Make sure you have enough metal between the bore and min threads... this really comes into play with button rifled barrels that bell out when you remove metal (button rifle barrels have stress in them).
Field guns tend to be that way - barrels with cut land don’t exhibit it because they aren’t stressed, so you go by the CIP metal / pressure specs for those.
Here’s a video, not all smiths notice this...
http://bulletin.accurateshooter.com/2015/04/muzzle-threading-dont-remove-too-much-steel/Final note - if you do a button barrel and it bells out you can recess the crown to help minimize the accuracy impacts of having the barrel bell out at the end...
Occasionally true but not always. The story about stresses in buttoned barrels is mostly propgated by makers of cut barrels. Most buttoned barrels will be just fine. Now and then, one may gat out which was not properly stress relieved but it is rare from any of the better makers. Likewise, the occasional cut-rifled barrel is made of steel which was not normalized and will distort when the exterior is machined.
I have contoured, re-contoured, fluted, machined octagon, and threaded for brakes, hundreds of barrels. These barrels have been cut, broached, buttoned, or hammer forged and very few have warped, belled, or distorted noticably. The very worst barrels, in this regard, I ever encountered were a pair of cut-rifled barrels. I had to straighten these after every pass an the lathe. Surprisingly enough, they shot pretty good.
My very best BR rifle barrel was a buttoned barrel which I contoured from a 1.250 blank. My second best was the same.
In addition to rifle barrels, I have machined many tons of hydraulic cylinders, valves, bushings, sleeves, and shafts and have a pretty good handle on what steel can do when machined and how to minmize it.
By the way, in the article it mentions the use of a smaller thread as a means to save weight. Seriously? GD
