Thread: 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

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

4 x 5 shot groups + 1 sighter (bottom right)



4 x 5 shot groups overlaid cetered on the P.O.A

It does look pretty good, but you need to overlay a common stable point of reference e.g. the point of aim, not the POI of each group, as the POI of each group isn't stable.

Originally Posted by gimp

It does look pretty good, but you need to overlay a common stable point of reference e.g. the point of aim, not the POI of each group, as the POI of each group isn't stable.

Ahhh hang on that was what I did....p.o.a not p.o.i fuckin diddled myself with acronyms

Edited original post with correct acronym

Here's what it looks like when you overlay the 4 groups with a consistent stable POA as the reference (I adjusted that one group POA by 1 inch to account for your scope adjustment). 1 inch grid.


I appreciated the single, clear, flat and square target with a grid line reference available. Nice.







edit: fixed a data entry issue and aligned the dot colours with yours

Originally Posted by dannyb

Ahhh hang on that was what I did....p.o.a not p.o.i fuckin diddled myself with acronyms

FDMWA that

Originally Posted by gimp

Here's what it looks like when you overlay the 4 groups with a consistent stable POA as the reference (I adjusted that one group POA by 1 inch to account for your scope adjustment). 1 inch grid.


I appreciated the single, clear, flat and square target with a grid line reference available. Nice.



Attachment 286306



edit: fixed a data entry issue and aligned the dot colours with yours

Just to clarify the grid is not printed to scale
Edit: close enough .9" grid

Looks good enough for hunting to me

Originally Posted by akaroa1

FDMWA that

Huh ??? Can I buy a vowel

FUckin Diddled Myself With Acronyms

Acronym FDMWA

Originally Posted by akaroa1

FUckin Diddled Myself With Acronyms

Acronym FDMWA

FFS that's fuckin gold walked right into that

Big thanks to @Bos and @MP270 for the barrel and the scope absolutely wicked combination

Originally Posted by dannyb

FFS that's fuckin gold walked right into that

" Death by acronym" has replaced " death by power point presentation "

@dannyb tell me about the scope, magnification, weight, reticle, price etc

Originally Posted by nor-west

@dannyb tell me about the scope, magnification, weight, reticle, price etc

Minox zx5 2.5-10×50 standard duplex reticle. Zero 3" high at 100y will see me 1" low at 300y which is pretty good.