.379 in .375win

WhelanLad

WhelanLad

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can get heaps of 38-55 cast but they are .379, rekon they will squeeze down the 375 winnie with mild loads in 38-55 pressure brackets??

thanks
 
I don't not have a lot of experience at fussing with cast bullet details, but had read, and believe, that you want to "fill the throat" - want a snug fit of the bullet into that "ball seat" area between end of chamber cut and start of rifling - some chambers do not have that - rifling starts almost right at the end of chamber cut - but some have 1/2" or so of "space" - so apparently want to fill that space - snuggly - at least as the bullet is passing through that area - but then requires case necks thin enough to allow to chamber. I think Veral Smith with LBT bullets used to sell a "throat packing" kit for determining that throat area / ball seat diameter. I have been doing cerrosafe castings to get a number. No doubt his way is "better", but I have never done it. So far as I understand, cast bullets of any hardness level are just going to swage down to fit grooves, once on their way. I think that is the thinking behind common recommendation to use cast bullets a couple thou larger diameter than the groove diameter - to fill up that "ball seat".
 
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A cerrosafe casting of a Husqvarna chamber for 9.3x57 - can see that the bore rider cast bullet will be well out of the case neck, before the part of bullet for riflings, gets there - will require a good fit through that "ball seat" area. Have not fired this one yet - barrel was sawed off and waiting for my muzzle turning tool to come back home...

I suspect this is fairly "extreme" - others have commented having not previously seen such a combination - but I would not have known without a chamber cast.

That brass was new PPU 8x57 - in a couple of steps had been opened up to pretty much "straight wall", then worked down in a 9.3x57 FL die to just so close snugly into that chamber - can see the resulting neck is much shorter than the chamber is cut for. My next attempt, if this does not work, will be to start with 30-06 brass - will have adequate neck length that way - just not certain what I will get for case neck wall thickness. All part of the fun of "experimenting"

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OP, I suspect there are similarities between 9.3x57 and the 38-55 - various designers involved - both approaching "ancient" - some of the original "standards" have apparently turned up missing - hence, at least two lengths of brass available for 38-55 - I could not find a GO gauge for 9.3x57 at all - could not even find the dimensions - what is published by NORMA is not the same numbers as is published by CIP. I suspect at least part of the driving factor for 375 Win - to get to "standard" dimensions - probably also "upped" the pressure a bit as well - sort of modernize the older 38-55 and clear up various confusions. Not sure that SAAMI anticipated cast bullets though - would seem to be almost a "natural" pairing - so best bet for you might be to follow cast bullet thinking - find out your throat and groove diameters - work to get the cast bullet sort of a couple thou larger than groove size, that fills the throat if your rifle has one, and that allows the case to chamber with a bullet of that diameter.
 
Or, purchase a cheap and easy push through size die like the type made by Lee. It is not difficult to draw down a bullet diameter a couple thousandth's. Spray on some lube, run through the die, and load 'em up.
 
mayb i have one of them?? rcbs??? its in a green box, lubed to the hecka, not sure what it does or whater eya use it..... i posted a picture of it here once upon a time i rekon!

il dig it up!!

they are 379s. i can get 300 for 75$ ... thatl keep me going
 
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