Hello, Pond, James Pond. This takes me back a few years! Back when I was in high school, I converted a Marlin .22 bolt action rifle to needle-fire..cases were std. rimfire with very small hole in head. .060" drill rod "needle" firing pin. Made a 40gr. heeled .22 bullet mould, & strike-anywhere match head primers. Match head sat on top of charge..pinched between bullet-base & pin.
Worked most of time!
But I wanted an honest-to -goodness centerfire. on lathe, I faced off rims of fired cases.
Turned up new case-head with small rifle sized primer-pocket & rim out of brass. This was a close fit in case. Low-temp. silver soldered in place.
These had a higher report than high velocity long rifles. Case life was pretty good with several re-loadings. All went swimmingly...until one evening.
I was returning home from late afternoon squirrel hunt..getting dark in woods & decided to attempt to hit a large walnut on stump. At the shot..an
orange ball of flame erupted around front of bolt..I figured I had a case-seperation..this happened sometimes. Upon extracting case..everything looked normal..case intact, no smoke smudges anywhere..primer was still tight.
I tried another..and another..every one exhibited this big ball of flame!
I finally figured that the red-heat I was subjecting that case head to during silver-soldering..plus the fact that the "walls" of that "head" were only some .020" thick..that case was expanding enough to let gases blow around primer..but then must have sprung back enough to permit a snug primer fit.
I kind of lost interest in that project after that.
I did turn up cases from solid brass..including primer pocket..but the problem of too litle metal in head was still there.
Back in the late 1800's..there was a .22 centerfire Maynard....the .22-10-45...It used a primer of smaller dia. than our .175" dia. small rifle primers.