Air Arms Owners Club

Gents,

I have a .22 TDR which is approx 7 years old and pre anti tamper which I have just purchased S/H( it has a security screw covering a 1.5mm alien grub screw) and only producing 7.4 ft/lb (485 average) on the chrono using 18gr crossman Ultra magnum.

I noticed that the grub screw was wound IN to within 1/2 a turn.

Can you please advise as to where this would normally be set? I have left it where it is for now as I do not want to undo it to far incase it becomes unseated (its a tiny hole)

I have a Chrono and intend to set the rifle at around 11.6 (unless I am told otherwise) to account for testing with heavier pellets

What pressure do you set your gauge at? The manual clearly states 190BAR but I am finding that I loose around 2-3ft/lb until I get to the 150/160BAR mark? Is this usual?

Also, having come across from a Webley Raider, what pellets are you using? Diablo Fields? Do the Diabalo field PLUS make any difference ( I am using the rife for pest control and target shooting at the Range inc HFT)
Any advise appreciated
thank you

I would use the most efficent pellet you can find which should be AA fields or any of the jsb made pellets and use a medium weight,set your cylinder pressure around the 150 bar mark as this should be the top of your sweet spot where your rifles valving is working at its optimum,i would set it around the 11.3 fb mark which should give you enough of a safety margin for using a heavier pellet

Road runner, thank you for the reply!

Would you know where the grub screw would normally be set?

How many turns between closed and open?

If I unscrew it too far will it just fall out?

Thank you

yes if you keep undoing it you need chrono to test it on.
atb paul.

Hi Paul, I have a Chrono to use ( I would not dream about working on a Rifle without one I was just trying to find out a bit more information on where to benchmark from.

There seems to be a lot of info about modifying the 410TDR with regards to polishing and adding spacers to improve the accuracy and performance within the limits, is this necessary?

hi lee , it makes the shooting loads better if the hammer rail is polished .
and the trigger shears polished , the whole thing is better .
all the different things add up to make more accurate and constant shooting .
at some point the grub screw will stop obstructing the transfer port .
atb paul

Paul, can you point me in the direction of a how too???? I am VERY new to all this