7mm Rem Mag Sierra GameKing Hunting Wyoming (Success)

Wyoming has long lured me for hunting and fishing. Elk, mule deer and pronghorn antelope from the Cowboy State have all filled my freezer. In 2020, I had tags for both mule deer and pronghorn antelope, and hunted the Great Plains of Eastern Wyoming. Anticipating wide open spaces with the potential for longish range shots, I turned to my 7mm Remington Magnum — a Ruger Number One topped by a 3.5-10x Leupold paired with the classic Sierra GameKing.

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I’d hunted with the 7mm Remington Magnum cartridge before, but 2020 was the first year I hunted with this particular rifle. I bought it lightly used off of Gunbroker. Ruger Number One rifles have performed well for me over the years and responded well to handloading. This one is a 1-S or “medium sporter” with a 26” 1-9 twist barrel and sights plus a  quarter rib for scope mounting. In the time since, we’ve used this rifle for a couple of stories here at Ultimate Reloader. 

High-Velocity 7mm Rem Mag Loads with IMR Enduron Powders – Ultimate Reloader

TESTED: Hornady 7mm 150 grain CX Bullets w/Ballistics Gel (7mm Rem Mag) – Ultimate Reloader

7mm Remington Magnum at the gun club for practice. The single shot rifle is equipped with a 3.5-10x Leupold Vari-X iii and a Montana Sling

I’m particularly fond of bullets around 160 grains pushed by slow burning powders. Knowing that Sierra’s GameKing often shoots well, I decided to try that classic bullet. I’ve also long used and appreciated both Sierra MatchKing and GameKing bullets for what I call “easy accuracy.” Whenever I get a new gun, these are one of my first two bullet choices, because if it won’t shoot those well, it won’t shoot anything well. 

From Sierra:

GameKing Bullets: All bullets in this classification are for hunting and all have boat tails. Their shapes include hollow point boat tail (HPBT), spitzer boat tail (SBT), and full metal jacket boat tail (FMJBT). The bullets in this classification have medium to heavy weights in each caliber. With their boat tail shapes, they have high ballistic coefficients, retain their velocities well, and resist crosswinds and vertical winds well as they fly. These bullets are designed for a combination of penetration and expansion in medium and heavy game animals for their calibers.

For rifles, the 160 grain #1920 Spitzer Boat Tail is a long-range big game bullet offering exceptional accuracy, good ballistic coefficient, flat trajectory, and high retained energies downrange. It can be used in all 7mm rifle cartridges, but is most useful in the magnums.

The bullet has a G1 BC of .455, providing good trajectory for open country hunting or cross-canyon shots. This sounds low compared to more modern developments, but this BC was actually very high when it came out. 

Alliant’s Reloader 22 has done a fine job for me in the 7mm Remington Magnum, and I used it again this time. Sierra’s manual lists a maximum load of 65.2 grains of Reloader 22 for 3100 fps. 

My load: 

  • Sierra 160 grain SPBT GameKing
  • 65 grains Reloader 22
  • CCI 250 large rifle magnum primer
  • Winchester cases

This load has always gotten me velocity between 3,000 and 3,100 fps with no pressure signs and tight groups. This is key because many have reported pressure signs with 7mm Rem Mag loaded near max, though I’ve never run into it with this load. 

I loaded these new cases on an older Lyman turret press. Hornady dies nicely sized the cases and seated the bullets straight, with an overall length of 3.295”. 

Range Results

The results had me smiling! Velocity was as anticipated at 3,050 fps and the rifle was producing sub 2” three-shot groups at 300 yards. I zeroed it at 300 yards in anticipation for the open country I’d be hunting. 

Three shots on steel at 300 yards, 160 grain Sierra GameKing SBT bullet, 7mm Remington Magnum.

The JBM Ballistics Calculator shows the useful trajectory of this hunting load. There’s no problem “holding on hair” even out at 400 yards, and there’s plenty of retained velocity for proper expansion at 600 yards. 

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Excellent range results are confidence inspiring, but the true test of a hunting bullet is afield, on game. 

Mule Deer

We were hunting mule deer and spotted a group of bucks from a mile away. Using the terrain to conceal our movements, we closed that distance considerably, before I began a careful stalk along a steep ridge. Walking, crouching and finally crawling to stay hidden, I managed to get within 150 yards of a pair of muley bucks. Neither were huge, but I focused on the larger of the two, a fat 3×3. My field-improvised sitting/kneeling shooting position got my line of sight above the low sage, and I dug my boots into the ground to keep from slipping down the steep slope. 

My shot placement wasn’t perfect — I got the rear of the lungs and a bullet fragment did perforate the diaphragm — but the buck collapsed and died instantly. I later found the nicely mushroomed Sierra bullet just under the off-side skin and recovered it. That bullet weighed 92.5 grains. 

Happy Guy, moments after a successful stalk and shot.
New versus recovered Sierra 160 grain GameKing SBT, #1920. The bullet performed splendidly!

Pronghorn Antelope

After several unsuccessful stalks, we spotted a buck and doe antelope together in the flats about 300 yards away. Unable to get closer, I braced off a solid rest and was slowly squeezing the trigger when the buck moved! The magnum barked and the buck dropped instantly, but it wasn’t a kill shot. I hustled forward and quickly dispatched the animal. That short range finishing shot made a bit of a mess of the antelope’s neck and no photos were taken out of respect for the animal. Both bullets passed through, inflicting massive damage, and were not recovered. 

A 7mm Rem Mag is a lot of gun for an antelope. A .25-06 would be just about perfect and a .243 Winchester would do nicely as well. Like any game animal, shot placement is the most critical. 

I thoroughly enjoy hunting antelope, and find the meat from my five October bucks has always been excellent. The backstrap steaks in particular have a nearly sweet taste, possibly due to grazing daily on the rancher’s alfalfa field! 

Antelope tenderloin sizzling, a real trophy!

Antelope are fascinating to watch and perfectly adapted for life on the Great Plains. Of the five I’ve taken, only the last one was at over 300 yards. The others have been between 160 and 250 yards. It’s entirely possible to stalk to reasonable ranges, at least where I’ve been hunting.

Photo by Guy Miner

They are, however, quite wary, and when one of the herd decides it’s time to leave, the entire herd will usually follow swiftly. 

Conclusions

Sierra’s GameKing is an easy bullet to work with. I’ve shot hundreds of them from various cartridges over the years and have always found good accuracy and dependable performance. To me, they’re a standard bullet useful in a great variety of hunting situations. As always, match the bullet with the intended use. For example, had I been hunting huge bull elk in a thickly forested area where shots might have been much shorter, I’d have selected a heavier bullet, probably the 175 grain SBT, which is also an excellent performer.

The instant drop and death of the mule deer despite less than perfect shot placement proved to me that the 160 grain Sierra GameKing is a serious hunting bullet. Its excellent accuracy at the rifle range is also a real confidence booster. 

Messier results on the pronghorn were my fault, as I didn’t shoot as well as I would have liked. Things like that happen sometimes when hunting — not every shot is perfect though you should do your best to make it so. We can stack the odds of a good hit in our favor by crafting accurate ammunition and practicing our field shooting skills before the season.   

Get the Gear

7mm .284 Diameter 160 Grain Spitzer Boat Tail Gameking 100 Count by Sierra (midsouthshooterssupply.com)

7 MM/.284 CALIBER 160 GR. SBT – Sierra Bullets

#250 Magnum Large Rifle Primer (1000 Count) by CCI (midsouthshooterssupply.com)

7mm Remington Mag Unprimed Rifle Brass 50 Count by Hornady (midsouthshooterssupply.com)

7mm Remington Magnum Unprimed Rifle Brass 50 Count by Nosler (midsouthshooterssupply.com)

Alliant Reloder 22 Smokeless Magnum Rifle Powder 1 Lb by Alliant Powder (midsouthshooterssupply.com)

7mm Remington Mag (.284) Match Grade Die Set by Hornady (midsouthshooterssupply.com)

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Thanks,
Guy Miner

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