Cutting shotcup walls for screw-on slugs?

[Petander]

I think I know the answer but:

These 20 gauge wad walls are too high for the scerw-in slug to seat. After cutting the walls, what are the chances ,even with a good jig, to center each and every pilot hole with a drill press? The same way every time... cutting the walls is already a random factor...

Has someone done this or is it just waste of time? I ordered these (half blind,bad pic) from Siarm to try before I read here that Svarog sells appropriate low wall brush wads also in 20 gauge. They center the slug base, I use similar wads in 12 gauge,googled and got them from Croatia,of all the places.

I will shoot these in a smoothbore 870. Will try C, IC and Carlsons rifled choke.

Slugs in the pic are just sitting on the wads for the pic ,not attached.

https://i.postimg.cc/Gmg2Ntc3/IMG-20211104-210031-032.jpg

[country gent]

Easiest and most accurate way I can see is to modify a wilson case trimmer. A holder bored to snugly fit the wad, a modified stop to locate on the slug and a drill made to fir and work in the cutter sleeve. Set up and ran carefully you should be able to hold .002-.003. on center and the same on depth.

A fixture could be made to do it in a drill press. but would be a lot more work.

Last idea is a mini lathe and collets.

[country gent]

For a short batch a hard wood 2x4 cut square drill thru with screw size turn over and open up to wad dia. polish to a snug fit then slit one side with a hack saw and drill for a 1/4" screw and wing nut to clamp it closed.

[longbow]

For the wad cutting I'd make a jig or used a piece of barrel and a utility knife to cut the cup off square and even every time... but then I have a lathe so its easy for me.

Not sure if any standard pipe or tube is close enough to use for .20 ga. to slide the wads into. A simple dowel depth gauge can be made to ensure same length each time and square face shouldn't be too hard to mark then hacksaw and file. A disk with a hole in the middle could be inserted to drill the screw starter hole or even a sharp (ice pick) like punch used through the disk.

Much easier to make stuff like that if you have a lathe though... hint, hint.

Country Gent's way should work fine too.

Longbow

[Petander]

For the wad cutting I'd make a jig or used a piece of barrel and a utility knife to cut the cup off square and even every time... but then I have a lathe so its easy for me...

...Much easier to make stuff like that if you have a lathe though... hint, hint.



Longbow



It's 3.32 AM and already the need/want for a lathe arises!

I like the wad cutting tube jig idea. This here I already have:

https://i.postimg.cc/HspNSDT3/IMG-20211105-WA0001.jpg

[country gent]

That may actually do the job Vee blocks or correct radius's would be better but if your careful. Maybe make a vee block to fit in the back and glue it in or clamp it. If those radius's arnt important drill them smaller to fit wads

[Petander]

Yes that radius is good and set up for 12 gauge.

[country gent]

Look at Mac Master Carr for a brass bushing the outside dia if the 1 gauge radius and the bore close to the 20 gauge wad. drill a 1/8" hole on center line and one in each of the aluminum blocks to match. Split the bushing in half lengthwise. set the bushing in on the pins and you have the 20 gauge jaws to clamp. Makes it an interchangeable fixture. make the bushing halves the press fit on the pins so they slide in and out of the jaws with no pins protruding from the original jaws.

The bushing will only cost a couple bucks