I’m looking at an early (1872) Francis Brebner hammer gun that was reproofed about 10 years ago according to the proof marks. Barrels were reproofed at 70mm which leads me to assume the chambers were lengthened. Is there any way of knowing if the chambers are, in fact, original to the gun. I suspect the gun may have been made for the pigeon ring due to its embellishments but that may be wishful thinking. Did black powder proof ever account for chamber length. Bores are still within the original .729” proof at .736”. Thanks
