Sig Cross Rifle

Goosey said:

The bullets for the NGSW program were 125-135 grains depending on source. With muzzle velocity also depending on source, but always over 3000 fps. So I'd guess it would be about 130 grains.

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Gtscotty said:

The .277 Fury looks to be about the same size as legacy short action rounds, I assume the AICS mags they are showing are the standard size. I remember from earlier articles on Sig's NGSW submission that they are using steel case heads and running higher pressures to meet the Army's velocity requirements. Just playing around with .270-.308 in quickload, you'd have to run ~83 ksi with 130gr bullets, and ~90 ksi with 135gr bullets to hit their advertised velocities in a 16" barrel. It would take a topped out .270 WSM to hit those numbers in a 16" barrel at normal-ish pressures.

I'm guessing the case has a little more capacity than a .308, but I'll be interested to learn more about the cartridge.

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Gtscotty said:

Edit: The Sig rep in this video confirms that the .277 Fury is a .308 based round, and states that the performance spec of 3,000 + fps out of a 16" barrel is with a 140gr bullet. That's STOUT, above .270 WSM performance!

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More info from "Tactical Life":


"Currently, SIG is moving forward with civilian versions of its 6.8mm cartridge developed for the [Next Generation Squad Weapons] competition, the 277 SIG Fury. This cartridge utilizes a hybrid case technology made from brass and other materials. The combination is rated to handle 80,000 psi of chamber pressure.

This added pressure will drive a 135-grain bullet from SIG’s Hybrid Match cartridge 3,000 fps from a 16-inch barrel, and produce 2,694 ft.-lbs. of energy. The 135-grain bullet has a respectable .488 G1 BC.

SIG’s 277 Fury Hybrid Hunting load features a 140-grain bullet with a .508 G1 BC, launching from a 16-inch barrel at 2,950 fps. That one produces 2,706 ft.-lbs. of muzzle energy, too.

One of the benefits of creating hybrid case technology for SIG is that the case is 20-percent lighter in weight for a loaded cartridge than a standard brass-cased cartridge."

https://www.tactical-life.com/gear/ammo/277-sig-fury-hybrid-case-design/

And based on the BCs they claim I'm going to say those are both Sierra bullets; the 135 gr MatchKing and the 140 gr Tipped GameKing ("GameChanger").

Goosey said:

And based on the BCs they claim I'm going to say those are both Sierra bullets; the 135 gr MatchKing and the 140 gr Tipped GameKing ("GameChanger").

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That’s what I thought as well

Goosey said:

More info from "Tactical Life":

"Currently, SIG is moving forward with civilian versions of its 6.8mm cartridge developed for the [Next Generation Squad Weapons] competition, the 277 SIG Fury. This cartridge utilizes a hybrid case technology made from brass and other materials. The combination is rated to handle 80,000 psi of chamber pressure.

This added pressure will drive a 135-grain bullet from SIG’s Hybrid Match cartridge 3,000 fps from a 16-inch barrel, and produce 2,694 ft.-lbs. of energy. The 135-grain bullet has a respectable .488 G1 BC.

SIG’s 277 Fury Hybrid Hunting load features a 140-grain bullet with a .508 G1 BC, launching from a 16-inch barrel at 2,950 fps. That one produces 2,706 ft.-lbs. of muzzle energy, too.

One of the benefits of creating hybrid case technology for SIG is that the case is 20-percent lighter in weight for a loaded cartridge than a standard brass-cased cartridge."

https://www.tactical-life.com/gear/ammo/277-sig-fury-hybrid-case-design/

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Interesting info, doodling with Quickload again, it looks like if the case has an overflow capacity of ~60gr, you should be able to hit those velocity with the SMK and the TGK at 80 ksi. I was thinking they would have to blow out the .308 case quite a bit to get that capacity, but by using much stronger steel bases, they may have been able to make the web area much thinner and pick up some capacity at the base.

80,000 psi is going to be a barrel burner and likely cause copper and/or carbon fouling much faster than lower pressure cartridges. They saw those issues in the Army's ASR program when they where pushing 300 Norma mag North of 70,000 psi. Hopefully they have something up their sleeve to deal with barrel life and fouling issues.

mcb said:

80,000 psi is going to be a barrel burner and likely cause copper and/or carbon fouling much faster than lower pressure cartridges. They saw those issues in the Army's ASR program when they where pushing 300 Norma mag North of 70,000 psi. Hopefully they have something up their sleeve to deal with barrel life and fouling issues.

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I'm sure that it will have a lower barrel life, and possibly more fouling issues than the same case size run at 60 ksi. The real question would be whether the .277 Fury fouls and burns barrels as quickly as the .270 Bee, it's closest analog performance wise.

https://www.sigsauer.com/press-releases/sig-sauer-cross-bolt-action-rifle-now-shipping/

Sounds like they should be out soon. I really want to get one, but I'm wondering whether I should wait for folks to wring them out a bit before laying my money down. Also, I'd like the camo version, but the $200 upcharge over black seems a bit steep. Decisions, decisions.

Gtscotty said:

but the $200 upcharge over black seems a bit steep.

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Don’t want to sponge paint a $4000 dollar rifle?

I’m waiting for a wring out, I have interest, but not in purchasing.

Me too:

ECVMatt said:

I think I will keep an eye on this one.

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I need to replace my 6.5CM I sold to a bud. I must have missed it; what's MSRP in the Cross?

sparkyv said:

Me too:


I need to replace my 6.5CM I sold to a bud. I must have missed it; what's MSRP in the Cross?

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Not sure if it's the MSRP or MAP, but I'm seeing them generally listed at $1,499 for the black versions and $1,699 for the camo versions.

Gtscotty said:

Not sure if it's the MSRP or MAP, but I'm seeing them generally listed at $1,499 for the black versions and $1,699 for the camo versions.

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Hey, that ain’t bad!

I agree though, a bit much just for camo.

But, a really exceptional deal for a rifle on the razor’s edge of performance.

I wound up picking up a Sig Cross in .308 right after they came out. I have to say I really like the rifle, every part seems well thought out, and the whole package works very nicely. I really like the short bolt throw, AICS mags, two stage trigger and the fact that I can quickly and easily adjust it to fit me or my kids perfectly. The rifle is about 6.5 lbs naked, which gives a system weight with can, mag and scope of just under 9.25 lbs.



I did just a little bit of load development, settling on 168gr BTs over AR-Comp.


I also started OCWs with a different powder and 150gr BTs, haven't had time to finish, but it looks promising.




Finally got out for an antelope hunt with it last Sunday and managed to catch this guy at about 260 yds.


The rifle will probably get another barrel in 6 or 6.5 Creedmoor at some point and maybe a paint job, but all in all I'm quite pleased with the purchase.

@Gtscotty, congrats on your SIG Cross. I don't see a Cross in my future but it seems to be a great choice for you and your kids. Given the combined weight of 9lb 3.3oz it prompted me to weigh a .308 Win rifle I've been "building" for while in my search for the "perfect" do it all hunting/tactical rifle. I was kind of amazed to see that it's within 0.05oz of the weight of your Cross, and that's with a Kimber 84M custom receiver, AG Composites stock, CDI Precision bottom metal, 10-round PMAG, 30mm 6-24x50mm FFP scope, 30 MOA rail, throw lever, TriggerTech trigger, adjustable comb, 24" Proof barrel, oversized bolt handle, SilencerCo Harvester suppressor, Tenebraex scope covers and HORUS ASLI. Not too shabby, and I get a locking bolt handle too! Your bolt/receiver is probably a lot smoother than the Kimber's though . That's the main challenge at the moment for this project.

That 24" tube is getting me 2,700 fps for 175gr LRX and 178gr A-MAX bullets with 5-shot groups around 1/2 moa. I'm going to bed the receiver next and see if I can shrink the groups some more.

MCMXI said:

@Gtscotty, congrats on your SIG Cross. I don't see a Cross in my future but it seems to be a great choice for you and your kids. Given the combined weight of 9lb 3.3oz it prompted me to weigh a .308 Win rifle I've been "building" for while in my search for the "perfect" do it all hunting/tactical rifle. I was kind of amazed to see that it's within 0.05oz of the weight of your Cross, and that's with a 10-round PMAG, 30mm 6-24x50mm FFP scope, 30 MOA rail, throw lever, TriggerTech trigger, adjustable comb, 24" barrel, oversized bolt handle, SilencerCo Harvester suppressor, Tenebraex scope covers and HORUS ASLI. Not too shabby, and I get a locking bolt handle too!

That 24" tube is getting me 2,700 fps for 175gr LRX and 178gr A-MAX bullets with 5-shot groups around 1/2 moa. I'm going to bed the receiver next and see if I can shrink the groups some more.

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sweet!