6.5 barrel burners

[Bart B.]

Do they have equal throat length? I've seen reports of 270wby mags shooting at some ridiculous speeds, faster then a 270-300WM and in large part due to throat.

SAAMI spec freebore (sometimes called throat) length, no rifling forward of chamber mouth:
.264W, zero
6.5CM, .199 inch

Some chambers are different.

 

[270WinDude]

SAAMI spec freebore (no rifling forward of chamber mouth):
.264W, zero
6.5CM, .199 inch

Some chambers are different.

Dang. Didn't expect that.

 

[6MMsteve]

.264 Win Mag doesn't burn barrels any faster than anything else. My buddies and I have never had one go less than 4000 rounds before they open up. With 300 fps speeds faster than a 6.5 CM with the same powder and bullets, it's a no brainer.

do you bump shoulders or do you have dies that size the case wall, at the datum

 

[Timinator]

Wilson FS sizing die and Wilson hand press seating die. However, it will shoot one hole at 200 with Hornady Custom 140 grain Interlock boxed ammo too but not the Remington 140 gr.

 

[Bart B.]

However, it will shoot one hole at 200 with Hornady Custom 140 grain Interlock boxed ammo too

One hole is .528" at 200 yards.

All the time regardless of number of shots fired and at the round count over 3000?

 

[seymour fish]

That's just not true. Same amount or the same powder and same bullet is faster by as much as 300fps in a .264 vs. CM. Try it. No math needed.

Here we go ! When given enough rope. Further explanation will require Gris-Gris, black cat bone, invocation of majic. Popcorn at the ready

 

[Bart B.]

With a custom barrel and the same amount of powder using the same bullet a .264 is up to 300ft faster than a 6.5 CM across the board.

Show us a table proving that and we will believe you.

It defies the laws of physics as the rest of us know it. Besides, if it was true, then a 30-06 powder charge shooting 180's 2700 fps should shoot the same bullet 3000 fps from a 300 Win Mag.

 

[Timinator]

Now I've defied the laws of physics too? Get a grip, now you're talking about 300 Win Mag's and 30-06's for examples? A .264 doesn't burn up barrels like was originally posted. I posted several articles to support that. Same bullets go faster with max charges in .264's vs CM, I posted that too. Same charge, same bullet, all I can say is there are sweet spots in ballistics and cartridge combinations and a .264 Win Mag with today's bullets is one of them. With the same bullet you get more everything with a .264 Win Mag vs. a 6.5 CreedMoore. But again, I don't ding gongs or shoot paper.

 

[270WinDude]

Now I've defied the laws of physics too? Get a grip, now you're talking about 300 Win Mag's and 30-06's for examples? A .264 doesn't burn up barrels like was originally posted. I posted several articles to support that. Same bullets go faster with max charges in .264's vs CM, I posted that too. Same charge, same bullet, all I can say is there are sweet spots in ballistics and cartridge combinations and a .264 Win Mag with today's bullets is one of them. With the same bullet you get more everything with a .264 Win Mag vs. a 6.5 CreedMoore. But again, I don't ding gongs or shoot paper.

I hear your point. However in my nerd brain i hear an efficient burn rate and a pressure argument wrapped into 1 with possibly now accuracy and bullets being plugged in. After dumping 57.5 grains of powder enough times to get the velocity I want I sure wish my 270win was more efficient like a 308. I think that to continue, if so desired, you’d have to narrow the argument to one of those factors at a time. Don’t get me wrong though, my 270win can certainly be used as a 22lr and a 338l and perform better ballistically then all of em’ ... just trust me on that though.

 

[Evan]

With a custom barrel and the same amount of powder using the same bullet a .264 is up to 300ft faster than a 6.5 CM across the board.

Was this a typo? Cause 41gns of RL17 in a 264 is a dangerously low powder charge and it wouldn't be safe or consistent, but that same charge shoots great in my creedmoor. I wouldn't recommend trying any powder charge for a Creedmoor in a 264.

 

[#40Fan]

That's just not true. Same amount or the same powder and same bullet is faster by as much as 300fps in a .264 vs. CM. Try it. No math needed.

According to Nosler reloading data, the 6.5 Creedmoor will drive a 140-grain .264-inch bullet at 2,672 fps when using a max load of W760 powder. The .264 Win. Mag., using the same bullet and 54.5 grains of the same powder (also a max load), achieves a muzzle velocity of 2,942 fps. The 6.5 Creedmoor is averaging just under 66 fps per grain of powder while the .264 Win. Mag. is making just under 54 fps with a grain of powder. The .264 Win. Mag. load requires 25 percent more powder to achieve a nine percent increase in velocity over the Creedmoor, and the .264 Win. Mag. requires a longer, heavier barrel to do so.

How about that math?

Looks like the .264 WM would need 49.4 grains of W760 to hit the same speed with the same bullet as the 6.5 Creedmoor does with 40.4.

40.4 in the WM would be 2181 fps.