I'm all about experimenting, and I still encourage you to do it, but I have extremely low expectations of success with BC or accuracy.
I never tried that but I did drill some in an attempt to make a whistle out it, you know, so it would basically scream, like an audio tracer round. No point other than to see if I could, and I could not... Pellets hiss a bit normally and all I could do is make that hiss a bit louder but no actual whistle sound, nor was it loud enough to be entertaining.
I think if you want BC you kinda hafta go the old fashioned route using aerodynamics and weight, which typically make for good accuracy too, and they come premade for cheap in tins of 500
If I were to attempt this test I'd no doubt use a JSB "Beast" pellet which is ~16gr with almost no waist, so it's sturdy, has plenty of area to drill out for experimenting with hole size, and of course it has mass so even if you remove half the weight it's still a mid-weight pellet which is good. Making a wad that'll seal the air but pop off I dunno... Depends on the gun but they can generate a lot of pressure so it would need to be pretty tough, yet shaped so that it doesn't press into the pellet and get stuck. I suppose I'd consider a setup like how a cardboard wad is used in 12ga shooting a pellet shaped slug. Ironically I have some giant 525gr wadcutter pellets that are for 12ga (Lyman 525gr slug) and I use cardboard that is extremely tough and ~3/16" thick? under the "pellet" and it works great. The pressure is substantially higher but between the pressure source and the stiff cardboard is ~1" of very soft cardboard, if you can call it that, it's almost cotton like soft. It cushions the blast but still amazing the stiff piece of cardboard doesn't simply get stuffed into the base of the pellet. I digress, but point is you need to think up something that's strong enough to survive but very light so it doesn't suck up power. You also need to figure out how to make said "wads" the perfect diameter. I'm thinking like plastic and a hole punch? Like a steel tube with the ID is the dia you need, like .018"? Then sharpen the outer edge of the tube till sharp and use it to punch the plastic or whatever your dealies will be made from.
Another idea, and I'm thinking outside the box a bit, but I spoze maybe making a "cold roll mold" (sorry I can't think of the proper nomenclature). Basically you'd punch, hammer or press raw lead into the shape you want instead of trying to drill it. Like a piece of steel ~1/4" thick with a .177 or so hole in it which you could pound lead into to make a slug, but add a steel rod to the center so it also makes your hold. If you google that Lyman slug you can see they kinda do similar to make the hollow base.
Just some thoughts.....