Weihrauch HW35 - First Pattern (early 1950s).
The HW35 was introduced some time after the HW50, probably around 1951/2 and presumably only once the factory owners had become convinced that the future for a sporting airgun business was bright.
The HW35's swept volume, greater than its stablemates the HW50 and the HW55, would have made the HW35 capable of velocities similar to the larger models marketed by rival manufacturers at the time, the Falke underlevers included.
The fine build quality of this Burgo-branded rare first model HW35 is also comparable with that of the Falke factory's output.
Features specific to this early example compared to the HW35's later incarnations include: a simple trigger adjustable via an angled grub screw in the rear of the trigger block, a basic version of the adjustable HW rear sight; a plain angled-blade front sight fitted in a dovetail; the absence of a buttplate (unlike the HW35 shown in the 1953 Akah catalogue); forward side stock bolts screwing up at an angle into threaded sleeves; and a narrow stock aperture to accommodate the barrel locking catch during cocking. This aperture seems to have been widened very soon after production began to prevent stock damage.
Weihrauch HW35 Barakuda.
With thanks to Mick Shepherd of micksguns.com for these pics.
Note the tube attached alongside the main chamber, which held a charge of ether. When introduced into the compression chamber this created combustion which added to velocity. Reportedly, the resulting accuracy was unpredictable.
The information below is taken from the catalogue advertising the auction of the Myron Kasok airgun collection, sold by the Rock Island Auction Company December 13-15, 2003. Pic is copyright Rock Island Auction Co.
Robert Law writing in Airgun Monthly (US):
Weihrauch HW35 (EUSTA marking)
With thanks to Johnbaz.
There is a discussion of Eusta on the AVA archive: https://forum.vintageairgunsgallery.com/ava_archive/index_summary.html?url=http://www.network54.com/Forum/405945/thread/1363706833/last-1363864247/+View+Thread