6.5-284 vs 6.5 wsm barrel length

[PersiMan]

Good afternoon, Team. I am once again infected with the 6.5 calibre bug. I am thinking about rebarreling a Kimber 84L to 6.5-284, vs an 8400wsm to 6.5wsm. Of course the wsm is faster. But if I set the barrel length at 24", I don't understand how the larger case is an advantage. Seems like a larger volume case needs a larger volume (longer barrel) to burn the powder. How much velocity difference would there be in equal barrels, and why?
For the Kimber product line, the 84L weighs 1/2 pound less than the 8400wsm. That's important to me as well.

 

[7.62 Gunner]

That's a common misconception, the powder is fully burned in something like the first 10" I don't remember the exact length but it's short.
A case with more capacity will be faster than a smaller case at any length.
I have a 16" 6.5 saum and it's sending 144 bergers at 2925, faster than a creedmoor with a 28" barrel.
I'd build the 6.5 wsm if velocity is your main goal, the 6.5x284 will be plenty fast at 24" as well

 

[Coyote Shadow Tracker]

I really like a 6.5X284, but using for a target rifle. I also love the WSM cartridges. We have 325WSM and 270WSM (in a Kimber Montana). If you are using for hunting I would go with the 6.5WSM in the Kimber. You can shoot heavier bullets faster. Make sure you get the right Twist Rate.

 

[Greyfox]

I think it comes down to your desire or requirement tor maximum velocity. I have had no issues with my 24" 6.5x284's achieving 3100 FPS with the 130's, 3000FPS with the 140-143's, and 2950-3000FPS with the 147-156's. Top quality Lapua brass is readily available and it's no fuss to load or achieve great accuracy, You will use about 15% percent less powder, and, likely see a 50% increase in barrel/brass life. But if you want to boost the velocity (perhaps)another +100FPS…I'd go for the larger WSM case. IMO…

 

[Outlaw6.0]

I have to admit, I am a velocity junkie. Always have been. I went 6.5WSM and have zero regrets. It's a hunting rig so a barrel will last quite a while, even though I've always regarded them as consumable anyway. I've run the 130 Cutting edge over 3400 & am now running the 160 Matrix.



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[R. Cram]

I just put a x-caliber barrel on my rpr that I use for high power and left it as long as possible, about 27 inches and shot it in a prone match at 600 yds and it shot a 200 17x with 42 gr 4350 about 010 off the lands and a mk140 the next match it also shot a 200 17x with 42 gr 414 so I was very happy with the accuracy, the best scores I have shot. The bullet according to the electronic scoring machine was traveling at 1925 fps at 600 yds. The next match I shot another rpr I use for hunting and I had rechambered the 6.5 creedmoor to 6.5x284 but the barrel is only 24 inches using 52 gr h4831 and a 140 the machine recorded avg velocities of 1950 at 600, almost the same as the 260 with the longer barrel. Very dissapointing to have a barrel burner like a 6.5x284 not doing any better than a 260 probably due to barrel length . I'm making a 6.5x284 on a m54 winchester right now and will have 28 inches of barrel and if I didn't tell any one who carried it they probably would not know the difference between that and 24 inches

 

[308win]

I'm not sure if this is helpful or not....but I'm running a 6.5WSM 135 Berger CH out of a 26" with N565 (very gentle load) @ 3215fps. Easy on brass and very comfortable to shoot. Do your own math on velocity loss from a 24" and compare. I have no experience with a 6.5x284. Just wanted to give you some real world numbers for reference

 

[cdherman]

I have a 6.5x284 that is perhaps my most accurate gun. I suspect the reason partly is the ease of getting quality brass (Lapua). I'd really research the brass making process and let it be part of this decision. Also easier to reload for, more data etc. BUT, you are the boss!!