Gamo Urban .22 velocity variations, why?

[hanleyfan]

I have been thinking about buying a Gamo Urban .22 but have seen a large difference in velocities from gun to gun. Some are stating velocities with 14.5 gr. pellets at 850 to 860 fps and others say they are just getting 750 to 780 fps. for the same pellet. Heck one guy said he was getting 820 fps with JSB 18 gr. pellets. this was for out of box stock guns. I don't want to buy a gun shooting below 800 fps so whats up.

[Talan]

We have two urbans.  They both came from the factory shooting in the high 800's.  They are very adjustable by tuning the hammer spring.  I turned both of ours down to around 800 fps and they will go lower if I wish.  I am just guessing, but I think they may go higher also.  Just by adjusting the hammer spring.  We are shooting the cphp and round head in the 14.3 wt range.  Perhaps someone who has tuned them higher may chime in.

[CraigH]

Yes, easily adjusted.   Mime came at 865 fps, more than I wanted.   Have set it at both 750 and 780 for testing.   I don't know what the upper limit is.   I doubt if they are tested when built, just screw in the adjuster to some point and box it up.   It is very unlikely you cannot get 850 with 14.3 grain pellets.

[Ribbonstone]

Don't really find 5% either side too unusual with any airgun...actually, that's closer than many higher priced rifles have managed. They may be advertised at 800, but not real surprised to see 760 or 840 fps.   Just part of mass production tolerances...somethings they stack up all to the plus...sometimes all to the minus...but if you bought 10 of them and averaged the outcomes, likely would be close to what is claimed.

(OK...except for some springers....think they rely on the lightest possible pellet and cherry pick the one freak reading for one test rifle.....or they just make it up.)