6mm Fat Rat data

[tonysnoo]

Ive found some old threads about this round, but nothing from this last summer. Are there any new combinations worth looking in to?

One of the posters on here shared a lot of data with me, but always looking under every stone.

I found some CFE223 and some H4895 that I will try with 105s and also some 87s. Hope to start testing in a few weeks for next season.

 

[Tireguy]

I have tried about 5 different powders and I settled on RL15. I am getting great FPS and sub .5 groups.

Jon

 

[Michaël T]

i own one for two years and it shoots really well.
90bergers@2.25"(mag.length) 30 gn of varget, 107 smk,105 bergers jump 0.005" 29.5gn varget, and F205m primed

 

[Rtheurer]

Im intrested in how your H4895 works out with the 85 to 105gr class bullets. Keep us posted.

RussT

 

[tonysnoo]

Im intrested in how your H4895 works out with the 85 to 105gr class bullets. Keep us posted.

RussT

Russ, you can bet I'll keep you in the loop, thanks for your help!

 

[finnaddict]

Check out 6mmAR.com. The 6mm Turbo 40 is virtually identical to the FAT Rat and there is load data on that site.

 

[Shooterman]

I've had really good luck with 8208, 87vmax, 87hpbt. Last 4 out of 5 groups I shot were under 1/2". Tried Varget, did not shoot as well as the 8208.

 

[tonysnoo]

Thanks everyone. It looks like the tried and true still works the best.

The only powders I have been able to scare up are Cfe 223 and h4895, so those will be my focus. I think H 4895 will be a no brainer....lots of dope on it. I really am very interested in making the CFE work. It seems to be one of the slowest of all the fat rat powders, that I have researched....plus it would be really interesting to see if it is as clean as advertised.

 

[Casey]

[size=10pt]87 Vmax, 105 Amax, 8208, standard oal and charge of 28.5gs. but confirm the charge with the material on Lee Well's site.
[/size]

600 yds

ditto

Attribute its accuracy to luck, day of the week it was chambered, by the way the builder was John Holliger, but whatever it was the gun and loads shoot exceedingly well.
*NOTE: Performance occurred in NW Louisiana for Density Altitude and atmospheric reference

 

[tonysnoo]

Hey Casey,

Did you only shoot two shot groups at 600. Are those 87s 105s or some of each. Judging by your thumb nail, those are crazy groups for 600. They look to be sub 1/4 min groups....is that correct?

 

[6fatrat]

Please note the 6rat and the 6fatrat are not the same.

 

[tonysnoo]

Please note the 6rat and the 6fatrat are not the same.

Agreed, I should be seeing my fatrat next week. Hoping to start fire forming the following week.

Ive been wondering about brass. I have some AA grendel, but couldnt 6PPC brass also used if there was no grendel available. I assume one would expand to 6.5 so you could false shoulder it for fire forming.

 

[Rtheurer]

We have Three choices that I have found for 6.5Grendel brass. The Alaxander arms head stamp (Lapua) Hornady and of course Lapua head stamp. I have all of the above and soo far all have been great. I have been using the AA/Lapua for one rifle and Hornady for another upper. That way its easier to keep track of each upper and its brass.

I dont know why 6ppc could not be made to work. Its the parent cartridge afterall. should you decide to give it a go keep us posted for future refrence. I have been using a 6PPC seating die for one of my uppers.

RussT

 

[Phil]

OK.................So,for those of us that don`t know what a 6mm FAT RAT or a 6mm RAT are would someone care to explain???????

Parent case????

Thanks,

Phil.

 

[Tireguy]

The 6FatRat has the neck opened up .002 over the 6Rat. I believe the initial speeds out of the 6Rat were not what people were expecting. So instead of having to turn the necks on the Lapua or AA brass, why not just open up the neck. When they did, speeds went up. I am getting over 2900fps on my 6FatRat with SMK 107s and RL15. It's an absolute hammer!

Jon

 

[Rtheurer]

Phil
Parent case is the 6.5 Grendel. Short and fat for use in a AR style gas gun. Uses Grendel Mags that work like a Gem.



http://www.accurateandreliablerifle.com/products.html

See the link for more info.

RT

 

[Phil]

Cool,

Thanks Russ.

 

[nmjwolf]

My rifle likes 29.1 of R15 - berger 105's, BR4 primer -- shoots ~.3 at 100 if i hold well -- shot a few .5MOA at 600 with it & good at 300 as well.



Some Chrono Data for H4895 with 105 HYB set to 2.288 OAL. Nothing shot particularly well at 200 yards. The 28.0 - 28.2 were the best (.5 moa at 200) others were ~.6MOA. Shot from (24" Krieger) brl.

Chrono data from Magnetospeed. (Seems a bit high to me)

Series Shot Speed
11 1 2805 ft/sec 27.6 H4895
11 2 2824 ft/sec 27.6 H4895
11 3 2793 ft/sec 27.6 H4895
11 4 2790 ft/sec 27.6 H4895
11 5 2813 ft/sec 27.6 H4895
---- ---- ---- ----
Series 12 Shots: 5
Min 2820 Max 2844
Avg 2830 S-D 9
ES 24

Series Shot Speed
12 1 2828 ft/sec 27.8 H4895
12 2 2826 ft/sec 27.8 H4895
12 3 2844 ft/sec 27.8 H4895
12 4 2820 ft/sec 27.8 H4895
12 5 2836 ft/sec 27.8 H4895
---- ---- ---- ----
Series 13 Shots: 5
Min 2808 Max 2842
Avg 2830 S-D 13
ES 34

Series Shot Speed
13 1 2832 ft/sec 28.0 H4895
13 2 2828 ft/sec 28.0 H4895
13 3 2840 ft/sec 28.0 H4895
13 4 2842 ft/sec 28.0 H4895
13 5 2808 ft/sec 28.0 H4895
---- ---- ---- ----
Series 14 Shots: 10


Charge 28.2
MIN 2834
Series Shot Speed MAX 2855
14 1 2849 ft/sec 28.2 H4895 ES 21
14 2 2834 ft/sec 28.2 H4895 AVG 2843
14 3 2840 ft/sec 28.2 H4895
14 4 2837 ft/sec 28.2 H4895
14 5 2855 ft/sec 28.2 H4895 Charge 28.4
14 6 2881 ft/sec 28.4 H4895 MIN 2875
14 7 2886 ft/sec 28.4 H4895 MAX 2886
14 8 2878 ft/sec 28.4 H4895 ES 11
14 9 2885 ft/sec 28.4 H4895 AVG 2881
14 10 2875 ft/sec 28.4 H4895

 

[jbarron]

What sizing die are you guys using for the FatRat?

 

[Rtheurer]

Fat Rat Die made by Hornady sold at the link above I posted for Phil.
Lee also sells this dern nice Case gage for checking your Brass. Very nicely done and I recomend it to anyone shooting a gas gun in this cartridge.
RT