Has anyone with any authority ever stopped you and asked to measure your barrel length? If so please describe. I'm curious when and by whom this would be checked. Thanks.

Nope. Course, I dont take my guns out into public much.

It could be checked by any LEO, in actuality, I only ever see it checked by Fish Cops (Fish and Game).

Yep, twice.  I shoot on public land and have been checked by both Fish & Game and a BLM Ranger.

Both were somewhat aware of the 16" requirement and postban vs preban requirements.  Was told by the Ranger that they receive this info from the BATF as part of their semi-annual training.

Fortunatly, I had a copy of my Form 1 with me and a serial no# listing for Colts or in one instance the gun may have been confiscated until I could have produced them.

Oh, and BTW, the Ranger was even aware of the NFA marking/engraving requirement for SBR's and wanted to see it.

The Ranger told me that a hiker had called him an told him that there was a man shooting a "machine gun." The gun is a semi-auto, pre-ban (Colt SP-1 lower) registared as an SBR

I make a point of always taking the 10.5" bbl. set up.  Then they don't have to guess if it's too short.

Nope.

I shoot at a range that has many LEO as members too.

One did ask whether it was pre or post, though.

Its always fun having LE drool all over my M4gery.

What requirements?

Southern_Raider

BATF has regulations on how large the lettering must be and how deep the engraving must go when marking the manufacturers name and serial number a newly manufactured firearm.