O.D. of .25cal
Can somebody please tell me the exact O.D. of the .25cal barrel where the breech slides.
Thank you
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Viewing 6 replies - 1 through 6 (of 6 total)
I find a tophat OD of 7.95mm is a nice snug fit into the breech-block and it’s x-ring. Any x or o-ring will do so long as it’s a nice fit onto the tophat, just cut the groove into the block to suit.
It usually depends on what size “O” rings you want to use
Metric/Impreial
I think the .22 is around 7.85mm but it’s got an imperial O ring for the breach .
Try using a 9mm or 10mm ID O ring with a 1.5mm section and work your breach out around that.
I think the english metric sizes are just imperial equivalents, ie 1.85mm section etc as apposed to German metric witch are dead sizes ie, 9mm 9.5mm 10mm …… so on and so forth.
Sean
Thank you very much sharpshooter
Only disadvantage the larger i.d. breech is more “dead air” space in the breech. For best effeciency, the air volume between the tophat and barrel should be minimized.
I think i would rather have a new breech made with a bigger ID so i can have a bigger OD on the barrel.
Thank you very much sharpshooter
same OD as the standard .22 barrel.
Viewing 6 replies - 1 through 6 (of 6 total)
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My setup at the moment is a standard LW from AF which has an OD of 7.88 and my tophat is also the same.
The ID of my breech is 8mm
I am thinking of drilling breech to 8.5mm and adding bigger O-rings like blodnob said. Barrel will be 8.45mm and so will the same for the tophat.
Sharpshooter i already have a smaller DEAD air area as i positioned my barrel closer to the tophat the gap there is only 1.6cm. I have thin fingers, but it is a good point.
Langsen i might just try your 7.95 OD and if i do not like it i can always take it down, we shall see.
This is where I think this guns are noise and not the stem in valve or hammer slap.
Thank you all for the help and cheat chat. 😀