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Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ?

Posted By: 6.5BR

Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/08/18 02:26 AM

Curious as the 7 is a bigger round, and larger bore to burn powder in the carbine length.

Considering 140s for each....I'm guessing the 7 has about a 200 fps mv edge. Anyone have solid #'s?

Anyone know how far out the 6.5 catches up?
Posted By: J.G.

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/08/18 02:41 AM

Can't help you on 140's in the 7mm.

162's out of a 20" + suppressor are 2640 fps.

140's out of a 20" 6.5 Creedmoor should be in the neighborhood of 2700 fps.

Look at powder capacity for each. That should help.
Posted By: ImTheReasonDovesMourn

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/08/18 03:07 AM

My 20" Bartlein 6.5 Creedmoor gets 2690 with 143s before I get pressure signs. Jason is getting more velocity with a heavier bullet in his 7mm-08 AI.
Posted By: J.G.

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/08/18 03:08 AM

That number is not the A.I. it is the standard 7mm-08. The A.I. rifle is 17" and making the same speed as the standard 7mm-08 at 20".
Posted By: Crews

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/08/18 10:55 AM

Originally Posted By: FiremanJG
That number is not the A.I. it is the standard 7mm-08. The A.I. rifle is 17" and making the same speed as the standard 7mm-08 at 20".


Damn!

My 6.5C has a 21” barrel + suppressor, so numbers will be inflated a tad bit: factory 120 ELD-M was 2910fps, and factory 140 ELD-M is 2686fps.

Even with the hundreds of fps loss in MV, the 140’s do a bit better in the wind and don’t take long to outrun the 120’s. Just goes to show you, worrying about a hundred FPS here or there probably isn’t worth the time you’ll spend on it, as long as you’re using the highest BC pills and getting something you’ll practice with.
Posted By: 6.5BR

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/09/18 01:57 AM

Thanks for the posts/info guys.

I'm not a speed freak, but I like 2700 as a floor on the bottom end, with a decent BC bullet. 2500 and below seems to be lacking for reach IMHO. Many variables. Seems a 20-21" 6.5CM is quite capable. No doubt I'd run a 162 for a top choice LR load in the 7, but for hunting feel a 140-150 will do about all I need, which is why I was looking at the 140s in each, no doubt they are not equal in BC.

Would it be fair to suggest the two rounds are very close when comparing factory 140 offerings in a short tube?

I do handload, but less and less as the years go by, and ammo quality goes up.

Guessing both will be within 1-2" of drop/drift out to say 400 yds in carbine length barrels - 20-21"
Posted By: ZenArchery

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/09/18 03:05 AM

Buddies daughter runs 139gr out of 7.08 getting 2975 FPS out of 22” barrel.
She tagged a cow elk last year at 300 yards. DRT.
Posted By: Brother in-law

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/09/18 03:15 AM

Originally Posted By: ImTheReasonDovesMourn
My 20" Bartlein 6.5 Creedmoor gets 2690 with 143s before I get pressure signs. Jason is getting more velocity with a heavier bullet in his 7mm-08 AI.


Gonna need that recipe
Posted By: ckat

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/09/18 03:43 AM

2735 FPS out of my 20" Model 7 7mm-08. 140gr SGK.

I have no numbers on 20" 6.5CM...
Posted By: 6.5BR

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/09/18 03:17 PM

Thanks folks. I have run several 7/08s in the past, 2 were chopped 21" 700s, another a 20" M70 carbine. The 700s did 2900-2960 with 139/140s, the M70 did 2850 with 139.

Do you guys who shoot customs, notice any significant difference in MV all else equal in custom barrels? I know chamber specs and bore dimensions, finish, and consistency will matter.

I would guess the 6.5 CM hunters are overall happy with their performance even in short tubes.
Posted By: J.G.

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/09/18 03:27 PM

Originally Posted By: 6.5BR
Would it be fair to suggest the two rounds are very close when comparing factory 140 offerings in a short tube?


I expect a noticeable margin in speed increase, in the 7mm. It has a shorter bearing surface than the 6.5mm does.
Posted By: Smokey Bear

Re: Anyone compare #'s on 7/08 vs 6.5 Creedmoor in a 20" ? - 05/10/18 10:47 PM

Originally Posted By: FiremanJG
Originally Posted By: 6.5BR
Would it be fair to suggest the two rounds are very close when comparing factory 140 offerings in a short tube?


I expect a noticeable margin in speed increase, in the 7mm. It has a shorter bearing surface than the 6.5mm does.


Yup. Less bearing surface In combination with the larger 7mm base that has almost 14% more area to be pushed on by equal psi should add up to higher MV.
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