6.5 Grendel vs 300 Blackout for hogs: reach against simplicity

Why the products on this page are scopes

This is a cartridge comparison, not a product comparison. Amazon doesn't sell ammunition or rifles, and we don't link either. The optic is the product we can link, so the two picks above are thermal scopes. Because the Grendel's case is longer shots, we chose two with built-in rangefinders and ballistic calculators: one between $1,000 and $2,000, one above $2,000. We haven't tested these units; scores come from published specs and the rubric on our How We Choose page.

The cartridge facts come from SAAMI (the U.S. ammunition industry's standards body), Texas A&M AgriLife, a national feral-pig shooting standard and named hunting writers. For the wider question of which cartridges suit hogs, see our guide to the best caliber for hogs.

6.5 Grendel vs 300 Blackout at a glance

Every SAAMI figure above comes from the Z299.4-2025 centerfire rifle standard. Its velocities are test-barrel reference values; SAAMI says there should be no expectation of duplicating them in firearms, and that barrel length adds to the difference. Check the maker's published velocity for the load and barrel length you actually use.

Energy at the muzzle and downrange

At the muzzle, the gap is real. SAAMI's 123 grain Grendel load at 2,580 fps works out to about 1,818 ft-lb (bullet weight in grains × velocity², divided by 450,240). The 300 Blackout's supersonic reference loads from 90 to 150 grains work out to roughly 1,175 to 1,420 ft-lb by the same math, and 125 grains at 2,185 fps lands at about 1,325. American Hunter's Jeff Johnston cites about 1,450 ft-lb for a full-power Blackout load (2018). Across those figures, the Grendel starts with roughly 25 to 55% more energy.

Downrange, the difference grows, because the two were built for different jobs. Philip Massaro (American Hunter, 2024) describes the Grendel as one of the first cartridges to rely on ballistic coefficient rather than muzzle velocity for long-range performance. His example: a 123 grain hunting load zeroed at 200 yards drops 9.1 inches at 300 yards and still carries just under 1,200 ft-lb there. He calls it fully capable on deer inside 300 yards, while noting most game is taken inside 200.

The Blackout was never meant for that. Massaro (2017) notes that a Blackout hunting load zeroed at 200 yards has to sit about five inches high at 100, and suggests a 100 yard zero with deer shots kept to about 100 or 125 yards. RCBS claims supersonic Blackout loads with controlled-expansion bullets are effective on hogs inside 200 yards (maker's claim).

Australia's national standard for ground shooting feral pigs, NATSOP-PIG003, gives a useful frame. Its recommended minimum is .243 inch caliber, an 80 grain bullet and 1,819 ft-lb of muzzle energy. By our math the Grendel's 123 grain reference load sits essentially on that energy line with a bigger, heavier bullet; the Blackout's supersonic loads sit below it. That standard is Australian animal-welfare guidance, not U.S. or Texas law, and Texas A&M AgriLife's own advice is simply to use a rifle you'd use for other large game (AgriLife).

What each asks of your AR

This is where the Blackout wins. RCBS says it was developed so an AR-15 needs only a barrel change, with no bolt or magazine swap, and SAAMI lists the same .378 inch case head as the .223 Remington. If you already own an AR, a Blackout barrel or upper is the whole job.

The Grendel asks more. Its case head measures 0.441 inches, "requiring a different bolt face than the standard AR-15 provides," Massaro writes. Its 2.26 inch overall length matches the .223, so the same length magazine and magazine well can be used. In practice that means a Grendel upper with its own bolt, and magazines chosen for the cartridge; ask the rifle maker which ones it specifies. Massaro also notes the Grendel is chambered in bolt-action rifles, not only ARs.

Suppressed and subsonic use

RCBS says 300 Blackout was built from the ground up with suppressor use in mind, and SAAMI lists subsonic reference loads for it (190 grains at 1,040 fps and 220 grains at 1,020 fps, about 456 and 508 ft-lb by our math). SAAMI lists no subsonic load for the Grendel. If quiet matters most to you, that is the Blackout's ground.

Just don't confuse quiet with enough. Johnston calls subsonic loads marginal for big game "for all but the closest, perfectly placed shots," and argues a suppressed full-power load does everything a subsonic one can, better. Massaro adds that 220 grain bullets move too slowly to expand reliably. Suppressors are legal for taking wildlife in Texas, but all federal, state and local laws still apply (TPWD); for the federal side, go to the ATF National Firearms Act Division.

What longer reach doesn't change

A cartridge that can reach farther doesn't make farther shots a good idea. The sources are consistent:

• Closest practicable range. NATSOP-PIG003 says the objective is to fire at the closest range practicable to reduce the risk of wounding, and its acceptable examples, including the .308 Winchester, top out at 200 meters.
• Prove your accuracy first. The same standard expects shooters to put three shots inside 7.5 cm (about 3 inches) at 100 meters from a bench rest, and to judge distance and wind. A rest matters in the field too; see our picks for shooting sticks and tripods.
• Know what's beyond. TPWD's shooting safety rules: know what is in front of and behind your target, have a safe backstop, never shoot at animals on ridges or hilltops, and know how far bullets travel. A longer shot means a longer stretch of ground to be sure of.
• Placement still decides it. AgriLife warns that a boar's shoulder shield can let a pig survive poorly placed shots, and the Australian standard prefers side-on chest shots on boars for the same reason.

Optics for the longer shot

If you choose the Grendel for reach, the optic has to keep up: you need to identify the hog, see its surroundings and know the distance. Both picks carry a built-in laser rangefinder and ballistic calculator, publish a 6000 J recoil rating and a five-year warranty.

A worked example from those specs. Each sensor pixel covers an angle of pixel pitch divided by focal length. Both scopes pair 12 µm pixels with a 35 mm lens, so each pixel covers about 0.34 milliradians: roughly 1.2 inches at 100 yards, 2.5 inches at 200 and 3.7 inches at 300. Per pixel, the detail is the same. The difference is how many pixels: the RIX's 640x512 sensor spreads that same detail across a wider view. ATN publishes 7.53° x 5.65° for the ThOR 6 Elite, which the same math reproduces. RIX's page doesn't list a field of view for the S6R, but the math gives about 12.5° x 10.0°, and oneleaf.ai publishes 12.5° x 10.1° for its own 640x512, 12 µm, 35 mm scope (oneleaf.ai), which suggests the figure is sound. That wider view matters when a sounder spreads out, and the 2x base helps when hogs come close after all.

The rangefinder earns its place with the Grendel's trajectory: with a 200 yard zero, Massaro's 123 grain example drops 9.1 inches at 300. A ranged, calculated hold is the difference between a clean shot and a guess.

Choose the ATN ThOR 6 Elite LRF 384 if

• Your budget is $1,000 to $2,000 and you want a rangefinder and ballistic calculator built in.
• You want the longer battery of the two (about 9 hours from two 18650s, one of them replaceable).
• You value a published IP67 rating and a published NETD of ≤15 mK.

Choose the RIX Storm S6R 640 if

• You want the wider view of a 640x512 sensor at a 2x base, for hogs that range from close to far.
• You're fine carrying spare 18650s: RIX states about 4 hours each.
• You accept that RIX's S6R page publishes no IP rating.

For more choices in the middle tier, see the best thermal scopes under $2,000, and for what sensor resolution buys, our 256 vs 384 vs 640 guide. Before any night hunt, check the Texas night-hunting rules.

Which one for your hogs

If your hogs come to a feeder at close range and you want quiet, the 300 Blackout is the simpler, cheaper step from an AR you already own, as long as you respect its distance limits and keep its ammunition apart from any .223 or 5.56. If your hogs cross open ground, the 6.5 Grendel gives you more energy at the muzzle and much more left at distance, at the cost of a dedicated upper and bolt. If your question is really 300 Blackout against the rifle you already have, read 300 Blackout vs 5.56.

Whichever you choose, remember what shooting is for in hog control: finishing what trapping starts. The full plan lives in our hog control hub.