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balttigger July 20th, 2021 10:53 PM

.277 Sig Fury "non-hybrid" loading (mind exercise)
I have been looking at the up and coming Sig Fury round. There has been no indication yet on whether the steel based rounds will be reloadable, so I got to thinking (always a dangerous consideration)....I am a relative newbie to reloading, so I decided to jump into the deep end of the pool.

Could reloaders load all brass cartridges to pressures more suited to .308 Win or 6.5 CM? If so, what would the parent be?

The base to shoulder dimension on the Fury is 0.0713" longer than a .308 Winchester but the .260 Remington is the same, but the shoulder angle is 10 degrees different. Could .308 be resized and fireformed? Can you change from a 40 degree shoulder to a 30 degree on when shrinking brass 13 and a half thou?

Unless Sig Fury unloaded cartridges will be plentiful and inexpensive, I can see the advantages of loading cheap 6.8 Remington? .277 Winchester? (What would you call it?) for deer and getting full power Fury rounds for distance locales.

Thoughts? Or am I getting too far in the weeds over nothing?

erwos July 21st, 2021 06:51 AM

This is an interesting exercise. I am just not sure fire-forming is going to work out based on the comparison pictures I'm seeing, but it's possible.

Sig has said they were planning on providing reloading components for the .277 Fury. The pictures I've seen online seem to show it using a standard large primer. Whether they have to crimp it somehow so it doesn't pop out under 80k psi is an interesting question, and swaging a steel cramp sounds... interesting.

balttigger July 21st, 2021 08:30 AM

Just piddling around with the numbers using a .270/.308 as a base round shooting a 145gr Hornady ELD-X @ ~62,000psi. Using the same test length barrel as 6.5CM (28 inches), the 270/308 would punch that pill at approx 3,000 fps for ~2900 ft/lb energy. The 6.5CM using a 143gr ELD-X is 2,710fps @ 2,283 ft/lb (per wikipedia). I would expect an all brass cartridge formed to a Sig Fury chamber would be able to hold more powder and get 270/308 numbers or better easily.

A more reasonable hunting length barrel of 20" would put out ~2,875fps @ ~2,660 ft/lb on a bullet with a ballistic coeff of .536 (G1) giving an 850yd hunting range and supersonic out to 1350yds or just over 3/4 mile.

Not too shabby.

kstone803 July 21st, 2021 08:31 AM

Not sure you'll be able to form those but there is brass available. Very expensive, but available.

balttigger July 21st, 2021 09:43 PM


Originally Posted by kstone803 (Post 6375643)
Not sure you'll be able to form those but there is brass available. Very expensive, but available.

Robertson only makes brass one at a time and charge an arms & a leg for each piece. This does make me wonder if brass manufacturers will produce all brass Fury cartridges and load data at the lower pressures?

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