300 Fireball AR15 (Brass forming - post #150)

Suputin said:
"Yes, I agree with your assessment - a 110-grain varmint .30 caliber bullet would probably do the trick expansion-wise..."

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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They may very well not, but the performance of a 168 Ballistic tip is not indicative of whether or not they will. The 168 was designed to expand in large, big boned animals, whereas the 110s are designed to disintegrate in tiny varmints. We're talking about two entirely different constructions in terms of jacket thickness and lead hardness.

If a 40 gr. .22LR bullet can be made to expand at subsonic velocities, something 3x (plus) it's weight surely can too. Its just a matter of construction and material selection. Drilling out a .22LR match bullet, for example, does not product even close to the same results as those purpose build Winchester 40gr. TCHP SS bullets. The lead hardness makes all the difference.

To get expansion at those low velocities, you definitely need a big hole. The HP pistol bullets that expand at those velocities are a good example. Maybe try the 110 Sierra Vaminter HP or a 125 TNT. And instead of drilling them, expand the hollow point using a punch like they do for .22LR bullets (to retain the weight). The die and punch are easy to make if you have access to a lathe.

You might even try the 90 gr. .308 XTP bullets... with powders like Titegroup and Trailboss, its possible to load them in rifle cases. Some of the boys in Norway were doing this using one of the VV pistol powders. Think it was N310...
 
Stop posting this stuff up. You guys are making it very, very difficult for me to put off building an AR for very much longer. Might have to come up to calgary and pay you guys at ATRS a visit one of these days.
 
the 110s are designed to disintegrate in tiny varmints. We're talking about two entirely different constructions in terms of jacket thickness and lead hardness.
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The 110's were still designed to operate at velocity's near 3000 fps. They don't do anything at 1/3 that velocity. I looked up the terminal data and found that I did try the 110 Sierra JHP and it does nada in wet phone book. I even tried packing the hollow point with grease to try to utilize hydraulic force to enable expansion and still got nada.
 
Some new info for you Fireball Fans: This is from another website so I can't verify the info. I will be looking into it though as I just noticed this problem the last time I had my Whisper out.

Existing AR magazines have a rib which normally contacts the 5.56mm case-neck. With 300 Fireball ammo, the contact is on the bullet. Because the bullet is a larger diameter, the rib will push the cartridges out of alignment, and can lead to binding potentially resulting in Failures to Feed. For this reason, it is important to load ammunition so that the contact point with the magazine rib is on the bullet ogive in an area of about 0.250 inch diameter. Here are some suggested OAL for popular bullets:

• Hornady 110 V-Max, OAL: 2.000
• 110 TSX, 2.015 OAL
• Sierra 155 Palma, 2.150 OAL
• Sierra 220, 2.089 OAL
• Lapua B416 200 grain, 1.960 OAL
• Hornady 150 FMJ-BT 3037, 2.065 OAL
• Nosler Ballistic Tip 125 grain, OAL: 2.085
• Remington AccuTip 125 grain, OAL: 2.085
• Hornady 130 SP #3020, OAL: 2.010
• Sierra H2120 125 ProHunter, OAL: 1.950
• Speer TNT 125 1986, OAL: 2.010
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I looked into these seating depth numbers and while I think there is some merit in going a bit shorter, some of those seat depths are very short.

I measured the distance to the lands and most are well over .100" with several over .200". That means the bullet has to jump between .130" to .220" to the lands which may not be so conducive to accuracy.
 
To be honest, I haven't even measured my seating depths yet... but I find that if I set the tip of the bullet back about 1/8" from the inside wall of a Pmag, there are absolutely zero problems using three different bullet profiles:

-147gn milsurp (ex M80 ball)
-180gn Ballistic Silvertip
-155gn Sierra GameKing (with the crenellated tip, not the lead tip)

-M
 
You've seen AAC has effectively commercialized the Whisper in their .300 BlackOut?

155gr Super Sonic and 220 plus Sub Sonics

There is a way to get SubSonic's to expand and give good terminal performance If you have friends at ATK. ;)
 
You've seen AAC has effectively commercialized the Whisper in their .300 BlackOut?
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Yes I have and thanks for bringing that up ..... again. :( You know how I feel about that.

There is a way to get SubSonic's to expand and give good terminal performance If you have friends at ATK.
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Care to send me some to test?

We actually met a guy who is machining bullets here in town. He is interested in working on an expanding subsonic so we may have our own fairly soon. :)
 
She is finally home, my new baby. I would like to introduce to you all "Spikey".

She is still in mock up mode but she is a 9.5", 1:8, .300 FireBall Heavy Profile from ATRS assembled on a Spike Tactical Billet upper and lower set. Missing a few odds and ends and then the final assembly will be done.

Can't wait to try her out and give a report.

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An interesting blurb off the Corbin site for in regard to the best subsonic bullet shape...

ht tp://www.corbins.com/bullets.htm

'Sub-sonic bullets are sometimes used for military special ops applications, where a quick strike and extraction with minimal noise is needed. Sub-sonic bullets are loaded to speeds below Mach I so there is no "sonic crack", and a silenced rifle (or handgun) will produce nothing more than a "puff" sound. In such applications, the bullet is most likely used against enemy personnel at relatively close range, to maintain the element of surprise. It is not called upon to produce a flat trajectory, or to defeat armour, because the shot can be placed with relative precision in an offensive action. Therefore, expansion may be more important than penetration.

To take advantage of all the available energy, the base drag needs to be minimized. At sub-sonic speeds, the ogive shape is less important than the base: a rebated boattail shape reduces the base drag compared to a flat base bullet, and a round nose design has nearly the same drag as a spitzer below the speed of sound, while permitting greater expansion at the same velocity. To further enhance expansion, a thin jacket wall is used and the jacket may be serrated (cut along its axis with four to six thin grooves) to provide evenly weakened lines along which the bullet can peel back.

The lead core may be also have a four point X-shaped hollow cavity punched into it during core seating, so that it is pre-fragmented to a certain degree. This further adds to the ability of the slow moving bullet to expand on impact. The combination of a lead tip, X-cut core, serrated jacket, and minimal drag base design makes an ideal sub-sonic bullet.'
 
It is not called upon to produce a flat trajectory, or to defeat armour, because the shot can be placed with relative precision in an offensive action. Therefore, expansion may be more important than penetration.

To take advantage of all the available energy, the base drag needs to be minimized. At sub-sonic speeds, the ogive shape is less important than the base: a rebated boattail shape reduces the base drag compared to a flat base bullet, and a round nose design has nearly the same drag as a spitzer below the speed of sound, while permitting greater expansion at the same velocity. To further enhance expansion, a thin jacket wall is used and the jacket may be serrated (cut along its axis with four to six thin grooves) to provide evenly weakened lines along which the bullet can peel back.

The lead core may be also have a four point X-shaped hollow cavity punched into it during core seating, so that it is pre-fragmented to a certain degree. This further adds to the ability of the slow moving bullet to expand on impact. The combination of a lead tip, X-cut core, serrated jacket, and minimal drag base design makes an ideal sub-sonic bullet.'
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Makes me wonder if the person who wrote that has ever even shot a subsonic rifle?

Subsonics do penetrate soft armour VERY well. I had a 150gr .30 cal subsonic punch through both sides of a level 2A kevlar vest (42 layers of kevlar), then blow through the 2x4 the vest tacked to.

Terminal energy is a moot point when talking about a bullet that can easily penetrate several feet of soft media. If the bullet flies out the back side of the target, what would be the point of maintaining extra energy?

I have tried all kinds of things and never yet had a subsonic rifle bullet expand in soft media. It takes a very special design to get a subsonic rifle bullet to expand.
 
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Kewl! :)

Looks great. I am really loving the shorty Whispers. I think you are gonna like shooting it.

I had mine out the other day and was ringing a metal gong at about 75 yds consistently with iron sights. The big 200 gr bullets make a nice satisfying "clang" when they hit. :)

I was also screwing around with 110gr supersonics but found the subsonics to be more fun so I will prob stick with them more.
 
Suputin said:
Makes me wonder if the person who wrote that has ever even shot a subsonic rifle?

Subsonics do penetrate soft armour VERY well. I had a 150gr .30 cal subsonic punch through both sides of a level 2A kevlar vest (42 layers of kevlar), then blow through the 2x4 the vest tacked to.

Terminal energy is a moot point when talking about a bullet that can easily penetrate several feet of soft media. If the bullet flies out the back side of the target, what would be the point of maintaining extra energy?

I have tried all kinds of things and never yet had a subsonic rifle bullet expand in soft media. It takes a very special design to get a subsonic rifle bullet to expand.
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You just may be right. Off the same site did you happen to read the following in respect to the Corbin Rebated Boattail with the .300 Whisper? Looked to be some good info. That said I'm just jumping on this particular bandwagon so still picking up info on the fly;)

ht tp://www.corbins.com/subsonic.htm
 
2katz said:
She is finally home, my new baby. I would like to introduce to you all "Spikey".

She is still in mock up mode but she is a 9.5", 1:8, .300 FireBall Heavy Profile from ATRS assembled on a Spike Tactical Billet upper and lower set. Missing a few odds and ends and then the final assembly will be done.

Can't wait to try her out and give a report.

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Great rig. Just curious if you found it heavy at all with the heavy barrel and with the Spike upper, and lower for that matter, being 'meaty-er' than the conventional faire.

Me likey though...:D
 
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