Some pics of the latest gun mod's.
Have the new polypropylene plugs - very easy to cut and drill. Since the plastic is also an insulator, using bare 1/16" copper tube as the power terminal with 0.012 nichrome (28guage) as the igniter wire.
Fired about 10 times. Very reliable. Polypropylene easily takes teh momentary high temp burst from BP ignition (m.p. is 490F)
Will be converting all barrels.
Great source for all sizes nichrome wire: www.PNJresources.com
Source for plastic breech plugs shown in pic.