“2 is one, one is none” - is the mindset.
I have a 6920 and have been 100% pleased.
I’m looking for a backup AR15 that will be used if the Colt ever goes down, and possibly be used w/ my CMMG .22 kit for practice.
I have looked over many, many options. I’ve narrowed it down to 2 groups:
More $:
Daniel Defense
BCM
or…another 6920…
Less $:
Delton
Stag
CMMG
Let me know what you think…
You said it.
I would go with one from your first group. You don’t have two if the second is from your second group.
HaHaHa that’s an easy one …buy another 6920
the best backup for the 6920 is the 6933 if your state allows SBRs. In fact, I bet you’ll find yourself using the 6933 as the primary and the 6920 will become the backup.
While I agree that “two is one, one is none”, I also believe that the “two” do not have to be identical twins. Fraternal twins, or even cousins, would be fine. Keep the stock, grip, forend and sighting system functionally similar just for familiarities sake and so that training with one feels the same as training with the other and you’ll be fine.
A Tale of Two Carbines
I still have both of these guns, and while I don’t shoot either of them much and they both have undergone some changes in the stock/grip department (and I wouldn’t build them like this today) the concepts are still sound.
+1 …that’s what I want to do now that the prices are down.
Since you have a carbine gas system, I woul look to get a middy. This means that BCM wins.
C4
Does that mean four is two? 
Don’t forget Noveske.
If it were me, and it has been, I’d get a complete BCM Mid-Length carbine for your backup.
However, I have a feeling that you’ll end up liking it so much it will soon be your primary 
Buy another 6920.
I mean, why not? They won’t ever be cheaper. You’ll buy a third AR eventually anyway, and that one can be a bit more exotic.
But I am old-school.
I would absolutely stick with your first selection of choices for your next rifle. I would also suggest heeding the advice from the knowledgeable people here when it comes to an SBR. I currently have two rifles, BCM Middy 16" and a Bushmaster varminter 24". If I could do it all over again knowing what I know now, it would be an 11.5" BCM and an 18" SPR. The SBR will give you all of the manerverability form a compact package and the SPR will let you stretch the legs on the 5.56 rounds, if you so choose. This is just my perspective though.
Stick with a good rifle and think about what you want to accomplish with a second.
My $.02
Quit reading my mind, eguns…
Maybe an FN Scar would do?
Nevermind, the price at the local shop is $2,699 + tax, goodness I could have 2 Colts and an AK for that price!
Right now, it is hard to not go with a Colt given how the prices fell if you want a carbine length system.
I also like the 6933 idea.
I might have to do the 6933, as I’ve been thinking about a SBR my self.
That should give you just enough difference to appreciate them both and still keep you happy with the similarities.
What’s the price comparison of the 6920 verses the 6933?
I like Rob’s suggestion on getting an SBR. Makes good sense. Although personally, almost being on the same boat, I would want to get a BCM hammer forged middy.
– Good brand, good barrel type, good gas system, Good BCG.
As cheap as 6920s are going, I’d get another AND, a BCM Middy.
6933 @ $1800. new.
Ditto. If you’re pleased with your 6920 then buy a second. If it ain’t broke…