Custom bullet mold and recipe for 540gr Hammerhead?


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Boberama
December 7, 2009, 02:48 PM
Garrett Cartridges makes the 540gr Hammerhead bullet for the .45-70 which has an excellent reputation for penetrating large game through and through. It is loaded to a claimed 1,550 fps and is made from their special "Super-Hard-Cast" alloy.
We designate our bullets as SuperHardCast to differentiate them from common hard cast bullets, as our bullets offer both greater strength...our alloy is very low in antimony, about 2.5% as opposed to the common 6-12% of popular commercial alloys. Our alloy yields a bullet that is very hard, but will deform modestly when stressed beyond its inherent strength.

What I want to do is buy a box of their ammo, pull some bullets out, and have Lee Precision make me a custom mold to the same dimensions.

I need a recipe for casting the bullets, as I want the same hardness ( 25 BH ) but I don't want any brittleness. I want to duplicate the bullet and it's properties as closely as is possible.
The second part is loading the bullet up to 1,550 fps, I need a load for that too, which is safe in a Marlin rifle.
I know I could just buy their bullets, but I want a backup plan if the Garrett 540 goes out of production.

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snuffy
December 7, 2009, 03:19 PM
That's a tall order, and an expensive one. Custom cut lee molds will run close to 200 bucks, and you'll wait about a year to get one.

As for that load in a lever gun, I doubt you can do it with powders we have to load with. Or to the limited pressure you could load to. Loads in the Lyman cast bullet handbook list loads for the 1895 marlin for the 457193 420 grain lead bullet, top load is 41.5-IMR-4198--1737 fps. Add 100 grains, you MAY approach your velocity goal, but it would be a max load.

Better bet would be several custom mold makers that routinely post over on castboolits.com.

rcmodel
December 7, 2009, 03:35 PM
http://www.lbtmoulds.com/moulds.shtml

http://www.intlmidway.com/intl/eproductpage.exe/ShowProduct?saleitemid=186072

Pure Linotype is about as hard as it gets before brittleness really becomes an issue and has a BH of 22.

rc

snuffy
December 7, 2009, 03:44 PM
Quote:
We designate our bullets as SuperHardCast to differentiate them from common hard cast bullets, as our bullets offer both greater strength...our alloy is very low in antimony, about 2.5% as opposed to the common 6-12% of popular commercial alloys. Our alloy yields a bullet that is very hard, but will deform modestly when stressed beyond its inherent strength.

Wow, that's quite a mouthful! You can't have a hard bullet that's also going to mushroom. Unless it posses some sort of magic inherent inside it.

I also don't go along with the BS that high antimony bullets are brittle. Antimony gives a bullet strength as well as hardness. What they're probably doing is heat treating an alloy that's close to Lyman #2 or wheel weights.

420-GR SUPERHARDCAST GAS-CHECKED HAMMERHEAD AT 1650-FPS

Now I see you made a typo in your original post, it's a fourhundred twenty grain bullet! Big difference, and your goal is easily reached in a marlin lever gun. There's ton of bullet molds available for 420 grain gaschecked bullets. 457102 Lyman is a nominal 426 grain gaschecked bullet. It appears to have the same nose profile, see if you can get a mold, then cast it using WW metal, then heat treat it. It helps to have a small percentage of arsenic in it to achive a good heat treat. Common chilled shotshell shot has arsenic in it.

Aw jeeze, if I had just scrolled down to the next offereing at Garret, I'd have seen what you were talking about! Sorry!

Boberama
December 7, 2009, 04:05 PM
Now I see you made a typo in your original post, it's a fourhundred twenty grain bullet! Big difference, and your goal is easily reached in a marlin lever gun. There's ton of bullet molds available for 420 grain gaschecked bullets.

Nope, scroll farther down the Garrett page.
540-GR SUPER-HARD-CAST GAS-CHECKED HAMMERHEAD AT 1550-FPS

THIS 45-70 AMMUNITION IS RECOMMENDED FOR USE ONLY IN MODERN MARLIN RIFLES WITH BALLARD BARRELS.

ENERGY: 2880 FT/LBS; TAYLOR KNOCKOUT VALUE: 55; MEPLAT: .360"; CHAMBER PRESSURE: 35,000-CUP; SECTIONAL DENSITY: .368; TRAJECTORY: +1.5" @ 50-YDS; ZERO @ 100-YDS; -6.5" @ 150-YDS

They also recommend it over 420 for use against bears.
Why do we recommend our 540-grain 45-70 ammo for close-quarters work against grizzly instead of our 420-grain ammo?
Although well suited to grizzly defense, our 420-grainer with its .330" meplat, higher velocity, and flatter trajectory is best deployed as a heavy game hunting round, whereas our 540-grainer with its huge .360" meplat, extreme weight, and lower velocity, is best deployed as a heavy game close-quarters stopper.

freakshow10mm
December 7, 2009, 04:06 PM
Beartooth makes a 525gr WLNGC for the 45/70. It's pricey but probably a better bullet than the Garrett.

There is a lot of hype about the Garrett cartridges and their reasoning is completely unsound. If slower is better then why are they increasing the velocity of 45/70? A "super hard cast" bullet that mushrooms? Doesn't make sense now does it?

That said, for custom molds I recommend Mountain Molds (.com).

freakshow10mm
December 7, 2009, 04:08 PM
If a 420gr bullet at standard velocity does not kill a bear at close range, a 540gr isn't the answer either.

Boberama
December 7, 2009, 04:39 PM
A "super hard cast" bullet that mushrooms? Doesn't make sense now does it?

It doesn't mushroom at the velocities it is loaded to (1550fps). If you push it too fast it might show some DEFORMATION but it doesn't fragment. Some bullets that hard would be brittle and fragment. The Hammerhead is just slightly mushed up.
That elasticity is what I am trying to achieve, while having a BH of 25 ( that's what Hammerheads are advertised to have.)

freakshow10mm
December 7, 2009, 04:57 PM
A BHN of 25 in any bullet, especially for hunting, is way too hard. A BHN of 18 is getting into the "why" category. A hunting bullet should expand. A 15 BHN is plenty hard enough for hunting yet will mushroom.

Mushrooming is a lot different that fragmentation. I am not talking about fragmentation nor ever mentioned it in my previous post.

Do you know how to alloy to get a 25 BHN?

rcmodel
December 7, 2009, 05:03 PM
I have never heard of any bullet alloy that hard that didn't have a large percentage of antimony in it to make it that hard.

They must be using a dash of Unobtainum in the pot to make mailable 25 BHN bullets!

Or a healthy dose of creative advertising like those "Silver Bullets" from Laser-Cast!

rc

snuffy
December 8, 2009, 01:53 AM
Nope, scroll farther down the Garrett page.

Yeah, ig you'll notice the edit I did on my post. I saw that AFTER I posted that you made a typo.

I have a question.? What are you shooting at that requires that kind of penetration? Another ?. Have you ever fired a 500+ grain bullet from that lever gun at those kind of velocities? You'd better have somebody make a lead butt stock for you, then put a 3" super soft recoil pad on it! That is going to be some serious recoil in a lever gun!:what::scrutiny::uhoh:

Jim Watson
December 8, 2009, 11:09 AM
I think one or another of the LBT FN, WFN, or LFN series would be as good as a slavish copy of the Garrett bullet. Tell them that it must feed through a Marlin to get the right shape.

If I were going to have a $200 custom mould made, It sure wouldn't be a Lee. Paul Jones makes the nicest ones I have seen for $220 with handles. He has a 550 grain Flat Nose Hunter that looks like what you are after. But I would still be sure to tell him it is to be for a repeater.

A top load with AA 2495 BR will get you 1600 fps with a 500 grain cast bullet, so the ballistics you want are probably within reach, or near enough to make no difference.

I don't know the secret recipe for a 2.5% antimony BHN 25 bullet, but I used to shoot the old Fusilier brand which got there with a combination of alloy and heat treatment.

I read that the guys shooting Sharps and other period rifles lean towards soft bullets for hunting. A 40:1 flatpoint or blunt roundnose at real black powder velocity of 1200-1400 fps is reported to do right well on up to the original target, buffalo.

MichaelK
December 8, 2009, 11:48 AM
You do NOT have to re-invent the wheel to make an exceptional bear load!

Just go through MidwayUSA's master catalog and pick a bullet that you like. There are 20 different choices between 400 and 540 grains made by RCBS, Lyman, Saeco, ect. I'm sure you'll find something off the shelf that is exactly what you need, and it will only cost 58-81$.

Checkout this mold on clearance at Midway. It looks identical to the hammerhead you want, and it's on clearance for 59$!
http://www.midwayusa.com/viewproduct/?productnumber=185567
I'd buy it today!

I like to mix 1lb of lead-free plumbing solder with 19lbs of wheelweight alloy to make Lyman #2 alloy, which is 90/5/5% lead/tin/antimony. This is wonderfull alloy. It fills the mold well, making beautiful bullets, and is hard enough to shoot at rifle velocities. I have chronographed loads at 1800fps out of my Marlin rifle with only marginal leading. Stuff that cleans out with just a cotton patch. And that's with plain base bullets not protected by a gas check.

Boberama
December 8, 2009, 12:20 PM
I want it to be able to punch through a bear or a moose from end to end and exit on the other side. I also like the large .360-in meplat.

Hand-cast by us from custom Hensley & Gibbs blocks, our low-antimony bullets possess superior hardening characteristics... Our hardening process takes our bullets to 25-Brinnell, without the brittleness so common to high-antimony alloys...achieving hardness with the brittleness of high antimony alloys is hard to justify when the game is heavy or possibly dangerous. By contrast, our SuperHardCast Hammerheads possess none of the brittleness of high-antimony bullets, and are therefore far more reliable when impacted into extremely tough game. If the stress of impact exceeds the strength of our 25-Brinnell bullets (as in pointblank impact into the heaviest game with our high-speed 420 grain 45-70 ammo), the bullet simply deforms modestly, retaining virtually all of its weight. This is in sharp contrast to the all-too-common shattering of conventional high-antimony castings when deployed under similar conditions.



Maybe I could take some Garrett cartridges to some science lab and get them to see what it's composed of. Any ideas?
I read online their bullets have arsenic in them.

Boberama
December 8, 2009, 12:31 PM
Randy Garrett posted this on the Firing Line forum:

Our blocks are state of the art Hensley & Gibbs heavy cast iron blocks, which provide unusually good temperature control. Our alloy is a special silver enriched, low-antimony alloy with a trace of arsenic for extra hardening potential. All casting is done with high temperature alloy and blocks, and the sprues are cut as soon as the cut can be accomplished without smearing. The bullets are then immediately dropped into cold water, which results in a Brinnell hardness of 25. Our choice of a silver enriched, low antimony alloy is significant as it yields bullets with low fracture potential. Most commercial efforts to produce really hard cast bullets involve the use of relatively high antimony alloys since those alloys are the easiest to work with when using automatic casting machines. However, high antimony alloys tend to fracture when stressed beyond their inherent strength, something that cannot be tolerated when hunting heavy or potentially dangerous game. Our selection of a silver enriched, low antimony alloy results in a bullet that when stressed beyond its inherent strength simply deforms modestly, as opposed to the castrophic shattering of high antimony alloys.

freakshow10mm
December 8, 2009, 02:09 PM
They are probably adding arsenic which lends itself well to heat treating. You can heat treat WW alloy that has a trace of arsenic to about 35 BHN. Been done many times.

Boberama
December 8, 2009, 02:44 PM
I want roughly the same Brinell rating, without brittleness. If I add arsenic will the alloy be brittle?
Those Garrett's can break both a bear's shoulders and exit the other side, or go through a hog lengthwise. If I can make duplicates then I would use them for Grizzly bear and whitetails. Ideally, I would like my duplicates to be exactly the same as the Garrett's. Unable to distinguish any differences. That's probably not going to happen, but I'd like to try.

MichaelK
December 9, 2009, 11:19 AM
"Those Garrett's can break both a bear's shoulders and exit the other side, or go through a hog lengthwise. If I can make duplicates then I would use them for Grizzly bear and whitetails. Ideally, I would like my duplicates to be exactly the same as the Garrett's."

Umm, I think in part you are falling for their hype. Honestly, a grizzly hit with a 500 grain anything is going to get a good thumping! Don't be so worried that you'll be in trouble shooting a bear with a wimply little 475 grain slug out of your 45-70! It's going to work for you. I'd buy that mold on sale. Think of all the brass, powder, and primers you'll be able to buy with the extra 140$ you saved.

As for whitetails, there better choices out there. I'd suggest casting Lyman's 457122 bullet, their 330 grain hollowpoint, or 457191, their 292 grain flat point. Either of those lighter bullets, even a very modest velocities will plow completely through a whitetail. I got 100 percent penetration on deer just with my .44 magnum rifle, so you don't need to hit them with a sledgehammer. If you really have to duplicate everything, just buy some silver plumbing solder to toss in your pot along with your lead alloy. Don't think you'll have to worry much about the arsenic.

GooseGestapo
December 9, 2009, 01:52 PM
The ad(s) is mostly hype.

I've shot numerous game with 300-405gr bullets from the .45/70.
You don't need some "SuperBullet" to attain your goal.

I simply add 3-4oz of Lead-Free solder (95%tin/5%antimony available at Lowes,HomeDepot, ect) to a 18lb pot (Lee ProIV) of WheelWeights. This casts a beatiful bullet. I then heat bullets in a toaster oven for 1hr at ~500degF, and then dunk in a 5gal bucket of water. Easier for me than water dropping-allows inspection of bullets and remelting rejects.....

Result is the "Magic" 25-27bhn as tested using the Lee hardness tester.

With the Lee .459-405grHB sized to .459" and lubed with SPG, over 50.0gr of IMR4064 I get 1,950fps from my 18.5" Marlin GG. Ditto the Lee .459-405hp. Accuracy approaches MOA.

This will completely penetrate a Cape Bufflo which is approx 2X the size of the Browns/Grizzlys you're likely to encounter.
How much more do you need ???????

My "working load" of the RCBS .458"-300grFNGC (simply air-cooled to 16bhn)W/Hornady GC over 29.5gr of #2400 and 0.5gr of dacron pillow-stuffing gives 1,650-1,700fps and will still shoot through most anything you'll encounter, shoots flat enough for deer to 200yds (4" high at 75yds, 5" low at 200yds) shoots under 2moa; and recoil dosen't loosen your fillings and detach your retina's........

snuffy
December 9, 2009, 06:20 PM
They are probably adding arsenic which lends itself well to heat treating. You can heat treat WW alloy that has a trace of arsenic to about 35 BHN. Been done many times.

I said it first!:neener:
Post #4
It helps to have a small percentage of arsenic in it to achieve a good heat treat. Common chilled shotshell shot has arsenic in it.


There certainly is nothing special about Garret cartridges. They do a great job of "selling" their ammo, nothing wrong with that. You can easily duplicate those bullets and the load with commonly available molds. Then heat treat them.

Water dropping, straight from the mold, is very inconsistent at best. In order for it to work, you have to have the bullet at exactly the same temp each time. Any delay in getting the bullet out of the mold will allow it to cool too much, it'll end up softer than one that went directly from being cast, then into the water. Also water temp has a lot to do with it, as you cast and water drop, the temp of the water keeps going up.

Heat treating involves a lot of work, but the end result is better than water dropping. The bullets MUST be heated uniformly to just below the temp that they begin to "slump" or in other words melt. Then hold them at that temp for at least 30 minutes. Then plunge them all at once into cold water.

http://castboolits.gunloads.com/showthread.php?t=69582&highlight=heat+treating

Read that linked thread, then read the linked thread in post #3. It will give you all the info you need on heat treating alloy lead bullets.

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