The part that answers your question:

"I match your example load of 117 gr of IMR4064 in a 26 inch barrelled 500 A-Square if I use and effective volume of 151 grains - well within QL guidelines. The pressure required in the model to get the bullet to 2503 fps in a 26 inch barrel is 70,000 PSI. That is about where good modern brass starts to show ejector marks, and is 7000 PSI above design pressure. A-Square had a reputation for publishing loads like that. Barnes in COW (not known for conservative loading practices) shows 104 gr of IMR4064 yielding 2280 fps for a 600 soft. My model predicts 2270 fps at a safe and sane 50,000 PSI using that load, so I'm fairly sure I have the model right.

I match COW's 500 A-Square load of 114.5 grains of IMR4895 at 2460 fps with a 156 grain effective volume and 60,000 PSI for the 600 grain RN.

I match COW's 500 A-Square load of 116.5 grains of IMR4320 at 2475 fps with a 150 grain effective volume and 64,000 PSI for the 600 grain RN.

I match COW's 500 A-Square load of 124 grains of IMR4350 at 2450 fps with a 150 grain effective volume and 57,000 PSI for the 600 grain RN.

It sure looks to me like the IMR4350 is a better bet for the 600 grain bullet in the 500 A-Square.

I get a 500 A-Square load of 102 grains of IMR4064 at 2170 fps with a 151 grain effective volume and 57,000 PSI for the 700 gr. RN.

I get a 500 A-Square load of 105 grains of IMR4895 at 2224 fps with a 156 grain effective volume and 57,000 PSI for the 700 gr. RN.

I get a 500 A-Square load of 104 grains of IMR4320 at 2184 fps with a 150 grain effective volume and 57,000 PSI for the 700 gr. RN.

I get 500 A-Square load of 115 grains of IMR4350 at 2250 fps with a 150 grain effective volume and 57,000 PSI for the 700 gr. RN.

It sure looks to me like the IMR4350 is a better bet for the 700 grain load in the 500 A-Square, because you get the best velocity and the lowest pressure in the event of high retention forces."

The search feature on this forum is a wonderful thing ;-)

Rob I do not know much so can you tell me will the rifle (due to it's long throat) still shoot well with the woodleigh's and other hunting projectiles even though the throat is set up for the A-maxes??. Just asking because I want to build something bigger than my .416 Rigby. Also what will max velocities be aproximately with the 570 gr woodleigh bullet (this is the one that interests me most)??? and is the 500 a-square more gun than say the 500 jefferies or .505 gibbs???. How easy would a jefferies be to do on a cz action, is it easier or harder than the a-square??. Do you just buy .460 weatherby brass and only have to run it through a 500 a-square full length Die???And if you take it overseas would you have to have the brass headstamp matching the caliber???

I had previously been considering a .585 nyatti but maybe I will take it in steps and go to the 500's first, especially since I am gettin conflicting reports about the type of action required for the Nyatti.

Regards PC

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[This message has been edited by PC (edited 01-10-2002).]

I'm also having my 500 Jeffrey cut with a long throat to handle the bmg bullets, the slightly larger case might provide a modest velocity boost, or milder pressures.

My question is, mine's being built with a 1-15 twist barrel, and do the learned folks here think it'll stabalize a 720 gr ap bullet? My buddy is about to order some 50 bmg bullets for his 50 whisper, and we're debating going in 1/2's, but I'd really be bummed getting $100 worth of bullets, and have them not shoot.

To PC's question, yes, they still shoot with the long throat, the key to accuracy is a throat of just slightly over bullet dia, that done, extra length does not cause accuracy problems. Another thing to consider, the large bores tend to have an accuracy edge in that holding the dimensional tollerances have less of an effect on accuracy as bores increase.

110 grains to 115 grains of IMR 4350 works great with 647 to 750 grain bullets. Start low and work up. You can go higher but I haven't.

115 to 116 grains of Reloder 15 with the 570 to 600 grain hunting bullets. You can go higher, but I haven't.

See Mitch's loads for the 500 A-Square in the reloading data pages of this site.

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Happiness is a warm double.
RAB

ps. Do you shoot in the FCSA? I'll be in Alliance in June.

I'm going to try and make it to the Nationals in Raton, but I can't promise anything. If I do make it and you are also there, we'll have to tip a pint and swap stories.

ps. The one good thing about waiting is there is time enough to research rash decisions :-)

quote:

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Originally posted by BMG:
The one good thing about waiting is there is time enough to research rash decisions :-)

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I'm going to have to remember that one, good line!