Subsonic expandable bullet ideas

[BT Sniper]

One of the challenges I often hear about is the challenge to get desirable results with accuracy and expansion from the new trend in shooting heavy rifle caliber bullets at subsonic speeds in calibers like the AAC 300 BLK (a 30 cal using the 223rem case) and the 338 Spectre (using the 10mm case necked down to 338). These calibers will shoot the heaviest bullets offered in their respective calibers at desired speeds just short of the speed of sound. I imagine the problem comes from the tough construction of the 240 grain 30 cal bullets and the 300 grain 338 bullets that where designed to hold together at speeds in the 2500-3000 FPS range so the chance for any expansion at less then 1100 FPS is rather slim.

So lets make a heavy bullet that will deliver a good thump and expand from these specialized cartridges.

How about some highly expandable 338s for the subsonic shooters? Make any weight you wish with a soft lead nose that should expand very well at subsonic velocities! Here I used some simple sized down .355 jackets, these jackets where pretty thin compared to traditional 338 jackets and should also aid in better expansion at the slower FPS in calibers like the 338.

Here is some varrious 338s I was experimenting with. The .338 Sierra 300 grain match king on the left.
http://i636.photobucket.com/albums/uu87/BTSniper/88b68f67-65fb-46fc-b742-97ed5537c4ec_zps4239d26b.jpg (http://s636.photobucket.com/user/BTSniper/media/88b68f67-65fb-46fc-b742-97ed5537c4ec_zps4239d26b.jpg.html)

here is a 30 cal 220ish grain short jacketed bullet next to a 180 grain Nosler

http://i636.photobucket.com/albums/uu87/BTSniper/P1070634take2.jpg (http://s636.photobucket.com/user/BTSniper/media/P1070634take2.jpg.html)


Imagine the expansion one should get from bullets like this!

We shall see I guess.

Good shooting and swage on!

BT

[reed1911]

I'm planning on something similar for the .30 cal. How have these done for you? Have you, will you, can you, shoot them through a suppressor? Are you thinking of any other nose styles?

[Outpost75]

87365

This is 1:25 tin/lead alloy launched from an 1894 .30-30 Winchester at 1320 fps, using a .38 Special case as a dip measure with IMR4064, approximating .32-40 Winchester ballistics, captured into water jugs at 100 yards. It has proven an effective deer load.

Penetration was 24" of water.

[TheCelt]

87365

This is 1:25 tin/lead alloy launched from an 1894 .30-30 Winchester at 1320 fps, using a .38 Special case as a dip measure with IMR4064, approximating .32-40 Winchester ballistics, captured into water jugs at 100 yards. It has proven an effective deer load.

Penetration was 24" of water.

That is pretty impressive!!! Got any idea how many grains of IMR4064 went into that 38 case??? Also, what was the boollit weight? Looks like around a 180 grain thumper.

[GRUMPA]

BT, after playing a bit with the 45cal dies and what you pretty much taught me I would go in a slightly different direction. You know those 8mm BB's that get inserted in the 40cal cases? It isn't a HP but once that BB gets hit it acts as the actuator and is forced into the lead which in turn flares the lead. I would get a design similar to that for the 30's only think about using a 6mm BB and see how that works. Gotta admit at lower velocities those 45cal pills have some scary results.

Edit: And if that works I want a commission or a killer deal on the first set of dies..:grin:

[Outpost75]

That is pretty impressive!!! Got any idea how many grains of IMR4064 went into that 38 case??? Also, what was the boollit weight? Looks like around a 180 grain thumper.

20 grains of 4064, bullet weight is 175 grains. Essentially a standard .32-40 load, but in a .30-30 case.

[TheCelt]

That'll get er done!!! Thanks for the info.

[HiVelocity]

6mm BB and see how that works. Gotta admit at lower velocities those 45cal pills have some scary results.

Yes sir, I can vouch for their (45 swaged) ability to expand reliably. Now, regarding a .30 swaged, I'd like to see someone develop a half or 3/4 jacket with both a flat hollow pointed nosed, and as an option, a pointed nose for 300BO, and other .30 caliber rifles (similar to BT's photos above). I think you would have the best of both worlds, "J" velocities from a (quasi) hybrid cast bullet.

Just my .02 worth.

HV

[bullet maker 57]

I can make you a 30 cal jacket up to 1.2 in. If you want to experiment, I will send a few in any length you want. I will make and send 10 jackets to the first 5 members that PM me with the length.

[clodhopper]

I can make you a 30 cal jacket up to 1.2 in. If you want to experiment, I will send a few in any length you want. I will make and send 10 jackets to the first 5 members that PM me with the length.
A little plug for Pete, he sent me some .243 jackets, nice uniform and they arrived quickly.
He does what he say he will do.

[Doc Highwall]

I think the jacket should be just long enough that when the bullet is seated to a OAL that will function in the magazine that the jacket will protrude past the case mouth for a light crimp or taper crimp to be applied to insure reliable feeding. The core could now be made from pure lead.

[BT Sniper]

Found some pics that go with this thread....

https://i.imgur.com/lGvJPDvl.jpg

[Mauser 98K]

for subsonic speeds i usually just stick with lead round nose with a softer alloy than normal. done correctly it is a lot more accurate than the pointed jacketed bullets and deforms rather well.. my way of thinking has always been save the jacketed stuff for high velocity and use cast for the slower close range stuff.. for the slower speeds there is no reason to really have the jacket unless you just want to as i have never had a leading problem with sub sonic loads with a properly lubed bullet and accuracy is such to where a dime can cover a group. but what you got up there is half jacketed or semi-jacketed and is quiet common in pistol bullets. but i have also found that for subsonic loads you want the bullets to be as short as possible for a given weight and LRN fits the bill, it is not blunt but the center of gravity is not so far back either. years back they did studies about the stability of a bullet at subsonic speeds and found that the really pointed bullets were unstable as there was usually not enough spin and the heavy end always wanted to face forward so it would wobble or try to swap ends degrading accuracy. the longer a bullet the more spin is needed and if your lowering the velocity then you also increasing the required spin for that longer bullet. the LRN has always been the preferred design for subsonic loads as it remove a lot of the problems associated with balance and spin that often plague pointed jacketed bullets..

[Butchman205]

https://uploads.tapatalk-cdn.com/20171122/36b65433bf99a8731a1b7da82d55c3c7.jpg

My suggestion...sell some lead. And take the $ to buy some Maker brand Rex bullets. They’re designed to expand at subsonic speeds, and do so better than anything I’ve seen.


-Butchman

[just bill]

Pretty neat stuff, I"m still trying to make my BTX work in conjunction with ballistic tips for my .30 cal pills????.

[clodhopper]

Butchman,
Thanks, but I will not follow your suggestion.
Doing stuff my self is so much more fun.

That bullet looks like it was a piece of copper rod, with a hole drilled in it, Then some triangular cuts.

Probably formed when hot.

[BlackoutBuilder]

https://www.lehighdefense.com/products/308-168gr-controlled-fracturing-subsonic-bullet?variant=1073765220

I shake my head and smile every time I see them. Right now they are in 300BLK nickel plated.

[M.A.D]

Did i send you any of my 1.4 inch 0.014 wall pure copper 30 cal jackets?

[Butchman205]

Butchman,
Thanks, but I will not follow your suggestion.
Doing stuff my self is so much more fun.

That bullet looks like it was a piece of copper rod, with a hole drilled in it, Then some triangular cuts.

Probably formed when hot.

Agreed!!!
I love the challenge of working out the details of a fun project...and even if my tests don’t perform well, I’m still shooting!

I’ve tried (and failed) on a buttload of tests, to make a cast bullet expand as well as the Maker bullets. I won’t stop trying, because I thoroughly enjoy trying to improve on what I can make at home. Thus far, the Maker bullets expanded way better than anything I can make...and the owner of the company is a pretty nice guy. I’ll keep some of those on hand for now on!!!
So I’ve got those as a solid performer in slow speeds. I’m not new to casting, but new to swaging. My stepdad gave me a bunch of swaging stuff, and I’m learning from you guys as I go...

Newby question-What about an inverted triangle or cone shaped piece, inserted in a hollow made projectile. Not like a standard ballistic tip (which is like a cone on top of a cone), but rather a cone with a flat bottom turned upside down and extended out a tad in front of the hollow point metplat?


-Butchman

[clodhopper]

There are some examples of a cone shape expander, one even predates the US civil war minie ball.
I think the high rotational velocity will make it easier to expand soft bullets.

A lot of 300 blackouts have a 1 in8 twist vs. a .357magnum with 1 in 18 twist.

The lengths of the splits need to balance with the strength of the petals, and the centrifugal force of the spinning bullet.

[Valornor]

Making a cost effective jacketed expanding subsonic bullet for 300BO is something of a holy grail for bullet manufacturers. All the designs I've see are expensive, and from some of the testing we did, not reliable. One brand, which offered a monolithic bullet, stuck bullets in the bore in when the ammo was chilled.

Half jackets are definitely one way to go, those look nice Brian :-). When we were playing around with the idea we made a skiving die. Once we staked the core in the jacket we ran the core and jacket about 50% of the way through the die which cut three grooves on the outside of the jacket about .015" deep. Then proceeded to form the ogive as normal, leaving the meplate about .080". They expanded beautifully. We never got past proof of concept as there were other priorities.

[Mauser 98K]

i know one thing, a thinner pure copper jacket and the softest lead core you can find works wonders for expansion/fragmentation of slower velocity bullets.. it has a jacket, it does not matter if the lead is soft as butter as the jacket separates it from the bore. the ones i make for my SKS will make almost flat buttons at speeds as low as 1,200fps. have not tried slower yet but will get around to it.

the biggest problem is the jacket material and the core wire as i said above. the standard alloy jacket has zinc in it. while this makes them less inclined to foul the bore it also makes the jacket tougher and less inclined to deform at the lower speeds. a thinner jacket of around 0.015-0.020 also helps a lot. im not even going to get into the brass jackets and the impossible feat of making them mushroom at subsonic velocities without putting slits in the jacket so it opens up like a flower.. as for the lead, as stated you want the softest you can find. you basically want a rifle version of a pistol bullet, the only difference would be the point shape. there are pistol bullets that will mushroom at lower velocities and all you need is to copy the material used..

another thing that is often overlooked is the point itself. a very sharp point is more inclined to penetrate and hold together than to deform and mushroom at the slower velocities.. you want a good ogive shape that is more blunt than the traditional ice pic shape and an open tip with about an 1/8in cavity in the nose so that a fluid medium can get inside and start peeling the jacket back. what works for super sonic bullets will not work when they drop to subsonic..