What really amazes us is, that after all this time has done by, no one, not one member who has purchased one of these Hern tubes, has even bothered to tell
the membership what the configuration of the breech plug within the liner is. This is a very critical shape that pretty much controls whether you can clean all
powder residue and cartridge bag fragments out of the bore's bottom BEFORE the next powder charge is rammed home. It is an important Safety feature and is
appropriately required by artillery organizations.
Take it from the old inspectors, you don't need an expensive borescope to check this out! All you need is a metal or hardwood rod or dowel with a squared off
end. Slide the rod down your bore, keeping it pressed tightly to the bore's surface until it stops at the bottom. Carefully mark the rod where the muzzle face
meets it. Place thin cardboard shims with a combined thickness of 1/16" between the bore surface and the rod; press the rod against the bottom again. Mark
again in a different spot. Repeat until your rod is near the center of the bore.
Look at your marks. If they are configured like a waterfall, you have a radiused breech plug, making cleaning much easier and more complete. If all your marks
are the same distance from the muzzle face, your breech plug has a flat end at the bore's bottom, making cleaning much more difficult and incomplete cleaning more likely. Experienced
artillerists we have talked to consider incomplete cleaning one of the leading causes of pre-mature discharge which can cause injury, dismemberment or death. So,
with properly made cleaning brushes and sponges, this squared off bore bottom configuration from any manufacturer can be cleaned effectively with a little extra effort.
Mike and Tracy
