Need help to identifying an early break barrel.

Definitely not a BSA Breakdown pattern. German. Probably out of the Oscar Will factory. Resembles a "Marco" very closely 1920-39. These guns often carried the name of the importers. 

See p 153 Hiller's third edition

This is a Breakdown pattern of mine from around 1936. A youth size gun. Not quite as well engineered as the underlevers. Smaller diameter cylinder. Millita style.

MILLITA, not militia!

Your gun is a millita style.

 I said it's a millita style BSA Breakddown pattern. I don't think yours is a youth model. A Breakdown pattern .177 is 5lb 7oz. 41.5 inches. A Light pattern front button .177 is 39 1/2" and 6lb 4oz. A Standard front button .22 is 451/2 7lb 10oz. Side buttons and duck bills weigh about the same. So do flat tops.

You have to know how to speak prewar BSA language. I've been collecting them over 25 or 30 years. 

I capitalized millita to emphasize for dyslexic airgunners who constantly call them militia style. Interestingly there actually was a Millita brand air rifle. I think it was marketed by George Lincoln Jeffries in UK. Inventor of the BSA prewar underlevers in 1905. Confusing? I know.

Scroll about half way down this page to see several unidentified guns similar to what you have. From the "Vintageairgunsgallery". You could spend a whole day there!

https://forum.vintageairgunsgallery.com/unknown-unmarked-airguns/unmarked-airguns/#post-340

You will probably never know who the actual maker of your gun was. Sorry. But you might at least have some idea. 

Lol! It's Millita!  Not militia or millitia. See what I mean? 

The Millita brand rifles were available about 1906-45 in UK. Manufactured in Germany by Friedrich Langenham. FLZ That's where the term apparently originates. Any barrel cocking quarter stock air rifle is generically called a millita. I don't think it has anything to do with military other than some air rifles were used during training of soldiers. 

Some of the German bolt action Mauser looking airguns were used in training but never referred to as a millita. BSA made the Millitary Pattern replica of an Enfield but it was never adopted by the military. Certainly never referred to as a millita.

Dennis Hiller 3rd addition p. 153 has a very good article on your gun and some various names it was sold under. Who made it. (Oscar Will) This barrel latch is a Lincoln Jeffries patent from 1903. Many years before the Greeners were available. 

If you don't have Hiller's book I would highly recommend it to any person interested in 1900's air rifles. The fourth edition is available currently. So much information in there that you will not find online.

https://www.gunstar.co.uk/roland-1927-177-air-rifles/Air-Guns/1274247

Exact same gun marketed as a model #1927 Roland. Pictures 5 and 6 are illustrations from Hiller's book under "MARCO"(another brand this gun was marketed under) where this gun is described as made by Oscar Will.

UK importers would often sell imported guns under various manes so buyers wouldn't suspect the gun came from "Nasty Germany".

This is a Millita brand air rifle re branded by Lincoln Jeffries as a "Lincoln".

https://forum.vintageairgunsgallery.com/millita/millita-air-rifle-lincoln-badged-engraved/

George Lincoln Jeffries was a fine shotgun maufacturer as well as airgun importer before he invented the famous underlever he had BSA manufacture parts for 1906. Underlevers assembled from the parts at his factory were marked "Lincoln Jeffries". Guns assembled at BSA wore the BSA name. BSA was far better at the marketing game and after a few years bought out George Lincoln Jeffries and his patents.