Easy difficult load development.....my latest foray from the lead shed
Sometime ago, I replaced my 30 06ai barrel on my stainless Weatherby mk V, due to complications beyond my control it has taken months to get the new to me 20" fluted trueflite barrel in 270win out on the range.
There were delays in getting the barrel fitted and getting the stock opened up and bedded, then every time I had a free day off it's been raining or way too windy to do any meaningful shooting....that's the end of the difficult part :yaeh am not durnk:
Last week I finally prepped some Federal brass and loaded up 21 rounds for a velocity ladder.
1 sighter and then 5 rounds at each of my 4 chosen charge weights (1 gn increments from mid range to 1gn over book max).
Now I have been following the latest controversy around sample sizes when doing load development and I know 5 rounds does not a good size sample make....however 20 rounds is getting up to a half reasonable sample size so my goal here was to load all the rounds to SAAMI dimensions and then shoot them all at different targets then analyze the data comparing groups using the same P.O.A. therefore getting a 20 round sample size from my 4 x 5 shot groups.
All rounds shot prone off my bipod (admittedly I'm a little rusty having not done any meaningful centerfire shooting since last April but I was reasonably pleased with the initial results.
All the loads appeared to shoot OK, but it was when I got home I realized how good it was once I superimposed the groups by lining up the P.O.A, it became apparent when measuring the furthest points of the group that despite the 4 grain difference in charge weight from lowest to highest, I had just pumped 20 rounds (in reasonably quick succession) into a 1.23" x 1.28" group (granted I adjusted the scope up 1" before the last group of 5 (this wouldn't have skewed the results anyway).
Gonna call it good there and load up some hunting ammo and shoot another decent sample to confirm zero.
I'm happy enough that the load I've settled on will be more than accurate enough out to further than I'm inclined to shoot it on game with a bullet that will perform well within these parameters.
The bullet is a 150gn Speer BTSP @ a healthy 2804fps.
I'll load some pics shortly
