7mm-08 vs 308 is a comparison between a parent and its offspring. The 7mm-08 Remington is the 308 Winchester case necked down to hold a .284-inch bullet, so it shares the 308’s case head, bolt face and action length. The 7mm-08 fires lighter, sleeker bullets a little faster with less recoil; the 308 fires heavier bullets with more energy at short range. Chattahoochee Munitions manufactures both on its CM10 large-frame semi-automatic platform.
7mm-08 vs 308 Specifications
| Specification | 7mm-08 Remington | 308 Winchester |
|---|---|---|
| Introduced | 1980, Remington | 1952, Winchester |
| Bullet diameter | .284 inch | .308 inch |
| Case length | 2.035 inches | 2.015 inches |
| Maximum overall length | 2.800 inches | 2.810 inches |
| Maximum average pressure (SAAMI) | 61,000 psi | 62,000 psi |
| Typical hunting bullets | 120 to 150 gr | 150 to 180 gr |
| CM10 barrel and twist | 18-inch 416R, 1:9 | 12.5, 16 and 18-inch, 1:10 (CM10-SD 1:5) |
Dimensions follow the ANSI/SAAMI centerfire rifle standard.
7mm-08 vs 308 Ballistics
This comparison uses two Hornady hunting loads of the same construction: the 7mm-08 150 gr ELD-X (published 2,770 fps, G7 BC 0.289) and the 308 178 gr ELD-X (published 2,600 fps, G7 BC 0.278), both from 24-inch test barrels. Downrange figures and the 18-inch rows are Chattahoochee Munitions calculations (200-yard zero, standard atmosphere, 10 mph crosswind; 18-inch velocity estimated at 30 fps per inch below 24 inches), not chronograph data.
| Range | 7mm-08 150 gr, 24-inch | 308 178 gr, 24-inch | 7mm-08 150 gr, 18-inch | 308 178 gr, 18-inch |
|---|---|---|---|---|
| Muzzle | 2,770 fps / 2,555 ft-lb | 2,600 fps / 2,672 ft-lb | 2,590 fps / 2,234 ft-lb | 2,420 fps / 2,314 ft-lb |
| 300 yd | 2,306 fps / 1,770 ft-lb, -7.6 in | 2,136 fps / 1,803 ft-lb, -8.8 in | 2,144 fps / 1,530 ft-lb, -8.8 in | 1,975 fps / 1,542 ft-lb, -10.4 in |
| 500 yd | 2,023 fps / 1,363 ft-lb, -43.3 in | 1,855 fps / 1,360 ft-lb, -50.6 in | 1,872 fps / 1,168 ft-lb, -50.3 in | 1,705 fps / 1,149 ft-lb, -59.4 in |
| Wind drift at 500 yd | 16.3 in | 18.8 in | 18.0 in | 20.9 in |
The 308 starts with more energy and holds that edge to about 300 yards. By 500 yards the two carry about the same energy, while the 7mm-08 has dropped about 7 inches less and drifted about 2.5 inches less. The 7mm-08 does it with a lighter bullet and less recoil.
7mm-08 vs 308 Recoil
Recoil grows with bullet weight and powder charge. With 150 gr bullets against 178 gr bullets, the 7mm-08 produces noticeably less recoil than the 308 from the same rifle weight. In a CM10 at 7 lb 14 oz before optics, with an adjustable gas block and adjustable buffer, both are comfortable, but the 7mm-08 makes follow-up shots and long sessions easier.
7mm-08 vs 308 for Hunting
- Deer, pronghorn and hogs: both are well suited with an expanding hunting bullet.
- Elk: both have taken elk with heavy, well-constructed bullets at moderate range. For more bullet weight, look at 338 Federal.
- Bear: Chattahoochee Munitions does not recommend either for bear. Choose 375 Raptor or 458 SOCOM XL.
7mm-08 vs 308 Ammunition and Subsonic Use
The 308 has the larger selection of factory ammunition, including military surplus and match loads. The 7mm-08 has a solid range of hunting loads but fewer match and bulk options. Neither CM10 here is a subsonic rifle, with one exception: the 308 subsonic AR10 (CM10-SD) is a dedicated subsonic-only 308 with a 1:5 twist. The CM10 7mm-08 is set up for supersonic ammunition and a flow-through suppressor rated for 7mm.
7mm-08 vs 308 in the CM10
Both use the CM10’s billet 7075-T6 receivers, rifle-length gas on the 18-inch barrels, a Superlative Arms adjustable gas block, an adjustable buffer and 5/8×24 muzzle threads. The 7mm-08 comes in 18 inches with a 1:9 twist in Black Tungsten, Cobalt Kinetics Green or FDE Metallic Cerakote. The 308 comes in 12.5, 16 and 18 inches; see District 308. Read more in What is 7mm-08 and What is 308 Winchester.
More Variant Valley Guides
- What is 6.5 Creedmoor?
- 6.5 Creedmoor ballistics
- 6.5 Creedmoor barrel length
- 6.5 Creedmoor twist rate
- 6.5 Creedmoor for hunting
- 7mm-08 vs 6.5 Creedmoor
- What is 7mm-08?
- What is 338 Federal?
- 338 Federal vs 308
- 338 Federal vs 8.6 Blackout
- What is 358 Winchester?
- 338 Federal vs 358 Winchester vs 7mm-08
- 308 Winchester cartridge family
- 308 vs 6.5 Creedmoor
- 6mm ARC vs 6.5 Creedmoor
- 6.5 Grendel vs 6.5 Creedmoor
7mm-08 vs 308 FAQ
Is 7mm-08 just a necked-down 308?
Yes. The 7mm-08 Remington is the 308 Winchester case necked down to .284 inch, which is where the “08” in its name comes from.
Which shoots flatter, 7mm-08 or 308?
With the Hornady 150 gr and 178 gr ELD-X loads, the 7mm-08 drops about 7 inches less at 500 yards in our calculations.
Which has less recoil, 7mm-08 or 308?
The 7mm-08, because it fires a lighter bullet with a similar powder charge.
Can I fire 308 in a 7mm-08 rifle?
No. Never fire a cartridge in a rifle not chambered for it. The two share a bolt face but not a chamber or bore.
Who makes a 7mm-08 AR10?
Chattahoochee Munitions manufactures the CM10 7mm-08 AR10 with an 18-inch 416R stainless 1:9 barrel, rifle-length gas and an adjustable gas block.