The HSM Game King 300 Remington Ultra Magnum (300 RUM) 165 gr Sierra GameKing Spitzer Boat Tail – 20 Rounds Per Box (300RUM12N, UPC 810742023157) is a premium hunting load purpose-built for long-range big game performance. Loaded with the proven 165-grain Sierra GameKing Spitzer Boat Tail (SBT) bullet, this cartridge delivers flat trajectory, excellent accuracy, and reliable terminal performance on deer, antelope, and similar game at extended distances. Buds Gun Shop+3GrabAGun+3ICB Firearms+3
300 RUM Power with a Versatile 165-Grain GameKing Bullet
The 300 Remington Ultra Magnum is known for extreme velocity and long-range capability. Pairing it with a mid-weight 165-grain GameKing SBT gives you a highly versatile hunting load:
High muzzle velocity and energy (typical of 165 gr loads in 300 RUM) for long-range authority. GrabAGun+1
Flatter trajectory than heavier bullets, reducing holdover and guesswork in the field.
Excellent combination for medium-to-large game, especially in open country where shots can stretch past traditional woods distances.
This load strikes a sweet spot between ultra-light speed and heavy, deep-penetrating projectiles—ideal for many North American big game scenarios.
Sierra GameKing Spitzer Boat Tail – Time-Tested Hunting Performance
The Sierra GameKing line has earned a reputation for accuracy and dependable expansion over decades of real-world use. Buds Gun Shop+2Range USA+2
Key advantages of the 165-grain GameKing SBT:
Spitzer (pointed) profile improves ballistic coefficient for better downrange velocity retention.
Boat tail base reduces drag and enhances long-range stability, helping maintain tight groups. GrabAGun+2Georgia Guns & Ammo+2
Designed for controlled expansion and solid penetration on deer-sized and similar game when shots are properly placed.
Matched with the 300 RUM’s powder capacity, this bullet becomes a flat-shooting, hard-hitting option for demanding hunts.
HSM Game King Series – Components Matched for Accuracy
HSM’s Game King series is built specifically around Sierra GameKing and Pro-Hunter bullets, with each caliber’s components tuned to maximize performance. Range USA+3Zack\\\\\\\'s Sports Inc.+3ICB Firearms+3
For the 300RUM12N load, HSM:
The result is a cartridge that behaves more like precision ammo than generic hunting fodder.
Ideal for Western & Open-Country Hunting
The ballistic profile of this load makes it particularly well-suited for:
Western big game like mule deer and pronghorn where you may need to shoot across canyons, ridges, or open prairie.
Long-range whitetail in fields, cutovers, and agricultural land.
Any hunt where flat trajectory and high retained energy at distance are critical for ethical, effective harvests.
When properly zeroed and paired with good dope, this 165 gr GameKing load helps simplify ranging and holds at real-world hunting distances.
Brass-Cased, Boxer-Primed – Reliable & Reloadable
Like other HSM Game King offerings, the 300 RUM 165 gr SBT uses quality brass cases and standard centerfire primers: Elk River Guns+3GrabAGun+3ICB Firearms+3
Brass casing for smooth feeding and extraction in bolt-action hunting rifles.
Boxer-primed brass is typically reloadable, making it attractive to handloaders after the hunt.
Designed as hunting ammunition, not surplus or budget plinking rounds.
This gives you reliability in the field and flexibility back at the reloading bench.
20 Rounds Per Box / 20 Boxes Per Case
Packaging is straightforward and hunter-friendly:
For the individual hunter, a couple of 20-round boxes is typically enough to:
Zero and confirm your rifle.
Practice from realistic field positions.
head into the season with proven, consistent ammo.
Great Choice for Zeroing, Practice & Real-World Hunting
Choosing a single load from sight-in to the hunt offers major benefits:
Your rifle’s point of impact stays consistent from the bench to the mountains.
You build muscle memory and confidence using the same recoil impulse and ballistics.
You avoid last-minute surprises from switching ammo just before opening day.
The HSM Game King 300 RUM 165 gr SBT is designed to be that one, do-it-all hunting load for your 300 Ultra Mag.
Key Features & Specifications – HSM Game King 300 RUM 165 gr Sierra GameKing SBT
If you’re looking for a flat-shooting, accurate, and hard-hitting hunting load that fully leverages the long-range potential of the 300 Remington Ultra Magnum, the HSM Game King 300 RUM 165 gr Sierra GameKing Spitzer Boat Tail (300RUM12N, UPC 810742023157) is an outstanding choice—pairing Sierra’s trusted GameKing bullet with HSM’s carefully tuned components for serious performance in the field.
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