6.8 SPC AR question

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Jul 11, 2007
Is a 6.8 SPC upper receiver compatible with a 5.56 lower receiver as long as I use a 6.8 magazine or will I need to buy a complete 6.8 rifle?
Another question:

Would a regular AR 15 bayonet fit a 6.8 upper with a mid length gas system or is the barrel profile too thick?
I wanted one but the price of 6.8 is just to much. If its for just target shooting and not for shooting people then its not worth it. Get a 9mm AR. Cheaper than all hell to shoot.
Darthbauer, I was just about to leap to the 6.8mm SPC's defense and say that it's considered a Major caliber by IPSC ... but it's not. (The 6.8mm loads I saw had power factors between 299 and 322; you need 340 to make Major.) The same goes for 300 Fireball and every other AR-15 caliber I've seen except 458 SOCOM (but I don't have data for 6.5mm Grendel or that new .50-caliber thingamajig).

Sounds like you're right ... until prices come down 6.8mm sounds like an expensive lark. Kind of makes me wish there was a nice medium category for IPSC rifles, but I'm kind of nitpicker! (I suppose 6.8 has hunting potential, but I don't know anything about hunting.)
even the new bushmaster .450 upper and barrel will fit on any mil-spec lower.

yes, a 250 grain ballistic tip zipping along at better than 2100 fps.....

from any mil-spec lower.
I know a guy who has a Mini14 in 6.8. He has no complaints about it as a hunting/varmint rifle. He says it is very accurate for him. He is not really a target shooter though.
What about a .50 Beowulf upper? Would that fit a standard lower?

i think it can, but some minor mods will need to be made.

that new bushmaster cartridge has better ballistic qualities in my opinion.

the bushmaster .450 fires a 250 gr projectile at better than 2200 fps.

this is about 300 fps faster than any load ive seen safely fired with the beowolf.

and it is a direct drop on upper for any mil spec lower.

you have to stop and think about 250 gr at 2200-2300 fps, and it can go boom boom boom boom boom.

thats a lot of wieght, flat out screaming.

i want one so bad it is going to be painful till i get it.

by the way, im a guitarist too >:)
my 458 was a cannon for sure, but i had probs just getting the rifle to run well. it was plagued by extraction probs, and i had probs with anything but once fired brass.

it seems to be pushing the envelope of the ar-style extraction systems. its a lot of brass to be dragging out of there.

could have been an isolated incedent, but i didnt keep it long enough to really find out.

for all i know, the 450 bushy is no better, but im dying to find out! lol
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