Primers

[Barrelnut]

What are you using for a chrony? If you throw out the high number in each group the ES would come down. The high number in each is kind of out of the norm in each group. It's the one with the '7' in it.

Maybe a faster powder would help.

The numbers might get better on the second firing of the brass.

What kinda dies are you using? Are they full length sizing dies? Do they use a bushing to size the neck? Having consistent brass volume and neck tension can also bring down ES.

Also make sure all of your rounds have the same jump to the lands. This can help keep case volume more consistent. All bullets should be seated within +/- .001 or so.

 

[frostop]

Using a magnetospeed chrono, currently only own rcbs dies but have plans to upgrade to Redding but not sure which set to get? I have the seater die setup to seat just off the land, but sometimes think when chambering a round that I am push into the lands-bolt doesn't close as easily as the last round? I set up the die using a hornady oal guage found my max for that bullet and turned the die in a half turn or so.

 

[Barrelnut]

Sounds like a good stuff. Consistency in each round is what lowers ES. Well that and a good primer powder combo....

I could measure each round with the OAL after seating the bullet and make sure that each bullet is seated close to the same depth. Inconsistent neck tension can cause each bullet to seat a different depth. If they aren't seating within +/- .001, you can back off the seater a 1/8 turn or so and seat the bullet, measure, turn the seater a tad, seat, measure. You can walk all the bullets in to be the exact same depth, if you really wanted this way.

 

[frostop]

I went ahead and ordered a Type "S" two die full length set this morning as well as some BR2 primers.