If, when drilling the flash channel, the end of the drilled hole is not cleaned up you can get a burr on the end of the hole. That burr can stick out into the chamber and block the cap's flash, catch patches, hold moisture/oil from cleaning, and generally make using the rifle a real problem.
If you have any production gun with a factory installed breech like a CVA, it can be a real pain to remove it. This I know for a fact.
DAve
Some of these Euroguns have a weird breech that can be a booger to get out. I made some of these snail types
in Bill Larges* shop and took a lot of time to make sure a breech would be RIGHT and not spoil a hunting
trip. The term "snail" comes from the shape of some of them.I have an antique snail or bolster hook
breech that Art Ressel gave me when he had the Hawken Shop in St.Louis that was part of the Gemmer
Estate at one time. I have kept it and it was the right style for a round ball gun.The English long range
rifles that launch a bullet over 500 grains in weight with 90 or more grains of powder are entirely different.
These are designed in such a way that little pressure is on the base of the nipple and the nipple will have
a platinum insert as a flash hole to prevent burn out.They are entirely different from the Hawken shop breech
and the one I have is one of the last from the late Don Brown for his Alex Henry.Neither one is for sale in
case someone inquires about them.
*Making these breech plugs was a great way to learn threading and the file contouring of oddly shaped parts.
I am grateful for it and the fact that Bill Large's shop was only 14 miles away.
Bob Roller