Fleener - that is very lovely rifle. The bore is super as well.
i am very certain Richard is "Spot-On" stating the rifle was meant and sighted for round ball. as Forsyth noted
there was often a conical, usually hollow base "minnie style" mould 'thrown in' with the round ball mould.
Many English makes thought faster and faster twists were needed, whereas, Forsyth and some others were
instrumental in turning those philosophies around, but it took into the ctg. era to do it. Some makes did indeed
cut barrels with slower twists, but too, many held to the faster twists.
Taylor's 1853 Joseph Lang is just such a beast, 16 bore and 48" twist. it shoots well with 85g.r which is just over
3 drams(82gr.)
The apothocary's weight of 1 drachm, is 60gr., Richard.
Taylor's Joseph Lang's barrel.
Personally, I would not shoot a slug out of that barrel, due to what Forsyth described as "shaking the stock". He meant breaking it due to the extra recoil.
Taylor's Lang put 5 shots into just about 2 1/2" square at 100 meters. (109yds - 10 rods (close enough)
It weighs just over 8 pounds.
The load was .650" ball with .020" denim, wet patch and 85gr. 2F GOEX. This group was shot after firing upwards of 20 or 30 shots at closer ranges,
NO WIPING as no wiping is needed with that combination. The muzzle crown was just a bit sharp, as it was cutting some of the patches, in a minor way.
No burning and just a bit of scorching from minor blow-by. I would have gone to a thicker patch (+ some crown polishing), but those thin patches worked a treat on target.
Fleener, I have total faith yours will too, using from 3 to even 4 1/2 drams. My 14 bore's 66" twist shoots identically from 140 (5.2drams) to 200gr.(7.3drams), so your 12 bore 45" should shoot up
to 4 1/2 (approx. 120r.2F) just fine. I would not use heavy loads as I did in my new (1986 rifle). 120gr.2F is quite a light, low pressure load in a 12 bore.
Seems to me, that was the load I used in my buddy's 11 bore with 600gr. round ball. That barrel has 56" twist, I think. 3 of us (3 different shooters 2 shots each) made a 6 shot group at 50yards
with that load, 2 1/2" centre to centre, offhand, in hunting camp. It was one (Purdey style) Taylor built, using a Getz bl.