Ritchie
Member
I've been working with powder coated bullets recently. Results are:
Gun: Beretta M92FS Compact
Bullet: Lee 124 gr. TC tumble lube, sized .358 in all instances.
Previous load: conventional lube sizing with Rooster Red lube. 4.0 grains of
AA#2. This load produced 2 to 4 keyholes in each magazine. Full profile
keyholes were frequently produced at as little as one meter distance.
Variations in powder charge resulted in no change in keyholing.
Light load: bullet powder coated with Harbor Freight red. 4.0 grains of
AA#2. Noticeably improved accuracy, closer to point of aim. Far fewer
keyholes but not entirely elimated. Fairly clean barrel.
Heavy load: bullet powder coated as above. 6.0 grains of Power Pistol .
Improved accuracy, even closer to point of aim. Fairly clean barrel. Shot
80 rounds, keyholing NONE.
Discussion: Typically, the 9mm Para seems to have "generous" dimensions
in the throat and leade. Jacketed, copper plated, and powder coated lead
bullets have less trouble with poor accuracy and keyholing than do greased
lead bullets. It turns out that conventional lead bullets are a challenge for
handloaders in 9mm. I speculate that when a bullet occasionally yaws on
leaving the case mouth, the base of the bullet drags on or is pushed into the
side of the throat/leade. In the case of the greased lead bullet, the base area
is smeared or otherwise distorted. The bullet with a coating over all has less
friction and greater surface protection, so does not suffer so much damage.
With powder coated or plated bullets, these treatments do little to increase
structural strength, but do protect the entire surface. It has not been possible
to recover fired bullets, but I would be most interested to examine keyholers
that were not greatly damaged in recovery.
Gun: Beretta M92FS Compact
Bullet: Lee 124 gr. TC tumble lube, sized .358 in all instances.
Previous load: conventional lube sizing with Rooster Red lube. 4.0 grains of
AA#2. This load produced 2 to 4 keyholes in each magazine. Full profile
keyholes were frequently produced at as little as one meter distance.
Variations in powder charge resulted in no change in keyholing.
Light load: bullet powder coated with Harbor Freight red. 4.0 grains of
AA#2. Noticeably improved accuracy, closer to point of aim. Far fewer
keyholes but not entirely elimated. Fairly clean barrel.
Heavy load: bullet powder coated as above. 6.0 grains of Power Pistol .
Improved accuracy, even closer to point of aim. Fairly clean barrel. Shot
80 rounds, keyholing NONE.
Discussion: Typically, the 9mm Para seems to have "generous" dimensions
in the throat and leade. Jacketed, copper plated, and powder coated lead
bullets have less trouble with poor accuracy and keyholing than do greased
lead bullets. It turns out that conventional lead bullets are a challenge for
handloaders in 9mm. I speculate that when a bullet occasionally yaws on
leaving the case mouth, the base of the bullet drags on or is pushed into the
side of the throat/leade. In the case of the greased lead bullet, the base area
is smeared or otherwise distorted. The bullet with a coating over all has less
friction and greater surface protection, so does not suffer so much damage.
With powder coated or plated bullets, these treatments do little to increase
structural strength, but do protect the entire surface. It has not been possible
to recover fired bullets, but I would be most interested to examine keyholers
that were not greatly damaged in recovery.