Originally Posted by bigtoe
Rob..I gave up on the batch and bought a fresh one, thru my TX it is exactly how I stated, from well under 700fps to hitting 11.5 at 780...i have nothing to gain from telling porkies here, it is the reason I spent money on the pelletgage so i could at least see what was going on with the pellets. I spend many hours reworking springers, I was testing with a batch of exacts that on the whole were showing 9fpe...I moved to superfields and was hitting 13fpe at one stage...its was a good job im not totally blinked to exacts.
Something else I found, power plant set up is critical, going from a 25mm piston to a 22mm piston opened the can of worms wider than I liked with regards to JSB die, lucky for me I just happen to have tins of most everything so I just started with prems and worked thru superdomes, superfields, LRG's, FTT's etc and found what would at least give good solid FPS performance and then moved to accuracy.
Maybe those early 2015 tins were just made on a friday late afternoon....its hard to say, they shoot thru the LGU just fine, they do NOT shoot thru my TX fine and remember my TX is seriously refined now, how many people do you know with a TX that runs a 22mmpiston with 83mm stroke?
So lets forget the rouge batch, the graph shows clearly 2013 pellets outperforming 2015 pellets that were sorted for size with regard to power output, I have not tested accuracy with them yet in the TX but I have shot the 4.51's in the LGU and they were seriously good.
So my conclusion is this, the barrel on the TX right now does not like the newer batches of JSB, this may be more pronounced since I refined the power plant. I can tell you the pellet fit with the 2013's is tighter than the measured 2015's...there is more resistance from the pellets going into the end of the barrel.
Hence...I want to try another barrel on the TX, the issue could just be the lead in was fine with the older pellets, or running 41CC of compressed air bellied out the pellets for a better seal than running 29CC of air does now.
Its probably something that simple.
I'm not saying you've got anything to gain. But 110 fps from the same tin? Something else is wrong there. I could put pellets in backwards and not see that variation. Seriously I don't see that going from RS to Exact.
I know that batches perform differently. My 97 likes the old blue tin express that not one of my other guns likes. My TX likes the 14's that my steyr with it's non steyr barrel prefers in the batch marked with a different head size. That's doing silly tight groups. Its chrono variation is no where as good as the walthers which prefer another batch again... but they also preferred it when i sized down to 4.48.
I've said for a long time, either my sizers are out, or not many of a tin is the size that's on the back, and when you measure it, it makes little difference. i.e. 4.52 on the back is less important than actually how they shoot.
Sizing and weighing and other things can make batches perform a bit better, but to date, the best batches i've had I don't do anything with. I might weigh a few now and then, but with the good batches i kind of gave up, it seemed pointless. With my walthers i may play with pellets a little, sizing, but i've seen negative effects of sizing with other guns (daystates seemed to hate my 4.48's).
I'll have a look, but i've definitely got batches going back to '05 in mozzy form, and express to '07 (iirc).
What i do know is my best gun (the steyr) has far worse chrono consistency than my best gun over the chrono, which on a short burst of 20 did 1 fps max spread, from the tin, a walther that's been really fiddled with. But I can't remember which tin we did that from. And i didn't shoot it for groups. But the steyr really is at a point where it's hard to improve, right from an '14 tin... it's super tight at 50m on paper.
In the mix though is scales which round up (mine despite weighing to 0.01grains, not 0.1grains, will not read any pellet at 7.84, or something like that, i forget) and chronos which vary 8-16fps depending on what the clouds are doing, or what the voltage is reading, and that's if they are working ok. I've seen 100 fps variation on competition chronos when they're not as they should be.
Groups are king. Or certainly royalty. We're not trying to kick anyone's reps into the gutter, but we do need to stand on solid ground in order to move knowledge on, and some of the claims about what a bad pellet or batch could do would intimate a good pellet or batch could impart world peace.
I have not figured it out. The good batches seem better on the scales, they seem to have less deformation on the skirts, have more uniformity, and seem to group well. But nothing i can do to a bad batch will make them as good (the 'bad' batch is still not as bad as a badly performing rig can make my groups..)
What I would say is none of this has lead me to surmise that the JSB factory is about to go under. And despite many threads about how to get the best out of pellets, JSB hasn't ever decided to write an open letter mentioning this site.
FWIW, it's not just HFT & FT shooters who use JSB pellets. And despite my theory that pellet worrying has no real effect on 10m shooters, many top international shooters do use JSB pellets. And around the globe, there's a lot more of them than us.