375 win jes rebore

[CZ93X62]

The JES chambers/throats/bores are a mite snug, and you need to make haste slowly when "stair-stepping" powder weights and relying upon published data to derive loads. I spoiled 20 new Starline 38/55 cases through over-pressure (loose primer pockets after first firing) using Ken Waters' data on 38/55 from his "Pet Loads" column info. I surmise that most rifles in 38/55 have wider dimensions in all respects, and the solution used to address slower velocities from the loose bullets/wide throat & barrel scenario was "Add more coal & make more steam". Scrapping once-fired brass hurts me right to the quick, so go slow/be cautious. When things fit well, they will work well......sometimes a bit too well.

 

[Roger Allen]

Nasty! So far mine acted fine. Well I’m using Lyman’s data and I am prob .5 gr higher than normal. Should be below 30k pressure range. So far seems so good but let me keep a eye on these casings. Didn’t ken waters go hard hard on things? Wasn’t he the guy that over loaded a 375 win without the lug in the rear installed to show how robust the m94 was?

 

[Roger Allen]

I do see what your saying about how the 38-55 brass is weaker than 375 brass and I should proceed w caution as to not wreck precious brass. I am curious on how many loads I can get w these