6mm Turbo 40 Ackley AR-15 Review By Robert Whitley


Mar 6, 2008
In recent years, there has been a huge increase in the number of 6mm wildcats being shot out of AR-15's. This movement was started and driven forward mainly by across-the-course high power shooters that have to compete at ranges out to 600 yards where wind drift can become a big problem. The existing commercially produced 6mm match bullet lineup has bullets that have a significantly higher ballistic coefficient (b.c.) than is typically available to those shooting with the .223 Rem. (or 5.56 NATO). For instance, the age old standard 600 yard loading for the .223 is the Sierra 80 gr. MatchKing bullet that has a b.c. of only .420, but the current 6mm Berger 108 gr. BT bullet has a b.c. of .546 and the 6mm Berger 105 gr. VLD bullet has a b.c. of .556. On a windy day at 600 yards the bigger 6mm bullets can be affected by the wind significantly less than the .223 Rem. counterparts. Read More...
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Nice article, that sure is an interesting cartridge and rifle. Sounds like they would be great for LRH coyotes and prairie dogs. Enjoyed reading.
It don't compare with a 243WSSM. The WSSM is much faster and shoots heavier bullets flater. This is the dream cartridge that long range AR shooters have been waiting for.
I have been researching wildcats for the AR-15 for upcoming AR benchrest class and "F" class style shooting for AR-15.

There are tons of cartridges out there for AR-15. It the article, Mr. Whitley discusses the dies, magazines, complete uppers and even complete rifles are ready. He also has load data for a variety of powders/bullet combinations.

The Turbo 40 looks great.

Major Competitors to Turbo 40 in long distance shooting in AR-15:
.223 - 80, 90gr bullets highly affected by wind.
6mm BR - available magazines.
6mm TCU, 6x45 - lack of velocity with longer bullets.
WSSM - lack of bench rest quality brass, but flatter trajectories.
Grendel - lack of velocity
Interesting read. I just received a tricked out AR in 204 ruger I haven't had to the range yet, and I am interested in replacing a good shooting 788 / 243 with something like this to enhance my 2# triggered lower.

I believe the issue with 223 length bumped to 6mm or 7mm ala TCU is the ctg OAL and having to single load them, correct? I laid one of my 7TCU 100 gn hp ammo on a AR magazine and it looks like a no go, or is my memory incorrect?

On the WSSM isn't bolt thrust an issue with the added pressure it must produce, or am I wet there also?

Dissapointing to me is the 10x reloads with expensive brass, if used for dogs by the hundred shots a day, although I suspect in a 12 hour day, 720 minutes, that's a shot every 3 1/2 minutes, and you must cool the gun....so maybe 75 shots with this gun a day isn't unreasonable for dogs. Brass at $72 /100 vs $22 / 100 for 204 ruger, $40/100 for my 221 fb....

Still seems like a cool thing to get. Anyone have a used setup they want to pass on for further development by me...? LOL
I have a great 788 to toss in the mix toward getting a good shooting 6mm upper......

I recently bought a Turbo 40 Varmint Upper, And I can testify it is a tack driver!!! It has done everything i have wanted it to out to 1000 yards consistently. I've even had my local long range shooters say they were very impressed ( none of them are fans of gas guns). it is a great round and the upper i purchased is very nicely machined and well built.

Turbo 40 Varmint Upper
Predator XT Billet Lower
Jard Trigger
Magpul PRS stock
Nightforce NXS 3.5-15 X 50

Lapua Brass
Hornady 105 Match BTHP ( Berger 105 VLD Hunting Also)
H4895 29.4 gr
i know this is an old post but does anyone know if robert whitley still does ar uppers? i can't seem to get ahold of him.