sagalout

👍

The mounts I'm using measured 15mm from the base of the mount (peak of the pic rail) to the bottom of the scope tube. This made me think that my measurements the other day must be wrong so I've measured again and got 12mm from centre or pic rail peak to mag at that point and 15mm from right hand side of pic rail peak to mag at that point. Sorry for the duff gen earlier.

Me and @scoie converted a sub 12 380mm 0.25 to FAC (with the OK from his FEO) but in the tuning did not change the transfer port core leaving that as 4.5mm sub 12 item. This gave us an easy 38fe with JSB 25.39gr pellets at 125bar reg set pressure with a nice smooth and easy cocking action. Changing the barrel to 500mm with a superior liner and no other changes to the tune gave a bit over 43.5fpe average. Later we drilled the transfer port out to 7mm with no changes to the tune and gained around another 3fpe with the 500mm barrel. Accuracy testing in all configurations has shown pellets to be accurate and the slugs we tried weren't very good but that might be because we were running them to slow at around 833fps. The gun was initially converted to FAC using a Huma pin probe in place of the standard probe (no other parts of the Huma slug kit fitted) but that proved problematical loading slugs from the magazine so we reverted back to the standard probe. The difference in muzzle velocity between the pin probe and standard probe was about 10fps. Obviously a 600mm barrel will be more efficient than the 380 and 500.

Hi All, My name is lout and I'm an addict. Currently got 3 Sub 12 MkII FX Crowns, 2 in 0.177 both with LW barrels and a 0.22 with a Silco HW barrel. Picture of 10 inch LW with custom 125mmx40mm mod and Immersive 10x24 prismatic scope.

The rest of of the info I gave Kenyan Kier that may be of use (and I'll measure the height of the mounts I'm using there in a minute). 18mm is from the right hand side of the rail to the top of the mag at that point. Beware that the mag is rising you need to allow for the circumference of the scope. I'll come back to the 0.25 question after measuring the mounts I'm using.