Tumbling Minies

[ead]

What causes tumbling minies or terrible inaccuracy? I've compiled a small list of known causes. Can anyone add to it?
1.Bullet too small for the bore.
2.Damaged muzzle crown.
3.Bullet base not square or not sharp.
4.Bullet alloy too hard
5.Bullet not expanding into rifling which can be caused by #1 or #2 or not using enough
powder.
6.Rate of twist (Rifling) not fast or slow enough for bullet style or shape.
7. Bad lube formula.
8. Minie skirt too thick or too thin for powder charge.
9. Lube too soft or too hard for outside air temperature.
10.Fouling build up (obliterating any advantage of having rifling at all.)
11.Bad bore. Pitting or bad machining in lands or grooves or both.
12.Improperly sized Minie.

[DAVE FRANCE]

I shot some Sharps rounds once with a different lube from what I had been using. It was one of the crayon type lubes, with a bright color. It is fairly well known that those lubes will not work well with blacke powder, but will work with smokeless powder. I think the black powder is not hot enough to soften the lube enough to work well.

If a bullet is only marginally stabile, cold weather, or rainy weather may cause it to tumble.

I shot a bullet that was similar to a maxi ball that would work fine in warm weather but would keyhole at low temperatures.

David

[ead]

Wow Dave, That's amazing. I never thought about the air density being a factor but it makes perfect sense. I have always wondered about how rain would affect a bullets path and stability. I agree that most smokeless lubes seem to usually be worthless for black powder. I've never used it but Alox seems to be an exception at least for smoothbores.

[efritz]

Happened to me once with a Numerich 3 bander tearing skirts on a trash can style wadcutter. Still use that bullet today. Shot and shoots well with any other gun I've tried it in. Numerichs patent breech didn't work well with that bullet.

[Gary Van Kauwenbergh, 101]

I'm not saying those other things can't cause tumbling, but in my experience, the most probable cause is hard lead.

It doesn't have to be wheel weight hard either. One year I cast over a thousand rounds with lead that passed the "thumb nail" test only to find they tumbled. That's the year I bought my LBT lead tester. The lead had a BHN reading of over 5, but less than 7. I had to recast everything. BTW, the colder lead gets, the harder it gets.

I worked in the Fire Direction Control Center of an artillery unit for four years on active duty in the Army. We calculated trajectories for the guns, and compensated for all kinds of things like how much the earth rotated beneath the round while it was in the air, the temperature of the powder, the temperature of the round, the temperature of the fuse, air density, wind direction, wind speed, variances in powder, variances in projectile weight, etc.

If you're trying to put it in a barrel ten miles away, all that stuff matters - but shooting off hand at 50 yards, most of it is academic.

[DAVE FRANCE]

ead,

I used a lube that was alox and beeswax for over 20 years for Minies and other carbine rounds I used.

It worked for black powder very well, but it left a residue that got hard quickly with my Henry, so I started using something else.

A high temperature version came out that would melt at a higher temperature and I started using that on my Sharps carbine rounds.

A friend of mine used to shoot in Schutzen competition with cast bullets and black powder. He shot a perfect 200 out of 200 at 200 yards. All ten bullets were in a 4 inch diameter. He tested many lubes he bought and said several of them worked well.

I read a lot about lubes several years ago.

Someone mentioned bullets that tumbled that had a hardness of less than 8 on the LBT hardbness tester. I collected MInes from people and tested them for hardness. Some were 8, and worked well, but I think a heavy bullet with a heavy load of 3f might work and with another bullet that hard, and with a different charge and a lighter bullet, it might not.

The finger scratch test is not a good test. If you have a soft bullet and a hard bullet, and drop them on concrete, the sound they make is very different. The same with ingots. I think a sound test is better than a scratch test.

A lot of people have cast Minies that were too hard.

People say that petroleum products should not be used in lubes. Waxes and I think Mobil One oil are made from petroleum products, but they are not made the same way that regular oil is, etc. My memory might be wrong about this.

David

[Lee Hoffecker]

Hello All,
One thing that I found that will cause a bullet to tumble thatno one else has mentioned is the thickness of the skirt.
I had a problem with the bullet not expanding enough to fully grip the rifling. I got a new base plug from John Dewalt
for my mold which cast a bullet with a deeper and thinner skirt. This solved the problem of minies tumbling.
Lee

[ead]

Lee,
What mould were you using?

[Joe Plakis, 9575V]

Regardless of what type of bullet you are using, unless you get the skirt to expand you will have tumbling bullets.

A ways back when I first bought my Whitacre barrel for my 63 Springfield I had a huge problem with tumbling minies. Problem was a size 580 bore, and sized 575 minies, 46 grains was not enough to expand the skirt enough to engage the rifling correctly. Even after going up to 578 and even 579, the 46 was still not enough, bullets flew out of the muzzle with a shotgun effect.

We had other problems with bullet molds. One that is well known is the RCBS hodgdon bullet, the skirt is too thick, 46 grains was not enough to get good accuracy, needed well over 55!. But after making up a new base plug that thinned the skirt, presto accuracy at 46 grains.

So both bore size and skirt thickness can be an issue! Or one or the other!

[Joe Plakis, 9575V]

Regardless of what type of bullet you are using, unless you get the skirt to expand you will have tumbling bullets.

A ways back when I first bought my Whitacre barrel for my 63 Springfield I had a huge problem with tumbling minies. Problem was a size 580 bore, and sized 575 minies, 46 grains was not enough to expand the skirt enough to engage the rifling correctly. Even after going up to 578 and even 579, the 46 was still not enough, bullets flew out of the muzzle with a shotgun effect.

We had other problems with bullet molds. One that is well known is the RCBS hodgdon bullet, the skirt is too thick, 46 grains was not enough to get good accuracy, needed well over 55!. But after making up a new base plug that thinned the skirt, presto accuracy at 46 grains.

So both bore size and skirt thickness can be an issue! Or one or the other!