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Load data for 700 gr. bullet in 500 S&W

Posted: Mon Jul 17, 2017 11:52 am
by mtngun
The best source of load data is John Ross. John worked with S&W to pressure test his loads, and pressure tested loads are always the final word on the subject. There's just one catch -- John's website is offline. :cry:

In the meantime here are some Quickload numbers for a revolver. Quickload is not always correct -- it should be viewed as a rough estimate, because that's all it is. I have not tested these loads and cannot vouch for them -- I'm merely reporting what Quickload says.

710 gr. cast / 0.65" seating depth / 30 gr. Accurate 1680 / 100% fill ratio / 1100 fps / 49,000 psi

710 gr. cast / 0.65" seating depth / 26.3 gr. either IMR or Hodgdon 4227 / 100% fill ratio / 1060 fps / 43,000 psi

710 gr. cast / 0.65" seating depth / 24.4 gr. N110 / 100% fill ratio / 1090 fps / 50,000 psi

For max velocities, H110 / WW296 might be the way to go, but I'm not going to post Quickload data for that powder because a 100% fill ratio generates 72,000 psi! :o Without pressure tested data you could get into trouble.

There are certainly other powders that can be used and have been used with the 700 grain bullet, but for safety's sake I only posted powders that were safe with 100% fill ratio.

If anyone has John Ross' pressure tested data, please share.

Re: Load data for 700 gr. bullet in 500 S&W

Posted: Sat Aug 05, 2017 11:36 am
by mtngun
Here is an archive of John Ross' load data. It is working as of today but no guarantee about tomorrow. I'm going to try to make a copy.

John refers to the now discontinued WW680 or WC680 powder. Accurate 1680 can be substituted.

Page 1. Sorry about the fine print, you may have to download the image to your PC, then zoom in on it to read it.

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Re: Load data for 700 gr. bullet in 500 S&W

Posted: Mon Aug 07, 2017 10:20 am
by mtngun
FYI there are some reports that some 700 gr. bullets tumble, though deets are sketchy. There are also reports that they shoot OK. It's not clear why 700 gr. bullets shoot OK for some people but not others -- not all 700 gr. designs are exactly the same, so that might have something to do with it -- but just be aware that stability may be an issue.

In an attempt to better stabilize heavy bullets, the Ross version of the S&W 500 revolver used a 10" twist, instead of the standard 18.75" twist. However, even the standard 18.75" twist provides a Miller Stability factor of 3.91 with the 700 gr. bullet at 1100 fps, so the twist is not a problem per se. More likely the problem is the "flying ash can" aerodynamics that can happen to any blunt bullet regardless of twist.

Sometimes blunt bullets can be stabilized if you drive them fast enough, but not always. I once played around with one of Veral's 230 gr. "Ogival Wadcutters" in a S&W wheelgun. It left oval holes in paper at any range and at any velocity, even with max loads that pushed it to 1500 fps, and generally never shot satisfactorily. The problem was due to the "flying ash can," not the twist.

I ran into oval holes while testing an 85% meplat, 160 gr. bullet in a 357 mag Ruger Speed Six. The problem went away when I switched to an 80% meplat. Once again, the problem was the "flying ash can," not the twist.

I am not aware of any standard formula to predict the stability of blunt bullets. The standard twist rules do not seem to be helpful. If you order a mold for a blunt bullet, be aware that you could experience the "flying ash can" problem.

I would appreciate customer feedback on the accuracy of any 700 gr. molds that I have made.