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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
need help designing a new case
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<blockquote data-quote="LouBoyd" data-source="post: 329694" data-attributes="member: 9253"><p>Maybe you don't need to design a new cartridge. Use 308/510 sabots in a 34" 50 BMG. With a 240 grain SMK bullet and a 60 grain sabot (300 grain total) about 250 grains of VV-N560 should give about 3800 fps+ muzzle velocity at under 47000 psi (a moderate load for a 50 BMG. Thats calculate with 0.5" sabot seating depth. You will need a barrel with a 10" to 11" twist to stabilize it at sea level. The standard 50 BMG is 15". Pac-Nor can supply a 10" twist 50 BMG barrel. </p><p></p><p> A 30-378 Wby can't quite drive a 240 SMK to 3200 fps with a 34" barrel. 103 grains of VV-N570 shows 3190 fps at SAAMI max. Anything in a 30 cal bore which will give 3300+ fps is going to have poor barrel life, but maybe thats ok. </p><p></p><p>I haven't tried i either of the above loads, they're just Quickload simulations but they should be close.</p><p></p><p>You could save a lot of bother by getting some surplus 50 BMG M903 SLAP ammo. It's got a 30 cal ~355 grain tungsten penetrator and is rated 4000 FPS from a 45" M2HB barrel. It's stable in a 15" twist barrel because tungsten is much denser than jacketed lead. I've seen it for sale at gun shows a couple of time for $25/round.</p></blockquote><p></p>
[QUOTE="LouBoyd, post: 329694, member: 9253"] Maybe you don't need to design a new cartridge. Use 308/510 sabots in a 34" 50 BMG. With a 240 grain SMK bullet and a 60 grain sabot (300 grain total) about 250 grains of VV-N560 should give about 3800 fps+ muzzle velocity at under 47000 psi (a moderate load for a 50 BMG. Thats calculate with 0.5" sabot seating depth. You will need a barrel with a 10" to 11" twist to stabilize it at sea level. The standard 50 BMG is 15". Pac-Nor can supply a 10" twist 50 BMG barrel. A 30-378 Wby can't quite drive a 240 SMK to 3200 fps with a 34" barrel. 103 grains of VV-N570 shows 3190 fps at SAAMI max. Anything in a 30 cal bore which will give 3300+ fps is going to have poor barrel life, but maybe thats ok. I haven't tried i either of the above loads, they're just Quickload simulations but they should be close. You could save a lot of bother by getting some surplus 50 BMG M903 SLAP ammo. It's got a 30 cal ~355 grain tungsten penetrator and is rated 4000 FPS from a 45" M2HB barrel. It's stable in a 15" twist barrel because tungsten is much denser than jacketed lead. I've seen it for sale at gun shows a couple of time for $25/round. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
need help designing a new case
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