Today I tested my Mexican Match slugs (Lyman 535 gr giant air gun pellet style) at 25 yards.
I shot from a rest with 3 different shotguns (rifled choke, Imp. Cyl. and Modified) in case the gun or choke makes a big difference. It did not. Two of the guns had a rear sight, as behoves an accuracy test. The Rem 870 28" just has a front bead, and groups were as good as the others. Go figure...
Targets at 25 yards.
Before
After
For control, I shot 5 Remington Reduced Recoil slugs. These are advertised as 1200 fps, which is in the same ballpark as my ammo -1100 to 1200 fps. My home made slugs felt about the same as the reduced Recoil – much nicer than factory full power slugs. And they cycled through my Hatsan semi-auto just fine.
This test was intended to find out if making Mexican Match slug ammo from target load ammo was a cheap and effective source of good plinker grade slug ammo. It is.
And to determine if the accuracy was good enough. It is. In fact it is as good as or better than the factory slugs. (At 25 yards. I did not test at 50 today, but I will in the future.)
Factory vs. Mexican Match (Mex Match targets are both 3 shots each)
And to determine if filling the skirt of the Lyman slug with wax aided accuracy. It did, but the accuracy of the hollow skirt was plenty good enough. With wax, some 3 shot groups were just one big hole. Without wax, groups were just under 2”. 50 yards might tell a different story.
Wax vs No Wax Same gun, top and bottom
Conclusion: The Mexican Match slug ammo is best made with the Winchester white box "Super Speed" ammo. Mine was 1 oz 71/2 shot. This size shot cup was perfect to tuck the top rim of the slug under the rolled edge of the crimp. This maintains good pressure on the wad column.
Velocity was about 1220 fps - similar to factory Reduced Recoil. The only tools needed to make these is a knife to cut out the pie crimp and a hammer to pop the slug into place.
Filling the skirts with wax improves accuracy, if needed.
Many thanks to Big Boar who gave me the slugs that made this test possible.