SIGforum.com    Main Page  Hop To Forum Categories  Mason's Rifle Room    Long Range cal. 308,6.5cm,7/08

Moderators: Chris Orndorff, LDD
Go
New
Find
Notify
Tools
Reply
  
Long Range cal. 308,6.5cm,7/08 Login/Join 
Like a party
in your pants
Picture of armored
posted
My Son has a Daniel Defense Delta 5 bolt action rifle. He got the rifle with a 308 barrel assembly. The 308 was picked because its versatile and ammo is available.
The rifle features interchangeable barrel assemblies. Daniel Defense offers 308, 7/08, and 6.5cm assemblies.
He has a 150yard range at home and a 600 yard range available at my gun club. I doubt he would have much opportunity to shoot farther than 600 yards.
At these distances I'm sure the 308 will work just fine, but if he did want another barrel assemble to shoot farther, what would be the suggestion between the 7mm/08 and the 6.5cm?
 
Posts: 3942 | Location: Chicago, IL, USA: | Registered: November 17, 2002Reply With QuoteReport This Post
Freethinker
Picture of sigfreund
posted Hide Post
I don’t know much about the ballistics of the 7mm-08 Remington, but I have always viewed it more as a hunting cartridge rather than one well suited for long range target work. A quick look at what’s listed at the AmmoSeek site seems to bear that out. There are any number of loads that are obviously intended for hunting, but none that I spotted that are in the same category as Hornady’s ELD Match loads for the 6.5 Creedmoor or several other manufacturers’ target offerings.

There’s nothing wrong, of course, with shooting hunting ammunition at targets (except, maybe, the monolithic bullet loads and steel targets), but they’re usually not going to give the same level of precision as top manufacturers’ “match” ammunition. There is also a common belief that some cartridges are “inherently” more precise across the board of loads and bullets than others, and the 6.5 seems to enjoy that reputation. The cartridge certainly performs extremely well from my rifle that it’s chambered for.

(I could research and go into a detailed discussion of the bullets suitable for loading in the 7mm-08 and how they would do for long range shooting, but I’ll leave that for one of our more technically-minded members. Wink )




“The fundamental cause of trouble in the world today is that the stupid are cocksure while the intelligent are full of doubt.”
— Bertrand Russell
 
Posts: 44830 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
Member
posted Hide Post
quote:
Originally posted by armored:
At these distances I'm sure the 308 will work just fine, but if he did want another barrel assemble to shoot farther, what would be the suggestion between the 7mm/08 and the 6.5cm?

For target shooting, at all distances the 6.5 Creedmoor beats the 308. Flatter flight, less wind drift, lower recoil, increased distance before the bullet goes trans-sonic.

7mm-08 is a respectable hunting chambering. It has possibilities for target work, but it just hasn't caught on. Commercial ammo is pretty much geared to hunting bullets. Issues that probably don't make 7mm-08 optimal for target shooting:
- The twist rates of factory barrels may be too slow to capitalize on the great and heavier 7mm target bullets.
- The case may not be optimal for heavier bullets. Think how the 6.5CM case is shorter than the 308 case.
- Steel-match target shooters jumped on 6.5mm bullets over .308 bullets fairly quickly. Then they moved on to 6mm bullets. Going to 7mm bullets is a step backwards. Some competitors are now looking at .257 bore cartridges.

I've never seen a steel-match competitor using a 7mm-08 chambering. A few years ago there was a guy in my squad with a 7SAW rifle. He shot pretty well. I wouldn't choose the 7SAW over my 6.5CM, however.

Go with a 6.5 Creedmoor. Also consider 6 Creedmoor, if it becomes an option.
 
Posts: 7144 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
Like a party
in your pants
Picture of armored
posted Hide Post
The 6cm is available in the new Delta 5 pro with a 26" barrel but not the older Delta 5 at this time.
At the distances he will be shooting there is not enough difference to warrant buying a 6.5cm barrel. If DD offers the 6cm in the older version rifle that would probably warrant a barrel purchase.
 
Posts: 3942 | Location: Chicago, IL, USA: | Registered: November 17, 2002Reply With QuoteReport This Post
Member
posted Hide Post
quote:
Originally posted by armored:
At the distances he will be shooting there is not enough difference to warrant buying a 6.5cm barrel. If DD offers the 6cm in the older version rifle that would probably warrant a barrel purchase.

600 yard drop and wind drift figures for my rifles at 6000' Density Altitude. More drop and drift at lower elevations, but the figures should remain relatively comparable. Wind at 10 mph, from 9 or 3 o'clock.

308 with 175 FGMM -- 14.7 MOA drop, 4.0 MOA drift
6.5CM with Hornady 140 ELD -- 11.6 MOA drop, 2.8 MOA drift
6CM with Hornady 108 ELD -- 9.8 MOA drop, 2.8 MOA drift

Both Creedmoors have significantly flatter flight than 308, with the 6 having an advantage over the 6.5. If one shoots at known distances and has good elevation dope, bullet drop figures aren't a huge challenge. Of course, with a scope that has good elevation dialing/holding capabilities.

Wind drift is a different story -- both the Creedmoors have 30% less wind drift than a 308. If one always shoots in dead calm conditions, then wind drift isn't a big deal. In my neck of the woods, a 10mph wind day amounts to favorable shooting conditions. Not only do I experience higher wind speeds, but substantial variations is wind speed from one moment to the next. Let's say you have a 17" wide target at 600 yards -- just an inch narrower than a full-sized IPSC target. If one can judge wind conditions within 10 miles per hour, the shooter can hit that target with either of the Creedmoors. To hit that 17" wide target with the 308, one must guess wind within 7 miles per hour.

This 3 mph wind difference may not seem like much at first blush, but it means a whole lot in the field. This and recoil management is why 308 cannot compete with 6mm and 6.5mm chamberings in target sports.
 
Posts: 7144 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
Like a party
in your pants
Picture of armored
posted Hide Post
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Thanks for the info.
I sent DD a email asking when a 6cm might be available for the Delta 5, that difference from the 308 could justify a new barrel assembly.
 
Posts: 3942 | Location: Chicago, IL, USA: | Registered: November 17, 2002Reply With QuoteReport This Post
Like a party
in your pants
Picture of armored
posted Hide Post
Proof Research makes a 6cm, carbon fiber barrel that is a drop in for the Daniel Defense Delta 5.
What are your thoughts on a carbon fiber barrel and Proof Research?
 
Posts: 3942 | Location: Chicago, IL, USA: | Registered: November 17, 2002Reply With QuoteReport This Post
Member
posted Hide Post
I have a Proof Research carbon wrapped barrel in 223. Great barrel, and I discussed it the following link. See the bottom of page 135 and near the top of page 136. It's easily a 1/2 MOA barrel, with multiple types of factory ammo. I have enough faith in this barrel that I bought a second carbon one, for when I shoot out my first Proof.

Long range thread -- 223 Defiance / Proof

My local gunsmith worked at Mile High Shooting for some time before going on his own. Evidently, quite a few Proof Barrels were installed on rifles there, and thus they had feedback from customers. Both full steel and carbon wrapped barrels were very accurate for bolt actions. AR15 barrels were good for full steel, but hit and miss for carbon wrapped.

I assume you understand 6 Creedmoor is hard on throat barrels. If you really demand great accuracy, a 6CM barrel will almost certainly be toast before you make it to 2k rounds. If you don't intend to put a bunch of rounds down range, then this isn't a concern.
 
Posts: 7144 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
Get my pies
outta the oven!

Picture of PASig
posted Hide Post
I know the 7mm-08 is a pretty flat shooting round, don’t know if that helps with your decision.


 
Posts: 29084 | Location: Pennsylvania | Registered: November 12, 2007Reply With QuoteReport This Post
Member
posted Hide Post
quote:
Originally posted by PASig:
I know the 7mm-08 is a pretty flat shooting round

The drop & drift numbers I used for .308 FGMM 175 are my own results with a muzzle velocity of 2620 fps. There is no comparable factory ammo in 7mm-08. However, using a 7mm 168 grain SMK bullet, we have a reasonable start. With a possible muzzle velocity of 2675 fps, elevation & drift:
13.1 MOA drop, 3.1 MOA drift
Better than 308 FGMM, but not in the league of 6.5CM and 6CM. Wind drift has improved.

7mm-08 with a better bullet, Hornady 162 ELD, possible MV of 2710 fps:
12.5 MOA drop, 2.9 MOA drift
Wind drift is now equal to that of the Creedmoors, but the Creedmoors are still flatter shooting. And from what I see on factory 7-08 loads, the MVs I'm estimating are likely notably faster than factory loads.
 
Posts: 7144 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
Biochemical
Superfreak
Picture of M4Super90
posted Hide Post
quote:
Originally posted by armored:
Proof Research makes a 6cm, carbon fiber barrel that is a drop in for the Daniel Defense Delta 5.
What are your thoughts on a carbon fiber barrel and Proof Research?


I just had a plain jane Rem 700 action rebarreled with a Proof wrapped CF barrel in 6.5 CM, and I've had a very positive experience with it. When testing the barrel initially, this is how it shot:






115 + 115 = 230
 
Posts: 3660 | Registered: April 29, 2000Reply With QuoteReport This Post
Member
posted Hide Post
quote:
Originally posted by armored:
Proof Research makes a 6cm, carbon fiber barrel that is a drop in for the Daniel Defense Delta 5.
What are your thoughts on a carbon fiber barrel and Proof Research?


I have a proof carbon barrel in 30-06. I have really enjoyed carrying it. It has shot great, too. I was getting pretty good groups on Day 1 with the rifle using Black Hills 180gr TSX. No complaints.
 
Posts: 214 | Location: Rocky Mountains | Registered: January 03, 2013Reply With QuoteReport This Post
Member
posted Hide Post
Do you reload?
 
Posts: 1093 | Location: DFW Metromess | Registered: May 20, 2011Reply With QuoteReport This Post
Like a party
in your pants
Picture of armored
posted Hide Post
quote:
Originally posted by Ox190:
Do you reload?


Yes
 
Posts: 3942 | Location: Chicago, IL, USA: | Registered: November 17, 2002Reply With QuoteReport This Post
Member
Picture of SigNutP225
posted Hide Post
It is my understanding that after 500 yards the terminal ballistics for the 6.5 Creedmoor and the .308 Winchester (with comparable bullet weights) are pretty much the same.

It's a great caliber. I have both and have shot both in long range precision matches. I hope that helps.
 
Posts: 736 | Registered: February 26, 2008Reply With QuoteReport This Post
Member
posted Hide Post
quote:
Originally posted by armored:
quote:
Originally posted by Ox190:
Do you reload?


Yes


I'd seriously look at the 7mm-08 paired with 162gr ELDX bullets. with the 1/9 twist rate on that barrel and handloads it would make a great long range gun.
 
Posts: 1093 | Location: DFW Metromess | Registered: May 20, 2011Reply With QuoteReport This Post
  Powered by Social Strata  
 

SIGforum.com    Main Page  Hop To Forum Categories  Mason's Rifle Room    Long Range cal. 308,6.5cm,7/08

© SIGforum 2022