Originally Posted by peterh
5. Observe how the manufacturer will discontinue them bullets, or will change dies, and you're back to square 1.
Yep. You've got it. Which why a lot of shooters test a few different batches, and the buy in bulk. Although the numbers suggest that there's a lot of batches out there, in reality there's only a few out there in different sale channels at the same time, depending on their distribution source (which may vary). Once that batch is used, shooters repeat the process. It's why you often see on here that batch number is mentioned when pellets are sold on here.
From speaking to JSB about the mosquitos that were sold here under the Webley brand, reps from JSB confirmed to me directly in person that they were the same as JSB Exact Express, yet they did run 12 dies, so any variation away from that pellet in terms of shape and performance could be explained that way. I assumed
from the conversation that Webley had the output from just one die, but that that die perhaps was used for JSB as well, or another the same was... but as it was retooled differences could occur across the dozen dies. How many dies they use on say the JSB Exact which is more popular is unknown to me.
Agreed Jon. I don't have the tools to measure 0.01 reliably. Using a 4.48 here but as you say, that could be different depending on what the sizer was made with/from and relies on the accuracy of the measurer. But 4.48 works for me here with my barrel, yet it shotguns in others. Could well be that my 4.48 is your 4.47 depending on what was used to measure and make. But yep, that's the size for me that consistently touches all heads. Go up 0.01-0.02mm and you can see gaps around the head despite 4.52 being written on the tin.
I reckon the reason switching pellets to say heavies or 4.53 or 4.51 or another less well known flavour is because demand sees the popular dies wear before they're exchanged for new ones. To satisfy it they may run for longer than other ones which haven't worn out yet.
I've got several batches to choose from. The best is as good as i've had, and the worst I can't use for reliability. Flyers out by at least 20mm at 50m. Some batches in between group on average less well but don't fly. All 4.52. Sizing improves to a certain extent, but not found anything to date that makes a bad batch as good as a good one which is good straight from the tin.
You have to be very careful from taking a sample of one and drawing conclusions. What the actual difference between a good performing batch and a bad is, is unknown (to me). Bad batches seem to carry more weight variation, yet weighing in my experience doesn't solve the issue. No matter what i've done, weighing, sizing, lubing, the better batch still out performs the lesser batch. You can get improvements, on both, but making them perform the same is something i've not been able to achieve.
There's an American chap somewhere who sized and videod the cork screw effect seen when the pellets didn't suit his barrel after sizing. Although he was shooting at 100yds at higher energies you could see the effect/problem. The videos may be in the video section.
So my advice is, find a source that will allow you to test several types and sizes of pellets, but will say hold back 50 tins of each. Test. Find the one you like. Buy as many as you can. If you discover them going off later, repeat. Ignore the head size.