Just a mention on Lee quality control....

[Harry O]

I bought two of the Lee 405gr 45-70 hollow base bullets to try with the Rolling Block I am having built. It has been recommended several places for BP 45-70's. I got two because they are single cavity. I can cast with two of them alternately almost as fast as a regular double-cavity mould.

Since this was the first time, I weighed a bunch of them. Got a horrible spread. Then I weighed every single one. Turns out there were two separate groups. Both groups were within 3 grains top to bottom, but they were separated by 11 grains. One was centered around 406gr and one was centered around 395gr. Both sets of bullets looked good. Looks like I am back to using one mould when I cast for that one.

I have two Lyman 40043 moulds that have a very slight difference. Those two moulds are about 1-1/2 grains apart. Close enough I can use them without separating them.

Oh well, at least they were cheap. I will see how they work before ordering a Rapine.

[dromia]

Have you measured the two bullets to see where the difference lies dimensionally?

[BudRow]

I don't know how you intend to shoot your custom made gun - bench rest - competition? My experience has been less than 3% difference in weight (in this case) won't show an apprecitable difference on target.

[Harry O]

Have you measured the two bullets to see where the difference lies dimensionally?

Not yet.

[montana_charlie]

I bought two of the Lee 405gr 45-70 hollow base bullets to try with the Rolling Block I am having built. It has been recommended several places for BP 45-70's.
I may remember incorrectly but, I thought that hollow base bullet was recommended for Trapdoors...because of the wide variation in groove diameter from one gun to another.

I would have thought a solid base would be preferred in every case that would allow it's use, and a custom made rifle shouldn't suffer from non-standard bore dimensions.

CM

[StanDahl]

My problem with this mould is filling in the tiny little rim around the base.
http://img.photobucket.com/albums/v405/StanDahl/90268b.jpg
This is about the best picture I could get... on the rim, you'll see one side filled out fine, and the other not. Other times there would be near-perfect fillout on the edge but small voids along the seam.
I think they look better in person than in this photo. The bottom looks very round here, but it really isn't so bad. These were the result of much pouring, and many rejects, with the ladle smack up against the sprue. I haven't tried shooting them because I only have about 20 of them and my local range got closed a while back. For now I just like looking at them because they're so much better than any before.
http://img.photobucket.com/albums/v405/StanDahl/90268.jpg
I'm wondering if that base is really supposed to expand. It's pretty thick.

[jim4065]

Best pictures I've seen in a very long time. Let me guess - the one on the right weighs less?

[montana_charlie]

Stan,
If Harry O doesn't mind us using his thread for discussing your problem, I have a question or two.

The little 'nick' in your base seems to be close to the parting line of the mould. Is it always in the same spot? If it doesn't 'move around', it looks very much like the kind of defect caused by a 'contaminant'.

Is it possible that something 'dirty' can get introduced into the mould by the base pin between fills?
CM

[Harry O]

I have a number of hollow-base moulds and all of them are more difficult to get good bullets from than with flat-base moulds. However, I have been able to get all of them to work -- sometimes eventually.

The most important thing is to keep the melt as hot as possible. I turn mine all the way up. If my melting pot would go hotter, I would, since it is barely hot enough now. Enough tin is needed, more than with flat base moulds. You need at least 2% with a hollow-base and 3% is better. I have cast flat-base fairly easily with 1% tin.

The next thing is to keep the bottom mould pin hot. After filling the mould, I rest the bottom of the mould on the top edge of the melting pot while waiting for the sprue to solidify. Even so, keep a candle burning whenever I cast with hollow-base moulds so that after I dump the bullet, I can put the pin over the candle for a few seconds (that is with an open bullet mould and holding it upside down). Then I close up the mould and fill it again. I can only cast most hollow-base bullets about one per minute. Very slow.

By doing all of these things (and after getting everything up to the proper heat), I don't have too many rejects. The key is to look carefully into the hollow-base. If the bottom (the narrow part) of the hollow is deformed, sunken, or there is a dark spot, it means there is a hollow cavity in the bullet. Throw it back into the pot.

[Harry O]

I did a lot of measuring tonight. It looks like the bullet part of the mould (of the two I have) are the same size, as near as I can measure. The length of the base plug is slightly different (approx 0.018"). That makes the rear driving band a little bit longer on the heavier one.

[StanDahl]

Yep, the one on the right is 3 grains lighter. (With 20:1 it weighs in at 383 gr's, it's supposed to be a 405gr bullet.) I thought that I had picked two good ones, but didn't look closely enough. This view makes it look pretty obvious:http://img.photobucket.com/albums/v405/StanDahl/90268c.jpg
The back side of the one on the right is perfect - it's only the one side that is badly filled.
I get the base defect generally along both parting lines, but not always. More heat is needed, I guess. I like the idea of keeping the base pin hot - not doing that may be drawing heat from the bullet base.