Subsonic expansion testing

Spindrift

Well-Known Member
Lately, I have been entertaining myself with a little expansion testing with subsonic loads, using HP bullets. I don’t really have any need for such loads; just some clean, innocent fun.

The sensible thing would probably be to start with a suitable alloy, like a binary lead/tin alloy. But my organizational capacity just can’t take another alloy, things are chaotic enough as it is in my reloading room. So, I’ll try two different alloys; range scrap BHN 11-12, and my default do-it-all BHN 15. I’ll test different HP sizes and -types, with my two alloys.

My main expansion medium will be water containers; because it’s free and convenient.

I’ve tested a few bullets now. The first was the MP 312-440 (a.k.a «Hammer of Thor»), BHN12. It expanded beautifully. One fragment in the second container, one fragment in the third and the rear end of the bullet in the fourth.

The MP 311-180 SIL, BHN12, penetrated clean through 5 containers before it exited my stack of containers. No fragments, no expansion.

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The MP312-159 («Hunter») have the same large HP as the Hammer of Thor. It is the red one, below. I wanted to see if it would expand when cast from BHN 15. I shot it through a half-gallon milk carton, stacked firmly with wet newspaper, then into water containers. It went clean through, no expansion.

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Observations so far:
-Large HP + BHN12: expands nicely
- small HP + BHN12: no expansion
-Large HP + BHN15: no expansion
 

Ian

Notorious member
MP 311-180 Silhouette shortest hollow point pin, 13.5 BHN wheelweights plus 2% tin air cooled, 2460 fps into floor sweeping compound at point blank range, 1 meter penetration. This is what the bullet was designed for

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I have had no luck with narrow hollow points, split points, or any other form of expansion geometry with .30-caliber bullets at subsonic velocities. However, like you, I haven't yet tried extremely soft alloy. I bet the powder coating would let us use near pure lead at 1,000 FPS.

Something else that I think is important to low-velocity expansion is the shape of the hollow cavity. A wide, flat nose bullet with a funnel-shaped cup (inside angle much more abrupt than the ogive) will encourage the mouth to open rather than collapse inward. Think of .38 Special swaged, hollow base wadcutters loaded backwards.
 

JWFilips

Well-Known Member
Well not a hollow point or a rifle bullet: But this recover from wet sand amazed me recently! It is the only one complete mushroom from me testing a load with my Lee 230 TL RN .45 acp bullets! The rest of the 21 shots were pretty busted up! I very rarely use Colored PC but this batch was PC'd in John Deere Green I estimated Alloy hardness at 9.5 bhn with pencils This was 3 weeks after casting and before coating.
Shot with 4.0 grains WST at 25 yards.( less than 925 fps I think) in my Remington 1911 R1s...for the 230 RN bullet this impressed me!
45 acp mush.jpg
 

Hawk

North Central Texas
I love these kind of threads!
PC'ed, Penta, HP bullets look pretty bad ass to me.
I have several MP molds in .357/.359, 402 and .429 caliber with Penta HP.
I'll be watching this thread with great interest.
 

JWFilips

Well-Known Member
I posted this awhile back on the other side of the street:
It sort of gives a look at what I have experienced with PC coating and Soft alloy over the past few years I worked with it:
Not sure if it is pertinent here but I think it fits:

I do Not Know how many of you guys ever did the egg experiment where you soak a raw egg in vinegar for a few days.
When the shell desolves, you are left with a tough rubber like coating that covers the raw ( soft) egg inside.
Now you can drop that shell-less egg on a had surface and it bounces. That protective skin is pretty tough!
Fling it against a wall and it explodes!

Now let us take a 10 BHN alloy bullet and coat it with a PC skin which some say comes in at 32 BHN! That skin is similar to what is around that egg!
It does real well going down the rifling but at impact the 10 BHN alloy takes over!
So do you see the true usefulness of PC coating now?
It is an amazing gift to all of us
 

Kevin Stenberg

Well-Known Member
As said before. Very interesting and important for my hunting loads.
Spindrift What velocities were you shooting at?
IAN have you experienced a difference in performance of a drilled HP versus a cast HP?
 

fiver

Well-Known Member
I have only 2 ways to get hollow points.
I either drill them, or I swage them.
the tool for cutting burrs out of punched primer holes works good on 44 and 45 cal bullets.
and of course swaging them breaks the alloy down and they expand if you look at them too hard.

I can see where Don's 45?-1 alloy would open like a champ, the choice for hollow points since like forever has been a 40-1 or a 30-1 alloy generally with a gas check on the base pushed to about 800-950 fps.
they'll open.
 

Ian

Notorious member
The only hollow points I've drilled were done on the lathe just to see if stability improved and they weren't very precise, so the 100 yard group wasn't great.
 

Spindrift

Well-Known Member
Kevin, I’m shooting them at 1020-1040 fps.

The bullets l’m shooting here are designed for different purposes. I’m not making any attempt to harmonize alloy/design/velocity. I’m just using the alloys that happen to be in my melting pots, to see how it works, and maybe learn something.

I’m looking forward to testing the MP311-410 (second from the left in post #2). It is cast with the «large HP», which really is a «deep HP». The HP pin reach halfway through the front driving band.
 

CWLONGSHOT

Well-Known Member
In my own testing. I like 20:1 (9 ish bhn) and powder coated @ 1200 fps. A larger hp will be slightly less a d a small hp slightly more velocity.

Thats in wet magazines. So tougher then flesh.

ONE deer shot with a 20:1 & 1400fps impact vel. It was a smaller ho MP 359-220 bullet. Thru a d thru on whitetail breaking two ribs and exit with nickel size exit.

CW
 

Jeff H

NW Ohio
Just to add to the "database," I have a boring ol' 358439 (HP) cast of 50/50 Seventies wheel-weights/pure lead, air-cooled and lubed with BLL or 45/45/10. I forget the charge, but it was enough HP38 or Unique to get it to an estimated 750 fps from a 2" 38 special. The expanded one was fired into wet clay soil from about 3' at a 45 degree angle and penetrated 8", leaving an impressive cavity/wake in the thick clay. The only damage cam from tiny bits of glacial gravel dispersed in the clay. This is such a universally wonderful bullet.

The intent is to use this in "cat-sneeze mode" from a 18" Contender Carbine for close-range extermination tasks. One of those "pop....THWAK!" loads. I haven't gotten that far yet.

Then, there's the LEE 358158 TL cast of the same mix and doing MAYBE a whopping 450 fps from a 16" Rossi 92, using a charge of W231 I won't mention. Explore at your own risk. That was a 25 yard hit on a half-scale "pig" made of steel plate. These loads go "Pphit,.................THWACK!" As quiet as a CB cap, but they take a while to get there. I fended off a season-long 'coon infestation with this load, but you ABSOLUTELY had to make a head-shot or a really, really good chest-cavity shot to end things decisively. These DO exit the bore of THAT rifle 100% reliably. Please research and test extensively before doing this if you've not already done so.

IDEAL 358439 (Copy).jpgLEE358158TL-400-400.jpg
 

Jeff H

NW Ohio
a dusting of graphite on the tumble lube helps get them out a longer barrel on a consistent basis when you goofing off at 450 fps.

CW 20-1 should have the same 12 BHN as 'new' ww's have.

I'd have to roll them in it while they're wet because this lube dries DRY. In the Rossi, with a mirror-like bore and .355" groove, it was VERY consistent. I had to boost the charge by over 60% to get them to clear a rough, nasty NEW 77/357 bore with .358" groove. That one went down the road for a variety of reasons, but increasing the charge that much negated to whole "quiet" intent of such a load.

Thanks for the tip, @fiver . I have graphite handy.
 

Spindrift

Well-Known Member
Range day today. No wind, 8 F. A bit cold for accuracy testing.....
Usually, I shoot groups at 100m. Today, I chose to shot groups at a slightly shorter range with my subsonic loads. The range finder said 68m/74yds, which is a reasonable distance for sighting in these loads. All bullets today were cast from BHN12 range scrap. And to repeat myself; this is not an alloy particularily suited to the task of subsonic expansion. A binary lead/tin alloy would most certainly give other results with these bullets.

The MP 327 Moulnir expanded beautifully, stopped in the third container, retained weight 100%. But accuracy was no good (like 4 inches, or so). This bullet has shot reasonable groups at hypersonic velocities.

The MP- Hunter expanded, lost a little weight on one side of the nose, tumbled and lodged base- first between container 3 and 4. Retained weight 91%. Accuracy is promising, considering this was shot with cold, stiff fingers.

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The MP 311-410 shot pretty well (again, considering the conditions). It did not expand. With a suitable alloy, I´m sure it will expand very well. The MP- sledgehammer was not particularily accurate (but not horrible either); it did not expand, however.

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Well, this was great fun! The MP- Hunter is the bullet with best accuracy for me, among the ones that expand with my BHN12 alloy. If I needed a short-range, expanding varmint load, I think I would get a softer alloy and work with the MP 311-410. I haven´t done any real accuracy tweaking yet, only shot a couple of loads that produced the velocity I wanted.
 

RBHarter

West Central AR
I probably don't need to say this here , but sometimes we forget or just don't think about it ........
"St Elmer" , as I've read him called , created the 44 mag with 16/1 . Seems like there was either a real scientific method or a lot of luck in tripping over the right combination of burn rate acceleration to mass and structure . With 83 other available powders , PC , and assorted check mat'ls to go with 80 yr of perfecting what he and the Pope's and Squibb's created we should be able to get jacketed results at half speed . It shouldn't be as hard as make it seem .

Of course with that said I admit that I too chased the double D 200 gr 30 cal too . Found it , made some notes , moved on to higher speeds , exploded a lot of bullets , found an alloy that defied any logic at all and like a sledgehammer to the forehead realized copper was the accidental answer to my wonder alloy . Add about 5-20% pure to your range metal water drop and see what happens .
Run 50/50 plated cores with WW and water drop . 16-1800 fps made those cute little almost round balls .610 and 196gr out of a 199.6-200.4 gr spitzer/spire point .07 FP 305-310 muzzle dia bullet seen in my avatar .
 
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