6.8mm Remington SPC, 6.5mm Grendel and SSK 6.5mm MPC

[Ocin]

Hey everyone,

These new cartridges mentioned above are better then the 5.56 Nato round and compatible with an AR 15 lower. Each is the best, according to its manufacturer that is. And there is just my problem: all I can find is what the manufacturars say/claim about their round and, surprise, it is THE BEST round ever made or anyone ever came up with.

I was wondering if there is anyone who has some actual experience with these cartridges though or could direct me to some independent information about those cartridges.

Many thanks.

[Bidah]

My first question is what do you want or expect them to do?  That will help to steer you towards one or the other hopefully, as they are not all the same performance.

I do not know of very many independent reviews, outside of what you may see posted on the forums.

-Bidah

[Ocin]

I have very little experience with firearms to be honest, so i do not really know what to expect. What i would like to do is to participate some combat style shooting matches.

[texcaliber]

I have very little experience with firearms to be honest, so i do not really know what to expect. What i would like to do is to participate some combat style shooting matches.

stick with the 556NATO IMHO. Save your money on the overly priced ammo which you asked about man, and spend it on a better AR.

Tex

[DDMac]

For use against no armor BGs (bad guys)  within 150 yards, do any of the newest and best rounds offer a significant enough advantage over 5.56mm to warrant a new upper? I am assuming they all run on AR platforms.
 Mac.

[Sponsor]

[Bidah]

If you are looking to do some competition, I would also suggest that you use 5.56.  While 6.8/6.5 is more expensive, it is not much more so than what 5.56 is now.  Availability however could be an issue depending on where you are.

The 6.5/6.8 are great rounds, although somewhat new, and make a pretty good hunting round as well.  If I had an AR, and did not have an investment in .308, and wanted to hunt, going to one of these would be my first choice.

-Bidah

[kilopaparomeo]

+1 to comments above.

If you are looking to play shooting games, or if you are looking for a SD round and believe your engagements are within 150 yards, 5.56 is your round.  In fact for matches, 5.56 will be cheaper and allow you to be faster because of lower recoil.

Here's my quick assessment of the 6.5 Grendel vs the 6.8 SPC debate.  Both hit harder than a 5.56 at all ranges.  Out to 300-400 yards or so, there is very little difference between 6.8 and 6.5...although 6.5 will be just slightly flatter in trajectory.  Beyond 400-500 yards, 6.5 G will take over with more retained velocity and flatter trajectory.  6.8 SPC will have the theoretical edge in reliability because of the slightly more tapered case...probably only will notice that in full auto. 

So, if you want something for short range and/or games -- 5.56
If you want a harder hitting round in an M4/intermediate range set up -- 6.8 SPC
If you want a harder hitting round that will carry out further with 20-24" barrel -- 6.5 Grendel

That said, I just set up a 24" Overwatch upper on a PRS-stocked lower for my DMR rifle -- in 6.5G

[Pathfinder]

stick with the 556NATO IMHO. Save your money on the overly priced ammo which you asked about man, and spend it on a better AR.

Tex

Tex -

This one comment caused me to stop and rethink what I was doing. My intent was to build up a 6.8SPC for the harder hitting power of that cartridge. Then I started looking into what the components are running, and I would end up with an $1800-2000 carbine when I was done - not buying bottom of the line stuff, but a KO upper is $550, Stags et al are more. One thing I like about the 6.8 uppers is that they seem to be piston driven instead of the buffer tube.

So now I am looking at a 7.62x51 (.308) upper. They seem cheaper, and I have brass etc. for reloading. Prices I was seeing for 6.8 cartridges were working out to $1 each, similar to 7.62x51, but I do have some battle packs of the .308.

Decisions, decisions !!!   

[DDMac]

Pathfinder, I have asked before elsewhere, but never heard back; how does one put a .308 upper on an AR lower as several people plan, unless they have an AR-10? Mag wells aren't compatable, right? Mac.

[Bidah]

Not to drag this too far..

Overall, the magwell for the .308 is not the issue so much.  The way that the lowers and uppers are cut, are.  The AR-10 uses one style of cut, and the DPMS uses another.  They also use different magazines.  So, the lowers are not cross compatible with the uppers.

Most, if not all of the 6.8/6.5 uppers are compatible with regular AR-15 lowers.

-Bidah