Interpreting 6.5 Creedmoor velocities with 140 gr. bullets

wildcat westerner

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Joined
Nov 14, 2009
Messages
551
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
 

Pdyson

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Joined
Nov 25, 2013
Messages
458
Location
Brownwood Texas
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

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Nov 16, 2020
Messages
1,777
Location
Fort Worth, Texas
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.
 

Salmonhead

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Mar 6, 2021
Messages
167
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Michigan
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

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Joined
Jun 12, 2022
Messages
294
Location
Southern Utah
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

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Joined
Apr 13, 2012
Messages
342
Location
Quincy IL.
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!!
 

bomberodevil

Well-Known Member
Joined
Feb 5, 2010
Messages
298
Location
Phoenix
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.
 

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