me, but I'm not sure that he has something to worry about...

Jeroen Hogema

[Albert]

Jeroen,
what kind of air rifle are we talking about? (fabr. type etc.)

Albert
(The Netherlands)

[JeroenH]

A Walther LGR. You know, the 'old' (?) pre-compressed type.

[Jim E]

Original factory VO specs for the LGR --- the venerable nmatch air rifle that was the first single stroke pnuematic and broke all the existing world AR records --- was between 165 to 170 m/s (550 to 570 fps).

It could just need breech seals (cheap and cheerful) or a valve seal. Cock the rifle and let it set overnight. It it still shots around 140 m/s, it is likely the breech seals and/or vlave seal. If it doesn't hold compression over night, have it complete resealed (~$75.00 USD).

To preserve the life of LGR seals alway leave the breech unlocked after your shooting session. Seals will last up to ten years it cared for this way.

[Albert]

Great!
Is there a procedure for storing a LGM-2 (also pre-compressed) so the seals have longer lifespan?
If the rifle is stored with the breech opened, will it reduce the lifespan of springs and other parts?

Albert
(The Netherlands)

[Jim E]

Albert -

The unique breech block (see picture) configuration of the LGR (and also somewhat repeated on the LG-90/CG-90) warrants leaving them in an unlocked position to preserve the front and rear seals on the breech block.

The breech on the LGM-2 is a different system and may not benefit from the LGR "un-locked" breech suggestion.

[JeroenH]

Original factory VO specs for the LGR --- the venerable nmatch air rifle that was the first single stroke pnuematic and broke all the existing world AR records --- was between 165 to 170 m/s (550 to 570 fps).

There's a reply from Walther now, saying that the V0 for the LGR is somewhat lower than those of modern rifles ("approx. 10 m/sec lower"). Which seems pretty much in line with the 165 to 170 m/s you mentioned. So our (estimated) level of 140 m/s would be too low indeed.

It could just need breech seals (cheap and cheerful) or a valve seal. Cock the rifle and let it set overnight. It it still shots around 140 m/s, it is likely the breech seals and/or vlave seal. If it doesn't hold compression over night, have it complete resealed (~$75.00 USD). .

We'll give it a try, thans for the advice.

To preserve the life of LGR seals alway leave the breech unlocked after your shooting session.

This is what I've been adviced for my FWB 601, and always did as long as I had it.

Thanks again,
regards,
Jeroen