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Ladedata for M/1886 Kropatschek (Patronvåpen)

av The Dane @, Danmark, onsdag 5. juni 2019, kl. 21:52 (138 dager siden) @ Lien

The 8x58R Danish (and Swedish) cartridge was developed in the era of BP, with the change over to Smokeless (or semi-smokeless) Powder. Bullets were cylindrical and long, whilst Grooves were deep (BP Practice). Excess Friction from a Long bearing surface on the Lands was reduced by making the Bullet of a diameter intermediate between Bore (8mm-.315" ) and Groove depth (.329-.330"). This Principle was used on all the 1886-1890s Long cylindrical bullets with Metal Jackets. The Flat or concave Base of the Bullet "Upset" to fill the grooves and give Obturation ("Base Upset Obturation") and created a driving Band effect, whilst the rest of the cylinder was lightly engraved with the rifling.
This Method of combining Bullet and rifling is usually called "the Austrian Technique" as Steyr was the first to manufacture rifles to this system in 1888. It will be found in all "8mm" Rifles, mm 7,62 (Russian), and in the Commission 88 (Germany). In effect, all rifles with long, RN, heavy Ball cartridges.

So to fit a bullet for the 8x58R Danish/Swede, one needs a RN, Flat Based .324" Bullet; if one wants to use a Spitzer Boattail, then one must use a .329" Bullet ( Boat Tails don't "Base upset obturate", so a BT .323 or .324 would suffer "Windage" and subsequent inaccuracy.) This was found in 1930 ( Austria) with the improvement of the .324" 8x50R to the Spitzer .329" 8x56R ( with Boat tail...the reduced contact area and the boat tail both required the "Upsize" to prevent windage.
Now: to get Bullets for .324 in the 8x58R...use RN Jacketed Flat based "8mm" bullets, or make your own Spitzer BT by sizing down Hornady .338" in a Lee .329" Sizing die and use a strong (Cast iron/steel) O-frame Press; or cast and size Lead to .329"
Or buy .329" 8mm M30 S bullets from AV Ballistics Technical Services (Australia)...CNC turned Brass to M30 (8x56R Profile, but 172 grains only...60/40 Brass vs. 205gn Lead core steel jacket Milsurp.) Or even Pull down 8x56R ammo for the .329" FMJs.
Best for the M1895 Swede RB in 8x58R is the RN FB .324 diameter Jacketed, or the Cast Lead at .329"; although later used with the improved Spitzer 8x58R later in its life, the RB prefers the (milder) Loads of the RN Bullet....and the rifles are too nice to use with spitzer bullets..."out of Character" and "out of Era".
Doc AV
AV Ballistics Technical Services
Brisbane Australia.


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