Peening on toggle question

unspellable · 05-18-2005, 05:14 PM

Until maxmanta checks in again we are wandering in the murk as to what the problem is that started this thread.

As for the question of how hard the toggle knobs hit the ramps the main spring has no bearing.

The recoil spring does not do nearly as much as you might think to slow the upper by the time the toggles hit the ramps. On firing, the impulse results in a force in excess of 500 lbf tending to accelerate the upper to the rear. The recoil spring will require something like 30 to 36 lbf to fully compress it to its smallest length in the pistol with the toggle all the way back. The force required to compress it to the length it has with the pistol in battery is on the order of 10 to 15 lbf. With a force in excess of 500 lbf pushing the upper back, the recoil spring has very little influence. The velocity of the upper is almost entirely determined by the impulse of the load. (If one were designing a pistol, the mass of the upper would be a very important consideration.)

The recoil spring should bring the upper & toggle linkage very nearly to a stop by the time they reach the rear most limit. It can do this because it is acting over a much greater distance and time than is required for the toggles to reach the ramps. So the first requirement for the recoil spring is to slow the upper and toggles to nearly zero by the time they reach the rearmost position. The second requirement for the recoil spring is to reliably return the action to battery. In doing so the next cartridge is loaded and the main spring compressed. It is vital that the recoil spring bring the action fully to battery as it is possible for the pistol to be fired with the action almost closed but not yet locked. The consequnces of firing with the action not yet locked might be rather ugly.

The biggest single influence on how hard the toggle hit the ramps is the cartridge impulse. (Since the pistol is already designed, we can't change that.)

05-18-2005, 05:14 PM	#1
unspellable User Join Date: Jun 2002 Location: Iowa Posts: 768 Thanks: 0 Thanked 19 Times in 11 Posts	Until maxmanta checks in again we are wandering in the murk as to what the problem is that started this thread. As for the question of how hard the toggle knobs hit the ramps the main spring has no bearing. The recoil spring does not do nearly as much as you might think to slow the upper by the time the toggles hit the ramps. On firing, the impulse results in a force in excess of 500 lbf tending to accelerate the upper to the rear. The recoil spring will require something like 30 to 36 lbf to fully compress it to its smallest length in the pistol with the toggle all the way back. The force required to compress it to the length it has with the pistol in battery is on the order of 10 to 15 lbf. With a force in excess of 500 lbf pushing the upper back, the recoil spring has very little influence. The velocity of the upper is almost entirely determined by the impulse of the load. (If one were designing a pistol, the mass of the upper would be a very important consideration.) The recoil spring should bring the upper & toggle linkage very nearly to a stop by the time they reach the rear most limit. It can do this because it is acting over a much greater distance and time than is required for the toggles to reach the ramps. So the first requirement for the recoil spring is to slow the upper and toggles to nearly zero by the time they reach the rearmost position. The second requirement for the recoil spring is to reliably return the action to battery. In doing so the next cartridge is loaded and the main spring compressed. It is vital that the recoil spring bring the action fully to battery as it is possible for the pistol to be fired with the action almost closed but not yet locked. The consequnces of firing with the action not yet locked might be rather ugly. The biggest single influence on how hard the toggle hit the ramps is the cartridge impulse. (Since the pistol is already designed, we can't change that.)