11" and 12" barreled uppers. who were they made for?

[trinydex]

a genuine article mk18 barrel is 10.3"

so why are there all these 11" and 12" variants? who was the original intended clientele? is this sort of like the advent of mid length gas system? something that just works better but wasn't made for anyone specific?

[eternal24k]

Are you referencing anything in particular? In terms of commercially available uppers, many choose them for increased velocity and reliability due to much longer dwell time. I personally favor the 12" as a do-all length

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[trinydex]

nothing in particular. just wondering how they came about, what the evolution's purpose was.

[Clint]

http://en.wikipedia.org/wiki/CAR-15#...AU-5_series.29

[C-grunt]

I believe the 11.5 predates the 10.3.

[Pappabear]

I run 11.5's and 14.5's. I hear the dwell time improves reliability but plenty oh plenty of 10.3's run like a house on fire. BCM doesn't make anything shorter than 11.5 and I heard thats why. I have two bought two Bravo SBR uppers that both ran perfectly.

[Benito]

Ditto for me, I like shorties, and wanted to get a DD 10.3 (which I am sure work great), but after doing some research and listening to much wiser people than I (Paul from BCM, among others), I decided to go for an 11.5".
Negligibly heavier/longer, with slightly better ballistics, but 40% longer dwell time.
Ended up getting a DD 11.5", and it runs like a raped ape.

[uffdaphil]

10.3" with a closed linear brake like a Troy Claymore or Noveske Pig would seem to make up much of that 40% dwell time.

[Vegas]

What velocity difference are we talking about between a 10.3 and 11.5?

[KingsideRook]

Disregard, wrong post.