Interpreting 6.5 Creedmoor velocities with 140 gr. bullets

[wildcat westerner]

Hello,
Thanks to a brazen theft of wildcat 6.5 ammo at a range, I know that the thief now has ammo no other rifle in New Mexico is chambered for. ( 6.5 IHMSA).
Sooo, that IHMSA barrel is being rechambered for 6.5 Creedmoor with only a 1/4" setback, as we speak.

I am noting velocities for 140 grain bullets are substantially (2-300 fps) higher than I got with the IHMSA cartridge, which is the .308 cut off 1/8" with a 40 degree shoulder. My new barrel length will be 25 1/4" and in looking at comparable velocities and talking with other experienced shooters, 2,800 fps seems possible, a full 300 feet per second than what I was used to, with this Krieger barreled rifle.
I note contributors to this website stating higher velocities also mention long throated chambers.
If long throated chambers help with velocities of equally accurate loadings at higher velocities, would it not be equivilant to consider seating those very long 140 grain bullets deeper to achieve perhaps the same result? Velocity is fine, but any time the groups start to enlarge, that is a path I will not be taking. Long, long ago I discovered "Hot" cartridges 6PPC and 6BR, were most accurate at really high velocities and pressures.The BR, less so. I feel the Creedmoor, with tough Lapua brass is a cartridge from that same limb on the ammo tree.

WW

 

[Dmagna]

I have reached 3000fps with 140 Bergers and RL 26 out of a creed. 28 inch barrel helped but I still got 2900 out of my 26 inch pretty easy.

 

[lancetkenyon]

I am more of an H4350 guy and 2750-2820 in a 24" is about the sweet spot. 26" should see 2800-2850+ pretty easily. Lapua SRP brass should last nearly forever at those pressures.

 

[Pdyson]

I’m working up a load for my new 18” 6.5 Creed and I was amazed to reach 2900fps and single digit SDs in Lapua brass with 49.2gr of RL-26 and the 135 Berger classic hunter ignited with CCI450s. I thought my V3 chronograph was lying…it was not. i reached 2950 w/ 8.7SD at the Berger book Max 49.8gr However groups opened up a lot. Still I saw zero pressure signs.

 

[QuietTexan]

I run my 26" barrel at 2750 FPS with H4350. I have pushed it up to 2950 but I pulled back for accuracy and better load stability/ wider nodes. And the end of the day it's a mid-sized 6.5mm, 2600-2900 FPS is about where it's going to run in most typical set ups.

Seating deeper in the 6.5 CM case is going to eat up significant case capacity, this isn't a RUM/WM where you gain capacity by seating longer than SAAMI - it was designed to seat long with heavy for caliber bullets (at least at the time) so you're really only losing against the benchmarks for the cartridge by seating shorter.

 

[dok7mm]

The easiest way to get over 3,000 fps is to use 120 gr pill.

 

[Varmint Hunter]

I've run 47.0 RE26 under various 134-140gr bullets and get 2,800+ in a 26 bbl. I could probably go a bit higher in the Lapua SRP brass but accuracy is good and I'd rather not push it further.

 

[Salmonhead]

my 26" Savage model 12 target gun easily gets 2900 from 130s, and 2800-2850 for 140s. im finding the loads on that rifle are often too hot for other rifles, but that rifle has no issues with them.

 

[Harry Knutz]

You probably could have reached the same velocities out of your 6.5 IHMSA if it was throated the same as the Creedmoor. More available case capacity means you can use more powder until you reach pressure. It seems like according to your description of the IHMSA they should have similar case capacities until you seat a bullet.

 

[mdmiller]

Well, hears my load for 140!

140 VLD​

Berger​

42 @ IMR 4350​

2783​

0.04​

3.137/2.810​

0.250 group/100yds ​

140 VLD​

Berger​

41.5 @RL17​

2848​

0.04​

3.137/2.810​

0.250​

Not supper fast but accurate!!

 

[mdmiller]

OOOPS 28" barrel

 

[bomberodevil]

Hello,
Thanks to a brazen theft of wildcat 6.5 ammo at a range, I know that the thief now has ammo no other rifle in New Mexico is chambered for. ( 6.5 IHMSA).
Sooo, that IHMSA barrel is being rechambered for 6.5 Creedmoor with only a 1/4" setback, as we speak.

I am noting velocities for 140 grain bullets are substantially (2-300 fps) higher than I got with the IHMSA cartridge, which is the .308 cut off 1/8" with a 40 degree shoulder. My new barrel length will be 25 1/4" and in looking at comparable velocities and talking with other experienced shooters, 2,800 fps seems possible, a full 300 feet per second than what I was used to, with this Krieger barreled rifle.
I note contributors to this website stating higher velocities also mention long throated chambers.
If long throated chambers help with velocities of equally accurate loadings at higher velocities, would it not be equivilant to consider seating those very long 140 grain bullets deeper to achieve perhaps the same result? Velocity is fine, but any time the groups start to enlarge, that is a path I will not be taking. Long, long ago I discovered "Hot" cartridges 6PPC and 6BR, were most accurate at really high velocities and pressures.The BR, less so. I feel the Creedmoor, with tough Lapua brass is a cartridge from that same limb on the ammo tree.

WW

I’m sorry some low life P*S decided he (or she) was entitled to your ammo that you invested a large amount of time and money developing. It would be tragic (dripping with sarcasm) if he were to lose a finger or two trying to fire the ammo in the wrong chambered rifle.

Good luck with the new rifle.

 

[skipglo]

I am more of an H4350 guy and 2750-2820 in a 24" is about the sweet spot. 26" should see 2800-2850+ pretty easily. Lapua SRP brass should last nearly forever at those pressures.

This is very accurate!

 

[73driver]

24" Brux, 142 Sierra, Lapua LR and H4350 load shy of max is 2759fps and good accuracy.