Steve Chapman and I finished off the tests on the flat flint breech today. We used a variety of vent systems provided by Dan Pharis and Jim Chambers. By now we think we have the flat breech pretty well rung out.
The chart below provide averages for the various liners. We timed them cleaning very carefully and also dirty. On the dirty trials we started clean but did nothing at all between trials. Seating the sabot became increasingly difficult and caused a sharper sound on the "dirty" trials.
vent type-------------------------clean---------------------------dirty
Phariss Chambers style-------------.0405--------------------------.0433
Phariss .055-.101*-----------------.0398--------------------------.0474
Phariss (large w ext cone)----------.0309
Chambers WL .064----------------.0370--------------------------.0400
Chambers WL .064 ext cone**------.0377
Chambers WL .064 ext cone--------.0510 --
ffg as barrel powderChambers WL .064 ext cone--------.0660 --
One try ffg in barrel and pan*Liner has vent of .055 and counter-bored inside to .101
** Exterior Cone is
very slight
We had fun trying to see if we could get some good pics. We basically held done the button and let it fly. We uploaded the shot that caught the ignition and the one that followed.
Note the sparks flying in the second pic.
This shot is just after the barrel fired. You can see fire just beyond the shield.
Again sparks on all sides.
You might note the haze developing in these last two shots.
Regards,
Pletch & Steve Chapman