Help Identifying Round

[ScouT6a]

I posted some time ago about a metallic cartridge collection that I have been working on. I am now at 100 different rounds and part of the fun has been in identifying a handful of rounds that were not marked with a caliber on the cartridge head. Well, I have a small rim fire round that I can't find any information on. It has a copper case with a lead bullet. The bullet mikes at .270" or 6.8 mm in diameter. The case is .308" or 7.82 mm long and the overall cartridge length is .453" or 11.50 mm. It is pictured here between a. 22 CB and .22 Short on the left side and a .22 Long and .22 Long Rifle on the right side. Any ideas?

 

[hammer24]

.277 rimfire? I don't know, I just know there is or was once a critter named such. Cool find!

 

[other dave]

6mm Flobert???

 

[chezuki]

.25 Stevens short?

 

[Doug]

Looks like a 7 mm Flobert.
Lot of 4 Rimfire Cartridges 6mm Flobert, 7mm Flobert, 6mm Flobert Ball, 9mm Flobert Ball Auction

 

[hoosierdaddy1976]

6mm Flobert???

my guess also

looking at dimensions, might be a 7mm. found a french site that shows a few rounds for sale
Trois cartouches différentes de 7 mm Flobert à balle (port offert) (1607286)

 

[hammer24]

The six mm flobert got me digging, I believe its a 7mm flobert. I have shot the 6 and 9 mm versions, but didn't know there was a 7mm version. Apparently the 7mm is pretty rare, and guys use the .27 cal nail gun blanks to shoot them (rifles/smoothbores.)
The smoothbore barrels typically mic at .285.

 

[ScouT6a]

Thanks for all the help, gentlemen. It is a 7 mm Flobert. This one does not have any type of head stamp.