TwoRivers wrote:TC wrote:
Unlike bolt action rifles, the rolling block doesn't completely enclose the breech and rear of the cartridge. The rotating breech block simply rests against the chamber. As a result, some gas surely bleeds through the chamber area I guess. This may lead to lesser report.
TC
No, TC. Only as long as the hammer is in the cocked position. The moment the hammer starts to fall its shoulder rolls under the breech block and locks it. With hammer forward, the breech block is locked and cannot move. And, the base of the case is completely covered and blocked by the breech block. If it were not, every fired case would self eject back into your face.
In any case, it is not the bolt, but the case that provides the gas seal in a cartridge firearm. (Those firing caseless ammunition excepted. But those are not on the market.)
Two Rivers,
It is true that the hammer locks the breech block while falling and completely locks it when down.
However, having disassembled and assembled this particular No 4 numerous times in these months and after examining the wear and tear (something that is making the little differences between theory and practice apparent to my eyes) I have come to a few conclusions.
In the No 4, the hammer is powered by a rather strong spring - a thick, tempered leaf. The trigger, extractor and breech block, on the other hand, are provided pressure (I rather used the word support) by the three arms of a little curiously shaped spring. This three-arm leaf spring, in my experience, is the most intriguing component of the Number 4 and cannot be found in any other rolling block that handle more powerful cartridges. Sadly, in my rifle, it's three arms cannot be as strong as it used to be. But luckily the action is still tight.
The chamber itself seems to have been polished quite a few times by people who owned and used this rifle for 110 years or so. Cartridges don't go in with a snug and tight push as you might expect from a rifle out of the factory. Its "easy going" you might say if you watch the video.
Add to that wear and tear and repairs to the extractor which led to loose fit and no capability to throw out the empties. I had to weld metal to it to get things right and make it rock against spring pressure, as I mentioned at the beginning of this post.
All this, tells my little knowledge in firearms, has created an air passage through the breech end, not much, just a little, narrow and invisible to the naked eye. Yet, it is wide enough to account for that lack of "crack" when a round is being fired. The barrel, despite erosion in the grooves is still good enough - as the target papers show - and the muzzle end is intact. Not the slightest sign of bell mouth.
So, I am yet to find a second explanation to the "less noise" phenomenon even while using high velocity hollow points that deliver a distinctive crack.
Would be obliged if you could help.
Regards
TC