277 SIG Fury

[comfisherman]

I am wondering about the "aluminum washer between the brass case and steel head. How does each firing affect it?

I wish I knew more about engineering but I sadly don't, but boats are what I do. In the boat world brass, aluminum and steel all pushed together never last very long.

I'm still hopeful there is some awesome thing over the horizon, but the last few years have taught me differently. Pragmatist in me says "awesome 5$ a pop factory ammo" or "reloadable brass that's essentially an oversized 6.8 spc".

Hopefully the optimist side wins. Logically pressure is about the only way for combustion cartridges to grow.

 

[akmtnhnt]

I wish I knew more about engineering but I sadly don't, but boats are what I do. In the boat world brass, aluminum and steel all pushed together never last very long.

I'm still hopeful there is some awesome thing over the horizon, but the last few years have taught me differently. Pragmatist in me says "awesome 5$ a pop factory ammo" or "reloadable brass that's essentially an oversized 6.8 spc".

Hopefully the optimist side wins. Logically pressure is about the only way for combustion cartridges to grow.

I've played around with the cartridge in QL a bit using my preferred projectiles, which do sit a bit into the case at SAAMI spec. Brass case - 18in barrel 140gr moving at 2800fps. Everything the same but steel and 80kpsi, now moving at 2980fps.

With the brass case, that's remarkably close to a 7-08 with a 140. So ya, a 6.8/277-08. With the steel head it tracks almost identically to a 270wsm only with a good bit less powder and recoil, and can stabilize a lot longer bullet than the wsm if you're going off the saami twist rate. Not even close to a 6.8spc in either case.

 

[comfisherman]

I've played around with the cartridge in QL a bit using my preferred projectiles, which do sit a bit into the case at SAAMI spec. Brass case - 18in barrel 140gr moving at 2800fps. Everything the same but steel and 80kpsi, now moving at 2980fps.

With the brass case, that's remarkably close to a 7-08 with a 140. So ya, a 6.8/277-08. With the steel head it tracks almost identically to a 270wsm only with a good bit less powder and recoil, and can stabilize a lot longer bullet than the wsm if you're going off the saami twist rate. Not even close to a 6.8spc in either case.

Fair enough. So 708 not spc. Short action 308 case head that duplicates a 708...

Duplicate a 270 wsm and I'm all in....

 

[bamban]

When I get around chambering a barrel I will most likely run a 20. In the meantime I need to get the 700 bolt modified - bushed and run 0.060 pin. Without the smaller hole and pin, pressure will do a number on the primer and primer hole..

 

[asd9055]

When I get around chambering a barrel I will most likely run a 20. In the meantime I need to get the 700 bolt modified - bushed and run 0.060 pin. Without the smaller hole and pin, pressure will do a number on the primer and primer hole..

Why not a Weatherby MKV action?

 

[bamban]

I have the 700, I just need to get motivated and fire up one of the lathes and mod the bolt.

 

[comfisherman]

I have the 700, I just need to get motivated and fire up one of the lathes and mod the bolt.

In the way back machine Richard Franklin did the 300 varimeter. It was just an overpressure 300 short mag flinging 125s. I'm assuming he just found a powder that worked good and consistent around the 80kpsi. Memories a bit hazy but he used a 700 clone action as the basis. And when questioned his logic was tight firing pin clearance and a higher confidence that the lugs were made out of what they were said they were made out of.

Over the years I've seen some velocity claims and loads posted on the internet that lead me to believe the Remington 700 can easily operate at 277 Fury pressures. People have been doing the overpressure "redneck" Magnum for years.

Will be an interesting project to follow

 

[bamban]

Over the years I've seen some velocity claims and loads posted on the internet that lead me to believe the Remington 700 can easily operate at 277 Fury pressures. People have been doing the overpressure "redneck" Magnum for years

Yes, they can. The guy who chambered the barrels for testing at Crane did the initial work using 700 with modified bolt.

 

[akmtnhnt]

In the way back machine Richard Franklin did the 300 varimeter. It was just an overpressure 300 short mag flinging 125s. I'm assuming he just found a powder that worked good and consistent around the 80kpsi. Memories a bit hazy but he used a 700 clone action as the basis. And when questioned his logic was tight firing pin clearance and a higher confidence that the lugs were made out of what they were said they were made out of.

Over the years I've seen some velocity claims and loads posted on the internet that lead me to believe the Remington 700 can easily operate at 277 Fury pressures. People have been doing the overpressure "redneck" Magnum for years.

Will be an interesting project to follow

Bolt thrust has a lot to do with case head diameter. The fury having a 308 size case head has less bolt thrust at 80kpsi than any magnum case head out there. So we know it's fine beause standard magnum cases people shoot every single day have more bolt thrust than this round.
Bolt thrust isn't the only issue, but as far as an action being able to handle the round, the answer is yes.

 

[comfisherman]

Fair point. Considering the amount of .590 bf 700s still running around, clearly they can take it.


My own personal anecdotal evidence is that pressure can offset a little bit of bore inefficiency. Higher kpsi rounds seem to loose less as bore decreaeses than low psi rounds. My hope is that a 6 or 6.5 Fury will give us better short barrel speeds, as compact short barrel rifles continue to replace our loooong ones.

 

[44-40]

This is an old thread, but those interested, I have 800 hybrid cases necked to 308Win, 6.5 Creedmoor, and even 358 Win.
Regular dies of every brand work just as they do with brass cases. The SS head is slightly undersize...like a small base die, and doesn't appear to expand at 80,000 plus psi. I have reloaded some 4 times with tight primer pockets. The 6.5 Creedmoor will shoot 140 gr bullets to over 3150 fps in a 24" barrel. So any existing 308 caseed cartridge can experience the similar increase in performance...not just the 277 Fury.
But the 277 Fury has a great case design IMO and could be just necked up or down to any reasonable caliber with its 30° shoulder for more performance at 80,000 psi...short or long barrels...I'll be checking barrel life and wear as I go with SS and Chrome moly barrels. Checking head space has not moved in the Rem 700 or the RPR 3 lug..the 3 lug appears to have an advantage with high pressure with more lug surface area...but either work if ya don't over do it, as these cases can handle a tremendous amounts of pressure.

 

[Aloeus]

This is an old thread, but those interested, I have 800 hybrid cases necked to 308Win, 6.5 Creedmoor, and even 358 Win.
Regular dies of every brand work just as they do with brass cases. The SS head is slightly undersize...like a small base die, and doesn't appear to expand at 80,000 plus psi. I have reloaded some 4 times with tight primer pockets. The 6.5 Creedmoor will shoot 140 gr bullets to over 3150 fps in a 24" barrel. So any existing 308 caseed cartridge can experience the similar increase in performance...not just the 277 Fury.
But the 277 Fury has a great case design IMO and could be just necked up or down to any reasonable caliber with its 30° shoulder for more performance at 80,000 psi...short or long barrels...I'll be checking barrel life and wear as I go with SS and Chrome moly barrels. Checking head space has not moved in the Rem 700 or the RPR 3 lug..the 3 lug appears to have an advantage with high pressure with more lug surface area...but either work if ya don't over do it, as these cases can handle a tremendous amounts of pressure.

Have you shot enough to have any indication on barrel life at the higher pressures?
being straightforward to reload is a great sign for this design.

 

[44-40]

Have you shot enough to have any indication on barrel life at the higher pressures?
being straightforward to reload is a great sign for this design.

Not yet, I believe it will be quite a few rounds, as I have checked with a bore scope. I have another barrel for the 6.5 with takes most of the abuse, but have used the case in 4 rifles but some in limited number of rounds, in 358 Win, but the 2 308s the 22"& 30" barreled ones get alot of high pressure rds too. Time will tell. Hybrid cases seem quite reloadable all primer pockrts are still tight, after 4 reloadings on the first one hundred plus cases. The 6.5 Creed is nailed down, as is the 200 gr SMK in the 308, looking again at 230 gr SMK and 230 tip, for the 9 twist 22" getting some good velocity and showing accuracy for heavy bullets in a lighter rifle. The Berger 208 hybrid may be the ticket but I do not have any. Experiments with other projects also keep me busy too.

 

[3chester]

This is an old thread, but those interested, I have 800 hybrid cases necked to 308Win, 6.5 Creedmoor, and even 358 Win.
Regular dies of every brand work just as they do with brass cases. The SS head is slightly undersize...like a small base die, and doesn't appear to expand at 80,000 plus psi. I have reloaded some 4 times with tight primer pockets. The 6.5 Creedmoor will shoot 140 gr bullets to over 3150 fps in a 24" barrel. So any existing 308 caseed cartridge can experience the similar increase in performance...not just the 277 Fury.
But the 277 Fury has a great case design IMO and could be just necked up or down to any reasonable caliber with its 30° shoulder for more performance at 80,000 psi...short or long barrels...I'll be checking barrel life and wear as I go with SS and Chrome moly barrels. Checking head space has not moved in the Rem 700 or the RPR 3 lug..the 3 lug appears to have an advantage with high pressure with more lug surface area...but either work if ya don't over do it, as these cases can handle a tremendous amounts of pressure.

Wow, 800 of those Fury hybrid cases did you buy these once fired or new? How much are new empties of those Sig 277's, like $4 bucks each or so? Are you worried at all the rifle will hold up to 80K pressure level or just sending em out luke warm for now?