I have a hunting rifle in 6.5-284 NORMA built on a Ruger 77MkII action. The barrel is a 26" #4 Krieger 1:8 twist. With 140g AMAX's, max COAL base to tip is 3.092" to the rifling. Best accuracy came in at 3.050" COAL. I have gone through a load workup with it according to the cartridge guide on this site. The high accuracy node is showing at 52.5g H4831.
With Norma brass, I was getting enough case head expansion that the fired cases met resistance going onto the shellholder. Using Lapua brass, the shellholder test does not indicate excessive case head expansion. Though I am seeing some primer flattening, it does not appear to be excessive. Bolt lift and extraction feel normal. However, the Lapua cases are showing very faint marks from the ejector slot. The marks were so faint that I did not see them when I inspected the cases at the range. I only spotted the marks under direct light at my reloading bench.
I have not chronoed the rounds, so I don't know what velocity I am actually getting. I am concerned enough about the ejector marks that I am inclined to pull the bullets from my remaining rounds and work up with a different powder rather than back down to the lower node. I don't remember exactly where the lower node came in and can't access my notes at the moment. I do remember that it was low enough on the workup that using that node would likely put me at a velocity low enough to defeat the purpose of shooting the 6.5-284 in the first place.
I am considering doing my next workup with RL-17, H4350, or Retumbo. Because of the relatively short COAL to the rifling (shorter than I expected for the NORMA version of the chambering), I am thinking that I am dealing with reduced case capacity compared to what was used to make up the cartridge guide on this site. That makes me lean more toward slightly faster powders such as RL-17 or H4350, rather than going a step or two slower with Retumbo.
This is my first 6.5-284. I don't have a lot of experience with the cartridge, so I don't know if I am on the right track or not. I would appreciate any advice from experienced 6.5-284 shooters.
With Norma brass, I was getting enough case head expansion that the fired cases met resistance going onto the shellholder. Using Lapua brass, the shellholder test does not indicate excessive case head expansion. Though I am seeing some primer flattening, it does not appear to be excessive. Bolt lift and extraction feel normal. However, the Lapua cases are showing very faint marks from the ejector slot. The marks were so faint that I did not see them when I inspected the cases at the range. I only spotted the marks under direct light at my reloading bench.
I have not chronoed the rounds, so I don't know what velocity I am actually getting. I am concerned enough about the ejector marks that I am inclined to pull the bullets from my remaining rounds and work up with a different powder rather than back down to the lower node. I don't remember exactly where the lower node came in and can't access my notes at the moment. I do remember that it was low enough on the workup that using that node would likely put me at a velocity low enough to defeat the purpose of shooting the 6.5-284 in the first place.
I am considering doing my next workup with RL-17, H4350, or Retumbo. Because of the relatively short COAL to the rifling (shorter than I expected for the NORMA version of the chambering), I am thinking that I am dealing with reduced case capacity compared to what was used to make up the cartridge guide on this site. That makes me lean more toward slightly faster powders such as RL-17 or H4350, rather than going a step or two slower with Retumbo.
This is my first 6.5-284. I don't have a lot of experience with the cartridge, so I don't know if I am on the right track or not. I would appreciate any advice from experienced 6.5-284 shooters.
