Pop, quickload question for a wildcat round

[jtoews80]

POP, I'm trying to figure out if it is worth building a severe overbore 6.5mm or possibly a 257 based on a 300 RUM case with a 40 degree shoulder. I would have to use the heaviest 6.5mm bullets possible at the lightest 130 grn accubonds or more likely 140grns. The selection of high B.C. bullets that are heavier than 140 is scarce. I would use a 30 inch pacnor poly rifled barrel, but the poly riflintg shouldn't reduce the pressure enough to mention, although it may help with prolong barrel life a little. SO, if you could run a load for 130 grn AB's out of a 30 inch barrel with a case cap of 114 or 115 grns it would be greatly appreciated. If you would run a couple of 257 bullets with the same capacity for comparison it would be great. I am favoring the 6.5mm because of the weight factor making it more useful for hunting and prolonging the barrel life to hopefully 600 rnds+/-.

Thanks, Jason Toews.

 

[jtoews80]

Regrettably, the 7mmRUM offers almost all that a 6.5mm could with a FAR better selection of bullet weights and loaded factory ammo etc. the only noticable differance being the lower Sectional density and slightly lower BC's. That would be a far more economical route, dies are 20% the cost of customs, and don't need to build the rifle.

One day I will have a custom, but I'm starting to lean towards building it myself for me. I don't have any formal training, but should be able to find enough info online and then perhaps an experianced smith to offer advice and hopefully check out the build before testing anything or do most of the heavy stuff like installing the tube. Most likely will just try a Mauser sporterize project with a barrel switch to a 257 roberts or a 6.5X55 with just a bolt turn and a new stock. might only do the stockwork, but I'll have to try my hand at it. Seems like an itch that won't go away.

CC

 

[Antelope_Sniper]

I don't think you could find a slow enough powder to make it work very well. You are describing a Very large, Very sharp shouldered cartrige, which means you would need and extremely slow powder. Maybe something like WCC 872, or US 869, both originally designed for the 20mm. If time and money were not an issue, it might be interesting, but for the rest of us, there are probably better solutions.