I started loading Cast 152gn .309 dia gas checked HP ( Walkers) in my Marlin 30-30 a few years ago and ran into a problem with misfires that saw me park the rifle and then I got sidetracked with other calibres. Anyway, long story short, I sorted the misfires and dug my box of test loads out and took the dirty thurty to the range today.
I had saved 3 rounds from a successful load that was grouping well at an average 2351 fps from 30.5gn IMR 3031 and a CCI primer.
While producing a reasonable group at 50m, this is a heavy feelin load at max but no pressure signs. It is based on Hogdon data for 150gn projectile, max charge 30.5/2192
fps. From a 24in barrel. My Marlin 336C is a factory 18.5in made in 1984. The recommended C.O.L is 2.550. My max over 30 rds made was 2.533, min 2.520. The variance attributes to the variation in the mouth of the HP bullet.
Hornady 2000 Ed. Manual, p316 gives a max charge of 31.4gn IMR3031 for 2200 fps with 150gn bullets.
My bullet is slightly heavier, but my barrel is a lot shorter. I calibrated my chrono with factory. 22LR ammo and it was very close.
An average of 2351 fps is therefore getting up there.
I saw from my logbook notes that the last time I shot these, a round that had been chambered and then ejected unfired, showed considerable engraving of the bullet by the lands. See attached photo. I suspect this is the culprit.
Given the groups I'm getting I'm not unhappy with the load. The rifle is strong and tight in the action and probably has rather less than 300 rds through it.
I can't see a way of of not engaging the lands using these projectiles. I can't measure pressure but there are absolutely no signs of over pressure- just solid recoil.
Where would you go with this?
Engraving ...
Attachment 200385
Fired cases...
Attachment 200386
3 shot group @ 50m...
Attachment 200387
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