My 1899 vintage 16 gauge Model 1894 AE Remington is marked 276 on the right barrel and the constriction is .018". The left barrel is marked 278 and has .027" constriction.

I have two 16 gauge 1900 models - I'll try to measure them tomorrow and post the results here. I'm glad to help with this project, it is something I have often wondered about.

As promised, here are the pellet counts and choke constrictions on my two 16 gauge Model 1900s:
K Grade made in 1904, 28" barrels: Right pellet count 318, choke .020". Left pellet count 324, choke .018".
K Grade made in 1908, 26" barrels: Right pellet count 282, choke .014". Left pellet count 277, choke .019". The pellet counts were Xed out on this gun but are still legible.
It's hard to draw a conclusion from these figures, but that's what I have.

Thanks everyone. Yes, the data is hard to interpret. That's what got me to thinking about these 16-gauge Remingtons some time ago and prompted me to post here. Let's give it a few more days and I'll try to summarize and add my thoughts.

OK Frank, here's what I have if you can figure it out. The lug is stamped 292 right ,300 left and is X'ed out if you can make it out. It's a 16 KED.

The bores are .673 r, .671 left with the corresponding constrictions of .006 r, .016 left. That certainly doesn't jive with the stampings. The chokes don't look like they have been touched but then again I'm not sure of the significance of the X'ed stampings.

Also, anyone have any idea what the 4 digits, 4487, stamped on the receiver flats and the fore end iron mean?

It's a pretty nice gun as it has the POW grip with 28" barrels.

Some have called those extra, usually four-digit numbers, on K-quality Remington Hammerless Doubles assembly numbers. All but two of the K-quality guns I've saved out pictures of have these extra sets of numbers. One gun in the 367xxx range has a three-digit number, 188, and that gun's lug is stamped CYL and MOD?!? The other is a 16-gauge two-barrel set that doesn't have the numbers.