Sat Apr 28, 2018 10:50 pm
I agree with Gary.
I bought a PelletGage and have measured over 50 pellet types and die numbers. Actually I measure weight, length and head size. JSB quoted sizes are pretty meaningless but within each batch (and different batches from same die) are more consistent than other manufacturers. H&N 'sized' pellets (e.g. FTT 4.51/4.52/4.53 or BM 4.51/4.52/4.53) average sizes are often closer to the stated size but show more variation within a batch.
Let me demonstrate the issue with JSB quoted sizes: I measured Weihrauch FT-Exact die 8 and JSB Exact die 8. Both were the exact head size, length and weight but the FT-Es are sold as 4.51 and the JSBs as 4.52.
The biggest difference between JSB batches is the length, which for 8.44gr can be from 5.97mm to 6.38mm. But the difference within a batch will be less than +/-0.02mm. It's possibly the best indicator of whether pellets come from the same die... and the easiest way to sort pellets if you accidentally mix pellets from different dies.