Quote Originally Posted by johnbaz View Post
hello dumdum

on my .177 mk3, the seal is so good that, if you cock the gun then open the tap and then pull the trigger whilst holding the cocking lever, it holds the pressure within the cylinder, there arten't any other underlever rifles that i know of that will hold the piston back in this way, certainly, my mk5 airsporter won't, i believe this to be due to the fact that the loading tap is tapered in the same way that a gas tap is, it was lapped in for a gas-tight seal- quality or what!!!

john
accuracy too is excellent as long as the rifle isn't dieselling

Conversely, I have 2 MK3's in .22 & a MK3 Supertarget in very good condition none of which will hold the piston back in the manner you describe; but my Airsporter MK2 & Airsporter Club that are in poorer condition both will! My personal view is it's a bit of a lottery in this area with all tap loading guns due to manufacturing tolerances & W & T over the years?