doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com SPRING STRENGTH

None of my reproduction Colt "Cap-N-ball" revolvers have excessively hard to cock hammers & I've never had a problem with them firing a percussion cap. In fact none of the percussion long guns I have had any dealings with have seemed to have springs any stiffer than those found in a normal break open sporting shotgun, except possibly Military Muskets etc. Some of those have truly massive locks, including powerful springs.
On a Lefever Arms Co hammerless gun with in-frame ejectors (Far & away the most often found LAC ejectors) the Main Spring does dual duty. They have V springs & the lower limb powers the hammer while the upper limb powers the ejectors.

I�m not a gunsmith but I think this is all explained by mechanics.

The hammer transfers energy (E=1/2mv^2) to the firing pin. There is a force (F=ma) and an impulse (I=mv). We can convert back and forth with math until we get a headache but, the relevant variables are always the mass of the hammer and the velocity with which it strikes the firing pin. I don�t think physics cares about the direction of movement (straight or rotational movement). Energy is energy.

All that said, the OP's observation is really about cocking effort, which is better thought of as work. W = force x distance. I agree it is very difficult to compressing the springs in a boxlock but, you only compress the spring a small bit. It is easy to move the spring in an autoloader but you load it through a long distance �usually an arc. It also easy to cock external hammer actions but, again you pull the hammer though a long arc.

I would wager that the work of cocking an SxS hammer (boxlock or sidelock) is about the same as the work of cocking an autoloader hammer. I also bet the different systems transfer equivalent energy to a firing pin.

Ryan,
my understanding of the original observation was that it was about force, irrespective of travel, weight , etc..

It seemed, to me, to be about mechanical advantage, because one spring was compressed with a lever, the other free hand. But, Shotgunlover address that and said the autoloader spring was still weaker.

It has to do with where in the barrel stroke the cams for cocking are actuated. Different mechanical advantages at different places in the arc.
Many shotgun brands could revisit their cocking systems and make them easier. And their customers happier.

But I believe it's a "Isn't broke, don't fix it" carryover from long ago.

I think cocking shouldn't commence until the action is mostly open. Many firms disagree.

Yes but, we can�t separate force and travel. The force in a spring = k*x. The potential energy stored in a spring = 1/2*k*x^2. The question is really, why so much k in a break gun?

The break gun uses a relatively big k with a relatively small x. The auto uses a relatively small k with a relatively big x. The energy released is probably equivalent.

Thinking in terms of force is inadequate for explaining mechanisms. I find it easier to think in terms of work and energy.

Ryan, +1!! Well said.

DDA

I think what some of the folks were commenting about is the 'x' may be more similar than you're thinking. The travel of an internal side by side tumbler may not be too different than the swing on the hammer of an autoloader trigger group.

If the 'k' is much greater in the side by side their may be design, execution, etc. differences. Or, maybe the 'k' isn't too different.

Thanks to all for the input and the ideas.

I have never measured the distances between fulcrum and lever edges in autos. Going by a rough visual comparison from memory I would say that most hammer guns have a larger radius between the axle (fulcrum) and thumb pad, than autos have between the hammer axle and the point of contact with the rear of the bolt.

I will also start comparing the springs of some real thumb buster hammer guns with the more gentle types. My observation is that quality is inversely proportional to cocking effort.

Hammerless actions probably were made with little regard to spring rate. The barrels doing the cocking are such an overpowering lever that not much thought was lavished on spring stiffness. Also spring making was probably a carryover from the flintlock days when the hammer on its way down had to carry the flint, overcome the frizzen and have enough power to rub against it to create sparks.

Looks like i got myself a project.

Excellent!! Keep us posted.

DDA