6.8 vs 6.5Grendel vs 5.56mm NOW


December 22, 2007, 02:12 PM
***Groan**** Why did I have to go and do this?:what:

Well, I have avoided posting this topic for a while now as I am no fan of dead horse abuse. To be frank I was quite happy when I realized this type of thread title wasn't at the top of every rifle/ammo board I visit.
However, I am currious what the CURRENT breakdown is looking like. Facts? Opinions? Experience?
I have performed many internet searches over the past couple of days and it appears most of the info out there is two-four years old at this point. A novel-length 6.8 thread spanning three years has a lot of info, but unless someone is regularly editing it it is rather confusing, and in some parts outright conflicting. For instance, are they getting the 115gr SMK 6.8mm up to 2600fps in the 16 inch barrel? I read a claim of that, but the Remington site say 2625fps out of a 24 inch barrel?
Read some interesting 6.5 Grendel stats is a magazine article a couple of years ago, but can't seem to find them online though I did find a mention that some early "projections" were done at 62,000psi in a bolt gun.....not
sub-50,000psi in an AR. However, even this comment was almost two years old.
It seems a lot of people are holding on to old "projected" info, from old articles that in some cases predate the cartridge release!

Did either one of these new 6mm rounds really deliver?

My motivation for asking is that I have decided to build the Lo-Pro DPMS upper I have had kicking around for the last couple of years and am considering something outside the 5.56 envelope. I hate tp follow the herd so I will probably do something moderately handy with a solid stock and 18 inch barrel.

Please, lets keep the info and links to sources within the last 12 months.


I remember reading about the 6.5mm MPC case a year or so ago. I thought that had a bit of merit for the short to intermidate range engagement. Seems to have disappeared though.

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December 22, 2007, 05:31 PM
Mods, should I have placed this in another forum?

Evil Monkey
December 22, 2007, 06:23 PM
Nah, it's definitely in the right place.

If you're worried about not getting any responses, it's just probably since there have been many topics about these calibers and such. As with many of these threads, they eventually turn into 223 vs 308 wars.

Not only has the horse been beat to a pulp, it's been shot, stabbed, mutilated, burned, bombed, and I believe one member chopped the head off and took it home.

December 22, 2007, 06:37 PM
There is a forum just for the 6.5 and Alexander Arms has a lot of info about it also.

Josh Aston
December 22, 2007, 06:52 PM
5.56 is still very much alive. The others, well I hear about them from time to time.

December 22, 2007, 07:27 PM
6.8 and 6.5 are both have limited powder capacity especially where long bullets have to be seated deeply into the case so the cartridge will fit within the magazine. They are further limited by the short-barrel rifle fad which reduces muzzle velocity. If you really want performance with a bullet larger than a 22, get an AR-10 or LR308.

December 22, 2007, 07:28 PM

Exactly. The 5.56 is still very much alive. What of the others? All smoke and no fire? Not able to deliver the much hyped performance? Simply not worth it? (Time, Money, Tooling)

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