Author Topic: Hardness of pellet alloys.  (Read 224 times)

Alan

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Hardness of pellet alloys.
« on: May 26, 2018, 09:32:25 AM »
I read this article over on H.A.M.: https://hardairmagazine.com/reviews/hn-sniper-magnum-14-97-grain-177-caliber-pellet-test-review/ As a result, I sent an email to the “powersthatbe” about the hardness of pellets. I suggested this device: https://www.midwayusa.com/product/1010308018/saeco-lead-hardness-tester (photo with thumb screw) Keep in mind, the Saeco is only a relative-measurement device, as described in their specs for the device. H.A.M. pointed out the fact that the projectile needs to be flat on one end. That’s true, but you can measure the “relative” hardness between pellets by just using the head of the pellet. So we’re on the same page, the Saeco arbitrarily sets the scale at 0 for pure lead, and 10 for linotype lead alloy.

After some searching, I came up with this device: https://leeprecision.com/bullet-casting/lead-hardness-tester/ If you have a reloading press (as shown in the video on this page), this hardness tester may be more accurate as indicated here: http://www.lasc.us/Shay-BHN-Tester-Experiment.htm#Lee

I’m interested in the hardness for a variety of reasons, not the least of which is hydraulic shock, albeit a minimal difference. To wit: I have a .25 caliber WAR Cobra. I use the 25.39 grain JBS pellets. Some months ago, I couldn’t buy any of them, so I purchased a quantity of AirArms 25.4 grain pellets. According to on-line sources (and Bob Sterne), they are the same pellet, made by the same company, with the (only) difference being the die used to swedge them. I will not dispute that, as I have no direct knowledge therein. However…

The JBS pellets seem to be made of a slightly softer alloy, than the AirArms pellets. That’s borne out by the Saeco’s readout of ≈1.5 vs. ≈2.1 respectively measuring on the heads of the pellets. If anyone can supply further information on any aspect of this scenario, I'd like to read it.




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Alan

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rsterne

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Re: Hardness of pellet alloys.
« Reply #1 on: May 26, 2018, 10:07:12 AM »
Perhaps AA have JSB use an alloy with a bit of tin in it to maintain the silver appearance better, and minimize damage from rattling around in the tin?.... Certainly when casting, using 40:1 (2.5% tin) maintains the nice, bright appearance for much longer, pure lead goes a dull grey in less than a year.... Pure lead is supposed to be 5-6 BHN, and 40:1 about 8 BHN....

Bob
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Alan

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Re: Hardness of pellet alloys.
« Reply #2 on: May 26, 2018, 12:14:39 PM »
One can buy a real instrument (read that as expensive) to measure the Brinell hardness of most common materials. But I wonder if the Lee device would be more accurate than the one made by Saeco? I may just have to buy one.
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Alan

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steveoh

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Re: Hardness of pellet alloys.
« Reply #3 on: May 26, 2018, 04:09:08 PM »
Interesting. I ended up buying a bunch of AirArms pellets because Pyramyd was out of JSBs. I saw no difference in accuracy in the Sumatra or the Marauder. Don’t think the rats noticed any difference.

There was a discussion about adding tin to big bore bullets when casting to help fill out.

So I cast a bunch using soft lead. Then I took a handful of Hunters Supply round balls that didn’t fit in any of my rifles and added to a pot of lead. Those HS bullets, slugs and roundballs are HARD. I figured the tin would help with my fill out. They seem shinier, but I swear the fill out wasn’t any better. Of course this wasn’t in the least bit scientific, but what the heck.

Let me know when you get your tester Alan, and I’ll send you stuff to test!
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Christopher

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Re: Hardness of pellet alloys.
« Reply #4 on: May 26, 2018, 04:55:08 PM »
Steveoh said
Quote
I ended up buying a bunch of AirArms pellets because Pyramyd was out of JSBs. I saw no difference in accuracy in the Sumatra or the Marauder. Don’t think the rats noticed any difference.

I would imagine the Rat Union is lobbying for the most inaccurate pellets you have....... :P

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rsterne

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Re: Hardness of pellet alloys.
« Reply #5 on: May 26, 2018, 04:56:15 PM »
The HS roundballs may have Antimony in them, which makes them hard but does not help fill-out like Tin does....

Bob
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steveoh

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Re: Hardness of pellet alloys.
« Reply #6 on: May 26, 2018, 05:03:13 PM »
The HS roundballs may have Antimony in them, which makes them hard but does not help fill-out like Tin does....

Bob

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Alan

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Re: Hardness of pellet alloys.
« Reply #7 on: May 26, 2018, 05:37:18 PM »
I'm not a metallurgist, and what little I know about lead alloys, I've picked up on the net. And from Bob Sterne as well.

When you say fill out, I'm assuming you mean in the mold itself? What little casting I have done, has been with used tire weight lead. By experience, you have to get that stuff much hotter. Too hot, and you start leaving internal cavities. I'm also sure the antimony content is high in tire weights, which would limit their obturation. However, when you're using a gas check, I suspect that doesn't matter much. But it isn't obturation per se, that I'm talking about. Rather, how well the pellet expands. This is a two way street.

There is no doubt that PolyMags expand better than common diabolo pellets. At least the instant kill rate is noticeably higher. Only problem is, I've never found a gun they shoot well in, past about 30 yards.

Bob mentioned color (lack of oxidation), but I shoot enough that pellets never stick around long enough to change color, save for red! All I want is a cleaner expansion, without losing long-range accuracy. I don't think this is a stretch by any means.
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Alan

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caniborrowsomeammo

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Re: Hardness of pellet alloys.
« Reply #8 on: May 26, 2018, 09:18:52 PM »
I can't find any used lead tire weights here. And that's through a friend that manages a large tire shop. Not many lead weights come through at all he tells me. Such is Kalifornia.
Buncha BB guns that I don't get to shoot as much as I like. Building duck boats now that I'm "retired".

Bullfrog

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Re: Hardness of pellet alloys.
« Reply #9 on: June 13, 2018, 06:01:52 PM »
Since I've been casting I've been thinkings a lot about hardness and also considering the difference in hardnesses between pellets.

There's a huge difference in penetration potential between a hard alloy and a soft alloy. I suppose that's obvious to an extent. But its very practical for the hunter who may need to choose penetration or expansion depending on what he or she is hunting and what kind of shot placement the hunter intends.

For example, I'm running my Flex Carbine around 74-75fpe with 44.75 JSBs. At 50 yards, those JSBs can shoot thru one foot of 12.5% ballistics gel. However, they cannot shoot thru a 2x4 at 50 yards. They penetrate about half way thru it. Yet if I use a hard #1 buckshot pellet with a lot of antimony in it, it will shoot straight thru the 2x4 at 900fps at the muzzle (slightly less energy than the pellets). Although the shape of the buckshot may play a role, I'm sure the hardness is the primary factor in causing it to shoot thru the 2x4.

Barracudas are the hardest pellets I've used in .25 caliber and also some of the most effective as hunting pellets. They do not deform at all in any practical sense (of course they take rifling and they can have ever so slight deformation around the head). They penetrate very deep at a give fpe and they're hard to catch in most media. I haven't found something that can catch them at 80fpe yet. Even several water jugs back to back can't catch them.

For whatever reason, H&N made a version of Barracudas in .30 that are soft like JSBs, not hard like .25 Barracudas. I'd far rather see an ultra hard .30 pellet that can provide some penetrations options the softer pellets cannot.