Best SBR length.

What do you guys consider the best SBR length to be? 10.5, 11.5 or 12.5?

Im not including the 14.5 because I already have a 16 and it just doesnt seem like much of a change.

Carbine would be used for home defense, range work and possibly classes down the road.

https://www.m4carbine.net/showthread.php?t=54320

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