Reloading for the new .277 Fury from Sig

[31perersen]

There are no hybrid cases in 308 and 6.5 Creedmoor...you have to find 277 Fury bi metal cases and form them. 308 is easy, just mandrel the 277 and run through the normal 308 sizing die. The 6.5 Creedmoor I use 308 FL die to move the shoulder then 6.5 Creedmoor FL die trim to length, and neck turned all on lathe. I haven't annealed anything so far. I used 3 powders in the 308 experiment with different bullet weights from 155 gr 3182 fps, too fast on powder choice ,168 gr 3255 fps, 200 gr 2951 fps, 225 gr eldm 2719 fps... and one powder in the Creedmoor with 150 gr SMK only bullet tried, at 3056 fps. I dropped these top velocity loads 50 fps and have been running the 308 200 gr SMK .715 Bac at 2900 fps and the 6 5 Creedmoor 150 SMK .713 BC at 3000 fps. With these cases. I do not give out powder or specific load data as this is a somewhat dangerous endeavor. Pressure signs are a little different with the SS heads...no marks at all on the case head, no blown primers, primers fairly round, primer pockets tight ss when I started after three firings....any action resistance on opening is a big pressure indicator with these, back off, your stressing the action. These cases are very strong. I have a new Bartlein barrel ordered for the 6.5 Creedmoor and will experiment with that rifle ... look for barrel wear, and check the action. So far it's all good...everything as it was on the go gauge of the 3 lug action which I will continue to use. Gonna fireform a bunch of 6.5 cases already made up with 140 gr. bullets. I do not recommend anyone doing this. I'm just looking at the possibilities with these new components, and would recommend that most would wait for the 277 Fury to fully develop and be available. I have a full machine shop and am retired machinist and build my own rifles....and this is a rather serious endeavor to answer questions I have.

44-40, we're you able to get the speeds you were getting with any temp insensitive powders? It seems like more often than not, the higher pressure powders that are getting good speeds are very sensitive. Not asking for load data or anything, just curious what powders you were finding success with. It sounds like Straight Jacket Armory was doing pretty well with reloads but I'm still not sure if that was with the all brass cases or the hybrid cases. They were very impressed with the Sig factory loads as far as speed but said their consistency was sub-par. They said the ES and accuracy wasn't there but the handloads were very good, which makes me believe they were using the bi-metal brass with their handloads, but not certain. Thanks

 

[akmtnhnt]

Oh, I see. So I was asking which barrel you were using earlier, who did your chambering/barrel?

I ordered one from Mcgowen, didn't want to go real high end on something that may or may not pan out. Great groups with the brass stuff for far from it.

If this one works out, I'm real interested in necking it up to 338 and running it in a 338 federal chamber

 

[akmtnhnt]

44-40, we're you able to get the speeds you were getting with any temp insensitive powders? It seems like more often than not, the higher pressure powders that are getting good speeds are very sensitive. Not asking for load data or anything, just curious what powders you were finding success with. It sounds like Straight Jacket Armory was doing pretty well with reloads but I'm still not sure if that was with the all brass cases or the hybrid cases. They were very impressed with the Sig factory loads as far as speed but said their consistency was sub-par. They said the ES and accuracy wasn't there but the handloads were very good, which makes me believe they were using the bi-metal brass with their handloads, but not certain. Thanks

I can't find a temp insensitive powder where you can get enough in the case to get up there. Running through both QL and GRT, there's only a couple powders that are viable.

 

[31perersen]

I saw a guy who had purchased a prefit savage 277 fury barrel from mcgowen in 16" that was getting 3015 across the lab radar with the bimetal 150 grain accubonds loaded by Sig. He didn't get a chance to shoot groups and I believe was deploying the next day or something, so didn't have enough time to shoot groups unfortunately. That's very impressive speeds, just curious what the accuracy would be. I'd be very interested to see what a fury can do with the BD-2 and a temp insensitive powder, even if it is giving up some speed due to the volume. I would assume anywhere near 2800-2900 in a short barrel with the 140 or 150 grain would be awesome if it was accurate.

 

[akmtnhnt]

I saw a guy who had purchased a prefit savage 277 fury barrel from mcgowen in 16" that was getting 3015 across the lab radar with the bimetal 150 grain accubonds loaded by Sig. He didn't get a chance to shoot groups and I believe was deploying the next day or something, so didn't have enough time to shoot groups unfortunately. That's very impressive speeds, just curious what the accuracy would be. I'd be very interested to see what a fury can do with the BD-2 and a temp insensitive powder, even if it is giving up some speed due to the volume. I would assume anywhere near 2800-2900 in a short barrel with the 140 or 150 grain would be awesome if it was accurate.

Varget is probably going to work pretty well in this. Only giving up about 80fps to the temp unstable powders. I'll have some more data this weekend.
Luckily where I live, hunting and shooting temp swings are from like 20 to 60F. Not really much, and so I don't mind the temp unstable powders that give extra performance.

 

[CBH Australia]

Dude the 277 fury is a 6.8

Yeah, so are some other 6.8mm calibre rounds

But , the version sold to the civilian market will be chambered as and marketed as .277 fury.

Yeah, but we will not be able to purchases the 6.8 military ammo. Sig is going to release a "civilian" version of the 6.8, the .277 Fury according a press release I saw yesterday.

Didn't read the last 13 pages, did he accept the correction?
The rest of us understood.

 

[31perersen]

Gotcha, so you aren't working with Varget then? Interesting to see what powder you use and what your results are. Keep us posted, thanks!

 

[akmtnhnt]

These were just loads for velocity today, hence the large jumps in powder, chosen for their estimated pressure. Except for the 1st load, they're all over 65kpsi and right up to the limit, so don't be using load data from some guy on the internet(me) and not looking into everything first. But, to give an idea of what this round will do for anyone thinking about loading for it...
5 shot averages, 18in barrel, 2.950 COAL, 140gr BD-2, lever evolution. 29F OAT, because with this powder, it matters.
45.5gr - 2832
46.6gr - 2876
47.8gr - 2955
48.4gr - 2972fps

 

[akmtnhnt]

Shot my DRT 152gr loads today, velocity where I was estimating 80kpsi was an average of 2885fps with 47.2gr of powder.

 

[31perersen]

great info... keep us posted. thanks for all the testing info!

 

[thanat101]

Couldn't find any reload data on the 277 Fury cartridge; so I am developing my own.
I am starting very low and will continue to increase. Will take several weeks. This is what I have so far:

135 grain FMJ with 16" barrel on .277 AR-10 Build.
Used Pulled Sig 135 grain FMJ projectiles.
Used Accurate 2015 smokeless powder
Used Unis Ginex, 5 5/N primer for large rife
Used once fired Sig 277 Fury Brass
Trimmed case length was 2.0185 inches
Overall cartridge length was 2.805 inches
33.4gr - 2392 5 shot average
34.1gr - 2410 5 shot average
34.8gr - 2486 5 shot average
35.5gr - 2501 5 shot average

150 grain SP with 16" barrel on .277 AR-10 Build.
Used Speer 150 grain BTSP projectiles.
Used Accurate 2015 smokeless powder
Used Unis Ginex, 5 5/N primer for large rife
Used once fired Sig 277 Fury Brass
Trimmed case length was 2.0185 inches
Overall cartridge length was 2.715 inches
33.0gr - 2289 5 shot average
33.6gr - 2319 5 shot average
34.2gr - 2344 5 shot average
34.9gr - 2389 5 shot average

 

[31perersen]

nice. good to see some data coming with reloads for the fury rounds. akmtnhnt and I were working some different loads up too with fairly good success. he was using leverevolution and I was using varget. both using badlands bd2 140 grain. he has also used some drt bullets. I was getting 2992 with the Sig 150 grain hybrid ammo and a 16" straight jacket armory barrel on the cross. about 1" group of 10 and 19 out of 20 from the box I fired were between 2984 and 2993 fps, with 1 round at 2965. so pretty decent spread and good groups for factory ammo. I was getting an average of 2838 with varget and the super long 140 grain bd2 with the liad I'm going to shoot. all loads with what we tried were accurate working with a .4 grain increase and varget and all hit the same spot at 100 yards with all 4 loads I loaded up, you could have covered the "group" of 12 shots at 100 yards with a quarter.

 

[akmtnhnt]

Couldn't find any reload data on the 277 Fury cartridge; so I am developing my own.
I am starting very low and will continue to increase. Will take several weeks. This is what I have so far:

135 grain FMJ with 16" barrel on .277 AR-10 Build.
Used Pulled Sig 135 grain FMJ projectiles.
Used Accurate 2015 smokeless powder
Used Unis Ginex, 5 5/N primer for large rife
Used once fired Sig 277 Fury Brass
Trimmed case length was 2.0185 inches
Overall cartridge length was 2.805 inches
33.4gr - 2392 5 shot average
34.1gr - 2410 5 shot average
34.8gr - 2486 5 shot average
35.5gr - 2501 5 shot average

150 grain SP with 16" barrel on .277 AR-10 Build.
Used Speer 150 grain BTSP projectiles.
Used Accurate 2015 smokeless powder
Used Unis Ginex, 5 5/N primer for large rife
Used once fired Sig 277 Fury Brass
Trimmed case length was 2.0185 inches
Overall cartridge length was 2.715 inches
33.0gr - 2289 5 shot average
33.6gr - 2319 5 shot average
34.2gr - 2344 5 shot average
34.9gr - 2389 5 shot average

What did you do to be able to run 80kpsi on an AR10?
Generally the AR's can't even handle a normal bolt gun 65kpsi load.

Or are you just going to run brass cases?

 

[31perersen]

as far as being able to read pressure when loading the hybrid brass, there's not really a way to tell where you are at. I'm curious what the volume of the brass vs the hybrid cases are? I would think, if they are the same, a guy could use normal reloading pressure indicators while working up using the all brass. once you start getting pressure, you know you'd be roughly 65k-70k psi and be able to move up another grain or so from there in the hybrid??? also, to be even more careful, just stay right in there. typically, you end up finding accuracy a bit below max but maybe you'd still have the accuracy using the hybrid case with the same liad and not have to back down to find accuracy. that'd only give you maybe 75ish fps increase over the all brass case but an idea??? from what I've heard (I think from straight jacket) even the numbers with the all brass case are pretty comfortable.