Back in the mid-1980s I was loaned a Spencer on which I had a centerfire breechblock
The mainspring surrounds a guiderod that passes through the top of the breechblock
and retains the pivoting operating handle.
Within a few minutes, he had successfully forced the breechblock
down without any apparent collateral damage.
Instead of a tilting barrel to delay the recoil impulse, the R51 features a tilting breechblock
inside the slide.
I removed the breechblock
and used a center punch to mark the spot so the drill wouldn't wander when drilling the firing pin hole.
If the springs wear out, closing the breechblock
is no easy task.
Reliability was increased thanks to the redesign of elements of the breech, breechblock
and automatic loading system, while state-of-the-art fire control system and automated navigation system was installed.
The design of the super gun called for a solid titanium breechblock
. The smooth bore barrel itself was to be carefully machined so that it fit perfectly into the next barrel section, with the tube tapering at the end.
The only thing missing from the tank is the cannon's breechblock
The rolling-block action was elegant in its utter simplicity, consisting primarily of two parts--a rotating breechblock
and a hammer locking the breechblock
in place at the moment of firing.
The ATF further clarified their position adding that they, "had determined that the receiver of a bolt-action rifle is the part of the firearm to which the barrel attaches that provides housing for the bolt and, in most cases, the trigger." Adding that according to Title 27 CFR [section] 478.11 's definition of a firearm frame or receiver, "That part of a firearm which provides housing for the hammer, bolt or breechblock
, and firing mechanism, and which is usually threaded at its forward portion to receive the barrel."
Closing the lever runs the bolt forward, picking up and chambering the cartridge, and raises the breechblock
Other markings include a "R" with a star and a "K" stamped on the bottom of the breechblock
. All parts have the same serial number.
The Model 99 is a hammerless lever action with a hefty breechblock
, the rear of which locks up strongly against the solid receiver when the lever closes.
When the cartridge was fired, by means of an external percussion cap, the expanding powder gases compressed the felt wad back against the face of the breechblock
, forming an effective gas seal.