Originally Posted by Tench
Tone, maybe it is because the pellets are manufactured to work in the production rifles that are available to buy, not rifles that are taken to the extreme of what can be done if you try hard enough. You have clearly built a border line rifle which on the limit has become extremely pellet fussy.
To say the pellets are no good in that situation is like complaining your car doesn't achieve the manufacturers claimed mpg after you fitted twin 40's!
twin 40's...not heard that quoted for a while LOL
I think it is just a barrel issue Simon, im not saying the pellets are bad, far from it, i think they have changed as per Lloyd from BAR asking on FB etc. I noted a change on the rifle here and was concerned enough i started measuring and compiling data so I could see what was going on.
I can tell you the efficiency of the TX has risen massively, it has less spring now with the smaller piston and makes more from the lower swept volume, my 77k hit near 60% efficient with a 23mm piston using the 2013 batch of exacts.
However...my concern are some (less experimental than I am) may buy a newer batch of JSB's and encounter the same issue...BUT feel they have a spring issue or the gun is just down on power...and start messing to get it up where it was...like i said with superfields the TX was touching 13fpe with ease.
The ultimate set up I feel will be a few barrels that easy interchange into the TX, a project for the winter maybe. I may have a .177 BSA I can use, I do have a Diana barrel I can use and may purchase a LW and CZ just so I can test all 4 with the same pellets and see what the chrono spits out.
In the short term I may turn up a pellet seater and see if pushing the pellet in exactly 1mm makes a difference just incase the lead in is slack just around the breech face.