Among these mechanisms, we considered the wraparound
breech mechanism as the best candidate due to its rapid breech opening and robustness to shockwave.
Importantly, he confirms, this means there is no loose metal flying around inside the
breech mechanism or gun barrel.
These were rifled muskets that had been converted to breechloaders by means of a Snider-type
breech mechanism. The navy, Corps Mariniers (Marines) and some units of the KNIL were issued a similar, but shorter, rifle known as the Marinebus M.64/67.
Over the long years of research for my book "Cosmopolitan and Gwyn & Campbell Carbines in the Civil War" (Andrew Mowbray Publishing), I surmised that most of the reviews from the Civil War field were really about the Cosmopolitan, which, as Garry notes, was an entirely different
breech mechanism. The truly simple G&C was nearly foolproof and sturdy.
I dismantled the
breech mechanism and am having some trouble replacing a major pin and part.
Water also gets into the main gun system, causing corrosion and damage to the
breech mechanism, bore evacuator components, and firing circuits.
The
breech mechanism is operated by a long lever under the receiver (which swings to the right) that extends forward, toward the forestock/handguard would be, if it had one (this model appears never to have had one).
The Srams is claimed to have a high rate of fire as it is fitted with a semi-automatic ammunition transfer system and a patented valve system in the
breech mechanism. This is to allow the bomb to drop faster down the barrel.
In fact, the receiver, bolt,
breech mechanism, extractor, ejector, and firing mechanism of the M54 were so good that very few changes were made to these components.
Exact details of the conversion remain classified but the barrel and
breech mechanism are new, while the mounting needs modification and the ammunition racks of the M60 need to be modified to accommodate the longer and wider 120 mm rounds.
There may be something to the claim that the rotary
breech mechanism reduces recoil.