New cartridge

[carbine86]

Im thinking of trying to design a new cartridge similar to the 300 black out but instead of a 30 cal bullet it would be shooting a .270 out of a modified 223 rem case any idea on how i should go about desigining the barrel should i modify the shoulder angle any help here on this thanks.

[blaser.306]

So in other words you want to build essentialy a 270 tcu? Might as well just duplicate the case length and use the 40 degree shoulder that has already proven itself time and again.

[carbine86]

Thanks i didnt think about it in that sense

[koehlerrk]

Take a look at the 6.8SPC. I think you'll find it's what you were thinking.

[felix]

Buying a whole new upper, or just getting a barrel replaced? Whole new upper calls for the 6.8. Barrel change, my option, would be the TCU but use same case shape as 223 standard. Feeding CAN be an issue otherwise. I'd prefer a 12 twist for 120 grainers, 14 twist for 90 grainers. ... felix

[carbine86]

Was thinking about doing this for a model 700 and just replace the barrel but im looking i to both option for the least expensive custom barrel