Forums.NitroExpress.com

I just took a Lyman mould cast bullet from #457125 that measured .458", ran a couple wraps of "PTFE THREAD SEAL TAPE 12MMX0.075MM10M" around IT and re-measured the taped bullet at .462".

I unwrapped the bullet and repeated the wrapping - .462" again. I think the enlargement is due to the tendency of the tape to fold on the edges and with the overlapping to get the length also adds to the diameter over what the actual single layer thickness X 4 would give. Of course, this is different than with paper patching which gives results closer to actual measurement X4.
Regardless, it worked to increase the diameter and can be done on bullets that just a bit smaller than you'd like, to make them better fit your chamber's throat. This should increase accuracy, of course.

I recommend you tape the bullets down onto the ogive, so the rifling lands start to engrave down a bit from the end of the tape to prevent balling up of that edge as the bullet starts into the lands.

A single piece of my Teflon tape measured .0005" using my N.S.K. mic.
Times 4 + .0016" - YET - the bullets increased .002" per side.

--------------------
Daryl

"a gun without hammers is like a Spaniel without ears" King George V

Post Extras