Bullet Casting Woes

[Patrick Chadwick]

Do it look something like this Patrick?

Yep, that's the gadget - I found mine this afternoon quite quickly in the Upper Cretaceous deposits. It's a tool from CH4D, for putting a crimp cannelure on lead bullets. However I think you need to make a plug to fill the case back to just in front of the cannelure and keep the neck round*, otherwise if you put enough pressure on to make a good groove, the neck might become distorted. I just dived in with an old, fired 45ACP case, not perfectly round, and that's what happened when the case slipped off the rolllers. But up to that point the case had been getting "groovy".

*And the plug can be made with a step to hold the case so that the groove is pressed in the right position.

[jmoore]

Welllll...The larger expander wasn't the "end all, be all" answer to curing leading just past the forcing cone with soft swaged bullets. But the offender today hasn't had but the three factory proof rounds through it since it was new back in the mid 1980s until this last autumn when I "ruin't" it for collectors by shooting it. Otherwise the larger expander seems a vast improvement over the smaller "as supplied" units. The new four cavity mould's recovered range lead bullets performed better than any of the store bought stuff, even though the lightest bullets were used.

Additionally, the storm yesterday uncovered lots of bullets for recycling! Cheap muddy fun we had picking "lead berries" from the berm. Possibly 60 lbs altogether in a fairly brief session.

One new woe: probably had the sprue plate screw a bit tight on one mould set. Fairly well galled in the area immediately surrounding the screw. Plate might be somewhat warped as well, but I think it's mostly the pivot area wear that's keeping the plate from sitting flat on the mould top.

A couple of photos from last weekend's casting session (Too busy shooting today to do range photos, so it must have been a good morning even though it was questionable at the start!):

[jmoore]

(See Post #64) Some recovered bullets that sat a little long in a plastic bag. Lost some of their "shiny" in the hot, moist conditions over the past week:
These are "pre-custom expander".

Swaged bullets. Note the erosion in the rifling groove near the base. Gas cutting or galling?



"Store bought" cast bullets (on the left side of the enlarged photo) loaded more less the same as the swaged and at about the same time:



They measured the same diameter (within 0.001") as the wsaged before loading. The bevel base and their hardness make them unlikely to "bump up" to fit, so it seems the swaged bullets were sized down at loading, especially near the base. Rifling just isn't nearly as well defined. Swaged bullets work great in .22 rf arms, even revolvers, so why not larger revolver bullets? There's got to be a way to do it. Or is that a subject for another thread?

These aren't milsurp revolvers or pistols being tested currently, but those WILL be tested before it's all over. Might as well abuse some more "range refined" examples first. And one day the .43 Mauser chambered Remington Lee, and the 50-70, and maybe even some 45-70s! Then there's the 1891 Argentine Mauser patiently awaiting a bullet mould and gas checks.

[Patrick Chadwick]

I'm not enough of a metallurgist to be sure about this, but maybe the swaging procedure causes a surface hardening and unrelieved stress that leads to bits splitting off the bullet, either when it is forced down the barrel or when it impacts the berm. A clue would be if you observe worse leading of the bore with swaged bullets than cast ones.

[villiers]

Those pics would seem to further convince that hollow based bullets are the way to go.

[jmoore]

Those pics would seem to further convince that hollow based bullets are the way to go.

Mmmm, a guarded "yes". But mostly in situations where using a bullet that is at or slightly above groove diameter is not possible. Rifled muskets for one instance. And not always then! (Hornady makes a nice reversed stepped bullet that engraves the front band, but it's still hollow based.) Some cartridges just won't chamber with a full sized bullet seated in the case. (Assuming that the case isn't doing further bullet diameter reduction upon seating as happened above!) But otherwise you end up having to forgo base wads that protect the bullet's base from the black powder's low grade explosion.

Here's the damaged mould set mentioned several posts ago (#72) after being attacked with a flat rock:

Attachment 43820Attachment 43818Attachment 43817

Added some copper based anti-seize and was very careful in setting the sprue plate tension at reassembly. There's a little light visible under the plate at the outer portion, but it's probably less than 0.003". I get nervous when I can see any light between flat surfaces, but it's often less than 0.0005", so consider the source!


Attachment 43819

I believe Patrick Chadwick mentioned an aluminum based anti-seize recently, but this can will do me for the foreseeable future. ETA: Here's a link for reference: A square screw?

BTW, IIRC, lead is generally considered "self annealing" at room temperatures, so swaged bullets are very unlikely to have a hard outer shell unless they're oxidized. Even heat treated wheel weights will slowly soften over time.

[Patrick Chadwick]

I believe Patrick Chadwick mentioned an aluminum based anti-seize recently, but this can will do me for the foreseeable future.

Yep, either will do. It was the spray can that persuaded me to buy the alu version.

[Patrick Chadwick]

BTW, IIRC, lead is generally considered "self annealing" at room temperatures, so swaged bullets are very unlikely to have a hard outer shell unless they're oxidized.

OK, just a hypothesis, but do you have an alternative explanation? I just know that the lead sheet I use for soft vice jaws develops cracks after extensive use, so I think there is a work-hardening effect, even if small.

[jmoore]

is a work-hardening effect, even if small.

In the short term, yes. And if there's microfractures, they won't heal themselves. As for the eroded areas in the lower grooves region, I'm thinking it's gas cutting. It was quite shiny just after having been recovered. A bullet trap that would damage the bullet less would be helpful. Could drag the revolver down to the "crick" on the hunting property and procede to get wet!

Cast a bunch of bullets, but fought with the process for well over an hour. Couldn't get good crisp edges! Even with the melt nearing 800°F. Finally just cast a mess until the pot ran dry, threw in the sprues, reject bullets and some overflow back in the pot and started again. Oddly, the bullets came out much better, even at much lower temperatures! The two melts will be kept separate. Would like the mould to drop bullets ~0.002" larger, but have yet to try "beagling" the blocks.

[villiers]

Mine came out crisper when I started adding a dash of tin.