faster bullet for 308 AR10t

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11 years 34 minutes ago #31056 by foxhunter
faster bullet for 308 AR10t was created by foxhunter
I have been studying some reloading charts looking at using 110 or 125gr bullets in order to get the muzzle velocity up to 3100 fps or higher, so approach the 243 cal velocities. My purpose is to get less windrift and drop for varmits.

I am using the ar10T. Given these guns seem to like heavi3er bullets, I would like some assurance that accuracy will not suffer before I expend the money and time in reloading these.
Also, I like to use IMR 4895 , so any data with that powder appreciated as well.

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10 years 11 months ago #31057 by dfc5343
Replied by dfc5343 on topic faster bullet for 308 AR10t
By a rifle 22-250 caliber. Problem solved

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10 years 11 months ago #31058 by Libertarian623
Replied by Libertarian623 on topic faster bullet for 308 AR10t
Fox I know what you mean I would like to see the same . Which will be difficult since COF is the square of cross sectional density show that you will never approach the ballistics of a 243 with a 308. full stop. But We can get some hope from the possibility of using a 155gr berger hybrid with a secant and a tangent ogive in the same bullet . That means we may get 3000FPS and still have a accurate 600yd round. I have someone loading some up as we speak. PM me and when I get them I will share.

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10 years 11 months ago #31060 by foxhunter
Replied by foxhunter on topic faster bullet for 308 AR10t

dfc5343 wrote: By a rifle 22-250 caliber. Problem solved


that is the easy way out, and not the cheapest. It's all about the challenge!

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10 years 11 months ago #31177 by OleCowboy
Replied by OleCowboy on topic faster bullet for 308 AR10t
Fox, if you want to really get that thing smokin, then shoot downhill, that is the secret of the pro's.

Heck, I put smaller diameter tires on the front of my car, so I am driving down hill all the time and wow, heck if I drive too long like that I sometimes find gasoline coming out of the fill spout.

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10 years 11 months ago - 10 years 11 months ago #31200 by SOC
Replied by SOC on topic faster bullet for 308 AR10t
I can get 3100fps from anything lighter than 200gn in my AR-10TU.

I'm wondering about using a sabot fire a really heavy 6.5mm bullet, or even to a heavy .224 bullet.

I've also found 1/4 inch diameter 1 inch long "pins" made from tungston.

Tungsten is 1.7 times heavier than lead. I wonder what the BC of those "pins" are.
Last edit: 10 years 11 months ago by SOC.

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10 years 11 months ago - 10 years 11 months ago #31203 by Sharkey
Replied by Sharkey on topic faster bullet for 308 AR10t
Some interesting stuff. I'd like to see some of these when you get em made..
Last edit: 10 years 11 months ago by Sharkey.

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10 years 11 months ago #31211 by Libertarian623
Replied by Libertarian623 on topic faster bullet for 308 AR10t
Soc- Those are definitely cool thoughts brother. Since, for a given bullet shape, frontal surface increases as the square of the calibre, and mass increases as the cube of the diameter, then sectional density grows linearly with bore diameter. With a heavy 6.5mm bullet stretched way out made of tungsten you could achieve unheard of BC's. I think it would be worth it just to have the bragging rights to the lowest BC bullet ever. You could have a screw machine shop turn out a couple hundred fairly inexpensively. Man that would be something to brag about.

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10 years 11 months ago - 10 years 11 months ago #31305 by Siscowet
Replied by Siscowet on topic faster bullet for 308 AR10t

SOC wrote: I can get 3100fps from anything lighter than 200gn in my AR-10TU.

I'm wondering about using a sabot fire a really heavy 6.5mm bullet, or even to a heavy .224 bullet.

I've also found 1/4 inch diameter 1 inch long "pins" made from tungston.

Tungsten is 1.7 times heavier than lead. I wonder what the BC of those "pins" are.


My father was a weapons engineer for forty years. In the 60's he worked on the SPIW- Special Purpose Individual Weapon, which used a sabot to fire a flechette at unheard of velocities. Like 5,000 feet or more per second. One problem: with the war du jour being Vietnam at the time, it was found that the smallest leaf would deflect the flechettes. As far as volume, the case was still a 5.56, so you really didn't increase the volume of fire, or give a tactical advantage of a lighter ammo load. They were not using tungsten, however, probably due to cost factors. The concept has been brought back several times since, but hasn't proven to be practical as of yet. With new technologies and improved metallurgy that could change.
en.wikipedia.org/wiki/Special_Purpose_Individual_Weapon
Last edit: 10 years 11 months ago by Siscowet.

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10 years 11 months ago #31306 by SOC
Replied by SOC on topic faster bullet for 308 AR10t

Siscowet wrote:

SOC wrote: I can get 3100fps from anything lighter than 200gn in my AR-10TU.

I'm wondering about using a sabot fire a really heavy 6.5mm bullet, or even to a heavy .224 bullet.

I've also found 1/4 inch diameter 1 inch long "pins" made from tungston.

Tungsten is 1.7 times heavier than lead. I wonder what the BC of those "pins" are.


My father was a weapons engineer for forty years. In the 60's he worked on the SPIW- Special Purpose Individual Weapon, which used a sabot to fire a flechette at unheard of velocities. Like 5,000 feet or more per second. One problem: with the war du jour being Vietnam at the time, it was found that the smallest leaf would deflect the flechettes. As far as volume, the case was still a 5.56, so you really didn't increase the volume of fire, or give a tactical advantage of a lighter ammo load. They were not using tungsten, however, probably due to cost factors. The concept has been brought back several times since, but hasn't proven to be practical as of yet. With new technologies and improved metallurgy that could change.
en.wikipedia.org/wiki/Special_Purpose_Individual_Weapon


If your limited to the energy you can put in a 5.56 case you hit a point of diminishing returns.

Anything over 4000 fps with conventional construction is going to distort due to burning up/ionizing in the atmosphere.

Another factor is the burn rate of a conventional propellent will limit you to about 5000fps.

A heavy 6.5 bullet would be a great anti fleshy creature round.

I want to know what kind of armor it takes to stop a tungsten pin going 4000 fps.

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