Breechplug
I just checked and the Win W209 Primers are a tad bit bigger than the T7's
Correct the W209's are slightly thicker in diameter than the Win T7 primers. so they should fit a little better.
Here is a picture of the primer sitting in the pocket on the Triumph. If you lay a straight edge across the primer and the breech plug - the primer is just slightly and I mean slightly taller than the edge of the BP. With the gun closed but not latched you can feel and see the BP touch up against the breech block. When you close the trigger it seems to tighten it just a bit more. This is a Win T7 primer in the cup. I can not actually say that the block presses on the primer but it is very close to that. If the primer expands in length at all during ignition it sure would be.
