Who is using a 6mmAR or a 6Rat for coyote hunting?

L

longrange2

New member
I am getting ready to build a new upper for coyote hunting in 6mm. I want more case capacity than the 6x45 so I am thinking about using a 6.5 Grendel based 6mm for the build. Right now I am leaning toward the 6Rat or the 6mmAR Turbo 40. This case should allow me to load 105 and 107 grain bullets to mag length for long range shooting. I plan on using 87 grain VMax and maybe the 58 grain for coyote hunting.

I am leaning toward the 6Rat because I can buy a barrel and bolt to build my own upper. The 6mmAr is proprietary and only available as a complete upper. The .243 lbc is attractive but the Grendel case is not blown out and improved like the 6Rat which offers more case capacity.

I don't want to build a 6mm DTI or 6mm WOA because the longer case length will make it difficult to shoot the heavier bullets at magazine length.

What barrel length are you shooting and what loads are working well? Who made your barrel and upper?
 
I'm having a 6mm Fat Rat built for the very same reasons you posted. I originally wanted to go with a 6mmAR but never could get a response out of Robert.........probably too many questions and too custom since I wanted it for coyotes and not competition. What I was looking for, was a builder who built for competitors using top grade components. I wanted a cartridge that would use Lapua brass and a builder who had access or stocked Kreiger barrels. I want a 1 in 10 twist as I plan to shoot 70 to 80 grain bullets. I'm currently shooting a 6x47 in a 1in 10 twist with Nosler 70 grain bullets and it is a hammer. I wanted something unique and different for my first AR build and the Fat Rat fit the bill. I'm having Lee Wells from Accurate Reliable rifles build this upper. Good luck with your decision........I know its a tough one I did a lot of research on the internet to make mine. Let me know if you have any other questions, hope this helps.

Kevin
 
I thought I read somewhere that the 243 lbc is blown out a little bit? If not, is it just a straight neck down conversion? I'm a sucker for simple conversions so the easier the better for me (even if I have to sacrifice a little room).

It sounds to me like the Rat/Fat Rat is right up your alley. My next build will for sure be another 6mm AR!
 
I think the .243lbc is a straight neck down. They are using 6mm PPC dies for the .243lbc so you don't even need to buy custom dies like you do for the 6Rat and 6 Fat Rat. The .243lbc retains the same shoulder angle as the parent cartridge. It is about the same as the 6mmAR, but you can't just buy a barrel and bolt for the 6mmAR and you need custom dies.

Supposedly these cartridges are very accurate even when fire forming the brass, some competitors are forming their brass while shooting the shorter 200 and 300 yard distances at matches.

I think I may order a Krieger Fat Rat barrel with 1:8 or 1:9 twist from Lee Wells.
 
I have been using the 6mm AR turbo 40 Improved with excellent results. Mine has a 24" Pac Nor barrel, 1:8 twist. I get excellent accuracy with just about any bullet and can load 107s to mag length with good results. My favorite bullet is the Berger 87gr VLD. I can get 3000 fps with sub 1/2 MOA accuracy.
 
soo many cartridges to choose from. Im looking into the 6WOA now, found a used upper, brass n dies for $750, but its a 1-12, wanted a 1-10 for the mid weight bullets....arrgghhhh, I have to decide!
 
I've been using a 6WOA for a couple years now. Couldn't be happier. Lots of choices out there now, I'm not sure I envy your position for that reason. It'd be a tough decision to make. Good luck.
 
Mike, mine is 22", 1 in 10 twist and I shoot 65 grn Vmax's over Benchmark powder. Can't say on the velocity. I would consider it pretty flat out to 300. It's does exactly what I wanted it to. Very solid accuracy and flat thumps 'em. That little bullet works great out of it. Most times you can't even tell the dogs been shot until you pick 'em up and hear all the "squishing" around inside 'em.
 
Lakeway,what load are you using for the Berger 87gr VLDs? I have heard you cannot load the Berger 105 VLDs in the magazine, is this true? Do you know if you can load the 105 A-Max in the magazine, the Berger 95gr VLDs? I gues my basic question is what is the bullet with the best BC you can load safely in the magazine, and what is the load you are using?

Thanks.
 
The 6PPC will push the shoulder too far back to fit properly in a .243 LBC chamber. The 6PPC dies must be set about .075 to 85" high off the shell holder as to not disturb the .264 LBC shoulder. It is a straight neck down. PM Ritch Johnson for info on the .243 LBC as he was one of the fellas that came up with that chamber design.
 
I don't have the knowledge regarding these wildcats like you guys but just curious why you would pick the 6mmAR over a .243WSSM? Again, I have no clue. I'm thinking about buying a new upper for my AR-15 and have emailed D-Tech about their uppers. Mostly just curious. Thanks!
 
I went with the 6mmar turbo 40 over the 243 WSSM because from everything I read, and from talking to DTECH, the 6mm is inherently more accurate because the 243 WSSM is overbore and finicky to load for, so a load that is perfect one day could be bad next with environmental changes. You give up about 250 - 300 fps with 6mmar turbo 40, but I care more about accuracy / consistency than velocity. Until the upper comes in 12 -13 more weeks, I was looking for the best bullet to kill coyotes at 600 yds or more. I originally wanted to shoot the Berger 105 VLD hunting bullet (.532 BC), but from Robert Whitely's comments on one website, those cannot be loaded in the magazine without cutting out the front of the magazine and limiting the number of rounds. I like the coyote to drop in its tracks; keep all the energy in the coyote; have its insides explode, and prefer no exit. This is a tall order for a heavy bullet, and may not be possible. The VLDs don't start expanding until two or three inches into the animal so they are for sure going to leave an exit hole and the coyote may run some even though it will die.

With all of that said I am leaning toward the 87gr V-Max (.400 BC) or Berger 88gr flat bottom (.391 BC). Seems the 87gr V-Max should do better long range based on the BC and being a BT. Does anyone know if these bullets can be loaded to 2.26 OAL and if so, do you have any load data on these two bullets for the 6mmar turbo 40 or recommend a better bullet?
 
I have a .243 lbc and it is the same as 6mmAR.

Resize 6.5 Grendel/.264lbc brass in one swipe. The .075 set forward using 6PPC dies is a rule of thumb. Before I managed to get mine dialed in I had to get a case length gauge.

In my experience you can set out with the best of intentions and say "I'm going to use the 87 Vmax" etc, but the gun likes what it likes. Mine doesn't particularly care for 87 Vmax, or at least turns in inconsistent results.

It loves the 70 grain Sierra Blitzking.
 
Oh and as for 87 Vmax to mag length, this is a cut and paste from a post I made on the BHW forum:
Quote:Bullet..........Length to touch...........neck engagement
87 Vmax............2.202....................... .247
95 VLD..............2.326....................... .155
85 TSX..............2.231........................ .260
85 Sierra GK.....2.154........................ .187
70 Sierra BK.....2.236......................... .045
70 Nosler BT.....2.261........................ .108
58 Vmax.............NA.............................zero
80 Berger.........2.226......................... .149

What does the above tell us? Yes, I know, I need to get a life. But the data tells us a bit. My neck engagement measurement is really just a point of data to consider when choosing a seating depth. It's the difference between the bullet just sitting in the opening of the case and when it's shoved back so it just touches the rifling.

What flies off the page at us is that the 58 Vmax is going to have a ton of jump no matter what we do. It doesn't touch the rifling no matter how far out it sits.

The Berger 95 VLD will either have to be single loaded or I have to find a sweet spot where it likes to jump (which is something that Berger claims they do if we peck around and find it). To clear a 2.260 mag length the bullet needs to be pushed .066 deeper

The Sierra 85 Gameking is one blunt pig and looking one over confirms this. It gets rave reviews in terms of both accuracy and terminal performance among those who hunt with them, so even if I can't get a bug hole I will need to pursue either the Gameking or the Barnes 85 TSX at some point. The good news with both of these bullets is that there is plenty to hang on to.

Read more: http://www.blackholeweaponry.proboards.c...6#ixzz2MELQYLhx


You can see I'm jammed into the rifling past 2.202 with the 87 Vmax
 
Dtech built me a 6mm Bench Rest which I used for 600 yd target shooting. Have you thought about one like that. I am replacing that with a 6BR F class bolt action rifle.

I will probably send it back to him and have it rechambered for 243 wssm. It is heavy with a 26 inch unfluted barrel. I have a BRAT 5 round magazine that would make it a autoloader. But the bolt need some slight mod to make it work.

Jimmy
 
My next build is 6mmAR. AR 15 Performance produces a barrel and that is where I will probably get it from. That or Black Hole Weaponry. I have a 6.8 from ARP and love it.
 
Thanks for everyone's response.

aftCG, so if I am understanding your chart correctly, on the 87gr V-Max, when to the bullet must be seated to 2.202 or shorter to stay out of the lands, and at that point it will be .247 into the case / neck right? Can you send the load you used for the 87 V-Max? Did you happen to try the 75gr V-Max? I can't get 87gr V-Max's anywhere right now.

Roger on whatever the gun likes.

Thanks.
 
Jeff,
Yes, .247 into the neck. So far the best load I can get to repeat consistently with the 87 Vmax is 26.5 grains of Benchmark.
IMAG0087.jpg

It's not a particularly hot load, but as I move up I do not find another node before I start bashing the poo out of my brass (AA).
I've managed to get tighter groups out of the 87Vmax with other powders but .2 grains on either side it's a spray gun. Too much like trying to nail down jello for me.

As mentioned, my rifle is much happier with the 70 Sierra - which is fine by me as I have a ton of them.
IMAG0089.jpg

It will consistently turn in this group size no problem.

Since shooting these groups I've installed a Timney single stage drop in, a huge improvement over what I had in there.

BTW, this is my completed rifle before the trigger upgrade:
243lbc_5274.jpg
 
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