Berger seating depth test

[8andbait]

There has been a bunch of discussion lately about seating depth for Berger bullets.
I decided to run a test so I could post a pic of what it looks like. I took my savage 6.5 creedmoor which is stock except an aftermarket B&C stock. It is the weather warrior with 22" thin sporter barrel. BTO on the 140 VLD is 2.210.

Starting at top left 2.220 then top center 2.180, top right 2.140, bottom left 2.100
the bottom center was for foulers and the bottom right was confirming zero on a different rifle so those two are not included in the test.

I shot these round robin every 4 minutes while I was shooting another rifle every 4 minutes so every two minutes I took a shot with one rifle or the other.

I just picked 41 grains because I knew it would be a light load and didn't have to worry about pressure with the jammed loads. 41 grains is just a number, no load development to arrive at this charge just a nice round number.

The chrono readings were as follows from the pro chrony, I don't totally trust it but it gives a good starting point.
2.220 2693, 2737, 2704 ES 44
2.180 2690, 2682, 2688 ES 8
2.140 2672, 2688, 2645 ES 43
2.100 2640, 2693, 2645 ES 53

Anyway this is a pretty good example except I only need to confirm that 2.180 is the best. Normally I would pick the best then seat on both sides .005 or .010 but I don't expect to do any better than this depth.

 

[bill123]

I'd say you pretty much nailed it both with group size and ES. Just 2 things. 4 rounds is too few in my opinion to get reliable SD/ES figures. Also, my OCD would force me to test .005" on other side of 2.180". Maybe try 1-10 shot group of each depth

 

[Mikecr]

You're close enough for now. Now it's time to move to powder testing(with your 2.180).
Move out further for a ladder, or OCW if you like.
When you've locked in on a powder load, shape best grouping with tweaking/fine seating about the 2.180.

Is that seating off the lands?

 

[8andbait]

Guys, this was just an example because people have been asking about it.

I wanted to show them the process. If I was developing a load for this gun and this bullet I would do an OCW up to about 42.8 grains in .3 grain increments with a BTO of 2.180.

After that I would load 10 of the chosen charge and shoot a 5 shot group at 200 and 600. 200 to get zero established and 600 to see how they do at distance.

I believe three shot groups are enough to prove something is bad but not to prove it is good.

Thanks for the comments, the more info new reloaders have the better.

 

[8andbait]

Is that seating off the lands?[/QUOTE]

2.180 is jumping .030

 

[Corey Schwanz]

Sounds like you are well on your way to finding a good load! Good review of the process.

 

[Canadian Bushman]

Its personal preference, but i dont ever shoot anything round robin when testing loads. I prefer not to spread out the error of barrel condition, temp, shooter position, and time of day. I like knowing which shot was cold etc etc.. Cant factor out mistakes and outside sources of dispersion if its spread out with all the other possible problems.

 

[bob4]

Thanks for this.