Testing (2) Different AR15s in 6.8mmSPC
In the May issue of "GUN TESTS" Magazine, on pg.6 they are discussing the AR15 platform and they state that "...the 6.8 SPC round pushes the performance envelope for the AR15." They also state "..the available data shows the differences between chamber specs. are minimal, so compatibility should not be a problem."
My question is: Will the the 6.8x43mm SPC round chamber and safely fire in an AR15 chambered in 5.56x45mm NATO? I've asked this of several but no answer as yet.
redvegas4
My question is: Will the the 6.8x43mm SPC round chamber and safely fire in an AR15 chambered in 5.56x45mm NATO? I've asked this of several but no answer as yet.
redvegas4
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NO!...and I repeat...NO!...absolutely not. THe 6.8 SPC has a 0.277" diameter bullet, and the 5.56x45mm NATO shoots a 0.224" bullet. That 0.277" bullet will not pass thru that smaller bullet without exploding it, or something it is attached to.
It is a larger case, any way, and will not chamber.
Best0 -
you're going to have a hard time pushing a bullet with a diameter of .277 through a bbl that is designed for a bullet of diameter .224[:0]
When they say the "chamber spec differences are minimal" they must be referring to case pressure because the 6.8 and 5.56 case dimensions are pretty different.0 -
[ They also state "..the available data shows the differences between chamber specs. are minimal, so compatibility should not be a problem."]
First, no this round can not be used in a 5.56x45.
I think the "minimal differences in chamber specs" is referring to the numerous variations of the 5.56x45/.223 Rem/.223 Wylde chambering(s){there are numerous other variations}.
The current 6.8 SPC II is slightly modified from the original 6.8 SPC.0 -
redvegas4. The simple answer is no. 0 -
Redvegas4, anybody that cannot answer your question INSTANTLY should not be considered as a source of information. 0 -
Just like 8mm Mauser cartridges have been fired out of 30-06 rifles.
you get the same effect: KABOOM!!!0 -
redvegas4,
The wording as you have selected it seems to be out of context as it could be interpreted a couple of different ways. But since your question is directly related to the two cartridges here is a photograph comparing the size of both together:
6.8 SPC (left) 5.56x45 NATO (right)
As stated above so many times, no you cannot chamber the 6.8 SPC in a rifle chambered for the 5.56x45 or .223 Remington. The 6.8 cartridge is too large to fit in either of those chambers.
Best.0 -
I tried.
The round stripped off the mag okay but would
not chamber it,even with repeated use of the
forward assist.Then I saw the red stripe
on the magazine....OOPs!0 -
Thanks for the pics nononsense. And, as noted no. Fortunately, that is not even possible.
However, if you are talking strictly 6.8's there is a difference in the 6.8 SPC and 6.8 SPC II chamberings.
The 6.8 SPC II has more freebore to allow a max pressure cartridge ignite without causing an over pressure. Much like the (real McCoy) 5.56 NATO has freebore, where the .223 Rem does not. On the outside the two cartridges are dimensionally the same. Inside, the 5.56 has more pressure in it's loading.
The freebore alleviates what could be an overpressure situation.
To your original question. Use 6.8 SPC only in 6.8 SPC chambers. 6.8 or -II will run in II chambers.0 -
quote:Originally posted by redvegas4
My question is: Will the the 6.8x43mm SPC round chamber and safely fire in an AR15 chambered in 5.56x45mm NATO? I've asked this of several but no answer as yet.
redvegas4
Your question is a little ambiguous.
To be clear, if you want to fire the 6.8spc round the most simple and for most individuals practical thing to do is to switch UPPERS on their conventional .223/5.56 rifle. IE, you take off the .556 upper and put on a dedicated 6.8 upper you're good to go.
Yes, it is possible to rebarrel a 5.56 gun into 6.8, but as above, most individuals (without tools or inclination to do minor gunsmithing at home) will find swapping uppers to be more practical.
To answer the question AS WRITTEN, as already mentioned above multiple times. . .
Trying to fire a 6.8 round through a 5.56 rifle (upper)? No. . .please don't do that!
Don't think it will chamber. . .in practice, you'll probably just jam your 5.56 gun with the 6.8mm cartridge and have to manually clear it. . .most likely without any real damage or injury, other than to your pride.
That said, its not entirely unheard of for people to somehow manage to "slam" larger cartridges/bullets into smaller chambers. It really "shouldn't" happen, but we've all heard stories of this sort of thing happening.
If you did get a 6.8 round to chamber in a .556 gun, firing would most definitely NOT be "safe".
Doesn't necessarily mean the gun would instantly blow up. . .but that's certainly a distinct (and the most likely) possibility.
As above, its also not entirely unheard of for shooters to manage to fire oversized rounds through undersized bores without blowing up the gun, or even causing major damage, but again you don't want to try this!
In short, 6.8 is its "own thing". If you own a conventional 5.56 AR you don't necessarily need an entirely new gun to fire this round, but you will need a new upper. New upper, by the way, isn't really a "firearm", so you can buy one "over the counter" without background check, if you're so inclined.0
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