I rub my fairly soft BP lube (BW/Vas - 60:40 or is it 40:60?) on the patch. Why? - this was suggested by Paul Mathews in 'The Paper Jacket" book he wrote. It helps the bullet start into the rifling without grabbing or tearing the patch- I think he noted. I did it and still would, although I'm shooting grooved lubricated bullets now.

Hardening up the alloy a bit with Antimony might increase the bullet's diameter enough to seal- if the groove diameter is .423". With only 10 brinel bullets, I'd most definitely have a base wad of some sort, but note,t hat was MUST be on the bullet's base, not down inside the case below the base.

Smokeless powders usually don't cause enough obturation to seal with undersized bullets - but trying it is the only way to find out for sure, with your load.

I would initially spray the bare lead bullets with moly spray - that might be all that's needed for lube - quite simple & the easiest method by far.

Dropping from the mould at .422", for a .423" groove diameter, will, if patched in paper, run them up to over .434" ((with .003" paper) or so and require quite a sizing operation to get them back to groove diameter or just over. If using "onion skin" paper, at .0015", the major diameter after patching should be around .428" (2 wraps) and require less sizing. If having to size down a paper patched bullet, the lube on the outside will help that operation.

With one rifle we worked with, masking tape, one wrap proved very accurate and was VERY easy to apply, using an exacto knife to cut the tape on the start of the first layer. The slight cut in the bullet's side made NO difference to the accuracy. That rifle made 1 1/2 MOA (3") at 200yards off bags with it's tang and globe front sight - using black powder loads - with pure lead bullets. The 'taped' (patched) bullets came out at exactly bore size and relied entirely on obturation to take and seal the rifling. Note that this much obturation usually only works well with black powder loads.