Air Arms Owners Club

This might sound daft but before stripping and polishing the hammer and hammer rail on my pre anti tamper .177 s410 it was running at 10.6ftlbs I've just chron'd it and it's only doing 9.2.i turned the screw fully in and it was going just over 4ftlbs and adjusted out so the transfer port was fully open and 9.2.any solutions has to what's happened and to how I can get it back running at 10.5

Forgot to add I was using weighed 8.4gn jsb exacts

Hi,

Things to look at are:-

1. Is the barrel the correct way round. i.e the hole in the brass piece facing the transfer port. (I find it easier to align the barrel to the bolt housing while in dismantled state)
2. Did you refit the very thin o-ring between bolt housing and hammer block assembly (S427 in the AA manual)
3. Did you fit the correct o-ring (trust me it made a difference to mine)
4. Is the pot screwed in the same amount as it was (typically so 57mm protrudes from firing valve body)
5. Did yuo loose the o ring in the breech end of the barrel

Mark

Did you put anything on the rail?

Geordie wrote:Did you put anything on the rail?

No gordon left is dry

Mark112 wrote:Hi,

Things to look at are:-

1. Is the barrel the correct way round. i.e the hole in the brass piece facing the transfer port. (I find it easier to align the barrel to the bolt housing while in dismantled state)
2. Did you refit the very thin o-ring between bolt housing and hammer block assembly (S427 in the AA manual)
3. Did you fit the correct o-ring (trust me it made a difference to mine)
4. Is the pot screwed in the same amount as it was (typically so 57mm protrudes from firing valve body)
5. Did yuo loose the o ring in the breech end of the barrel

Mark

Barrel is the correct way round,o ring re fitted between housing and hammer block,didn't touch the pot (had no reason too)now the o ring in the breach end of the barrel I'm not sure about so the barrel will be off in the morning.if it is indeed a lost or damaged o ring how do I remove it has it sits inside the brass bit on the barrel

Bend a pin slightly, take the brass off the barrel, a bit of heat will loosen it then push the O ring out from the muzzle side. Failing that, just try to hook it out from the breach end with some fine stiff wire. Be careful not to scratch the brass.

Have stripped the rifle and the firing pot is showing 57mm,have replaced the barrel o ring and put back together and still only getting 9.2ftlbs,any others solutions?

Hi, just a thought but if you've checked everything you can think of on the rifle and can't find a fault are you sure your chronos batteries are good and it hasn't lost calibration. It's not always the test subject that's at fault it can also be the get apparatus

Have you checked the "brass barrel o-ring retainer" thing hasn't slightly rotated obscuring the transfer port opening?

Sorry, just checked, this has already been suggested..