6 vs 6.5 Creedmoor opinions wanted

[lancetkenyon]

How hard you stepping on the 25cm for that speed? I tested rl26, and it was the only thing capable of running above 2930 without significant case expansion. Believe 3080 was psi signs from a 26in barrel. I know all barrels are different, brass and chamber all makes a difference.

The 6cm runs a mild load with 112mb, which has a 308g7, 2950-3000 very easily. Similar dope as your 25, and the prc referenced, with even less recoil. I run the 112 from an 18in barrel with 44.5gr rl26 at 2950. Case webs after firing are 47025 from 46975 sized. I ran up to 46.2gr over 3040 before bolt lift, ejector marks.

Not at all.
I have two 25CMs and a 6CM.

25CM Hunter
26" 1:7" Bartlein 400MODBB CF
Alpha 25CM SRP
CCI BR4
42.6gr H4350
133 Elite
2975fps


25CM target
26" 1:7.5" Brux
Lapua 6CM SRP necked up to .257
Fed GM205M
42.4gr H4350
135 LRHT
2986fps


6CM
24" 1:7.5" Proof CF
Lapua 6.5CM SRP necked down to 6mm (long before 6CM brass was available)
Fed GM205M
42.0gr H4350
105 Hyb
3188fps

 

[Justice1327]

Which bullet? What powder and charge? If it is easy, why is most of the factory ammo running 2700 to 2850?

My wifes 6.5CM is 2980/123gr/[email protected]

 

[Justice1327]

Meanwhile, I'm over here shooting the .308 win and not a care in the world about barrel life. I dropped a cow elk with it at 600 yards last week so the distance thing is fine….for me. With a suppressor, recoil is manageable.

If I had to choose between the two you mentioned…6.5 CM.

Brand new M24 .308 here.
My last true model 700,M24 went just over 6000 rounds before it started shooting over over one MOA. just got the new barrel spun on shoots great using M118

 

[WA Coyote]

Not at all.
I have two 25CMs and a 6CM.

25CM Hunter
26" 1:7" Bartlein 400MODBB CF
Alpha 25CM SRP
CCI BR4
42.6gr H4350
133 Elite
2975fps


25CM target
26" 1:7.5" Brux
Lapua 6CM SRP necked up to .257
Fed GM205M
42.4gr H4350
135 LRHT
2986fps


6CM
24" 1:7.5" Proof CF
Lapua 6.5CM SRP necked down to 6mm (long before 6CM brass was available)
Fed GM205M
42.0gr H4350
105 Hyb
3188fps

133 at 3k is mighty impressive. I'm thinking that's got to be in the 70k psi range though. That SRP brass sure helps hide pressure.

 

[RB II]

For wind, BC wins out rather quickly.

Lets take the 6.5cm and 2 rather common bullets. The 120 Nosler BT at 3000fps and the 142ALBR at 2700fps. Those MV are pulled from nosler's load data.
10mph crosswind. At 75 yards, the 142 ABLR is already doing better in wind drift than the 120BT. It's only .1", but it only grows from there. By 500 yards it's 18.5 and 15.1".

Pretty sure I did mention that BC matters at long ranges didn't I? 3" at 500 yds is hardly enough to even discuss considering wind drift is almost impossible to discern at that distance. 1 mph up/down would change that as much at 500 yds.

I am a hunter, not a long range target shooter so to me 3" wind drift at 500 yds means basically zero.

 

[WA Coyote]

I am a hunter, not a long range target shooter so to me 3" wind drift at 500 yds means basically zero.

1. You DO realize this is a Long Range Hunting forum?

2. If 20% means basically zero, I'd be happy to accept a check for 20% of your annual income…. I bet that's not "basically zero".