I use JSB exact 8.4 , 4.52's at the moment.
Sometimes washed, lubed and sized, sometimes just out of the tin...doesn't seem to make any difference as to when a clean is needed.
I've tried different head sizes, tested quite a bit.
The gun was awesomely accurate when new but seems to have lost it's edge, particularly in the wind....seems to take a lot of wind... but could be pellet choice and a rubbish shooter...hard to pin down as so many variables..
It also seems to me that this summer is windier than the winter just past..at least when I manage to get out to shoot...
The fact it goes off at 50 pellets or so in still air and is obvious to see make me wonder if in windy conditions it is more prone to inaccuracy earlier...?
I read something supporting that proposition...and it seems to make sense. This barrel accumulates debris that causes inaccuracy much more quickly than other barrels...that seems to be a fact.
Also the fact that you know it's going to go off erodes confidence..
After several thousand pellets down it, it still goes off at around 50 pellets and I'm loosing belief in the claim that it takes time for the pellets to lapp and polish the nickel lining so that it doesn't accumulate so much gunk..
Perhaps it will improve but it seems to be taking a very long time to get past that 50 pellet mark...it's been 50 pellets or so from the start and doesn't seem to get better.
I've had some great advice and some fantastic offers of help which I'm gratefully going to take up...Going to try some other barrels in it and do some testing soon..
Putting another barrel on it is not an irreversible action and it seems daft not to try ....
Thanks again to those who have come up with brilliant help and support...some lovely people on here..