# Reply To: A theoretical exploration of physical possibilities, AKA Let's Make A Monster

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You will need a proportionally longer barrel in order to achieve the velocities. That is if a caliber .22 barrel that is 18″ long is needed, then for a caliber .44 it needs to be twice as long—slightly longer for the .45. If , for example, the .22 can get by with a barrel of 12″ then our big bore .45 will have a 24.5″ barrel.

Spring guns by their nature have different and improved efficiencies over a PCP, in that not nearly as much heat is lost in the cycle. The PCP starts with ambient temperature high pressure air that cools upon expanding as it is released down the bore. The spring gun, on the other hand starts with ambient temperature and pressure air that is rapidly compressed, thus heated. As it propels the pellet the air cools back to ambient, minus a little bit heat that transfers to the barrel. This is a more efficient system.

Just as another example of scaling, let us say that our sample .22 has a 1″ diameter piston, and a stroke length of 1/2″. (These are numbers grabbed out of the air and probably do not reflect a real springer). To maintain the proportion, our .45 will need a piston of 2.045″ diameter and a stroke length of 1.022″

For the spring, however, if the sample .22 has an average force of say 100 pounds over the 1/2″ stroke, our .45 will need a bit more than 4 times that. The spring force will have to go up as the square since our piston area goes up by this amount.

If we are making a break barrel, the actual cocking force will be just about double. Our barrel is twice as long which gives you more leverage, but the spring force is about 4 times greater.

As I pointed out earlier, this thing may take on the proportions of a punt gun. Although a gun with a 30″ barrel is not all that unwieldy. We just have to tidy up the spring compression end, by perhaps having half of it surround the barrel.