72 cal - options?

I have a Pedersoli Gibbs African Hunter, in 72 caliber.

Barrel is .72 caliber,
Broach rifling - .004" deep. 1 in 75" twist.
6 lands - .724 & 6 grooves - .732.

Currently I'm shooting a .715 roundball with .010 patch with 120gr FFG. I'm getting about 4" at 50 meters. Its a real bear to load and I usually find it easiest to mallet the ball to start it. I am considering going down to a smaller ball, but the most common is .690 so that's too small really.

Id like to try something different altogether and with my .50 I shoot Lee R.E.A.L bullets. They really are easier to load compared to the patched roundball as the fouling builds up. I read that they work best is slow twists. Obviously Lee doesnt make it this large.

So I have two questions:
1) do you guys think a R.E.A.L. bullet, scaled up would work?
2) who could custom make it?

check out the accuratemolds.com catalog. He has a couple of designs for that rifle. Hang on tight, it's gonna kick a bit.

You could go with a hollow base/Minie style design too. Accurate can make the mould but the core pin would have to be made by someone else.

Moose Moulds has a variety of round ball sizes including 0.695" and 0.710". They also make a 0.715" Minie that could be paper patched to bore diameter or a bit under.

Then there's Ball Moulds in the UK:

https://www.ballmoulds.com/

They'll make whatever size you want.

Longbow

http://accuratemolds.com/img/bullets.../73-1050-D.png
http://accuratemolds.com/img/bullets.../73-1050-D.png

http://accuratemolds.com/img/bullets.../73-780M-D.png
http://accuratemolds.com/img/bullets.../73-780M-D.png

These are basically a Lee REAL sort of design, right?

I assume the smaller bullet (that's a relative term) would be easier to load. I wonder if the larger one would have issues stabilizing, what are your thoughts?

I'd think the 73-1050 would be too long to stabilize in 1:75" twist but you'd have to check with your choice of rifling twist calculators.

Seems to me the Greenhills formula gave me 1:110" for 0.735" RB or "square" slug. I wanted to be able to shoot a slightly longer slug so made my rifling machine for 1:72" but that's another project not yet completed.

I think that 73-1050 would need even faster twist to stabilize.

Longbow

Thanks Longbow. I'll stick with the tiny 780 grain mould and start with small game like gophers until I gain confidence in taking on big game.

All jokes aside, 780 grains should be enough for everything when stuffed with 120 to 150 grains of 2f. I'm hoping it loads easier & faster than the patched roundball.

If sized to suit your bore and cast from soft lead they should load easily like a Maxi ball.

You'll want base driving band to be bore diameter or a hair under so it fits into the muzzle and lines the slug up for short starting. Nose driving band should be groove diameter.

Those are pretty wide driving bands so it might be a bit of work short starting and may require a fairly clean bore for loading... as in wiping between shots.

A felt wad may be a good idea to help ensure sealing and slugging up base band to groove diameter. No personal experience here but I have read that it works well for some people so is something to consider if lubed slug isn't performing well.

You might also search for Idahoron who has posted about his paper patching methods using patched to bore cylindrical slugs before deciding on a mould.

Longbow

I'd probably want to try a Lyman mold #575213 machined to be a smooth sided hollow based boolit for paper patching.

For example, this is a #57730 modified for adjustable length and use in a .696" bore. The mold design was chosen for its blunt nose but the 575213 could give you more ogive so to speak.
http://i.imgur.com/zHWfv45.jpg
http://i.imgur.com/xh3Rjyh.jpg

Nothing revolutionary. Here's the same thing in .40 caliber.
http://i.imgur.com/CE5ZYTd.jpg

Time out...
This might be borderline for .72 caliber because the side to side dimension on Lyman blocks is only about 7/8".
But other mold makers use the same approximate dimension so I know I don't know.
What about paper patching with the Lyman 12 gauge hollow base mold?