Ever wonder how big a bullet you can throw out of an AR-15 standard package? Marty Ter Weeme was at an old backyard barbecue with some men who couldn’t list where they’ve been or what they’ve done. Call me Thumper!
The requirements were very simple. It had to be either an upper or a rebuild that would work on a standard AR-15/M16/M4 low. It could only use standard AR-15 magazines. It had to hit like an axe. They chose the.458-inch diameter bullet. The case was next. Next, the case.
But, the case was too small and the rim was too large. Marty and Tony Rumore from Tromix decided to lengthen the.458 SOCOM cases by.50 AE and have the brass maker reduce the rim diameter from.514 to.473 inches. It is the standard rim diameter for the.30-06 family, along with the 8mm Mauser, and other cartridges. It is also the maximum size you can make your AR-15 bolt face while still having enough locking lug metal to allow you to safely shoot your rifle. (Right) Too many and the bolt face would be gone. Next, we had to decide how big a case neck and what case capacity to provide. The heaviest bullets were what determined the case neck dimension. At 500 or 600 grains, you need a lot neck tension to keep a bullet from moving around in the case. It’s as simple as any other AR-15 project, and you can count on the parts manufacturers to keep everything within the AR-15 envelope. You don’t need to spend on special, proprietary buffer weights and springs. The gas tube that you use for your barrel length build is the same as the gas tube that you would use for any other build. This last part is a little more variable than the rest. We’ll get to that in a moment.
I pulled a Brownells bolt and barrel off the shelf and began looking for build candidates. Oh, my goodness, there’s a complete rifle at the rack with a shot-out barrel. (Yes, Virginia, ammo was cheap enough that you could just shoot a barrel. The old is gone, the new is in. Brownells’ barrel clearly marks caliber and twist rate. Take the old handguard (so old it’s a four-rail) and the barrel out. Then, plug the Brownells .458 SOCOM barrel into the upper, tighten the barrel nut (tight-loose-tight-loose-tight to alignment), install a gas tube into a gas block and then install that and tighten it into place. Take the handguard off the bench and install, align, tighten. Make sure to check alignment and eye relief. The.458 SOCOM is a powerful weapon, so you don’t want your scope to be too close to the scope when you touch one of the more robust ones. Hi-Lux 1-4 in LaRue QD mounted was the likely candidate. The Magpul UBR stock with its rubber recoil pad and.458 SOCOM protection promised to keep the rifle’s.458 SOCOM from becoming too much. This is in contrast to the hard plastic checkered buttplate that you would find on a mil-spec carbine.
You can load the.458 with bullets from 140 to 600 grains. The lightest ammunition (if we can call something that weighs in at 140 grains “light”) will leave your immediate vicinity at more than 2,400 fps depending on the barrel length. You might lose a few fps if you use a carbine with 16-inch barrels. You can use a rifle with a 20-inch barrel to get 2,400 fps. This would be possible with Polycase ARX ammunition. The range of weights that you can throw from a.458SOCOM. Well, almost. The 140-grain ARX loading is fast to the max. It’s possible to achieve speeds of 575-600 PF momentum. This gets really interesting if you choose the heavyweights. You can move up to 500 grains and generate 1,300 fps from a full-length barrel with a power factor of 665. Yowza! A 12-gauge slug with an 1-ounce projectile at 1,600 feet per second generates 700 PF. It has a trajectory similar to a softball. The.458 SOCOM is a tough opponent, but has a flatter, but still arcing, trajectory. And This Out Of An AR-15
The.458 SOCOM is a joy to use with heavyweight subsonics. 600-grain JSP (which is not capable of expanding) in the subsonic velocity area becomes an entertaining range time. The thump is amazing. The noise is not as impressive. The noise can cause your target to be thumped…hard. The Wilson Combat Whisper suppressor can be used in conjunction with your.458 HAMR. This will ensure that you don’t need any hearing protection. You might need some audio suppression if you shoot at a short range, such as a 25- to 50-yard backstop.
It’s not difficult to reload. The.458 is just like any other bottlenecked rifle ammunition, so you will need to lube the cases for resizing. Next, clean the lube to be loaded. It uses large pistol primers, slow-burning powders for pistols, and fast-burning powders for rifles. Jacketed bullets are best for heavyweights and speed loads. You’ll need to trim the cases and apply a firm neck tension for the most powerful loads. Acme bullets manufacture a.458 SOCOM-specific bullet, 576 grains in weight, with a bright red HiTek coating. It is important to note that you should not shoot steel with any.458SOCOM load unless you are shooting at steel plates that have been rifle-rated and are placed at least 100 yards away. It hammers whatever it hits, no matter how ferociously it thumps you. Steel that is not rated for rifle will be dented. Non-rifle-rated steel will be dented. The idea was to create the.458 SOCOM feed from standard AR magazines. They do, and they often do. However, magazines can be different. It is possible to burn a lot of ammunition trying to determine if the magazines you have and are using will work with your.458 rifle and ammo. I recommend investing in 458-specific magazines. DuraMag makes.458 specific magazines. The rounds are single-stack in a tube, just like any AR-sized magazine, but with.458 feed lips and follower. Download your Storm Tactical printable target pack62 Printable MOA targets with DOT drills – Rifle range in YARDSThis amazing target pack is from Storm Tactical and contains 62 printable targets for rifle and handgun range usage. Target grids and bullseye sizes can be found in MOA. Get Free Targets
