300 Fireball AR15 (Brass forming - post #150)

What is a better twist to go with 1-8 or 1-10?
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1:8 is better but 1:10 works fine. Don't let Doc fool you there are lots of choices for a 1:10 barrel. We have gotten a load to cycle with 150gr pulled mil bullets and I know for sure that the Lapua Subsonic 200gr bullet stabilizes in a 1:10 twist.

Right now your choice with us is limited by what barrel blanks are available and as it turns out we only have the 1:10's.
 
Suputin said:
1:8 is better but 1:10 works fine. Don't let Doc fool you there are lots of choices for a 1:10 barrel. We have gotten a load to cycle with 150gr pulled mil bullets and I know for sure that the Lapua Subsonic 200gr bullet stabilizes in a 1:10 twist.

Right now your choice with us is limited by what barrel blanks are available and as it turns out we only have the 1:10's.
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Perhaps I should have clarified myself... it's not that there's anything WRONG with a 1-10, and it absolutely WORKS (thanks in large part to hard work from Suputin and myself with regards to load testing - more him than me, really).

However, if you really want to maximize the punch of a .300 Fireball/Whisper - and I'm talking like 220-grain moose bullets for maximum kinetic energy with minimum velocity - then some projectiles won't stabilize in a 1-10 barrel. All I'm saying is that, given a choice, 1-8 is preferable over 1-10... but I'm not saying 1-10 isn't workable... hell, mine runs just fine thanks! ;)

-M
 
However, if you really want to maximize the punch of a .300 Fireball/Whisper - and I'm talking like 220-grain moose bullets for maximum kinetic energy with minimum velocity
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Doc, you are disappointing me .... :(

I have been arguing against this kind of point for years now. Kinetic energery is a totally moot point with respect to subsonics. The reason is that subsonics will penetrate to a HUGE degree without expansion and they will almost always go all the way through a soft target and take a bunch of energy with them. There is just no way to get a subsonic to dump all its energy in a soft target.

So, if a 150gr bullet with X amount of energy flys out the back side of a target, what would be the point of using a 220gr bullet with 1.5X energy when it is also going to fly out the back side of the target? The net result being you just end up wasting more energy.

Lighter weight bullets do have less felt recoil and tend to have a flatter trajectory. Both of which are meaningful in a subsonic system.

To give you an idea of how badly subsonics tend to overpenetrate, I did some terminal testing into wet phonebooks. In those tests, a 150gr subsonic penetrated 16" of wet paper, blew through the bottom of the bucket and disappeared into the dirt, never to be recovered. We also had a 150gr subsonic punch through both sides of a level 2A vest (42 layers of kevlar sheet) as well as the 2x4 the vest was attached to and then disappear into a dirt berm ... and that was from 100 yds away.

Would anyone like to argue that the extra energy of a 220gr subsonic will improve terminal performance?
 
Well, I learned something today.

I honestly didn't know all that, Suputin. It's not often I get served an entire humble pie to the face... off to lick my wounds I go... ;) I honestly thought that a 220-grain flat point or expanding roundnose with a generous expansion cavity drilled into it would dissipate more terminal energy than a 150-grain spitzer FMJ... but if neither expands terminally, then you're right - what the hell's the point of adding the mass?

-M
 
Interesting stuff. Was it a FMJ, JHP, JSP, cast lead or what? I'm wondering how much it would deform at that velocity. Did it tumble?
 
I honestly thought that a 220-grain flat point or expanding roundnose with a generous expansion cavity drilled into it would dissipate more terminal energy than a 150-grain spitzer FMJ... but if neither expands terminally, then you're right - what the hell's the point of adding the mass?
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I tried all sorts of things to get rifle bullets to expand at subsonic velocity. I even cut off the nose of a Lapua 200gr and then drilled a HUGE hollow point cavity in it. In clay it would expand somewhat but in wet paper which is closer to flesh in consistency, it just bored straight through.

I tried a cast lead 200gr with a monstrous hollow point and it did fack all in wet paper other than go straight through.

The problem is that rifle bullets are simply not designed to expand at low velocity. They use thicker jackets and harder lead alloys. If you were to cast your own using a softer alloy then you could prob get it to work but I have had zero success with commercial bullets.

I'm wondering how much it would deform at that velocity. Did it tumble?
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ZERO deformation. You could reload and shoot the bullets a second time. Never got one to tumble either. Apparently spoon nosed bullets will tumble but I never tried any.
 
Hey, guess what we just got in?

Bags of brand new Remington 221 Fireball brass. :)

Best thing is we are selling them for less than Wholesale was selling them for .... when they had them, which they don't currently.

Oops almost forgot, we are bringing in a couple of sets of Redding dies for the 300-221 as well.
 
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Check these out. Now we just have to figure out a way to get some north of the 49th.

http://www.lehighbullets.com/products.asp?cat=26

308-500.jpg
 
Holy shee-yit!!!

$65 for a box of $50 though... yowza!

That'd be fun to see first hand in a gelatin block though...

For Hbean - if you want to see a subsonic .300 Fireball grouping at 300 yards, punch a few holes in the dirt and look down. :D

With a 1050 fps load, zeroed at 100yd:

200yd -33"
300yd -104"

Like throwing a football. :D

-M
 
hbean said:
LOL, perfect for closet fighting
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Exactly! :D

Actually, in the supersonic loadings around 2,200 fps (someone correct me here - I haven't worked up any 'supers' yet), it's almost like a 7.62x39. I imagine that, with the match-grade barrels and chambers ATRS put on these rigs, they'll shoot quite well.

Mine is awaiting an optic that will allow me to do it justice, however. :)

-M
 
Suputin said:
I tried all sorts of things to get rifle bullets to expand at subsonic velocity. I even cut off the nose of a Lapua 200gr and then drilled a HUGE hollow point cavity in it. In clay it would expand somewhat but in wet paper which is closer to flesh in consistency, it just bored straight through.

I tried a cast lead 200gr with a monstrous hollow point and it did fack all in wet paper other than go straight through.

The problem is that rifle bullets are simply not designed to expand at low velocity. They use thicker jackets and harder lead alloys. If you were to cast your own using a softer alloy then you could prob get it to work but I have had zero success with commercial bullets.



ZERO deformation. You could reload and shoot the bullets a second time. Never got one to tumble either. Apparently spoon nosed bullets will tumble but I never tried any.
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The best solution would be a large scale version of the .22LR CCI Subsonic Segmented HP bullet. Its just a copper plated, segmented lead bullet. Splits into 3 pieces on impact very reliably. I've tested them on cantaloupes.

Corbin sells dies for making segmented bullets. I've been meaning to make a set, but haven't found the time...

You might try some of the light varmint bullets as subsonics. The jackets are thinner and the lead is softer. The harness of the alloy plays a big factor in expansion. Winchester's new 40gr. TCHP Subsonic .22LR bullets expand reliably because of the alloy they use. The sierra 110 gr. HP bullet has a pretty good hole in it to begin with.
 
You might try some of the light varmint bullets as subsonics. The jackets are thinner and the lead is softer. The sierra 110 gr. HP bullet has a pretty good hole in it to begin with.
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As in most things there is no free lunch. It is a lot more difficult to get the lightweight bullets below the speed of sound and then even more difficult to get an AR to cycle reliably with that kind of ammo.
 
kombayotch said:
Oh, you'd never get an AR to cycle with the light bullets... was just looking at expansion.
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Yes, I agree with your assessment - a 110-grain varmint .30 caliber bullet would probably do the trick expansion-wise... but it'd never cycle reliably in an AR. 150's are bad enough, lol! :)

In a boltgun though...

-M
 
I wonder how a sabot would work? Much like those Remington accelerators.
It would allow cheaper 22 cal bullets to be used, but I'd imagine accuracy would suffer.
 
I wonder how a sabot would work? Much like those Remington accelerators.
It would allow cheaper 22 cal bullets to be used, but I'd imagine accuracy would suffer.
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Well ........ one would assume that as we have to go to great lengths to get 150gr bullets to cycle and that most here figure a 110gr bullet would not cycle, that a 55gr bullet in a 10gr sabot wouldn't have a hope in hell of cycling.

Maybe things work differently in your world but I am pretty sure that is how things work in the real world.

And if we are per chance talking about terminal performance, then I can tell you from personal experience that a .224 bullet won't expand at all at subsonic velocity. It simply acts like a needle only it is a much smaller hole than a .30 cal bullet, which is the entire point of using the 300 Whisper case rather than something .224"

Yes, I agree with your assessment - a 110-grain varmint .30 caliber bullet would probably do the trick expansion-wise...
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Actually I doubt that it would. I can't remember if I tried that when I was doing terminal testing or not. Regardless those bullets are designed to expand at near 3000 fps so it is highly unlikely they will do anything at 1/3 that velocity.

I tried all kinds of things and all kinds of bullets and never got anything to work. I know that I tried a 168gr Ballistic tip with and without its tip and neither did a damn thing. It is going to take a specialty bullet to expand at less than 1000 fps.
 
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