I will tell you that the American made Thompson/Center sidelocks use SAE threads (1/4" x 28tpi), while the Traditions guns (being foreign) use metric threads. The package should state what the thread size is. If you see the measurement in millimeters, it is the wrong nipple for a T/C rifle. If you have a Traditions rifle, then the metric threads are correct. Just be aware that Traditions has two different thread sized for their guns. The "standard" size is 6mm x 1mm, and the "LFS Magnum" nipples are 8mm x 1mm. Of course, it's not possible to mix these up, and they are nowhere near close.

Mike