(24 November 2013, 16:00)Midnitemo Wrote: i figured with propellant detonating behind the slug the skirt would flare on its travel up the bore creating a seal before its exit...figured a loose fit is ok as long as its not rattling around in there.
Sometimes it will flare and sometimes not. That is one of the reasons slug accuracy is a variable.
It has proven difficult for testers to measure the bases of slugs since they are usually damaged when recovered. I suppose recovery from water might provide measureable projectiles. I have never tried it since all the folks I know that own swimming pools would object.
One thing we do know is that in the old days of fiber wads there would often be a plug of the fiber wad inside the base of the slug. That t4ended to give inconsistent accuracy. Occasionally I would find a box or two of the good German Berndeke slugs with the wad base screwed to the solid slug they used. Those were acceptably accurate at 50 yards, which used to be accepted slug range.
I find that the loads I make using a plastic shot cup get around much of the inconsistency. They function much like the patch on a muzzle loading rifle. They seal the bore, hold the slug in consistent position inside the bore and compress with the lead as they pass the choke.
As I stated earlier, we have several states over here that do not allow rifles for big game and there has been a great deal of work done to improve shotgun and slug accuracy. We have available barrels with slow twist shallow groove rifling. When used with saboted slugs they are as accurate as any rifle out to 100M. The slugs are shaped like a large 500 grain air-gun pellet but encased in a thick plastic sabot that does all the sealing, expanding, and transferring of the rifling torque to the projectile.
The rifled shotgun bores with specialized slugs consistently provide 1-2" groups at 100m.
I took the cheap way out and purchased a rifled choke tube for my interchangeable choke system. The fully rifled barrel for my shotgun runs $200 U.S. and I did not wish to spend that much. The choke tube is only $40.
It works much like the old Paradox system and provides 3 inches of rifling at the end of the bore. I am not finished with my testing on that device at the moment. Naturally, it would be on your prohibited list.
All the material I have found gives its performance between the fully rifled barrel and the better shooting smoothbores; 3-4" @ 10M. When the weather warms I will let you know more. I want to test it with both slugs and round ball before making any recommendations on its worth.
My real goal is to do some research that you fellows might not be able to easily accomplish due to your restrictions. I can then hand the KNOWLEDGE over to you for use in an emergency. If you chose to use that information SHTF that is up to you.
My basic plan was to test various projectiles and shell modifications that would turn the run of the mill single, double or pump shotgun into a weapon capable of putting down an assailant at 75 yards with absolute certainty every time one pulled the trigger.
I also wanted to be able to preform the modifications to weapon and/or ammo within an hour or two, and do nothing to the gun that could not be reversed or that would make it illegal.
I have been working with two pump guns, both of which are heavily tricked out beyond what your regulations allow. I am about to convert one back to stock form and see what it is capable of with less modification. In this case converting back to stock form means changing back to the 28"vent rib barrel and testing with every choke tube in the kit.
Having the interchangeable choke tubes removes all the variables from testing except for the performance of specific choke restrictions on the projectile.
I also have some plain Jane singles and doubles to work with that might inspire more confidence in using whatever one might pick up from the cabinet, though I realize some of you have pumps.
Right now the weather if fighting me. It is well below freezing and a 20 mph wind is whipping snowflakes along at a horizontal angle. Of course that would probably be the exact conditions of use in a SHTF situation anywhere but on a tropical island, and they have to worry about typhoons, hurricanes, tsunamis and earthquakes.