Thread: 10 Shot Load Development

I had a go at using this method today with my 6.5 Creedmeme.

Components: 147gr ELD-M, once fired Lapua brass, 2209 and lit with CCI450's.

Sized with a Redding FL bushing die, using a Wilson .288 bushing, with my brass this gives neck tension measuring .289-290. Seated to 2.8" OAL with a Redding competition seater.

Oh and rifle, Bergara HMR

I loaded 10 shots and chronied them -

39.0gr - 2411fps
39.2gr - 2446fps
39.4gr - 2455fps
39.6gr - 2473fps
39.8gr - 2482fps
40.0gr - 2496fps
40.2gr - 2506fps
40.6gr -2520fps
40.8gr -2520fps
41.0gr -2530fps

I thought it was interesting that there was a near linear increase in muzzle velocity for 39.2gr up. 40.8 appeared to be in the middle of a plateau, which is what I was looking for.

I didn't shoot at paper while doing this, just shot rounds over the chrony into the berm. I only wanted to see a plateau in velocity.

Back at the bench I fired up my Lyman powder dispenser and set it to 40.8gr, and loaded up another 15 rounds. It usually gives me a variation of .1-.2 gr either side of the target weight if I just let it do it's thing and don't re-weigh. Some of the charges were spot on 40.8 gr, but others were 40.7, 40.9, 41.0.

With the last few minutes of daylight I was unable to chrony the loads, but I got pretty reasonable results on paper at 100m.



Bottom group is the last shot, with more care, and POI adjusted .1 mil down and the same left. All loads were selected at random. Now to see how they do over the chrony. It seems like a good way to save components and time with a new gun. I could probably tighten those groups by playing with seating, or working up further and looking for another plateau, but if it looks good SD wise I might just run it.

Anyone else do it this way?