308 Win vs 6.5 Creedmoor

[can1010]

played with the 200 hybrid and 208 ELD with SW precision @ 2.950 in 24" barrel.
200 hybrid 2430-2450
208 eld 2350-2375
both will win in the energy and wind drift but fall well short on recommended velocity for proper bullet function shortening the effective range quite a bit

 

[nralifer]

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

I'll give it a try as soon as we get dome decent weather

 

[nralifer]

played with the 200 hybrid and 208 ELD with SW precision @ 2.950 in 24" barrel.
200 hybrid 2430-2450
208 eld 2350-2375
both will win in the energy and wind drift but fall well short on recommended velocity for proper bullet function shortening the effective range quite a bit

Thanks for that info. Those are long bullets so loading them to 2.950 seems like it would cause impingement into the powder space. Lengthening the free bore would help I would think.

 

[xsn10s]

I'll suggest a search for "MontanaMarine, RL17 and 308". He got some pretty good velocities but I believe his bullets were moly coated. He's post on here, LRO and the Hide.

 

[Muddyboots]

I went down this road before and still will take .308 for my purposes.

 

[can1010]

Thanks for that info. Those are long bullets so loading them to 2.950 seems like it would cause impingement into the powder space. Lengthening the free bore would help I would think.

loading longer helps some but not as much as you would think. if you compare them to your 195 and 205 even loading long the gain in usable case capacity is minimal. 205EOL @ 3.000 47.1 usable, your 205 at 3.300 46.8 usable. even if you load your 195s to 3.2 the gain is less than 1.0gr. now if you try some of the high energy powders that are available you should be able to do better but i have never played with any of them, but they might make it interesting

 

[StanleyActual]

.

 

[nralifer]

loading longer helps some but not as much as you would think. if you compare them to your 195 and 205 even loading long the gain in usable case capacity is minimal. 205EOL @ 3.000 47.1 usable, your 205 at 3.300 46.8 usable. even if you load your 195s to 3.2 the gain is less than 1.0gr. now if you try some of the high energy powders that are available you should be able to do better but i have never played with any of them, but they might make it interesting

You definitely seem to be on the right track in your thinking. Here are some of my thoughts. I would be interested in your opinion on these. There are a couple of Winchester ball powders that are presumably temp stable and double base, implying higher energy. StaBall65 and StaBallHD. I have tried the SB6.5 in the 308 Win loading the 150 gr BD2 to 2.950 OAL with 54 gr which puts the powder level to half way up the neck. It compresses extraordinarily well but did not increase the speed from either a 20 or 24" barrel. From the 24" I got 2950 fps which I can get using Leverevolution (LVR) from a 20" barrel. I have taken a few shots with SB6.5 at 51.5 gr and 52 gr at 2.950" OAL using the 175 gr BD2 from the 24" barrel with no clear pressure signs. We are having winter storm winds and below 0 wind chill so I have not been able to use my radar to document speed yet. The idea was to see if I could get to 2800 fps with that bullet from the 24" barrel. SB6.5 is slower burning than LVR. Now, there are a couple of additional tricks to be used. One is to use SRP Palma 308 Win brass from Lapua which withstands higher pressure, and has a stronger primer pocket. The other is to lengthen the throat in the chamber and seat the 195 and 205 bullets out further and see if we can use 54 gr of SB6.5 safely. That would be a full 5 grains more than I use to propel the 150 gr BD2 with LVR. The goal is to get either the 205 SBD2 to 2550 fps in 24" barrels. That would put the supersonic range to 1850 yds and the 1670 fps expansion range to 850 yds at sea level altitude (SBDs because of the slightly thinner ogive SBD2s open at speeds below 1700 fps). Of course other ball powders such as Ramshot magnum, LVR and Superformance would be tried, but 54 gr or so of a ball powder is the max I think could be used in the standard 308 Win case dimensions. I will need an 8 twist barrel to do this though (stability factor for the 205 SBD2 is 1.6).

 

[sea2summit]

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

I haven't played at the top end in .260 or 6.5, the nod I went with was just above middle of the road. I'm not into the maximum size bullet at the maximum length type shooting as I shoot mostly semis so even 175s can get hard to keep within COAL restrictions for my 308. But for the 6.5 out of a 24" barrel I'd probably do 140 VLDs and expect high 2700 to low 2800 if I was maxing it out. I'm on the other side of the planet right now from all my books so I can't really pull BCs down outside of my AB app. But for most efficient I really like the 130 eldms, cheap bullets, and don't take much powder to get them cooking.

 

[Creoleboy]

Nralirer over the past 25 years I too have gone to the 308 win. Which is crazy because I started my deer hunting career with a 25-06. Really fast, really flat. Then something really strange happened when I started guiding and seeing animals get killed. You get to see first hand hundreds of animals get shot. And 99% of those shots are under 500 yds. In the guiding world I'm guessing 75% of shots were not perfect placement. But if they were shot with a 30 cal hole we were able to track and recover the animals. Not so much with the smaller calibers. 308 pros are number one for me it kills better. Ammo availability and cost, 308. Barrel life, 308. Inherit accuracy prob a tie. Brass and reloading components 308. And that is probably due to the popularity of the 6.5 but there is less on the shelves. I have a 6.5 Creed and had a PRC. Advantage for them is gonna be lighter recoil for the Creed I notice no difference from the 308 and PRC. Biggest advantage is past 600 yds. If you are going to shoot a lot of paper and steel 600 yds and beyond the 6.5 has the advantage here. Hype...6.5 definitely wins that trophy. For a nuts and bolts hunting rifle out to 600 yds from Javelina to Moose give me a 308!

I hunt in the south were shots are under 400 yards, give me the 308, have shot both and reloaded for both. I will take the old 308 every time.

 

[Creoleboy]

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

Why is your 308 at 2450 Fps , I have 3 that will do at least 2750 in 20 inch bbl.

 

[nralifer]

I haven't played at the top end in .260 or 6.5, the nod I went with was just above middle of the road. I'm not into the maximum size bullet at the maximum length type shooting as I shoot mostly semis so even 175s can get hard to keep within COAL restrictions for my 308. But for the 6.5 out of a 24" barrel I'd probably do 140 VLDs and expect high 2700 to low 2800 if I was maxing it out. I'm on the other side of the planet right now from all my books so I can't really pull BCs down outside of my AB app. But for most efficient I really like the 130 eldms, cheap bullets, and don't take much powder to get them cooking.

 

[cohunt]

I like the 308 because 220gr subs are fun and easy to load.
You have the choice of 100-220 grain bullets-- supers or subs--- short 16" barrels still work well, yet longer batrels will give you faster velocities. Easy to find .308 bullets and loads of options for brass ( i even see range pick up brass available).
A 308 seems more efficient than a 6.5cm in an sbr or pistol if that's your thing.

Ultimately they are close ( I have several 308s, and a 6.5cm too)-- my 12yo daughter likes the 6.5- I prefer the 308.

The 308 vs 6.5cm thing reminds me of the 6.8spcii vs the 6.5G thing.

In the end-- pick 1 or both-- "you do you"

 

[can1010]

You definitely seem to be on the right track in your thinking. Here are some of my thoughts. I would be interested in your opinion on these. There are a couple of Winchester ball powders that are presumably temp stable and double base, implying higher energy. StaBall65 and StaBallHD. I have tried the SB6.5 in the 308 Win loading the 150 gr BD2 to 2.950 OAL with 54 gr which puts the powder level to half way up the neck. It compresses extraordinarily well but did not increase the speed from either a 20 or 24" barrel. From the 24" I got 2950 fps which I can get using Leverevolution (LVR) from a 20" barrel. I have taken a few shots with SB6.5 at 51.5 gr and 52 gr at 2.950" OAL using the 175 gr BD2 from the 24" barrel with no clear pressure signs. We are having winter storm winds and below 0 wind chill so I have not been able to use my radar to document speed yet. The idea was to see if I could get to 2800 fps with that bullet from the 24" barrel. SB6.5 is slower burning than LVR. Now, there are a couple of additional tricks to be used. One is to use SRP Palma 308 Win brass from Lapua which withstands higher pressure, and has a stronger primer pocket. The other is to lengthen the throat in the chamber and seat the 195 and 205 bullets out further and see if we can use 54 gr of SB6.5 safely. That would be a full 5 grains more than I use to propel the 150 gr BD2 with LVR. The goal is to get either the 205 SBD2 to 2550 fps in 24" barrels. That would put the supersonic range to 1850 yds and the 1670 fps expansion range to 850 yds at sea level altitude (SBDs because of the slightly thinner ogive SBD2s open at speeds below 1700 fps). Of course other ball powders such as Ramshot magnum, LVR and Superformance would be tried, but 54 gr or so of a ball powder is the max I think could be used in the standard 308 Win case dimensions. I will need an 8 twist barrel to do this though (stability factor for the 205 SBD2 is 1.6).

i am not a fan of highly compressed loads so SB6.5 would be off the list for me until i have tested it which i have not.
powders like.
RL15
RL17
A2520 / SW match rifle
H414 / W760
should be able to get you to 2500+ without being highly compressed.
based on 3.320 with your 205 SBD2 and quickload calibrated to my gun, used .275 boattail length as a rough guess based on the original bulldozers having longer boattails and trying to keep as much usable capacity as possible.
RL-17 seems to be pretty popular in different treads, i might give it a try when i get a chance with 200 and 208s. I don't have the twist to even think about the 205s.