Sabotloader has done an excellent job of explaining and drawing.

I have actually gone to the next step beyond his Modifications, I believe you should start with his mods and then let it evolve from there. I hunt/shoot even in extreme cold temps. It was -4F here one day during our late ML season. I had no fear that BH209 would light in my T-Bolt. The gun was being carried by a 16 yr old family friend that got so excited when we put deer right past him several time less than 10 yards, he couldn't move. Life and excitement is great :-)

My plugs are done/modified to ignite BH209 in my customized Knight T-Bolt and even harder to light powders in My Rolling Block ML.

I look forward to seeing Lehigh Dave's design, It will probably fit my T-Bolt.

Make lots of noise :-)