500 Phantom

[375rifleman]

I was wondering if the 500 Phantom is a viable hunting cartridge I'm mainly asking about the 750 grain Hornady A-Max at ~ 1100 FPS ? If it is what animals if any and at what distance if any that is ? Thanks in advance for any thoughts, opinions, and answers.

 

[Bravo 4]

I had a rifle built with the idea of a subsonic/suppressed .510 caliber, mostly for the 750 Amax. If you do the numbers, with the high BC Amax it will loose little velocity out to 500 yards. Some will say that you will not get much terminal performance out of a bullet that slow and no expansion. However, if people do fine with large cast bullets out of smaller cartridges then how can you argue with a bullet that is already the size (or larger) than most expanded hunting bullets. It'll knock a large hole through about anything, just won't get the temporary wound and shock of a high velocity projectile. I have shot the Amax into wet media and found that the tips will come off or deform and maybe cause a larger wound, but they weren't consistent enough to count on. They are too expensive to just go out and do a lot of shooting with. If you want some extremely good terminal performance look into the Lehigh subsonic fracturing bullets. The front 1/3 of the bullet will fracture into large petals and the large rear shank will penetrate like no one's business.

 

[375rifleman]

I've plugged the numbers into jbm ballistics and was surprised that how far that it holds 1000 ft lbs all the way out to 2000 yards with the amax bullet. Most people hold that 1000 ft lbs is needed for white tails and even on elk with good shot placement . . . so even if there is no expansion there will be a .510 caliber "hole" in whatever it is that you're shooting at. I also looked at the Taylor index on jbm ballistics and figured the thornily stopping power (TSP). Both of which were surprisingly high considering the slow velocity.

 

[Bravo 4]

I've plugged the numbers into jbm ballistics and was surprised that how far that it holds 1000 ft lbs all the way out to 2000 yards with the amax bullet. Most people hold that 1000 ft lbs is needed for white tails and even on elk with good shot placement .

Yep, and with well over 7,000 inches of drop.

The 750 Amax is pretty impressive. I have run the numbers multiple times, I researched this build for several months before it began.
Those projectiles will have a lot of penetration as well at those velocities.

 

[375rifleman]

I don't mean to complicate things but I was intending on using a Cold Shot M.O.A.B. With 300 MOA of Adjustment to compensate for the massive amount of drop. I was also considering the 50 Thumper with will put the same A-Max at the same velocity much cheaper being based on the 7mm WSM or other WSM, SAUM, or RUM cases the 500 phantom is based on the 500 Jeffery which is very expensive in its self

 

[Bravo 4]

300 MOA of adjustment???!!! Wow!

You better have some crazy tall rings, I've got 40 MOA added with the mount and rings and can see my can in the bottom of my scope field of view with a 100 yard zero.

As far as complicating things, the moment you step out of the ordinary it becomes complicated. The round I use is based off the longer RUM case, nobody makes anything for this specific cartridge so it's all custom and brass is hard to find. If I had it to do all over again I would have just had JD Jones @ SSK build be an Encore in .50 Alaskan. I reinvented the wheel...but it's my wheel. There are reasons why I did it the way I did it but it has been a huge headache and either the rifle or suppressor has been in the shop about 75% of the time for the past several years. You know how some builders seem to be, not in a hurry to get something done. It's been in the shop since spring and was supposed to have been finished a month ago-"I'll have it done next week"..."next week"..."next week". Last time this happened it was over 13 months!
But I digress:


Good luck.

 

[375rifleman]

Actually it's an adjustable Scope Base so the entire base changes elevation check it out sometime the website is www.coldshotusa.com for the 150 MOA Base and http://www.heritage-arms.com/PDF/ColdShot_News_flash_06-14-11.pdf for the 300 MOA Base so if you use this system the only thing that you will need to adjust on the rifle scope itself after you get it zeroed at the distance you want is the windage. Would be perfect if someone wanted to shoot a subsonic rifle cartridge REALLY, REALLY FAR like me. The only downside I can see is the price I think its around $400 for the 150 MOA base don't know about the 300 MOA base.

 

[Bravo 4]

Actually it's an adjustable Scope Base so the entire base changes elevation check it out sometime the website is www.coldshotusa.com for the 150 MOA Base and http://www.heritage-arms.com/PDF/ColdShot_News_flash_06-14-11.pdf for the 300 MOA Base so if you use this system the only thing that you will need to adjust on the rifle scope itself after you get it zeroed at the distance you want is the windage. Would be perfect if someone wanted to shoot a subsonic rifle cartridge REALLY, REALLY FAR like me. The only downside I can see is the price I think its around $400 for the 150 MOA base don't know about the 300 MOA base.

Yes sir, I understand the concept of an adjustable base. What I was getting at is the front of the base pivots and only the rear of the base gets elevated. This will make the objective end of the scope angle down and point at the barrel. The shorter the rings the less of the adjustment in the base you will be able to use because at some point the barrel will obscure your view of the target when looking through the scope. Also, watching a couple YouTube videos shows the cheek piece will have to be extremely high to get a good view/cheek weld when looking through the scope.
I'm not saying it's not doable, just voicing my opinion on some observations.

 

[375rifleman]

Thanks Bravo 4 that's kinda what I thought about the 150 MOA - 300 MOA adjustable base. I also realize that 1100 FPS and below there won't be any hydrostatic shock but as you said the penetration of the big heavy high BC bullets will still be there I just don't know if I should or can trust that on big game animals like elk and bear? I just don't want to build a subsonic 50 cal and only be able to shoot paper/steel targets with it.

 

[375rifleman]

Bravo 4 I was wondering as to how far you've taken a subsonic 50 caliber possibly the 750 grain Hornady A-Max or the Lehigh Subsonic Facturing Bullets you recommend and what the results were as I'm looking for a long range (1500-2000 yards) large caliber subsonic thumper. I could still use the A-Max or Barnes 800 grain Banded Solid if I was looking to maximize the BC of the projectile (although the Barnes 800 grain solid is a bit longer). But as you have much more experience than I do regarding these things I must ask you. Thanks

 

[Bravo 4]

The furthest I have shot mine was 300 yards (I believe) with the Amax, Lehigh, pulled API and M33 projectiles. If I ever get mine back from the gunsmith (yesterday I was told 6 more weeks!!!) I will load some up and stretch it out to 600-800 and see how it does. If you want a LR or ELR subsonic anything I think this is the way to go. Another problem I see is accuracy. I don't know anybody getting extreme precision with subsonic loadings, nothing I would consider consistent for LR.

 

[375rifleman]

I have read and re-read the article by Jerry Teo about shooting a 223 Remington a mile accurately and if the 223 Remington can make it out to a mile accurately than I'm pretty certain that a subsonic 50 cal like the 500 Phantom can make it to a mile or beyond accurately. 750 grain Hornady A-Max has both a better BC and is a lot heavier than a 80 grain Berger VLD with a BC of .445 as well as a 80 grain with a BC of .453 even if the 223 Remington starts out at around 2890 FPS. So 80 grain with 449 BC at 2890 FPS muzzle velocity VS 750 grain with 1.07 BC at around 1075 FPS muzzle velocity. However I have personally not plugged these numbers into JBM Ballistics for comparison.