Air Arms Owners Club

ok so ive got a s200 mk3 in 177 and the difference between bisley magnums running at now 11.7 and jsb at 7.8 is massive. if/how do i reduce the differnce between the two as the rifle prefers (most accurate) the jsb but as its for hunting i would like the jsb to be at around the 11 mark any help would be great cheers

Are you using the correct pellet weights in your calculations?
What speed are they doing?

the jsb must be very heavy , find some pellets that weigh less , till you get what you want,

the biz mags are 11.7 now (was abit hot) and the jsb about 8ftlbls and yeah all weights have been checked

eddie666 wrote:the jsb must be very heavy , find some pellets that weigh less , till you get what you want,

In this case it's JSB Exacts Eddie, only 8.4 grains.

Timmytree wrote:

eddie666 wrote:the jsb must be very heavy , find some pellets that weigh less , till you get what you want,

In this case it's JSB Exacts Eddie, only 8.4 grains.

they must be tight fit to only get 7.8 fpe

just a quick update as i was running some other pellets (all at 160bar) i noticed the power drops after the first jsb first i used cheap vmx pellets 8.2 and got

1.11.30/788
2.11.28/787
3.11.24/785

next were crossman premier heavy 10.6

1.10.79/680
2.10.70/677
3.10.58/673

then the jsb 8.4
1.10.94/766 (i thought yes that will do)
2.8.69/683
3.8.62/679

got to be seal thing surely as it does this every time i switch from another pellet to the jsb first shot fine and then lose 2odd ftlbs

Clutching at straws now, barrel clean and new breech seal, get your hands on a tin of AA Fields and try them.

seals in the post should get them tomorrow hopefully but i only just replaced it so i dont know also just put some accupels through and getting 10.6 so if they group fine ill just stick with them i think should be plenty for hunting

do not trust the gauge on the rifle they can say all sorts ,

fill to 190 and shoot with one type of pellet,
shoot strips of 10 shots on 15 seconds for each from the time you cock the rifle, then 2-3 minuets rest before the next strip of shots to let the barrel cool ,
this will give you a consistent time of pressure in the chamber ( if there is a seal leak ) all shots will be about the same consistence, on the chrono readings, write down what your rifle gauge is reading after every 10 shots ,
if you do this for 4 x 10 strips of shots or when ever your gauge says 100 , you will get a good idea were the sweet spot of consistent shots start and finish also what your rifle gauge is telling you.
even if you have a leak the shots will still show you whats going on.

make sure your chrono is working right and has a consistent distance and light and same timing with every shot , if you weight the pellets thats better but is not crucial ,
constancy / timing / cooling / distance and what your gauge is saying , sort out a timing system thats easy for you and the chrono to achieve, then if some thing shows up wrong it should be a constant wrong ,