New to paper patching

I would like to try my hand at paper patching. What dia. mold should I be looking at? Its for a 40-65 30" barrel 14 twist with a bore of .400 and grove .408. Using smokeless powder. Thanks, Rob

Paper thickness factors into the bullet dia. you use 2 wraps of paper so paper thickness x 4 ( 2 wraps = 4 layers) minus bore dia. So with .002 thick paper thats .008 subtracted from .408 I would try a .400 or .401 dia bullet.
Also wrapping damp will allow paper to stretch thinning it slightly.
If using BP loads with a full case of powder and wads leave a small dia of base showing in the wrap ( tailless). This gives a much flatter base to work with. It dosnt need to be big from dia of pencil lead to BB is fine.

A post in swapping and selling for test bullets in different dias may help give an idea of what works. MVA also sells some un wrapped slugs that may help determine what works before buying a mould. I also prefer a cupped base as it makes for a better crease and base.

So that means I want to wrapped to grove diameter and not bore diameter? I've read both bore and grove dia. that had me confused.

First off I have yet to paper patch a single boolit, although it remains on my bucket list. Two or three years ago I did a lot of research and based on recommendations here I bought this lil book 'The Paper Jacket' and it is worth it's weight and more: https://www.amazon.com/Paper-Jacket-.../dp/1879356023

There may well be better (collectable) books out there, but none are priced within my willingness to pay. I have read it cover to cover at least two times.

Page 21 says: the unpatched raw bullet should be .0005" larger than the BORE. The paragraph preceding that describes how to slug the barrel and get a slug that you are able to measure the bore. Measuring the bottom of the engraved slots in the slug can be challenging. The slug needs to be sized just large enough to get a faint impression of the bore.

edit: note for black powder/Pyrodex the unpatched boolit should be .004"-.006" smaller than the diameter of the bore, page 23. You really should get a copy of this book before buying/doing anything else, IMO.

edit2: There is more about ordering your mold for as cast with pure/soft lead, rather than an alloyed as cast size and explains why.

I have The Paper Jacket, by Mathews and Loading and Shooting the Paper Patched bullet a beginners Guide, by Wright. I much prefer the later book.

My bullets are wrapped to bore dia and only seated in the case around .125 -.187 It almost like breech seating.

Recovered patches can tell you a lot.

Country Gent is on the money, if your running smokeless your at groove diameter. In my 40-65, it's a .400 diameter 25# vellum, two turns, wet and I end up at .407. Black powder, .395 wrapped wet with Strathmore tracing paper, two wraps, end up at .402ish. Black seems to work best (for me) at bore diameter and smokeless at groove diameter. A harder alloy seems to work better than one that's "soft". You might check out the Shiloh Sharps forum, those guys KNOW paper patching. They helped me a ton when I started out. As one member puts it, "Your rifle will let you know what it likes" Good luck, PP is a flat really neat once you get the hang of it. If you want to try some bullets, I have 370/.395 and 265/.400, I' d be glad to send you some. Just PM me.