.22 barrel length question

[gibbens89]

I just recently built myself a dedicated .22 (17" cmmg barrel with noveske nsr 13.5" rail) and I am very pleased with the results. So I am contemplating building another, so my question is where does the barrel technically start on these .22s. I want to go the opposite direction with a look-a-like sbr type setup while keeping it a non-nfa gun. It looks as though the barrel is about a 1.5" longer then the standard ar barrel which would leave me with something that looks around 12.5" with a pinned 1.5" flash hider but still be compliant. Any thoughts? Thanks

[shadow65]

A 16" .22 barrel will look close to a 14.5" M4 when installed.
I figure 1.25" inside the receiver to be safe.

Just make sure you get your measurements right before you have the barrel cut.
Dave N