I’m wondering if antique British pipes were uniformly made with orific bits or if some companies may have used elliptical bits. Here’s an example. I have this Lowes cased pipe with short and long stems. The straight pipe is missing but 3 stems remain. Hallmark is well worn but looks like a London U for 1895. All the bits look like good ellipses. If these are modified it’s interesting because I have rarely seen it done on American pipes.