TargetTalk

Just curious but what muzzle velocities do you set your LP10 on and with which pellet?

Thanks.

Rustam

P.S.: I believe Steyr set it at 155 m/sec. at the factory

Rustam,
If you really want to do the job properly then you need to optimise both for your gun. That involves one hell of a lot of testing though so most people just pick to the best pellet and stick with it.

Rob.

Rustam - Robb has provided probably the most honest and technically accurate response to your question. I know it's probably not what you're looking for, but it's the truth.

If you have a large supply of a particular pellet, then tune your velocity to make the best groups with that pellet. My LP10 had to be adjusted to less than 500fps in order to comply with Canadian law. Since I had a case of a particular pellet I tuned the pistol to that pellet as best I could and ended up with two "sweet spots", one at just slightly over 400fps and the other at just slightly below 500fps. I went with the latter and it seems to have worked well.

Many posts in the past have suggested the overall LP-10 system of recoil absorption, barrel venting and muzzle compensator seem to work best in the 520-540fps range. Whether you can find a pellet that shoots well at those velocities will be largely limited by the range of pellets available to you.

My Steyr from factory is around 160 m/s.
After a little gunsmith job i had to reset the velocities (the man don't check the screw and velocity was so high that air go all over around the transfer port).
I cannot put it in a vise, so i pick my favourite pellets (finale match 0,50 grams) and adjust to my own taste. Seems to me that around 175 m/s give a nice feeling (no recoil, no movement, great stability sensation) over the shoot.

I check velocities from 180 bar:
180,3 179,6 180,2 178,8 180,3
180,2 178,7 169,5* 179,3 179,3
178,4 178,4 178,1 177,8 178,1
178,1 171,4* 178,4 177,9 177,6
179,5 179,7 176,7.
I don't understand * number, maybe is my fault reading the crony (combro) or maybe i moved it during measure.

I reduce slighty (to stay on legal limit), now from 150 bar:
175,3 177,4 178,0 177,6 178,4
178,1 177,9 177,6 177,8 176,1
And from 130 bar:
178,0 176,2 176,7 178,8 178,0

I'll reduce another bit to stay around 175 m/s.

Are normal number? or there is too much differences from shoot to shoot?
Thank you,
best regards,
LukeP.

As long as the pressure of the cylinder is in the green, it has no influence on the velocity since an air pistol has a regulator.

The values you got are on the high side. For a 0.50g pellet it should be around 165m/s. But as long as the group is good and the velocities variance small, its OK.

About the bad lower velocities, they can come from a bad measurement due to a shot at a bad place with respect to the sensors of the Chrony. Limit light conditions may also be the cause, did you shoot indoor or outdoor, if it is indoor, what kind of light ?

As long as the pressure of the cylinder is in the green, it has no influence on the velocity since an air pistol has a regulator.

Ok, mine (and mine companions too) don't change point of impact a bit more than half yellow.

The values you got are on the high side. For a 0.50g pellet it should be around 165m/s. But as long as the group is good and the velocities variance small, its OK.

I set to 175 only for feeling question, i'll make other test.
So if the velocities variance is between 1-2 m/s is good.

About the bad lower velocities, they can come from a bad measurement due to a shot at a bad place with respect to the sensors of the Chrony. Limit light conditions may also be the cause, did you shoot indoor or outdoor, if it is indoor, what kind of light ?

Indoor with (i don't know translation) "neon". I have two "auto lecture", no shoots fired but the device measure something.

I started out at 550 fps and adjusted from there to find the best group. I know I did not have to adjust very much. the only problem is I use more air that at a lower velocity. I suppose if I had the time I would look for a lower value that produces the same or smaller hole and conserve some air for a just incase I need more air for some reason. If there is some reason i would need to shoot a match and a final on the same charge I would feel safer. I think I can make it now but i have never tested to see how many shots I can get off of fully charged cylinder.

Chris wrote:... i have never tested to see how many shots I can get off of fully charged cylinder.

Hi all

A few months ago I tested this issue using a Combo CB625. My conclusions was that with a full charge air cylinder (190-200 bars) the bore velocity was very stable after 150 shots and that happen with the cylinder air pressure indicator almost at 0 in the yellow zone....

Next URL show a excel graph with the results.

http://img249.imageshack.us/img249/1037/lp10nx6.jpg

That test was done using JSB Match Diabolo 4.49

Regarding the Combro "bad readings" I think this is not caused by light illumination problems due the Combro don’t need external light to properly work. Many others chrono (like Chrony) are "shadow detectors" and need an external light source to work. Combro has a couple of infrared emitters/receivers that are interrupted when pellet cross the bean so, in theory, it could work even in dark.

Regards
BP