Strange hardness tests....

[Harry O]

I normally file off a flat and test two or three bullets after they have had a week or two to stabilize. The tester is a Lee. I usually average the results, unless one is way out.

Just last week, I tested some 358156-GC bullets that had been cast a couple of weeks before. I was trying for Bhn 13.0 to 14.0 with the mix. This time, I decided to try several tests on a single bullet instead of sacrificing three of them. The results seemed strange, so I did it two more times. All three bullets showed the same thing.

The indentation near the base of the bullet showed a hardness of 13.0 to 13.5 Bhn. The indentation in the middle showed 14.0 to 14.5 Bhn. The indentation in the nose showed about Bhn 15.0 to 15.5.

I was not expecting such a variation in a single, short bullet. Normally, I do the single test in a spot between the first and second one. Any thoughts on this?

[Mk42gunner]

Was the mold up to temp when you cast these bullets?

I haven't had my Lee hardness tester out of the box in a few years, I'll break mine out this evening and try a few older boolits.

Robert

[country gent]

Look at the "mass of the cross sections, Base middle and nose. base is bigger and longer farther from the nose, mid section is same dia but closer to nose, nose is smaller dia long and skinny. Nose is cooling faster and sucking heat from mid section faster, base is last to cool possibly a annealing effect? Mu only expalanation for it right now. Would be interesting to see if the spread is as great with water quenched bullets thru the bullet.

[jhalcott]

MY question is HOW do these bullets react when shot into wetpack or animal flesh? Accuracy up to your expectations, wound channels good to great? We can over think this game, or just cast and shoot! Did you ever weigh a box of factory bullets?
ALL of those BHN's you quoted are within good hunting range. It is most likely a symptom of slower cooling off the fatter bases as has been said.

[bangerjim]

I have a Lee but now use a Cabine due to ease of use.

With the Cabine, I test 1/2# ingots I draw off the pot when I am done mixing the next bacth B4 shutting down. I see 4-5 increases over several days.

I have tested single boolits using a T-nut for the nose and the Cabine point in the base. Works great. But I never test the sides or nose due to the geometry and holding the thing in the tester!

It is interesting you are finiding differences. Could be caused by the above mentioned temp profiles. Or the difference in the dispersion of the lead by the hardness tester due to the geometry (flat/round/grooves) of the test point spot on the boolit.

I just stick with the base-only test if I am testing old boolits. It may be wrong, but with the Cabine, it is repeatably wrong, so that is what matters.

I agree that your range is well within hunting specs! I run all my standard boolits around 9-12 and then powder coat them, so I can use softer lead and save alloys. And no leading!!!!!!!

bangerjim

[Harry O]

Look at the "mass of the cross sections, Base middle and nose. base is bigger and longer farther from the nose, mid section is same dia but closer to nose, nose is smaller dia long and skinny. Nose is cooling faster and sucking heat from mid section faster, base is last to cool possibly a annealing effect? Mu only explanation for it right now. Would be interesting to see if the spread is as great with water quenched bullets thru the bullet.

Interesting theory, and very possible. These were air cooled and dropped on a towel. The quicker it would quench, the harder it would be. It would probably cool quicker (quench) at the nose.

The mix is my standard mix for this bullet. I have been using it for years and it gives me very good accuracy in all of my .357's. The bullet is sized to 0.358" with NRA 50/50 lube, Hornady gas checks and 13.5gr of 2400. There has never been a problem with these in the past. The only difference between the ones I have been using for years and these is that I tested these in different places.

[303Guy]

I have a mould and had an alloy that would frost on the lower section (the base). The base section was that much harder than the nose section which I thought was great for a hunting boolit. The base section of the mould was thinner and therefore cooled quicker. Trouble is, the mould needed to be heated to the melting point of the alloy then set to cool for each boolit which equals painfully slow! I might even try it again one day just for a batch of hunting boolits. I'd say that with the right alloy and the right mould design this could be done with normal casting.

[Mk42gunner]

Harry,

I didn't get a chance to do the test this evening, I ended up watching a movie at Mom's when I went to town to check on her. I will try to get it done tomorrow. I don't even know if I can see well enough to use the Lee tester anymore, this gives me a good reason to check.

Robert