cljohnson24 said:
.............. Make sure the "flash hole"(aka touch hole) is at least .031" (#68 drill bit). I've found .033(#66 bit) to be optimum and replace BP/vent when a .035(#65) will pass thru................
Gee, That sure seems limiting. Using a breech plug only when the flash hole is 0.033" to 0.035". That plug will be good for about 75 shots, then it will need replacing.
Back when Blackhorn was first available for purchase i used it for hunting in my X7. Never had an issue, and never knew there were ignition issues. Do recall hunting one day when it was a way below zero. The rifle/powder ignited perfectly when i took a shot.
When i had an urge to try a break action, i ended up with an Accura. When it was cold, i noticed delays ever once in a while. Still, i took it hunting. While hunting it misfired. After that i studied up on breech plugs, and read several posts on these forums about ignition issues with CVA rifles. After the misfire, i set out to improve the old CVA breech plug. What was done, is a vent liner was utilized to make the CVA hex head plug look like the Omega plug. It worked good. However we weren't satisfied, and tested, tested, and tested the modified plug to make sure it was 100% reliable.
To be sure the modified plug would be reliable in cold cold weather, i waited for forecasts of sub-zero weather, and when they came, i loaded the rifle, and put it out in the truck over night. In the morning i took the rifle, and wrapped it in my coats, and put it in the back. After i drove up to where i could shoot, i took the rifle, and shot it. It was so cold i had to be careful when touching the barrel, because my fingers wanted to get stuck. Our modified plug never failed to instantaneously ignite Blackhorn, using W209 primer. This was done, maybe 25, or 35 times over a couple winters. The same thing was done using the X7 with a standard factory plug. Neither of the rifles had a delay, after spending the night in way sub-zero weather. Both rifles had breech plugs with flash holes of 0.028". The only primer used was the W209 standard shotgun primer.
Back then is when i learned beyond a doubt, when one has the properly designed breech plug, standard shotgun primers are plenty hot, and 0.028" flash holes work to ignite Blackhorn. Then came the idea to make breech plugs from grade 8 bolts. These home made plugs also had flash holes of 0.028", and they also reliably ignited Blackhorn, after being left out over night, in sub-zero weather, using the W209 primer.
All these plugs worked good in all weather, and they worked good when the flash hole was 0.028" up until it grew to about 0.037", which takes about 400 shots, or there abouts.
To me, what matters when hunting is, the rifle shoots accurately without delay. In my experience the 0.028" flash hole using W209 primer accomplishes just exactly that, iff the breech plug is right. The CVA Blackhorn QRBP does not need modifying to be reliable, nor does the standard Omega plug. This i know, after shooting thousands of shots, verifying.