S400F power creeping up

[Ken G]

As per title I have an S400F purchased new in December last year, bought myself a chrony in February and found that it was running very close to the limit, ended up taking it back to the shop where I bought it who dropped it to 11.4, I checked it myself a couple of weeks later and it was at 11.7, I gave it the benefit of the doubt and made the assumption it could be the readings of the two chromos being different, so I set it to 11.4, have checked it today and its back up to 12.14 at 150 bar with AA fields, so does can anyone tell me the possible causes please. I realise it will probably end up going back but would like your thoughts on possible causes. (as for altering the power myself the shop left the anti tamper out at my request)

[raygun]

Is the adjustment screw moving ?

Sounds like it's unscrewing itself. If it is, another grubscrew on top of it should cure the problem.

ATB
Ray.

[Ken G]

Is the adjustment screw moving ?

Sounds like it's unscrewing itself. If it is, another grubscrew on top of it should cure the problem.

ATB
Ray.

It has a second grub screw on top, thanks anyway

[Raj]

Bedding in ?
Weather getting warmer ....?

[james79]

Is the adjustment screw moving ?

Sounds like it's unscrewing itself. If it is, another grubscrew on top of it should cure the problem.

ATB
Ray.

I'd go with that personally. On my year old s410 carbine its unbelievable just how loose that screw is, its so bad its sometimes difficult to tell if the Allen key has actually engaged with it as you try to adjust it rather than it just slipping adding a secondary "locking" grub screw can only be beneficial.

[wezdavo]

I also think the adjusting screw may be loose...

Mine is very loose, I have used a longer bolt cut down to suit to make sure in nips up against the adjusting grub screw to lock it off..

[Ken G]

Thanks to all will investigate further tomorrow