Satterlee load development PtII

[MJR]

So, round two of trying this type of load development. This time using 308 with 155 Sierra TMK with Varget powder in Palma brass and Br4 primers. The round were loaded to 2.880" and as the graph shows velocity increases steadily as the charge weight increased. As regards accuracy all rounds fired with the magneto speed fitted could be covered with a pound coin which made me wonder how an ocw test would have compared. I did plot the individual shots but to be honest its such a tight cluster i'm not sure what you can interpret from the plot.

Anyway I chose 46gn as the best load and fired another 10 rounds over the chrony. The result was all ten shots into less area than a 1" shoot n see circle, average velocity of 2946fps and s/d of 7fps. Very happy with the velocity and now looking to shoot the same load at longer ranges.

 

 

 

 

155TMK Velocity graph.xlsx

[TJC]

Just loaded up 15 in 0.1 increments to try with the 130gr RDF. 

I might be mistaken but thought I heard Scott say his approach doesn’t work as well in the .30 cals. Not sure why but you seem to have a great result. 

[trucraft]

Very nice.

How many rounds have you fired to achieve this load?

I think this will be my method when I'm working up the next new load. 

 

[VarmLR]

Good result. I find the .308 very undemanding and anything from 43gr N140 or RS50 to 46gr shoots very well.

I don't bother shooting groups of 3 for ocw any more. I just fire a ladder of 10 to 15, establish velocity plateau and load 5 or 10 at the centre for SD/ES check.  It works well providing you're anal about brass and load consistency and accuracy.

[MJR]

10 rounds to do the load development and 10 to confirm velocity and accuracy. It could probably be tuned further with seating depth but I'd be chasing maybe a 1/10" tighter group. 

One thing I've found out. I've stopped using 1" aiming discs and now use 1/2" hence why the middle of the group is missing, it got shot out.

[MJR]

Farm, that's the thing. I didn't batch brass, just the first ten to hand after resizing and the first ten bullets out of the box. I do make sure loaded rounds have little to no run out though.

[MJR]

Sorry,  that should be Varm. 

[TJC]

2 minutes ago, MJR said:

Farm, that's the thing. I didn't batch brass, just the first ten to hand after resizing and the first ten bullets out of the box. I do make sure loaded rounds have little to no run out though.

Good point. Don’t forget Scott is loading for PRS not F Class. Most targets are 1-3 MOA, they are are typically a forgiving size. Perfect handloads aren’t the most important thing. 

[VarmLR]

I think though that Scott was the first to say something like  "this only works if you're careful and are already getting all your brass uniform".  Absolute load tolerance obviously isn't so much of an issue so loading to the nearest 1/10th is probably good enough for all but the smallest cals.