308 Win vs 6.5 Creedmoor

[Steves1911]

I think the 308 is more versatile with the ability to load from 110gr varmint bullets to 220gr subsonic and everything in between. I honestly can't tell a diffrence in recoil between a 140gr 6.5creed and a 168gr 308 from similarly weighted rifles and on game performance is basically a tie. I wouldn't use either cartridge to hunt deer size game past 500yds but I'm sure plenty of people do successfully

 

[sea2summit]

so what are the loads you are comparing?

Here's my .260, 130 ELDMs, 2800fps and .308, 168 SMKs, 2450. At 500m the are close, but by the time you hit 600m…not so much. My daughter shoots the 130s out to 1300 yd pretty consistently but I'm pretty sure they go transonic before this targets, the 308 is pretty well done with these loads at about 800m, farthest I can recall shooting them was 770m at a propane tank and they were doing okay.

 

[Raudy707]

That's grandma with a walker velocity for the 308. I shoot the 168 eld-m out of my 20" Rem 700 at 2660 fps. At least give the 308 a little more respect. 2450 you can probably do with a 185 Berger Hybrid. Make the playing a little more even. Never gonna keep up with the 260, but it will fair a lot better.

 

[brcfo_outdoors]

Last time this got discussed I think we basically found that trajectory wise to intermediate ranges they are about the same. Its once you start out past 500 or so that the flatter trajectory of the 6.5 begins to shine. .308 will have more kinetic energy because of bigger and heavier bullets. When comparing light for caliber and heavy for caliber factory loads the 6.5 had a 10-15% lower recoil than .308. Ultimately critters and medium ethical ranges won't be able to tell the difference with good shot placement. I personally wouldn't use 6.5CM (120gr lead free here in CA) for much bigger than a pig or mule deer.

 

[sea2summit]

That's grandma with a walker velocity for the 308. I shoot the 168 eld-m out of my 20" Rem 700 at 2660 fps. At least give the 308 a little more respect. 2450 you can probably do with a 185 Berger Hybrid. Make the playing a little more even. Never gonna keep up with the 260, but it will fair a lot better.

16" semi, it's the meat stick.

 

[Raudy707]

16" semi, it's the meat stick.

Oh that's a cool one!! My brother in law has one of those. 300-400 yd meat stick for sure. Here in California I wouldn't shoot a mono much passed that. We're shooting 150 Hammers but I should switch him over to the 124's.

 

[nralifer]

Here's my .260, 130 ELDMs, 2800fps and .308, 168 SMKs, 2450. At 500m the are close, but by the time you hit 600m…not so much. My daughter shoots the 130s out to 1300 yd pretty consistently but I'm pretty sure they go transonic before this targets, the 308 is pretty well done with these loads at about 800m, farthest I can recall shooting them was 770m at a propane tank and they were doing okay.
View attachment 419588View attachment 419589

The difference is simply a BC problem. The G7BC of the Berger 0.288 and that of the SMK is about 0.240 which is going 350 fps slower to start with. The result is predictable. Try recalculating with the 308 shooting a 175 gr BD2 bullet at 2750 fps whose G7 BC is 0.310. At standard conditions the 308 shooting the heavier bullet has more energy at virtually any distance, is passing the 130 gr bullet at 500 yds with 460 ft# more energy, and at 1000 yards has 395 ft# more energy. Wind drift at 1000 yds still favors the 308 Win.

 

[sea2summit]

The difference is simply a BC problem. The G7BC of the Berger 0.288 and that of the SMK is about 0.240 which is going 350 fps slower to start with. The result is predictable. Try recalculating with the 308 shooting a 175 gr BD2 bullet at 2750 fps whose G7 BC is 0.310. At standard conditions the 308 shooting the heavier bullet has more energy at virtually any distance, is passing the 130 gr bullet at 500 yds with 460 ft# more energy, and at 1000 yards has 395 ft# more energy. Wind drift at 1000 yds still favors the 308 Win.

The most efficient 6.5 bullet will ballistically outperform the most efficient .30 bullet (fired from a 308 case)…change my mind.

But, as I said, for the OPs question I prefer .308.

 

[nralifer]

The most efficient 6.5 bullet will ballistically outperform the most efficient .30 bullet (fired from a 308 case)…change my mind.

But, as I said, for the OPs question I prefer .308.

So what grain and BC do you consider the most efficient 6.5 bullet and how fast could you launch it from a 6.5 Creed case say from a 24" barrel? Agree on the ops

 

[Creedmoor shooter]

So what grain and BC do you consider the most efficient 6.5 bullet and how fast could you launch it from a 6.5 Creed case say from a 24" barrel? Agree on the ops

Just for comparison. If you look at your 6.5mm 135 sb2, you'd need your 205 to get a higher bc than that 135. 6.5 creed will also shoot that 135 faster than a 308 can shoot the lower bc 175 or 195 sb2 id imagine.

Inside 500 yards it don't matter. Flip a coin.

 

[nralifer]

Just for comparison. If you look at your 6.5mm 135 sb2, you'd need your 205 to get a higher bc than that 135. 6.5 creed will also shoot that 135 faster than a 308 can shoot the lower bc 175 or 195 sb2 id imagine.

Inside 500 yards it don't matter. Flip a coin.

 

[nralifer]

I like your thinking. I wonder how fast I could shoot the 205 from the 308 but my 24" barrel is only a 9 twist. Perhaps it could work well enough to get a muzzle velocity but I would not give you 2 cents for the accuracy due to the twist. That 135 gr bullet would be outstanding from a 6.5 PRC or a Weatherby. The 205 really was designed with the 300 Norma, WM or PRC in mind. There are ways that we could improve the 308Win throat to get more speed and use a 3.2" action to use the 205 though. We are looking in it.

 

[can1010]

why do we have to handicap the 308 with 200gr bullets? BC is just clicks on your scope, if you run the numbers for bullets in the same weight class the extra 150-200fps of the 308 easily makes up for the loss in BC. making both almost identical out to 700yds which is where both fall below 1000ft. lbs. which is my personal choice for energy.

 

[Creedmoor shooter]

I like your thinking. I wonder how fast I could shoot the 205 from the 308 but my 24" barrel is only a 9 twist. Perhaps it could work well enough to get a muzzle velocity but I would not give you 2 cents for the accuracy due to the twist. That 135 gr bullet would be outstanding from a 6.5 PRC or a Weatherby. The 205 really was designed with the 300 Norma, WM or PRC in mind. There are ways that we could improve the 308Win throat to get more speed and use a 3.2" action to use the 205 though. We are looking in it.

Id be interested to see how fast a 308 can push that 205.