Jeffeosso,

Your ignorance knows no bounds. At 80,000 psi I would have blown primers, if nothing else! More likely I would have a ruined rifle!

Get over it man. The loads you are referring to, at least the ones I think you are referring to i.e. 405 Win, 400 Woodleigh, 2160 fps, are in the 64500 to 66500 psi range! I have stated this NUMEROUS TIMES. This load isn't as hot though as a 460 Weatherby mag doing 2600+ fps with a 500 grain pill. That is around 70,000 psi.

Now the 'uniqueness' of Mitch's load has more to do with quantity of powder than it does with pressure. I honestly don't have a clue what the pressure would be, since your cannot fit 136 grains of IMR 4350 underneath a 600 gr Barnes, Woodleigh, A Square. Let me spell it out for you, that is a 120% compressed charge nimrod! Now Mitch says he loads his rounds out 4.15" (or was it 3.95 which again is physically impossible to compress the powder column that much without bulching the f...ing case leading to none chambering), so that is .480" longer than the cannelure would place them (3.67" loaded to cannelure) in the case of a Woodleigh that would leace 0.05" of bullet in the case. Since the Barnes Original is very close to the same length as the Woodleigh (although the Barnes Original has no cannelure) you would still have less than 0.1" in the case. Going to a Barnes mono solid and you are back to not enough case volume again.

So with a long throated chamber it would be possible to about a 106% compressed load with a COL of 4.15". Cannot hunt with that load, cannot feed it from the magazine, more than likely the powder column would quickly push the bullet back out, etc, etc.

I owned a 500 A Square, have you? I know what it can really do, and I know how much marketing hype A Square generated about it. My rifle had a 27" barrel too.

Hey want to talk 500 Jeffery, 500 AHR, or 505 Gibbs. I have owned two out of three of those and loaded for all of them! Sorry Jeff, but unlike you I am not a newbie to big bores, and the ability so simply screw a prefabricated barrel into an action, as well as dropping a barreled action into a prefitted stock doesn't impress me a whole hellaluvalot! But hey, you can call me whatever you like.

When I learned about internal ballistics we had to do it the old fashioned way. See there was no such think as Quick load, or Accuload, or RCBS load, or any other load, but powder in case and bullet, chronograph and laws of physics.

Done ranting, I feel better now.

Scott

I don't understand the compaction instability issue you
mention.The beauty of ball powder in big straight cases,
is the fact that IT CAN BE COMPRESSED, and fired with right primers, and in the thousands of rounds I tested, gives
3% better power per grain than any stick powder I used.
Plus being denser gives more grains to get power out of.
Just wait, one of the 550 guys will get it full loaded with
W-760 or H-414, Fed 215 primers and it will do what my formula says.And I helped develope it.I Don't believe
quikload on any straight cases.Its a pissy ass program for
260 Rem and the short fat necked genre.Ed.

Assuming equally suitable powders and equal pressure the percentage increase in kinetic energy will be equal to half the percentage increase in bore area.

550/510 squared = 1.163 So a 16% increase in bore area and thus an 8% increase in energy.

The 550 should be about 100% faster than the 500 A2 with equal bullet weights Or do the same velocity with bullets 8% heavier but it will be about 100 f/s slower with bullets of equal sectional density. However, the larger bore size will always allow bullets of higher sectional density to be used, assuming they are available.

All that aside, I think the big plus for the 550 is that it can deliver all the power that can be used from a shoulder rifle made on a conventional action and do it with an easy brass situation and in addition it is an easy deal for someone with a CZ 416 or a 30/378 Wby Synthetic.

Actually, come to think of it the 30/378 and 550 just about cover the extremes at either end

Mike