Re: Is the R700 SA OK for the 6x47 ?
eddybo,
Yes, comfortable pressures. A good example of this was the 30-06 loaded with 4895 in WWII. Initial pressure ran around 52-55k PSI. By the time the bullet reached the exhaust/operating port it was down to 17k PSI. In the M1 Garand, no matter what, the pressure had to be close to 17k PSI. Anything less and it didn't always operate. Anything more and you could slam a bolt back and crack the receiver. This is why 4895 was chosen as the powder for the M1 Garand. The relative speed and pressure of the powder along with the bullet weight worked for that rifle.
As we apply this to a bolt action rifle, we are not nearly as tied down to one formula. We don't have to limit ourselves to 17k PSI down at the end of the barrel. Meaning if you took the same .30 cal, 152 gr. bullet and loaded it with the max of 4350 in a 24" barreled bolt action, you would get a lot more performance from it than you could with the M1 Garand. Initial ignition pressures reach the same 58-60K PSI. But, at the end of the barrel pressure is around 20-21k PSI. More pressure pushing the bullet = more velocity. The slower burning powder is producing more pressure at the end of it's burn cycle than the faster burning powder. The drawback of course is having enough barrel to facilitate the improvement.
The common myth also is that small rifle primers won't ignite large powder loads. Especially ball (double base) powders. They will, they just need to ignite the same amount of powder they do in a 5.56/.223 case. Once that happens the pressure and heat will do the rest. The difference will be the rate at which the powder burns. For powders made specifically for pressure like the ball powders it will also reduce somewhat, initial pressures. As the entire case ignites, however, pressures tend to build a lot more on the normal scale than one thinks.
