My 6x6.8 build.

[5spd]

For those who have this or looking at it vs the other 6.8 line necked to 6mm.

I built a 6x6.8 or (6x43), this is the 6.8 straight necked down to 6mm w/no shoulder changes last week using all parts for the upper from Joe Bobs and the 22" 1/10" P3 barrel from BHW. 6.8 Bolt head from midwayusa. 3lb timney trigger.
Took maybe 20 min to put it together for my 1st upper build.
The fact that very little load data for this cartridge is floating around w/the 55/58/65g/80g bullets that I have to extrapolate most of my data from the close 6dti/6Woa data I can find and go from there.
I loaded up 100 rounds (20 different loads) using various powders I have on hand and ran everything over my chrony.
All my COLs were 2.270"
Remington brass, cci 200 primers.
NOT one single issue w/pressures, primers ALL were nice & rounded, no bolt or extractor marks at all.
Good powders & speed depending on charge using 55/58/65g bullets.
W748.........3048-3214fps
Benchmark....3318-3413fps
H335.........3130-3199fps
xbr8208......3104-3208fps
Varmint pro..3141-3185fps & some of the best groups.
Odd one:
My best group was w/31g w748, 65g vmax, 3214fps @ .377"
I dumped 8 loads and will change 12 others in weights.
My best groups were .377/.467/.627/.577/.957/ and some over an inch. Wind was at 15-23 mph, 32-43* & sunny.

 

[platapus]

Nice work 5spd, I hope you find your niche.

 

[Rundownfid]

I would ber interested in hearing your thoughts on this cartridge especially how you think it compares to the 6MM Fat Rat (also being discussed here). Questions I have (I am sure there are more and ecven better ones), are; 1. is there any real advantage in terms of bolt head strength between the 6 FAt Rat and the 6X6.8? While they case head is slightly smaller on the 6.8 is it enough to matter? What is the capacity of both cases? What kinds of velocity advantage with heavy bullets, can one expect (I'm assuming theat the 6 Fat Rat will be faster with say a 105 gr but how much faster)? OK what questions have I missed?

 

[5spd]

I have not done a case fill w/water, but I have w/various powders to see the top line on each of them. I got a low of 30.4 w/stick to 36.2 w/ball case capacity w/actual powders I use fills to the top & weighing them. Now of course I do not load that way. All my loads are running 30.5 to 33g depending on what powder for that specific load.
I am loading for 55/58/65g bullets since this will be a coyote rig. I will load 80g/95g for antelope max weights. I have no need to shoot anything heavier.
I am getting groups from .377" to .960". I have 24 new loads to test & run over my chrony.
The bolt head is PRI from midwayusa, nothing fancy but works like a charm. Mag max COL is 2.295", but I run all mine at 2.280" so nothing hangs up at the tips in the mags.
I have not read anything on the FatRat, looked at posts, but its not of any interest for my usages at all so I cant compare them side by side.
I do not like short fat cartridges so never looked at anything off the 6.5 cases.
Im sure its faster w/the same weights though.

 

[Tx_Flyboy]

5Spd,

What you just described sounds like something my gunsmith is trying to buuild a market around for highpower shooters.

Its called 240 tomahawk...check out his website for loads he has developed...might save you a ton of time and money.

I will build something like that in a year or two, but first i want to be convinced of the staying power of the 6.8 components.

Oh yeah, his website is .240 Tomahawk, Keystone Accuracy Custom Rifles .240 Load Data

 

[5spd]

TX
Thanks. Ive seen that before, but still wanted a build around nothing more than a neck down 6.8 case & no fire forming cases so I went w/the 6x6.8 (6x43).
I do not plan to shoot heavier than the 65g vmax for coyote as it works perfect in my 6x45 and have no need to shoot 87-105g bullets.
The only heavy load will be w/an 80g ttsx for antelope.

 

[Mod Adahy]

JFI, Tomahawk pushes 105 Hornady HPBT at 2845. It is easily made from 6hagar brass with no fireforming. Simple to size down, trim and shoot.

 

[Mod Adahy]

Although I still love the 6WOA.

 

[steve123]

Although I still love the 6WOA.

But your 22-6.8 with those 90's/.551BC at 2980 fps rock!

 

[5spd]

Im posting this for you 6x43 (6x6.8) users.
My build, 22" BHW P3 1/10" twisted, AR15
Shoots 1"+ w/many powders and much smaller groups with others.
All shot w/bipod, rear on a bag & tucked into my shoulder inside the shooting house over a chrony.
Remington 6.8 brass necked to 6mm. Large primer pockets.
All loads were at 2.260-2.290" in the beginning and down to 2.270" and had loads from 2.250/2.260" also.
All primers including magnums were perfect, no craters, no over pressures. NO FTF, NO FTE all ran in my AR perfectly.
LR magnum primers didn't do much for speed or groups, but I will try them w/more loads.
This will not be a heavy bullet gun, 65g MAX for coyote.
They may shoot better or worse in you gun, I make no promises whatsoever here, use at your own risk/discretion!

I combined all the weights together. Many are the same loads, but shot on many different days to check grouping.
55g NBT:
33g h335, cci200, 3569fps, .520"
33g h335, cci200, 3546fps, .750"
31g w748, cci200, 3159fps, .880"

55g Combined Technology (coated):
30g x8208, cci200, 3208fps, .630"
33g h335, cci200, 3466 fps, .310"
33g H335, cci200, 3529fps, .900"
30.5g BM, cci200, 3413fps, .467"
31g varmint pro, cci200, 3141fps, .627"

55g sierra BK:
33g h335, cci200, 3539fps, .750"
33g h335,cci200, 3583fps, .800
33g H335, cci200,3489fps, .830"
31g blc2, cci200, 3048fps, .420"
32g blc2,cci200, 3142fps, .620"
31g BM, cci200, 3474fps, .350"
31g w748, cci200, 3122fps, .480"
30g imr4320, cci200, 3073fps, .810"
27g H4198, cci200, 3499fps, .950"

58g Vmax:
31g varmint pro, cci200, 3185fps, .577"
30g h335, cci200, 3199 fps, .627"
31.5 x8208, cci200, 2.270" col, 3374fps, .940"
31.5 x8208, cci200, 2.280" col, 3513fps, .900"

65g Vmax:
31g h335, 3348fps, .850"
33g h335, 3532fps, .650"
31g blc2, 3015fps, .750"
31g blc2, 3117fps, .730"
30.5 x8208, 3298fps, .880"
31g w748, cci200, 3214fps, .377"
32g w748, cci200, 3242fps, .730"
32g w748, cci200, 2.280"col, 3320 fps, .750"
27g H4198, 3411fps, .580
27g H4198, 3430fps, .990"

 

[LRRPF52]

Thanks for your work in uncharted territory. Looks like a lot of the powders that work well in the Grendel are great with this:

H335
W748
BL-C(2)

I'm interested in the .224x43 and .257x43. That 75gr A-MAX in the .224 version is a screamer.

 

[angus6]

5spd thanks for sharing the data, fairly new with the 6x68 so every bit helps.

little high jack

I'm looking for some suggestion for a 85gr TSX load, was given 20 bullets and would like to try them deer hunting. Rifle would be 6x6.8 18",1-10
powders on hand
REloader 15- 10 - 7
LT-32
TAC
Varget
IMR4895
AA2200
1680
WC844
WC846

 

[5spd]

Id run with Tac/Varget/RL10 & start at 28g and see what they do and go up from there if I was testing those powders.
I don't have the other powders.
I only did 3 heavy bullets tests so far only due to the fact I want only a 55-65g bullet for coyote in this gun.
80g ttsx, 28g h335, 2.270" col, 2937 fps.
85g SGKHP, 29g TAC, 2.270 col, 2854 fps.
95g Nosler HBT, 25g H335, 2.275"col, 2452 fps
1/10" twist, 22" barrel.

 

[angus6]

Give Tac a try with 28.4gr and the 85gr TSX, very very bad had just switched scopes before trying so ran a mag of 87 Vmax and back to normal. Guess I'll grab some Sierra 85gr GK tomorrow and load a mag over 8208 for deer season and come back to the 85gr TXS's later.

 

[5spd]

This was the first outing calling coyote w/my new 6x6.8 build.
Dropped 2 coyote calling Thanksgiving day w/my 65g vmax, 29g 10x, cci250, 3411 fps.
Invited to the ranch for dinner again and met 2 other ranchers that stopped in for said dinner and picked those ranches up as well...another 40k acres...what a great day!
I was happy....

 

[5spd]

Some more NE coyotes w/the 6x6.8, 55g NBT load at 3411 fps.
Popped this and his pal over a cow pile at 1130 am when I went to check it out after the rancher said he dumped one up there 4 days prior.

Also in NE the other day, dropped at about 90 yards as it spun on a pin head when it busted us after flying into the call.
Was nicely fed and thick fur BUT yup had a tad of mange on its legs.

Moved to the hunting forum...forgot this was under SA when I added it.