key holed bullets

[bigotto]

I posted this question on a few other fotums and gotanswers that made sense but I want more ideas.

.45-70 trapdoor with a green mountan 1:18" twist sharps barrel. Bullets cast in a Lee 500 gr. .459" mold. Lubed with home made soy wax, crisco and canola oil. 62gr FFG BP and a tablet back spacer between bullet and powder.

1st shot hits 1/4" rifgt at 25 yards. next shot the bullet tumbles and enters target sideways at 90deg. swab out bore until patch comes clean and the process and results repeat. did it 3 times with same results.

Whatare possible problems?

[303Guy]

Welcome aboard bigotto. :drinks:

It seems that your problem is directly related to the BP. May I suggest also posting on the Black Powder section? You may get more viewings and suggestions from those folks in case they don't frequent this section.

Might I also suggest having a look under Black Powder Paper Patching? You might pick up some ideas from there too. You might even be interested in giving it a try. It's fun. :mrgreen:

[Larry Gibson]

Actual bullet mould?
Alloy?
bullet sized to?
Has that home made lube worked with other BP loads?
How much neck tension on bullet?

Larry Gibson

[bigotto]

Ok everybody, let's hear a great big giant DUH!!! for the guy in the corner with the pointy hat.

I sized my bullets to .457" for a .458" barrel!

There are moments in life when I wonder how I find my way out of bed without missing the floor.

[btroj]

Sounds like a likely cause. Small bullets never seem to work out very well.

[1Shirt]

The only people who don't make mistakes are those who do nothing! Good catch!
1Shirt!:coffee:

[462]

When I saw the thread's title, my first thought was a too small boolit.

Wouldn't it be nice if all our casting problems were so easily solved?

[Rangefinder]

Yup, good to see my diagnosis skills are in the right chapter too. Started typing undersized causing skidding in the bore, then finished reading everyone elses posts to see if it had already been touched on. I only know this because I did the same thing with my winchester. I'd estimate sizing to .459 to .460 ought to solve all problems on the key-holing.

[mooman76]

I was thinking too hard of an alloy. When I first started with my Trapdoor I was using a hard alloy until I was told that they like the softer alloys better. That cured it but is seems like you already solved your problem. Glad to have yo aboard.

[T-Bird]

Have done exactly the same thing ,with the same results, with the same caliber. My first cast boolet gun back in the '90s was a Pedersoli 45/70 Sharps. T-Bird

[geargnasher]

Glad I'm not the only one! Undersized was my first guess since bore/groove/actual boolit dimensions weren't mentioned in the OP.

By the way, that lube recipe is superb in my experience, since the soy "wax" is just hydrogenated soybean oil (similar to margerine), and there aren't any real "waxes" in the formula. Seems to do a better job of keeping fouling soft than lubes containing beeswax. It also makes a great patch lube and revolver "capping" lube, although it will melt and run out of the cylinder of a hot revolver.

Gear

[44man]

Someone did a test with a bunch of BP lubes some time ago. The difference in groups between lubes was pretty dramatic. Seems like too slippery is not good. I know my patch lube is real poor on a boolit.
Everyone is right about the boolit size and it always was my gripe that so many BP molds cast too small.

[geargnasher]

Too slippery not good with smokeless powder, either! Guess that one's universal.

Gear

[bigotto]

So, I cast new bullets and load them up and shoot one round. Still getting keyholed bullets!!! *** I am thinking. I go down range and dig all the fired bullets out of the sand. There are no rifling grooves on the bullets. I go home and measure the newest casted bullets and they are .459" to .460". I try to force a lubed bullet down the bore and it is very tight. It would require a hammer to accomplish this. ***!! not the bullets and not the barrel? Next, I make a chamber casting and something appears very wrong. The chamber has no throat and is cut a full 1/8" short! So in my disbelief I make another casting of the chamber and it is exactly like the first. So I was seating my brass into the rifling and basically extruding the lead bullet into the barrel. If it weren't for the soft lead I never would have been able to close the action. The gunsmith that fit the barrel and cut the chamber said it would close hard so I didn't give it a second thought when it did indeed close hard. I feel very lucky the damn thing didn't grenade in my face.

[curator]

That particular Lee bullet has a under bore size nose which contributes to key holing. Shooting real black powder if you bullets are BHN 8 or less, undersize should not be a problem if the design is good. The Lee bullet 457-500 bullet is not a good design for your rifle.

[SharpsShooter]

Some of those Trapdoors had .462 bores. Have you actually slugged the bore? You may well still be undersize. Measure that chamber casting and report back. That sounds ...uh ..interesting to me. Apparently you were swaging the boolit to quite some diameter less than bore.

SS

[44man]

That particular Lee bullet has a under bore size nose which contributes to key holing. Shooting real black powder if you bullets are BHN 8 or less, undersize should not be a problem if the design is good. The Lee bullet 457-500 bullet is not a good design for your rifle.
I tried that boolit for BPCR and it did not work. Other shooters said it slumps the nose bad.

[Larry Gibson]

So I was seating my brass into the rifling and basically extruding the lead bullet into the barrel.

That's what it sounds like to me. I'd take the chamber casts and rifle back to the gunsmith and take a look at his reamer to make sure it was the correct length.

Larry Gibson