Load data variants on the s/w 460 mag!

It is my opinion (FWIW) that the 460 is very easy to work loads up for. The main pressure sign I look for is difficult extraction. From everything I have read, most factory loads are only 55-60k psi, while the cartridge is rated for 65k psi, and the reason always given is that full pressure loads would expand the brass enough to need hammering out. In my testing of loads so far, I have started to get difficult extraction before I get to the max published charges. In your scenario, I would load up one round each starting at 37.5gn and step in 0.5gn increments. Stop when you get the first difficult extracting case. Then load a few rounds each, narrowing the charge range based on the earlier results.

I've ran into huge variances in many different books for other calibers. I use win 296 in all my 460 xvr loads so I cant say for that particular issue, but I have some books that list pretty big differences in 44 mag and .40 especially. Just start low and work up. Reading primers is pretty much useless in 460 as they should all be flat. Exaggerated crimps are mandatory in 460 and 500 so maybe that's a variable in testing? If loading in a test barrel vs a revolver then the bullet jump wouldn't matter. Maybe that makes a difference in the data idk
I've learned to take book data lightly as it varies by book, start low and work up. A lot of guys hop from book to book and find the higher max and use that, I dont.

Toprudder said:

It is my opinion (FWIW) that the 460 is very easy to work loads up for. The main pressure sign I look for is difficult extraction. From everything I have read, most factory loads are only 55-60k psi, while the cartridge is rated for 65k psi, and the reason always given is that full pressure loads would expand the brass enough to need hammering out. In my testing of loads so far, I have started to get difficult extraction before I get to the max published charges. In your scenario, I would load up one round each starting at 37.5gn and step in 0.5gn increments. Stop when you get the first difficult extracting case. Then load a few rounds each, narrowing the charge range based on the earlier results.

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I agree.

Many factory loadings and manuals have reduced their loads since the caliber first came out because of sticky extraction....not because pressure was dangerously high. Some of S&W's performance center guns also have tight throats, which also tends to up pressure and lead to sticky extraction.

The use of magnum primers alone is not making the big difference, so a different test firearm(Lyman used a universal receiver and it appears Western used a actual revolver) and different brass(western used Hornady, Lyman used Starline), probably made up for the rest of the difference. Note that Western also tested to higher pressure.

My P.C. X-frame has tight throats so I never make it to max`in any recipe. My velocities are still up there tho. I use my .460 for Wisconsin whitetails and have found the gun does not have to be loaded to max to be effective on even the largest of them. What I have found that loading for accuracy is more important. Even with a shooting stick or solid rest, and thousands of rounds of practice, I still am only confident out to 100-125 yards. Thus I like 300 grainers over a slightly compressed load of IMR4227. Ain't quite as fast as H110/W296 or Enforcer, but extremely accurate and fast enough. I think sometimes powder companies are loading simply for velocity. Hodgdon's start loads for H110/W296 and a 300 grainer in .460 are the max charges in Lyman. Similar to your experience. One reason I always reference at least 3 published sources before working up new loads, is because of these types of variances. I tend to throw out the extreme low start charge and the extreme high max charge and stick more to the middle of the road where the three sources average out. As for your bullet, Hornady shows a start charge of 39 gr of Enforcer and a Max of 47.1 under their 240 gr XTP-Mag, using their own brass and standard primers.. They kinda over lap both of the other recipes. Knowing that, I would probably start at 39gr with standard primers and go from there. Iffin I was using Mag primers I would probably start @ 38gr. and then stop either when I got to Westerns Max or sticky extraction. Iffin sticky extraction occurs first, I'd back down till cases eject easily.

Both the 454 Casull and the 460 S&W Magnum are rated for 65,000 psi. The Freedom Arms version of the 454 Casull has highly polished cylinder chamber and one only ejects one case at a time so one can get by with higher pressure and still get acceptable ejection. In S&W revolvers one ejects 5 cases at a time and the chambers aren't as highly polished so one will have to be satisfied with a lower pressure.

Now in an Encore, one can get the pressure up to where it was designed to be.

Another intresting thing about S&W revolvers is that they have a gain twist barrel (1:100 at the throat and 1:20 at the muzzle). A S&W rep I talked to called an engineer that had worked on their development. The gain twist was not to keep bullets from stripping but because without it, the torque was too hard on scopes. Between my Encores in 460 and 500 S&W Magnum I believe I've broken 3 or 4 handgun scopes scopes (the Leupolds were repaired free of charge). Encores don't have gain twist barrels.