308 vs 6.5 creedmoor

[usmc1974]

I guess I need a little help here. I am not understanding how 6.5 is way better then 308 Same temp, alt and humidity same zero. Hodgdon reloading tables Hornady ballistic calculator

Ballistics Results - 308 SMK 175 BC .545
Muzzle 2752 2943 -1.5 0 0 0 0 0
100 2595 2617 0 0 0 0 0 0
200 2444 2320 -3.7 1.8 0.5 0 0 0
300 2297 2050 -13.2 4.2 1.2 0 0 0
400 2155 1805 -29.3 7 2 0 0 0
500 2019 1584 -52.9 10.1 2.9 0 0 0
600 1888 1385 -85.1 13.5 3.9 0 0 0
700 1762 1207 -127 17.3 5 0 0 0
800 1643 1050 -180.1 21.5 6.3 0 0 0
900 1532 911 -246.1 26.1 7.6 0 0 0
1000 1427 791 -327 31.2 9.1 0 0 0
1100 1332 689 -425 36.9 10.7 0 0 0
1200 1246 603 -542.7 43.2 12.6 0 0 0
1300 1172 534 -682.7 50.1 14.6 0 0 0
1400 1111 479 -848.2 57.8 16.8 0 0 0
1500 1060 437 -1042 66.3 19.3 0 0 0
--------------------------------------------------------------------------------------------------------------------

Ballistics Results - 6.5 SMK 140 BC .535
Muzzle 2736 2327 -1.5 0 0 0 0 0
100 2577 2064 0 0 0 0 0 0
200 2423 1825 -3.7 1.8 0.5 0 0 0
300 2275 1608 -13.4 4.3 1.2 0 0 0
400 2131 1412 -29.8 7.1 2.1 0 0 0
500 1993 1235 -53.9 10.3 3 0 0 0
600 1861 1076 -86.7 13.8 4 0 0 0
700 1734 935 -129.6 17.7 5.1 0 0 0
800 1615 811 -184.1 22 6.4 0 0 0
900 1503 702 -252 26.7 7.8 0 0 0
1000 1399 608 -335.2 32 9.3 0 0 0
1100 1304 529 -436.4 37.9 11 0 0 0
1200 1221 463 -557.9 44.4 12.9 0 0 0
1300 1150 411 -702.8 51.6 15 0 0 0
1400 1091 370 -874.1 59.6 17.3 0 0 0
1500 1043 338 -1074.7 68.4 19.9 0 0 0

Edited May 9, 2016 by usmc1974

[gixxerjunky]

For one I think your MV is low on the 6.5 and I know my 1k dope is exactly 8 mils up from my zero. I know that's not really helpful but when you shoot next to .308 you see how different they are. The wind doesn't affect the 6.5 near as much as the .308. (That's why I was called a cheater at the rifle class I took) I was getting hits at 800 long before anyone else was with the .308. The 6.5's were the first ones getting hits out to 1k.

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[usmc1974]

the first number is the FPS the second is the energy 308 muz 2752 muz energy 2934 ect... 6.5 muz FPS 2736 Muz energy 2327 ect...

Edited May 9, 2016 by usmc1974

[DWFAN]

2736 is too low for the creed. 2800-2850 is easy to get to.

[TonytheTiger]

Sierra lists the 175 SMK as having a .505 BC at 2800 fps or higher. I just googled some factory 175-178 308 loads, none of them are listed much over 2600 fps out of a 24" barrel.

[usmc1974]

Sierra lists the 175 SMK as having a .505 BC at 2800 fps or higher. I just googled some factory 175-178 308 loads, none of them are listed much over 2600 fps out of a 24" barrel.

Sorry listed wrong letters.7775 .308 dia. 175 gr. Tipped MatchKing (TMK) .308 175 .264 .545 @ 2400 fps and above. This is coming out of my Savage McMillan at about 2712.

[TonytheTiger]

That makes more sense. For what it's worth, I know a few guys shooting both 260 and Creedmoor out of bolt guns. They are shooting Berger VLD's and similar bullets with around .6 BC at well over 2850 fps. They all used to shoot 308 but say they will never go back.

[gixxerjunky]

The rifle class I attended had a guy shooting a 260. He was next to me and kept calling out my dope for me. They were almost identical.

If you want barrel life and shoot under 1k majority of the time go with .308. If you want the cool factor and the new kid on the block go 6.5. Your barrel life and pocketbook will suffer.

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[BrianATL]

If your dope was the same you are not shooting far enough or he was shooting some sluggish loads

[gixxerjunky]

It wasn't exact but we were shooting at 1k. He is a PRS competitor but I have no idea what loads he was shooting. Being his rifle probably cost 6k plus before optics and he had multiple custom builds I assumed he knew what he was doing. Hell he could have been adjusting it in his head.

He had a .260, 6mm creedmoor, and a 6.5x47.

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[Stlhead]

magic

[usmc1974]

The rifle class I attended had a guy shooting a 260. He was next to me and kept calling out my dope for me. They were almost identical.

If you want barrel life and shoot under 1k majority of the time go with .308. If you want the cool factor and the new kid on the block go 6.5. Your barrel life and pocketbook will suffer.

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does a 6.5 cm have a short barrel life?

[gixxerjunky]

Compared to .308? Yes. I personally know a guy that has 25k through a custom built .308 and it's still well under MOA. A 6.5 CM won't last until 4K. Most guys are changing barrels at 2500-3000.

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[Rob01]

25,000 round on a .308? Have heard of around 10,000 but that's much more than I have ever heard of. Mine have never lasted anywhere near that.

If you push the 6.5 Creedmoor to get the most out of it you will get about 2500-3000. If you shoot a lighter load you will be in the 4000+ round range. Yes it's less but you have a much better round ballistically. A 6.5mm bullet with a .610 BC going 2850fps versus a .308 .530BC bullet going 2700fps is no competition. There's a reason most competitors are shooting a 6mm or 6.5mm bullet in competitions.

If the guy with the .260 was calling your wind then he was probably adjusting or just giving you .308 wind calls for the wind speeds he was seeing. You will not get a .308 performing like a 6.5 in the wind.

[Stlhead]

Unless it was magic.

[davsco]

assuming we're talking precision shooting and not hunting applications (where bullet diameter and energy would be more applicable), the BC is the meaningful difference between the two. assuming known distances, easy to dial for your drops. wind is the big unknown and a higher BC bullet gives you more cushion in your wind calls. i will say that splash from a .308 175g is easier to see than for a 140g 6.5.

[Stlhead]

Not just BC. Velocity and recoil also matter. Higher BC, Faster, and with less recoil, but at the expense of shorter barrel life.

[Snopczynski]

in my AR10 with 130gn Berger AR Hybrids on Varget I am shooting 6.5 at 2,796 fps.

Wind calls with a 6.5 are half of what a .308 is because of the amazing shape of that thing.

[jeff1383]

2736 is too low for the creed. 2800-2850 is easy to get to.

I'm getting 2922 from a 26" tube with 130 Hybrids and Zero signs of pressure

[DocMedic]

Not just BC. Velocity and recoil also matter. Higher BC, Faster, and with less recoil, but at the expense of shorter barrel life.

[ccoker]

Having both, I would say the 6.5 is just easier to shoot long range..

Having said that, I will always have at least one 308

[RecoilJunkie]

the 308 is classic... the 6.5 is higher BC and faster. Your goal is to find a mix of the highest BC and fastest bullet you can send downrange. if you're shooting unknown range you want faster, whereas on a known distance range you can use the higher BC, slower, heavier bullets.

[usmc1974]

Prices are starting to come down, I saw one of the new improved 6.5 models go for 1275 on Gun broker. I may have one by December, you know Christmas..

[logiztix]

I'm not getting more than 2792 FPS out of any factory loads with mine. It is a 20" barrel in an LR-308 platform and all I've run so far is factory ammo. (I was wanting to see what it was capable of before selecting an appropriate scope for it and going full Type-A on it.)

2792 FPS - Hornady 129gr SST Superformance

2738 FPS - Hornady 120gr A-MAX Match

2603 FPS - Hornady 143gr ELD-X Precision Hunter

2574 FPS - Hornady 140gr ELD Match

2572 FPS - Winchester 140gr Match

The Hornady Superformance is loaded short and has nearly 0.200" of jump. It produces the worst groups and doesn't give me the warm fuzzies to run due to some other behaviors. The Precision Hunter is also loaded surprisingly short and had the second worst groups.

I realize it is largely the 20" barrel that has my velocities lower than much of that posted here, but I assume most of you guys are loading your own to achieve your listed velocities and running 24"+ barrels?

Also worth noting, two of those Hornady loads are within 0.010" of SAAMI spec at the throat and won't even chamber in some Savage rifles without marking the bullet. There is much griping in the cloud suggesting that Hornady shorten their loads, but it rather seems Savage needs a new chamber reamer.

As for the debate at hand, I wouldn't have had a 6.5 Creedmoor on the radar had I not made a 1600 yard shot in a 3-Gun bonus stage with a borrowed one. I hit the 800 & 900 on the clock with my 26" barreled Remington 700 in .308, but it didn't have the gas (or optic) for the 1600 bonus stage. In a variable 10-15 MPH wind I used my 1000 yard .308 wind correction for the borrowed 6.5 at 1600 yards and connected. That was the proverbial (take my) money shot.

[usmc1974]

A 1600 yard shot in 3 gun? Holy dog shit I never even heard of such a critter. Never went past 600 yards in a 3g match. WOW!!! We only go to 1400 in LRP round here.

Edited May 30, 2016 by usmc1974