Not exactly Travels with Charley, but still a bumpy, lumpy road from Part 1 to Part 2. A good deal of time was spent wallowing around in components and combination at no one’s suggestion, only to find the 450 Bushmaster is not at all difficult to handload or to make accurate. The greatest hindrance to getting results was a combination of my old guy’s know it all attitude at the onset and overlooking what should have been the obvious. Experience is a valuable tool if not applied while napping.
Making a transition from an AR based 450 Bushmaster with 1:20″ or 1:24″ rifling to a bolt action 450 Bushmaster with 1:16″ rifling, empirical findings dictated the use of longer spire tip bullets. Both handloads and factory loaded 450 Bushmaster ammunition with spire tipped bullets can routinely produce sub MOA accuracy. Additionally, the ballistic coefficients and sectional density of these bullets support the 450 Bushmaster narrative that includes an effective range of 300 plus yards.
The selection of bullets below, with the exception of the Hornady’s 450 Bushmaster specific 250 grain SST bullet, were cannibalized from .50 caliber sabot ammo. Designed to work with modern triple charge, magnum muzzle loaders, these .45 caliber projectiles can hold 1 MOA out beyond 300 yards and impact with controlled, but full expansion at 450 Bushmaster velocity.
|Barnes Spitfire MZ||HPBT||245||0.968||0.4504||2.260||44.0|
|Barnes Spitfire TMZ||PTBT||250||1.110||0.4506||2.260||38.3|
The SAAMI bullet diameter specification for the Bushmaster is 0.452″ +0.000″/-0.003″, so all of the bullets indicated meet that criteria. All .50 Caliber sabot projectiles do not. As an example, the Remington AccuTip 260 grain bullet contained in a .50 caliber sabot projectile measures 0.448″; close, but no cigar. The design muzzle velocity and impact velocity that governs the degree of expansion is right in line with the external ballistics of the 450 Bushmaster. The 450 Bushmaster is the subject of a good deal of attention these days, so I would not be surprised if all bullets were all soon available as stand alone components and not just parked in a sabot.
Ballistic coefficient for the bullets indicated fall between 0.203 and 0.250. While significantly better than their blunt nose handgun bullet counterparts with a BC between 0.150 and 0.180, there is little chance that they will skip off into low orbit. Excepting the subsonic Trail Boss load, the rest will hold 1000 ft-lbs at 300 yards while remaining supersonic and shoot point blank between 185 and 205 yards without wandering an inch above or below line of sight.
|Barnes 250 Grain Spitfire TMZ|
|Velocity – fps||2223||2035||1857||1689||1534||1395||1272|
|Energy – ft.-lbs.||2743||2299||1915||1583||1306||1080||898|
|Momentum – lbs-sec||2.46||2.25||2.05||1.87||1.70||1.54||1.41|
|Path – in.||-1.5||1.8||3.0||1.6||-2.7||-10.8||-23.4|
202 Yard Point Blank Range +/- 3″ Ordinate 174 Yard Zero
What does this look like down range? Above, table data for the Barnes 250 grain TMZ. There is greater potential to exercise in this bolt action, but this is a load that would not cause a problem if shared between AR and Ruger American Rifle.
So where does this leave us?
I do believe this takes us back to where we began. The Ruger American Rifle Ranch with 450 Bushmaster chamber, can out perform what is generally considered a big bear capable 460 S&W Magnum revolver and do so at a significantly lower pressure and firearm stress. It is a particularly accurate combination, easy to shoot and clearly a good fit for my part of the New England woods. Nice little carbine, lots of power and built to last.