What does a .308 do that a 5.56 cannot?

[Rogue7a]

@ MistWolf: just trying to keep it simple. Personally, I avoid citing performance specifications if non fielded ammo and only stick to what is issued. Sure a 6.8 SPC or .458 SOCOM have some increased performance attributes, but where the heck are you gonna get it when you run out? Same reason I'll continue to haul along an M4 variant (or something that uses an M4 mag) so when the MK-13 runs out of ammo I can ditch it instead of hauling around a paperweight. Call me old fashioned but I still prefer a .308 precision rifle. It may not do as well as a .300 but if it runs dry I can feed it MG ammo lol

[jonconsiglio]

The trend, of late, seems to be to ignore completely those kinds of caveats.

Yeah, I kind of lost track there but I always try to answer the OP's questions according to his needs, not my own. I actually had started to post about the topic on either the phone or iPad then got interrupted. I came back on the computer and got off track.

For defensive use, I see no real advantage to the 308. It's bulkier, harder recoiling and I guess some could make the argument of over penetration, though personally that's one of the things lower on my list when comparing different defensive rounds.

I have a SCAR-L and a SCAR-H, for example. The SCAR-H having the same length barrel is still a bit bulkier. It's still a very lightweight gun for what it is, but it's thick and the lower receiver is a bit beefier in comparison which makes it more cumbersome.

There's a number of reasons I wouldn't use it as my home defense gun and the only way I see it being a better choice than 5.56 is if it's used as a patrol rifle in a rural area, but even then i'd most likely opt for a 5.56, but that's not what you asked.

[TXBob]

For the OP.
Yes in general the 308 has better ballistic coefficient And terminal ballistics. The real question is how much are they improved versus the disadvantages that you acquire when moving from 5.56 to 7.62. Now I will be speaking in general terms there will always be specific cases of comparing one specific 5.56 cartridge to a separate specific 7.62 cartridge.

7.62 advantages:
Improved terminal performance
Improved ballistic coefficients
Legally allowed for hunting

7.62 disadvantages:
Cost
Carrying capacity
Non-standard AR platforms
Increase recoil.

Also note that while the ballistic coefficients go to the 7.62 to be inherrant accuracy of the rounds is about equal As mentioned above the 5.56 has come to dominate the military shooting sports event at long range.

In my evaluation the advantages of 7.62 do not outweigh the disadvantages of 7.62 for a civilian home defense purpose. If your concerns are about terminal performance read the articles In the terminal performance section. In general the terminal performance of 7.62 is overstated and the performance of 5.56 is understated. People tend to imagine 7.62
As some wonder bullet, when it is not a huge leap in performance.

[Hootiewho]

Unless part of your home defense plan is having to take into account a 200 yard driveway alone, much less a shot across the property. Factor in that a majority of the evildo'ers in my area drive older, thicker, heavier built cars jacked up as high as a 4x4 truck. Say you run them off without a shot fired trying to gain entry to your house, They leave, then grow a set halfway down the drive & decide to come back or better yet fire on you from there to prove to the world then are not the ghetto version of chicken little, what then? I personally have more confidence in 7.62mm being able to handle that kind of situation. You have to remember, out in the country sometimes things are not just across a room or street.

I had a former Sheriff show me the aftermath of a shootout involving one of these clown cars & 5.56mm carbines. I believe the ammo was either M193 or some 55 gr soft point. None of the many rounds hitting the car made it through from the trunk past the back seat. Granted there was quite a good bit of stolen goods in the trunk. The 7.62 has a place.

For the OP.
Yes in general the 308 has better ballistic coefficient And terminal ballistics. The real question is how much are they improved versus the disadvantages that you acquire when moving from 5.56 to 7.62. Now I will be speaking in general terms there will always be specific cases of comparing one specific 5.56 cartridge to a separate specific 7.62 cartridge.

7.62 advantages:
Improved terminal performance
Improved ballistic coefficients
Legally allowed for hunting

7.62 disadvantages:
Cost
Carrying capacity
Non-standard AR platforms
Increase recoil.

Also note that while the ballistic coefficients go to the 7.62 to be in Herrick accuracy of the rounds is about equal As mentioned above the 5.56 has come to dominate the military shooting sports event at long range.

In my evaluation the advantages of 7.62 do not outweigh the disadvantages of 7.62 for a civilian home defense purpose. If your concerns are about terminal performance read the articles In the terminal performance section. In general the terminal performance of 7.62 is overstated and the performance of 5.56 is understated. People tend to imagine 7.62
As some wonder bullet, when it is not a huge leap in performance.

[TXBob]

Unless part of your home defense plan is having to take into account a 200 yard driveway alone, much less a shot across the property. Factor in that a majority of the evildo'ers in my area drive older, thicker, heavier built cars jacked up as high as a 4x4 truck. Say you run them off without a shot fired trying to gain entry to your house, They leave, then grow a set halfway down the drive & decide to come back or better yet fire on you from there to prove to the world then are not the ghetto version of chicken little, what then? I personally have more confidence in 7.62mm being able to handle that kind of situation. You have to remember, out in the country sometimes things are not just across a room or street.

I had a former Sheriff show me the aftermath of a shootout involving one of these clown cars & 5.56mm carbines. I believe the ammo was either M193 or some 55 gr soft point. None of the many rounds hitting the car made it through from the trunk past the back seat. Granted there was quite a good bit of stolen goods in the trunk. The 7.62 has a place.

Speaking of wonder bullet claims--
The 7.62 has its place, yes. But at 200 yards, its a 5.56 world. M193 is not a good barrier blind choice (you will note my comment to check the terminal performance articles here). 7.62 won't help you much at that range and that situation. 7.62 is not going to magically start whizzing through trucks and bad guys while 5.56 gets stopped by a stiff breeze.

http://www.dtic.mil/ndia/2008Intl/Roberts.pdf

Yes its about the 6.8 but addresses the very concerns discussed here. 7.62 is not a magic bullet.

[Hootiewho]

Completely agree. The guns used in that shootout were Mini14s and 55 grain ammo was about all that was available at the time.

Here's the thing, I 110% agree 5.56mm in the right spot will kill most critters in North America. I know for a fact that a well placed shot with a 22lr will kill any animal in the SE. I have plenty of 5.56mm rifles and have 110% confidence they'll do their intended job. That said there are circumstances where the 7.62 shines. Just like the 7.62x51 will work at 800 + yards, there are better tools for that kind of range. I guess I'm saying this from a rather unique perspective as I have had some quality time now on the 13" SCAR H, running drills back to back with the L and my ARs on the timer. That particular gun has swayed my opinion of the place of a 7.62x51, as it blurs the lines on some of the negatives associated with 7.62mm guns. Yes it kicks more, but to me a piston 5.56mm AR has a more sharp/jarring recoil even over the H. Yes ammo is heavier, so you would need to carry less ammo for the same weight loadout. I hope to never need to carry a combat loadout of any rifle, but I do realize others have to, and completely understand this pro/con. The gun fully loaded is nearly identical to a equally equiped 5.56mm rifle of the same length (and yes I know the 5.56 will have 10 more rounds).

I have had some shooting partners time me and the difference on common close range drills is telling, there is hardly any difference. The only thing that slows me up is not currently having a decent open top mag pouch to use for emergency reloads, but that'll change this week. If I should need a rifle, considering where I live and my home occupants, I am not the least bit concerned with overpenetration. Infact, I'd rather have more penetration out of a rifle than less. I have a private range & have shot both 5.56mm & 7.62mm through just about everything I could see as being a barrier on my place (cinder blocks, pine trees, steel, glass, mini walls of common construction materials) & as a whole the 7.62 does a better job of making quick work of those things. I'm not saying the 5.56mm doesn't do a good job, it does, but for my needs I feel more comfortable with my M4 sized 7.62mm. I didn't want to be that way back before I bought it, but after time with it, for me I have the most confidence in that gun as a do all gun for any situation I may encounter. If I lived in close proximity to anything other than cows I may feel differently.

[shootist~]

Maybe it's just me, but I'll get equal or better/faster hits on steel plates (due to fewer shots needed) at 80-100 Yds (and probably further) with a 9+ Lb 20" FAL than I will with a 6+ LB 14.5" LW AR (both supported and not). Not 100% relevant here since it's the weight and stability of the platforms and not the ammo. Different story at 10 Yds, of course.

[Hootiewho]

OK, just a simple demo. I have done this in the recent past but had to run back to the shop to get a clean piece of steel for the pics. Here's what your looking at, a 3/16 piece of AR400 plate. Behind this plate was a treated 4x4" post proped up with a 2x4. Those are not pictured, as I just snapped a pic of the plate. I shot the plate at 100 yards with my SCAR 17 CQC using Federal Mk319 130 gr SOST, and German DAG 147 gr ball. I also shot it from 100 with a 10" barrel SCAR 16 using Federal Mk318 and real deal M855. I also shot it from 100 with a Colt 6921 14.5" barrel M4, using M855 and from 25 yards with the 6921 using M855. The only thing to penetrate was the M4 with M855 at 25 yards and the Mk319 from the 13" SCAR at 100 yards. Here is the kicker. The M855 from 25 yards barely completely (I'm saying the bullet barely completely embedded into the lumber) the 4x4 post, and this was from 25 yards. The Mk319, which is fired from a shorter barrel than the M4 has, from 75 more yards away penetrated the plate, the 4x4 post, and the 2x4 holding all that up and kept on getting it. Needless to say, I am very impressed with the Mk319 in a SBR package. I imagine it is a penetrating SOB from the 16 +" barrels. It is also very effective. I have shot a hog with it last year and it worked beautifully. In reality 3/16ths isn't very thick for cover, and the 5.56mm barely dented it at 100 yards. What's it going to do with a vehicle at that distance and beyond. Not considering having to fire on hostiles, but getting rounds into critical running components to try and disable an oncoming (or outgoing) vehicle, obviously you'll have a better chance with 7.62, esp at distance. If you are concerned with over penetration, the 110 gr TAP is said to be awesome. A guy I know who is a very switched on former mil, contractor, & current LEO used the 110 gr TAP in a close in shooting and his description of the wound are spot on with what Doc Roberts says about the 110 gr TAP.



So here is a good example of something a 7.62x51mm can do that a 5.56mm can't.

[Heidevolk]

Wow, someone posted actual photographs and a test they did instead of just relaying their opinion or stories they heard and *bam* thread comes to a total hault.

[Waylander]

Wow, someone posted actual photographs and a test they did instead of just relaying their opinion or stories they heard and *bam* thread comes to a total hault.

So?
While the results are interesting and I'm not sandbagging his tests, they're not terribly shocking.
It still doesn't factor in round count availability, weapon weight, and recoil like has been discussed to death. It still gives no more credit to the lethality of the .308 other than it'll blow bigger deeper holes through shit.