S410 Classic power drop

[airarmstommy]

Hi guys, my S410 was chronoed and only shooting 8.1f/lb. a member at the club removed the dome head screw and adjusted the transfer port allan bolt around 4 weeks ago and it was showing 746 ft/sec on the chrono which he told me was 10.4 ft/lb. The reason I left it at that power is because when he tried to get it to shoot around 777ft/sec with every pellet over the chrono it just kept rising in feet per second and was over 800 ft/sec It just so happened that the club were chronoing everyones guns yesterday and my S410 was only shooting 664 ft/sec 8.3ft/lb!!!! Does anyone have any Idea why it is dropping power? its a 2014 rifle.

[Blackbaronfish]

Have you lost a breech seal.

BBF

[ray7]

Had a similar problem with my s200. After buying it second hand found that the former owner had removed the anti-tamper and done some adjustments. The transfer port screw had become loose and moved every time the rifle was cocked and fired. I solved this by putting a longer grub screw in that stuck out the side and put a lock nut on it making it like the mk1 s200. Not looked at an s410 so not sure if you could do the same.

Ray

[Roger5]

Not long sorted an s510 with what seems to be the same problem, the power adjust screw can wind itself in and obstruct the airflow, I just put a new one in, sorted. Ask Julian to send you a couple. Rog

[airarmstommy]

Thanks for the replies guys. BBF, I had it in for a service so I assume it was done but who knows? I'll give it a couple of weeks and try another chrono. The thing that is annoying is that it is a lovely rifle but as I shoot HFT the holdovers change all the time and I would just like to have a consistent power output. I'll let you guys know what happens over the next couple of weeks and maybe get a better idea what's happening.

[Blackbaronfish]

They can pop out at anytime. Load a pellet and when you fire check for any air leaks around the breech area. Breech seals can be seen if you look closely.

BBF