Drill flash holes for my 30/40 Krag cast loads?

[Finnmike]

I picked up a very sweet 1896 Krag today, not only due to it's unmodified condition, but also because my MW gauge hit at .75, and bore slugs to .3075. It has a brilliant bore with sharp corners to the lands, and the throat slugged at .3075 as well. Just what I was looking for; my lips were getting warts from kissing alot of "toads".

This is my only Krag, and I wondered if drilling the flash hole is a good precaution. I do this with my 06's, but I've not shot rimmed cases before.

[Mark Daiute]

I'm curious- why would you drill the flash holes. I shoot my Krags, a lot, and I've not drilled the flash holes.

Thanks,

Mark

[madsenshooter]

I drilled the flash holes on some 06 once. I hoped a larger hole would give me more flamefront to light some slow powder. Seemed to me I got pressure signs earlier, if one was going by only the flatness of the primer, which is quite unreliable. I have a batch of WLRM primers that look pretty flat if the primer alone is fired, with a standard flash hole!

[Finnmike]

I believe the Harris article recommends drilling flash holes to prevent shoulder setback. But, it sounds like it is not necessary for the 30-40 ...

[curator]

Drilling larger flash holes was the "fix" for shoulder set-back (and resulting long head-space) with bottle-necked rimless cases like .35 Rem and .35 Whelen when loading reduced cast-boolit loads. It does work but so too will seating boolits long so they contact the rifling leade as the bolt is closed. Some action types and magazine lengths won't allow for seating boolits out long enough. Drilling flash holes to .096" won't cause primer failures under normal conditions but may cause problems with near-maximum loadings in high-pressure cartridges like .270 Winchester. The .30-40 Krag won't have shoulder set-back problems since it is rimmed and the rim thickness determines head space.

[Finnmike]

Great! One less task today!

[Larry Gibson]

If the headspace is good on the 30-40 you won't need to drill the flash holes to prevent shoulder set back. If you are using small amounts of fast burning powder it does get the flame to the powder "quicker" and lessons the adverse effect of powder positioning.

I regularly drill out flasholes in bottle necked cases that are well fireformed for my light loads. I use a #28 drill which is about the largest you can use with LR primers and still leave a shoulder big enough for the anvil legs to rest on for reliable ignition. I get no shoulder set back with such. I have also thoroughly pressure test such cases in .308W with load of 4895 pushing a 200 gr 311299 upwards of 2000 fps. I could detect no increase in psi (measured with Oehler M43) with the flash hole drilled cases vs identicla loads in cases w/o the flash holes drilled.

Larry Gibson