300 Fireball AR15 (Brass forming - post #150)

Suputin

Suputin

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Just a few pics of a 300 Fireball AR15 project I have been working on:

The barrel is a stainless match heavy profile at just over 9" OAL. The gas system is pistol length and incorporates a JP Adjustable Lo-Pro gas block to allow the rifle to cycle subsonics as well as conventional supersonics.

300Fireball1.jpg


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The specially bored out and rethreaded .30 cal SPEX brake.

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The top mag contains 180gr subsonics and the bottom mag 150gr supersonics. The really nice thing about the 300 Fireball is it was designed to operate through the AR rifle without the need to modify magazines or the bolt.

300Fireball4.jpg


300 Fireball ammo from left: 125gr JHP, 150gr FMJ, 170gr cast, 180gr RNSP.

300Fireball5.jpg


The 300 Fireball is a true multipurpose cartridge. It can operate effectively with bullet weights from 110gr to 240gr, with velocities ranging from about 2200 fps down to 950 fps.

For those concerned about terminal ballistics, consider what a 1.1" long 150gr, .30 caliber bullet moving at 1700 fps is likely to do to a soft target. G:
 
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How manageable is the recoil? I'm guessing its probably not gonna be anything to write home about but how does it compare to your standard .223?
 
OK must know more about the SPEX. Especially when used on a .30.

Besides being a flash hider and redirecting sound, does it does it have any significant function as a brake or does it act as a gas booster? I'm interested in it for use on a short barreled 7.62x39.

Sorry about the derail.
 
OK must know more about the SPEX. Especially when used on a .30.

Besides being a flash hider and redirecting sound, does it does it have any significant function as a brake or does it act as a gas booster? I'm interested in it for use on a short barreled 7.62x39.
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To be honest we never tested its recoil reduction effect so I really can't comment. Internally it is quite similar to the KX3 so it should act to increase the gas pressure dwell. Contrary to popular misconception it does NOT increase the gas pressure in the system. It can only increase the dwell time of the pressure curve.

It was designed to push noise and blast downrange because the shorties are so obnoxious to shoot with a conventional brake. It is also a VERY GOOD flash suppressor.
 
jdman said:
I see a 699 norinco conversion in the making here. :)

What about brass, is it re sized from something else, i have never heard of this chambering.
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Same as 300 Whisper. necked out .221 fireball or just order factory rounds from Corbon.
I use 240g Sierra MatchKing
 
You slimy BASTARD! Now there are TWO threads where you can taunt me while you fondle my soon-to-be new 'girlfriend!'

Oh, btw, for those wondering about the efficacy of the SPEX with .223/5.56, ATRS has a YouTube video up:

[youtube]65C3Vw37N84[/youtube]

Pretty convincing stuff IMO.

And regarding forming .300 Fireball from 5.56/.223, that's how I plan to feed this puppy... and if the case wall thickness makes for troubles at the neck (I don't think it will, but just in case) some fellas go the extra mile of neck turning or reaming the brass just to be safe. I probably won't, but it's possible if one wants to do it.

I also plan on doing a rough-cut with an abrasive blade or endmill, then doing a final trim to length with an RCBS trimmer I've got drill-adapted. This should save a fair bit of "overtrim" time, I hope.

Damn I'm excited to get this puppy.

-M
 
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