Building a hunting AR 15

[Swamp Fox]

I want to build an upper for my AR in a hunting level caliber. Use will be for deer and hogs, at less than 200 yards. In all reality most of my kills have been closer to 50 yards than 200, or even 100. Looking at it I have been primarily considering 6.5 Grendel, 450 bushmaster, and 458 socom. I like big slow moving bullets with good knock down power, so I’ve been leaning towards the 458, as I think it has some advantages over the 450. But it is so much more expensive to buy factory loads for, and in the end I think one or the other caliber will win out, and it’s looking like it will be 450 BM. The 6.5 doesn’t seem like a bad choice, but it seems more suited for longer ranges and the bullets are on the light side of what I would be comfortable with. But I’ve seen some deer killed with them and no problems.

Any body have any advice or things to consider? Or want to talk me into another caliber? I know people will say 300 blackout, but it just doesn’t impress me. Once I decide on a caliber I’ll have other questions but I need to pick one first.

[Nobade]

Wilson's new 300 ham'r. We've been playing with their 7.62x40 with great results, and the new one is just more of the same. And it makes a way better cast boolit gun than a 6.5 does.

[Rcmaveric]

Cast bullets work in all those calibers. Anyone of them will do it. I have a Grendel and built it too heavy. I plan on the building a new one with an 11 twist 21 inch barrel. I also plan on building a .277 Wolverine.

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[Smoke4320]

I have both the 6.5 Grendel and a 458 Socom
the socom would be my choice for anything under 150 yds .. Its big, its bad and nothing walks away from a well placed hit
there are multitudes of bullets designed for the 45-70 and will move to the socom no issues Bullets ranging 180 gr (color button) to well over 500 grns

Mine loves the RCBS 45-300 the NOE 460-350 HP and for subsonic the Lee 500 grn pointed

[Moleman-]

450bm has a lot going for it. Works well with cast, can be run subsonic or standard, and there is factory ammo available should you be away hunting and have a need for ammo....

[Texas by God]

6.8 SPC kills way out of proportion to its size. I am an eyewitness to this phenomenon. Having said that my latest project is a 6.5 Grendel. I have a 300 Blackout and I consider it to be the equal of a 357 Magnum carbine. Although I wouldn't mind having one of each, the 450 Bushmaster and the 458 Socom wouldn't get much use where I live.

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[popper]

If you have carbine lower you have to go carbine (16") to be legal and suffer the weight penalty. My pig gun is 10" BO pistol with 185gr RD style cast, 1700 fps? Not sure what the FN boolit gr. limit in the 40WT or Hamer is. Guy I worked with got the BM or socom, don't remember which for pig hunting. He's a big guy and didn't like shooting a lot of rnds at the range, very accurate @ 50 IIRC.

[fredj338]

My hunting ar is a 6.8spc. I like the round, hits quite a bit harder, on steel anyway, than an 223. Recoil is also quite soft.

[nannyhammer]

Another vote for the 6.8 SPC. I run 100gr Accubonds at about 2850 and they work just fine. Have killed deer, pigs and coyotes and have no reason to change for my hunting needs.

[pertnear]

+1 for the 6.8mm SPC II.

It has become my favorite whitetail rifle.

[rockrat]

I would go with the 450 Bm or even the 7.62 x 39. I have the Grendel also but since hogs are in the mix, the 450bm. Quite accurate

[Swamp Fox]

Seems to be a lot of people liking the 6.8. I’ll have to do some research on them. I thought it had become less popular since the Grendel came out.
I have the most trouble between the 450BM and the 458. I like the 450 because it’s got a better selection of lighter billets, and it’s much cheaper to buy factory ammo for. But it headspaces on the cartridge mouth, so no roll crimps. On the other hand, the 458 can share bullets with my 45/70. And it can run on standard mags. Really there’s probably not a bad choice in the bunch. Everybody seems happy with whatever they have. That just doesn’t make the choice any easier.

[dkf]

The .450bushmaster is a SAAMI cartridge now, the .458socom was submitted but since Remington and the big companies sit on the SAAMI board it is unlikely it will go anywhere with them soon. The .450 bushmaster is cheaper but several of those factory loads have bullets that are soft and will even come apart really quick in a deer. The .458socom has more companies loading for it and a much broader array of ammo available for it than the .450. There are more .458socom specific bullets available for it as well as 45-70 bullets that are designed to be in the velocity window of the .458socom. The .458socom also doesn't have problems with rounds riding too high and popping out of the mags either like the .450 does.

[pmer]

I went with the 458 SOCOM and had it hunting with 405 grain Marlin boolits going just over 1600 FPS. It groups this load like no problem. If you go this way get the Tromix. I thought I'd save some money and get a lesser known brand. I had to work through light primer strikes, feed troubles and case neck turning because my chamber neck is pretty tight. The Tromix chamber utilizes a bigger chamber neck than what mine has and should be much easier to work with.

[Marine Sgt 2111]

Well I built a 6.5 Grendel and for Pure accuracy and distance it will surgically plant a bullet in any animal out to 300 yards quite comfortably. But I also recently bought a 450 BM upper, and I have to tell you right out of the gate it will have three holes touching at a hundred yards all day long. It shoots Hornady 250 grain FTX a 2140 FPS out of a 16 inch barrel with all holes touching at a hundred yards. About the only thing I don't like about it is the one in 24 twist. But whether it's my Ruger number three in 45-70 with a 1 in 20 in twist are my Shiloh sharps with a one in 20 twist also in 4570, so I guess the one in 24 twist isn't that bad a handicap. I've shot mine and I've shot another rifle in 450 BM and both of them will shoot 1 inch Center to Center at a hundred yards. In Michigan we have to use a straight walled case if you want to hunt in traditional shotgun and handgun areas. And if you look, the 450 BM usually has more energy then the 458 Socom.

[BigBore45]

7.62x39. Cheap. Available. Roughly 30-30 ballistics.

[crankycalico]

450 bushmaster... just a wonderful cartridge. It can create wounds that scare the **** out of game processors who have customers hunting with 300 win mags.

[DougGuy]

If I wanted a hunting AR, I would seriously investigate the Wilson 300 Ham'r. Bill Wilson himself kills tons of hogs on his Texas ranch, he has probably tried every caliber that you could cram into an AR magazine, and the 300 actually outperforms the vaunted and trusted 150gr 30-30 cartridge by a notable margin.

https://www.americanhunter.org/artic...m-r-cartridge/

Then again, I can always drop a 150gr load in my 300 AAC and hunt with that, at 1900fps it's marginally slower than the 300 Ham'r but deer or pigs wouldn't notice if hit in the right place.

[Swamp Fox]

The 300 hamr looks interesting as it fixes my gripe with 300 blackout, aka not enough power. But will it ever catch on? I don’t want to buy something that I won’t be able to get ammo for in 10 years. Although really I guess I’d only be out the cost of a barrel

Looking at the 6.8 spc stuff now, but it seems harder to find than a few years ago. Seems like a great round though.

450 BM seems like an easy answer though. You can get lighter, flatter shooting bullets than for 458. And it seems to be catching on.

So many good calibers....

[DougGuy]

I would only handload for the 300 hamr anyway so I wouldn't be concerned with store ammo.

Ok, I think this needs airing.. Consider the hard limitations for the AR. 1st and foremost, magazine length. No matter what the load it still has to cycle through the mag.

2nd, in the last what 20yrs, there have been hundreds of "new" rounds invented for the AR that are all a compromise between case capacity, and boolit weight, in all the calibers.

So... You keep going up in power until you have maxed out the curve under xxx grain boolit, so you go larger with diameter and heavier. Once again the curve starts and it keeps getting incrementally improved until the max energy can be pushed out with xxx boolit weight in the caliber. Not too hard to follow this process..

Ideally you would want to arrive at the combo that suits your needs the best. For some nothing smaller than 45 caliber will do, for others anything 150gr ~ 175gr in 30 caliber will do, and the sweet spots are many.

You can take any boolit diameter, and you can look at the myriad choices of case sizes and wildcat names. Eventually you will see that this entire AR game is broken down into "tuning and tweaking" the individual boolit diameters until the most efficient combo is reached in that caliber.

Basically, at this point in time, you can pick your caliber and then go find the best case scenario (pun intended) and buy dies, brass, and powder and a barrel and you are up and running.

Straight walled cases with 5.56 breech face would allow the biggest boolits, 40 caliber and above, but now you basically have the BC of pistol boolits, and ultimately the laws of physics will dictate trajectory, which establishes effective hunting ranges for the round.

Bottleneck cases will let you use rifle boolits which have a better BC and a better trajectory which stretches the effective range for the round.

If I got out my old crystal ball and rubbed it a time or two and asked what the optimum 30 caliber round would be, I am sure the answer would ring very close to one or more of the better 30 calibers out there now, like the 300 Ham'r.