How come my bullet keyholes?

[Khornet]

Supposedly

according to an article in the Rifleman years back, it is is proved by physics that a bullet cannot 'strip' the rifling whatever the velocity or bullet materials. Why would the softer bullet then shoot so poorly? I'll guess that it achieves too low a velocity, and thus doesn't spin fast enough to be stabilized, or its base gets cut by powder gases so it gets tipped on leaving the muzzle.

 

[Warthogga10]

Had The Same Problem

I had the same problem loading my 9mm, until I figured out that I was crimping the case a little too much. Seems the case was cutting into the cast round and setting up the steps for making it tumble.

 

[triple4]

.430 cast bullets may not be the best, measure the cylinder throats and do not use a bullet smaller then the throat measurement, smaller then throat bullets can enter the barrel throat a little sideways and that raises heck with accuracy (more so with softer bullets). Rule of thumb is .001/.002 larger then throat diameter. That also brings up a point about knowing what your barrel throat is (diameter) the cylinder diameter and barrel throat diameter should be very close.Never have a cylinder throat diameter that is too small if so have a smith open it up. Ruger was real bad about that. If I have learned anything in shooting Hardcast its fill the barrels throat, you do that and good things happen.

 

[JMusic]

I have two books that list Max loads for 240 grn at 9.2 grains of Blue dot. This should give you a velocity in high 600 to low 700. fyi

 

[cropcirclewalker]

Yes.

The same loads with the harder alloy do not keyhole. My alloy was too soft.

My Charter Arms .44 Bulldog has rifling that is really just a suggestion.

I recovered some slugs from a log that was backing up my targets. Rifling is apparent but not so deep that it looks like rifling.

3" barrell with suggested rifling requires a hard bullet or jacket. I have some store bought jacketed bullets that shoot fine. My home made cast bullets just have to be real hard.

Live and learn.

I move a lot of lead down range. Fifteen cents for a store bought bullet in a round that if I cast my own I could be shooting for four cents is hard for me since I am old and poor.

I probably don't depend on my Bulldog for like a "snake gun" or anything like that since it is not very accurate except for like "under the chin" distances but I like to exercise all the pieces in my arsenal.

Thus, without jacketed HP bullets like a bunch of 200 gr. Hornady XTPs that I loaded up to 1000 fps velocities that might be useful for self defense use I guess my 240 gr SWCs are just useful for some occasional target practicing.

I just love the freight train thought of a big slow moving hunk of lead.

 

[Ben Shepherd]

Thanks for an interesting thread folks. I guess I've been lucky in my bullet casting, never had trouble like you did.

Glad you got it figured out!