Not sure how popular this will be as DTA dropped the 243 barrel due to poor sales.
I found a charge i was pretty happy with while running in the barrel and fireforming cases and havent really changed it for 200 off rounds. It was on the slow side but it shoudl make the barrel last a bit longer which the 243 isnt known for. I decided to load up some rounds with .005 thou differences in the OAL to see if there was any fine tuning possible. The load i have been firing had an Base to Ogive OAL of 2.225 and shoudl be touchign the lands based on the hornady oal gauge. The conditions at the range today were far from perfect but i had a go anyway and got some useful results. I was using a Farley Rest (first time) off a mates table at 300y. The temp was about 20 celcius, overcast and 10-15mph cross winds.
The base load
Brass: Lapua
Projie: 105gr A-Max
Powder: AR2217 (H1000)
Charge: 45gr
Primer: Fed GM
Base to ogive OAL: 2.225"
Velocity: 2805fps ave
I tested 8 different loads with a 0.005 jump in lengths, here ar ethe best 2:
LOAD 1 - OAL (Base to Ogive) 2.235" jamed 10 thou
This was the last and best group i shot today. It measured 1.09" with about 0.8" vertical.
LOAD 2 - OAL (Base to Ogive) 2.215" - 10thou jump
This was the 3rd group i shot and it was the worst at 3.6" but had the smallest vertical of just over 0.5".
The spread of group sizes was 1.09 to 3.6" with verticals ranging from 0.5" to 2.1". If you look at just the vertical spread all groups were under 3/4 MOA on a windy day. I had some 338LM testign to do but ran out of time.