The bore of the le Page is 9mm diameter give or take. The chamber where the powder goes is actually 7mm diameter for a depth of about 8mm. With a small bp charge it's possible to have a small gap between the powder and patched ball. Not enough to be a hazard but possibly enough to be inconsistent perhaps. This is number 8721 in my book of excuses for missing the target. I've fitted a 7mm drill bit on a rod to clean out the gunk in the chamber every ten shots or so. It's quite suprising how much builds up in there quite quickly, changing the size of the chamber, (number 8722). Maybe the filler helps. The bloke Tac mentioned who shoots rather well for Pedersoli uses an equal measure of filler to BP.
Added to the above, I've never had a patch burn through while using filler.
[I]DesG
Domani e troppo tardi
Might be some difference between US and UK patents here. Henry Nock took out a UK patent on a breech design which (in various different ways) incorporated a small "pre-ignition" chamber either in the nipple pocket or at the base of the breech, for UK guns this is known as the "patent breech". The essential feature is that a part of the charge is constrained in the pre-ignition chamber and when ignited will project high pressure gasses into the main charge. Claims to increase Mv.
This does not seem to be the same configuration as described by DesG (or have I not understood it properly).
True freedom includes the freedom to make mistakes or do foolish things and bear the consequences.
TANSTAAFL
Tac, A little research suggests to me that there is a US patent breech whereby the nipple and flash hole is drilled through the breech plug. While this might have a similar effect, I don't think that the respective innovations are equivalent. Interesting stuff tho'
True freedom includes the freedom to make mistakes or do foolish things and bear the consequences.
TANSTAAFL
My Parker-Hale Whitworth rifle has what Parker-Hale described at the time as a 'Patent or High pressure' breech. The .451cal hexagonally-rifles bore terminated at the breech end into a reduced volume chamber about two inches long, this effectively raising the internal pressure on ignition over that of the larger, full-calibre 'hole'.
tac
True freedom includes the freedom to make mistakes or do foolish things and bear the consequences.
TANSTAAFL