Good Morning guys...........
Doing a bit of research this morning, nothing any of you can't do, Just Googgling.......LOL...............One of the first things I ran across is here;
https://www.ballisticmag.com/2020/04/17/big-horn-armory-ar500-auto-max-review/
One of those test review reports........
What I learned, is the rifle is actually a AR 10, and NOT AR 15. I was going on AR 15 because of the magazines and the length of the cartridge in them. It indeed uses AR 15 Magazines. I assume the longer AR 10 magazine might have given issues with the shorter cartridge? That is not my area. Anyway, first photo on this review the rifle looks like some sort of Anti Tank Weapon it is so damn big. Yeah, about like my 50 B&M SA.
Buffalo Bore is doing the loading and factory ammo and using mostly conventional bullets from what I can tell. They don't specify actual bullet. But these numbers fall more in line with what I would expect, they are still pushing it hard however in the attempt to lay claim to "Most Powerful".........Blah blah blah........
This is what is reported........
Load Velocity Avg. Accuracy Best
Buffalo Bore 440gr Hardcast 1,925 2.50 inches 2 inches
Buffalo Bore 350gr JHP 2,235 2.25 inches 1.75 inches
Buffalo Bore 400gr JFN 2,012 3.00 inches 2.33 inches
Steinel 350gr JHP 2,186 2.33 inches 2.25 inches
Steinel 350gr Brass Warhead 2,005 2.66 inches 2.50 inches
The gun used in this report uses a 18 inch barrel, weighs 9.2 lbs, and is 40.25 inches with stock extended. Sometime today I will measure my guns.
My take on the loads.........direct comparison to 50 B&M Super Short.... in a 16 inch bolt gun. Since 500 Auto Max and 50 B&M Super Short are very close to being the same.
440 cast at 1925 fps..................
I have tested 450 North Forks in the 50 SS at 1800 fps 56000 PSI with Lilgun. There is a 425 #13 Copper Solid I have worked with to 1925 fps at 58000 PSI. These are close to the 440 cast in physical size, length. They might be pushing a little here, but not too bad actually.
350 JHP at 2235 fps................
The closest data I have with the 50SS is running a 345 Brass Raptor at 2260 fps for 59000 PSI. Looking at other data, without pressures I have run various 350s to 2200-2250 without concerns. So this is a realistic number, and while slightly over pressure, not by much.
400 JFN 2012 fps........................
With a conventional lead core bullet this is reasonable, and probably at proper pressures. I tested a 405 #13 Solid in 50 SS at 2020 fps at 64000 psi, but this is not a good comparison as this is solid brass, longer bullet, seated deeper and so forth. Other pressure tests with 385 Remingtons showed 2150 fps at 56000 PSI, this being more conventional lead core. So 400 at 2012 fps is very reasonable, and under pressure I would think.
The other 350 JHP at 2186 is zero issues with pressures.
I have not located any real load data yet, I suppose they are keeping that close to hand since it appears Buffalo Bore is doing all the Loading and Factory ammo. In reality in this size case, to reach optimum there is not much of a choice in powders. In all the Super Shorts, it comes down to Lilgun and WW 296. With LilGun winning most of the races with some higher velocity and lower pressures. Other powders are too slow, or two fast.
I will probably look around a little more this morning, but this has pretty much satisfied my curiosity on this.
I still hold that anything that comes from Big Horn is most likely going to be of good quality. About a year ago I thought I might look into one of the lever guns, I did, and prices were reasonable, but I could not justify it with all the B&M 500s laying around......... ???????
