What/why is the bore damaged? What kind of damage?

Can we see the rifle and bullets you shoot? Coat? Hard back? Sling?   

Martoony rifle?

          Joe.

There's a bit of a bulge - hardly noticeable in the 1st third of the brrel, and it looks like a bullet got stuck there once - damaged lands, scratches,...
Meaning she leads, and needs a frequent clean to get rid of the accumulated leading.
And extra velocity - I might gain some 10-15 fps, but as it's a BP only proposition...

Joe,

Shooting jacket?  What's that?  I do use a shooting glove and an old paker-Hale 2-point sling, in the spirit of the original.  And of course it's my little 12/15 Martini with 308 barrel, all of its 9 pounds.  Parker-Hale Apertures front and rear.

What are the approximate muzzle velocities and chamber pressures of the two BP loads you have tried so far?? What is weight of "Pope Bullet"?

I have a 32-20 with approximate 13:1 twist and am interested to try some heavier than 115gr bullets with BP or some nitro powder giving even less chamber pressure. Need to find load not exceeding SAMMI chamber pressures. Can be either fixed or bore seated load.

Thanks,
Grisen

FWIW, this rifle is the 'mule' or guinea pig - the intention is to build aBP match rifle for the round.  I'm seriously considering going with a 1 in 12 twist, polygonal rifling barrel from Lothar Walther.    OTOH, they have a larger choice in traditionally-rifled barrels, with 1 in 10, 11,12 and 14 being available.  That 14" twist is also tempting...
The final rifle will of course use the same action (BSA small martini action) and BSA sights (no. 8 tang sight at the rear, the original Parker-hale aperture front)

I've shot a 14 twist, Douglas, .308 barrels since 1987. They will shoot a bullet, at least 1.2 long (longest I have), in the 1400 fps range (haven't tried slower). My Bo Clerke, 14 twist .308, will also. I had Ron, make a 13 twist for me but, that was so I can shoot a bullet longer than 1.2.

I also have a .308 12 twist by A&M in AZ and one thing I noticed about it, was that the accuracy came at a lower velocity, 1300 as oposed to 1400+ fps.

Based on the velocity that MartiniBelgian is getting, I would suggest a 10 or 12 twist.

Regarding the 32 cal 11 1/2 twist RKS barrels, I've seen them tip at least once, at the Spokane shoot. Might have been the cold but, it could have been that it got in the transonic range or maybe a weird wind?

Frank

The goal of this rifle iis to develop a competitive BP target rifle for short range - 100, 200m - if possible, 300.  I'm designing the bullet/load combination to stay subsonic all the way, trying to optimize ES in order to compensate.   Which is why the relatively heavy for calibre/case (for BP at least) bullet, and the relatively small case capacity.   Goal is to minimize wind drift while upping the BC in order to be able to reach out as far as possible with accuracy.
1st trials have been pretty encouraging, getting pretty consistent MV's - and accuracy too, in spite of the leading issues.
The reason I'm looking at the polygonal barrel is to minimize fouling accumulation - no sharp corners should help there.  Of course a bit a step in the dark, but....

Frank,

The Pope bullet I'm currently testing is .950 long,  and yes, some minor tipping is apparent.   Still, it does seem to be accurate.  The other bullet I'm using is 151gr and perfectly stabilized at .895 long with my 1 in 15 twist.   So here's me hoping that a 1 in 12 should be ample to keep both stable at 1060 - 1100 fps.
Maybe I should also try a softer alloy with these small charges.