277 Sig Fury Steel head brass formed to wild cats-Action strength issues

[AckleymanII]

I am seeing some incredible results in forming 308 Win and 260 AI from 277 Sig fury Steel head brass. On You Tube, a guy is shooting a Rem 783 with 125s at 3600+ with absolutely no extraction issues. I have killed a lot of deer shooting the 125-135g bullets in the 308 and 3200 is just about top end velocity/ Pressure.

ON the 260 AI, an internet acquaintance is shooting the 140s over 3000 with accuracy and no pressure.

A couple of things come to mind, first action strength to take the added pressures with metal fatigue being my main concern. Second, if this steel head case catches on, we could be on the cusp of a revolution.

I am somewhat reluctant to jump on wildcatting the 277 Sig Steel head brass until I get some feedback on pressures exerted on actions. as not all actions are created equal in this regard. For instance, not all actions are rated to handle 338 Lapua pressures, etc, and Wild cats formed from 277 Sig cases are running pressures equal to or above and beyond what the 338 Lapua runs.

I would appreciate any comments.

 

[Tommie]

 

[SeabeeKen]

I never was nor will i ever be obsessed with speed. I am content with brass cases

 

[SD guy]

Not for just anyone or any action. Personally, I'll pass at this point. Though this does suggest that additional factory offerings in calibers other than 270, may be seen b4 long. How long till we are seeing PPC fury variations on the market.

Guessing the more I see of this cartridge the more I will like it. Currently A bit much for me at this time. When more civilian rifles are offered beyond the Sig, then perhaps we will embrace this. Exactly what the military wants I suppose. We are not overly anxious to see the oposition having the same capabilities.

 

[joshb]

I never was nor will i ever be obsessed with speed. I am content with brass cases

Ditto. I’m very content with lower velocity. Although I’m currently pushing my 45 Colt rifle WAY beyond it’s intended velocity, 1600 f p s isn’t really screaming along.

 

[CJ6]

You might want to check with what Walt Kraft has already posted in other posts about the Sig Fury...
Personally I'm having one done for using standard brass to use up the 270 bullets on hand instead of using the 270 Winchester I have.

 

[Straightshooter1]

I am seeing some incredible results in forming 308 Win and 260 AI from 277 Sig fury Steel head brass. On You Tube, a guy is shooting a Rem 783 with 125s at 3600+ with absolutely no extraction issues. I have killed a lot of deer shooting the 125-135g bullets in the 308 and 3200 is just about top end velocity/ Pressure.

ON the 260 AI, an internet acquaintance is shooting the 140s over 3000 with accuracy and no pressure.

A couple of things come to mind, first action strength to take the added pressures with metal fatigue being my main concern. Second, if this steel head case catches on, we could be on the cusp of a revolution.

I am somewhat reluctant to jump on wildcatting the 277 Sig Steel head brass until I get some feedback on pressures exerted on actions. as not all actions are created equal in this regard. For instance, not all actions are rated to handle 338 Lapua pressures, etc, and Wild cats formed from 277 Sig cases are running pressures equal to or above and beyond what the 338 Lapua runs.

I would appreciate any comments.

I've recently started playing with these 277 Sig Fury cases, necking them up to .308. I went out and just initially fire formed 10 to come back and measure case capacity. Loaded them up with a 190 SMK's and some IMR-4064 (medium load). Was very surprised getting such a good SD and ES for the 10 shots (4.5 and 15 respectively) and just over a .5 MOA. I'll be uping the charges once I get a feel for how some powders work. The steel case heads tend to not show pressure signs, like primers not blowing out, so need to work cautiously and rely somewhat on what QuickLoad suggests the pressures are at. Though I really don't plan on pushing the limits, like going to 80k psi. I'll be collecting data as I usually do to get a decent picture as to how the cases work out in my gun.

I bought 5 boxes of these cases and they come with more that 100 cases per box, AND. . . mine came with 4 different headstamps. There a substantial difference between their case volume . . . about 1 full grain of H2O. So. . . if you're inclined to order some and try them out, be sure to weight sort them or at least sort them by headstamp.

The 10 cartridges I loaded up had the headstamp year "24" on them which were the heavier ones at 161 grs with 56.3 grs H2O. Those that come with the headstamp "277 Sig Fury" are around 150 grs in weight having ~ 57.5 grs H20 (I'm talking .308 case configuration).


I'm looking forward to having some fun with these case!

 

[SD guy]

Suppose the question just triggered for me. What primer will be withstanding the higher pressure?

 

[Straightshooter1]

Suppose the question just triggered for me. What primer will be withstanding the higher pressure?

From what I seen from other's who have run some high pressures in these hybrid cases, the standard primers don't seem to be affected much. My guess is that because the steel base's web isn't expanding like a brass web does. A brass web tends to expand enough to not hold onto the primer as tightly as it does when first seated and when the pressure subsides it'll usually springs back.

 

[Fuj]

Doing a little simple math......Hmmnnnn. "30BR-Fury" running a
20 twist barrel, maybe a crazy 21 to 22 twister ??......Yeah, I would
worry more about case stretch separation just ahead of the steel
If you do not keep resizing and bump numbers tight......I'm fine
with all brass cases.

 

[Darkside]

I've recently started playing with these 277 Sig Fury cases, necking them up to .308. I went out and just initially fire formed 10 to come back and measure case capacity. Loaded them up with a 190 SMK's and some IMR-4064 (medium load). Was very surprised getting such a good SD and ES for the 10 shots (4.5 and 15 respectively) and just over a .5 MOA. I'll be uping the charges once I get a feel for how some powders work. The steel case heads tend to not show pressure signs, like primers not blowing out, so need to work cautiously and rely somewhat on what QuickLoad suggests the pressures are at. Though I really don't plan on pushing the limits, like going to 80k psi. I'll be collecting data as I usually do to get a decent picture as to how the cases work out in my gun.
View attachment 1661695
I bought 5 boxes of these cases and they come with more that 100 cases per box, AND. . . mine came with 4 different headstamps. There a substantial difference between their case volume . . . about 1 full grain of H2O. So. . . if you're inclined to order some and try them out, be sure to weight sort them or at least sort them by headstamp.

The 10 cartridges I loaded up had the headstamp year "24" on them which were the heavier ones at 161 grs with 56.3 grs H2O. Those that come with the headstamp "277 Sig Fury" are around 150 grs in weight having ~ 57.5 grs H20 (I'm talking .308 case configuration).
View attachment 1661698

I'm looking forward to having some fun with these case!

Who makes Sigs brass? Thanks

 

[Walt Krafft]

Who makes Sigs brass? Thanks

Sig makes thier own brass.

 

[hoz53]

I am seeing some incredible results in forming 308 Win and 260 AI from 277 Sig fury Steel head brass. On You Tube, a guy is shooting a Rem 783 with 125s at 3600+ with absolutely no extraction issues. I have killed a lot of deer shooting the 125-135g bullets in the 308 and 3200 is just about top end velocity/ Pressure.

ON the 260 AI, an internet acquaintance is shooting the 140s over 3000 with accuracy and no pressure.

A couple of things come to mind, first action strength to take the added pressures with metal fatigue being my main concern. Second, if this steel head case catches on, we could be on the cusp of a revolution.

I am somewhat reluctant to jump on wildcatting the 277 Sig Steel head brass until I get some feedback on pressures exerted on actions. as not all actions are created equal in this regard. For instance, not all actions are rated to handle 338 Lapua pressures, etc, and Wild cats formed from 277 Sig cases are running pressures equal to or above and beyond what the 338 Lapua runs.

I would appreciate any comments.

thanks for the report Ackleyman— id like to neck one of those up to 7mm and be running a 168 at 3800 out of a 26” barrel. that mite revoulutionize Fclass and LRBR. Im like you though Im not gonna blow up a few guns experimenting with it. when the action comes out designed to do this I may try it.

 

[SeabeeKen]

Update us on bore condition as testing goes on.

 

[CJ6]

Update us on bore condition as testing goes on.

Stellite may be the best option.

 

[joshb]

 

[LVLAaron]

Sig makes thier own brass.

5-6 years ago Cabelas had tons of Sig brass on the shelf. I got a couple hundred pieces of 308, it measured as well as lapua. Good stuff for sure.

 

[CJ6]

Yup good stuff.

 

[ebb]

If only they made it in a magnum bolt head size! 300RUM cases will lose primer pockets with just a tiny bit more pressure than called for. Ive never shot a hot load but lost more than I wanted to just in load development.

 

[AckleymanII]

Hoz53, for your application, I would go AI for sure.