now is the crazy swede here again with an idea, hope you will excuse my lack of English language knowledge when it comes to difficult technical language .
sorry if I'm only talking in the metric system here but I'm not familiar enough with the inch measuring system when it comes to extremely small tolerances .
I have been looking here at the "William Green" method , but for an projectile shooting barrel I didnt like it .
you will always get empty space in the bottom of the drilled and tapped hole , and at those drawings attached here it seem to be very little material between the bore and the tapped hole .
maybe the barrel wouldn't crack open , but it could at least become an cavity from the inside of barrel where the trunnions are attached if its done that way when shooting full service loads .
and it takes a lot of machining skill to do that in an good way .
wouldn't it be much easier and much safer to shrinkfit the trunnions in the barrel and tig weld them to the barrel ??
as an example , lets say we make an barrel with an 30 mm bore, if you follow old dimensions you should have approximately the same diameter of the trunnions.
where the trunnions is placed on the barrel you have approximately 24 mm wall thickness , if you are milling an diameter 30 hole there 12 mm deep and makes an trunnion 6 - 7 hundreds of an millimeter larger and shrink fit it to the hole .
you have an absolutely level surface in the bottom of the hole , that mean you have absolutely no air between the barrel material and the trunnion . then when the trunnion is shrink fit to place and tig welded I would guess that it is very close to as strong as if it had been produced in one piece .
ideas and opinions please ??