Mid-power (NOT Powderpuff) loading for the .500 S&W Magnum
I regularly get requests for load data from people who want to load the .500 Smith & Wesson to less than top levels, or for bullet weights that aren't listed. Apparently, many of these people seem terrified of constructing a load for any bullet that is not found in a powder company's manual. Before I get into specifics, let me give you some general rules that should stand you in good stead.
First of all, when we are talking about loads which are nowhere near maximum, exact bullet weight is not important. If the bullets from your mold weigh, for example, 410 grains, there aren't any 410 grain bullets listed in any powder company's manual. No problem. Feel free to use data for any slightly heavier bullets that are commercially available and for which there is published data, such as the 440 grain Cast Performance offering. You cannot get in trouble doing this unless your bullet has a much deeper seating depth than the one in the loading manual. (An example would be if your 410 grain bullet is a full wadcutter and you load it so that the entire bullet is below the mouth of the case.) Compare the loading manual's OAL with yours to double check.
Second, there are certain powders that I WILL NOT use in the 500. Chief among these are the fast pistol and shotgun powders frequently used in the .38 Special, .45 Auto, etc. They are ill-suited to the massive case capacity of the .500 S&W. The powder that merits special mention is the one that I will not allow in my home: Titegroup. EVERY .500 that I have personally examined that was blown up (six so far) was blown up with Titegroup.
Third, don't be afraid to try rifle powders normally associated with cartridges such as the .223 or .308 in your .500. Take a sized case and hold your bullet next to it with the mouth of the case even with the crimp groove. Note where the base of the bullet is, and put powder in the case up to that level. Then seat and crimp the bullet, and see how you like the load.
If doing this worries you, because you've never seen a load for the .500 using a rifle powder in any loading manual, think about this for a moment: there are probably 50 or more powders that are safe to use in almost every rifle caliber, but you won't see them in loading manuals because many of them will not give the results that most people want. Most people don't want to use a powder that cannot give factory level performance. As an example, you will never see 4350 listed in any manual for loading the .223. This is not because 4350 is unsafe in that caliber, but because a case full of 4350 under a 55 grain bullet will only give about 2600 FPS in a 24 inch barrel, at a pressure of 30,000 PSI. Most .223 shooters want more speed than this, and it's likely that 4350 would not generate enough port pressure to cycle the action of an AR-15. However, in a bolt gun, this load might prove to be very accurate and exactly what a small game hunter might want.
Similarly, using fast rifle powders such as 4198 or Reloder-7 in the .500 may give you just what you want. I have tried many of the powders in this burning rate range, and the one that has impressed me most is BLC-2. This powder shows outstanding uniformity in the .500, with standard deviations in the low single digits. H322 has also proven to be an excellent choice.
Let me give you an interesting example of four different rifle powders in the 500. The slowest powder I have used to date is H335. Under my short shank 510 grain Sledgehammer bullet that only has .300"of shank in the case, 57 grains is all that will fit. This load gives 1240 FPS. A 510 at 1240 is almost double the power of the .44 Magnum, but nowhere near maximum in the .500. It's a great load and I like shooting it.
Leaving the powder measure on the same setting, and filling the hopper with another ball powder, BLC-2, we get the same 57 grain charge, but the velocity goes up to 1305 FPS. Another great load.
With the less dense extruded powder 4895, the measure throws 45 grains, and this gives 1240 FPS, the same as the 57 grain charge of H335.
Finally, switching to the faster 4198, the measure throws another 45 grain charge, but velocity goes up to 1435 FPS.
All four of these loads are at 100% loading density, all are very powerful but well below maximum, and all are safe. Remember that I am using bullets of my design with long noses and short shanks to give the maximum net case capacity. If you use bullets of the same weight with shorter noses and longer shanks, you will not be able to get as much powder in the case and your velocities will be somewhat lower, but the loads will be just as safe.
Two powders that have come on the market in recent years should be of particular interest to .500 shooters. These are CFE-BLK from Hodgdon and MP-300 from Alliant. I haven't had the time to develop hard data with either of these powders, but reports have been coming in that show great promise. First, if you want to use either of these powders, start with any .500 data using H-110 or 296. These new powders both appear to be about 5% to 7% slower than H-110, so that will be a safe place to start. Second, it appears that these powders may not have the squib issues of H-110 when loaded to pressures below 30,000 PSI. That could open up a whole new world of loads for shooters who want ammo that is below the factory full strength offerings, but far above what you can get with TrailBoss.
As a final note, a powder that is almost ideally suited for .500 shooters is unfortunately now discontinued, and that is 4759. This bulky powder, beloved by many shooters of the old black powder buffalo cartridges such as the .50-110, has a burning speed similar to H-110 or 296, but takes up more case capacity and does not have the squib issues when loaded below certain pressure levels or used in subzero weather. You cannot overload a .500 (in a Smith & Wesson revolver) with this powder unless you use bullets made of something that is considerably denser than lead. The reason for this is that filling the case to the base of the bullet results in a safe pressure level with any weight bullet, because heavier bullets reduce the usable case capacity, and you can't get enough 4759 in there to create an overload with any round that will fit in the cylinder and still let you close it. If you can find any cans of this stuff, grab them.
A while ago, I suggested making a table of all the bullets you .500 shooters are using, with weights and shank lengths, so that I could make loading recommendations for various desired power levels. As I recall, only two people responded. I'll make the offer again: If you would like me to suggest loads in a specific power range for the bullets you are using in your .500, send me the specs.
Hope all of this is of some use.
JR
