243 Fury

[Greatgrandad]

243 Fury -
I started by resizing the 6.8x51 Sig hybrid case to 243, turned the necks from .017" to .012", worked up a load using RL17 and the old 105gr AMAX, and settled on 45gr of RL17 for a 5 shot average of 3,373fps with an SD of 5.4, 3,367fps low and 3,381fps hi. Indications were I could easily go into the 3,400+fps range, but 3,373fps with the 105gr is well above a 240Bee and my 6-06. After fire-forming, the first 5 shot group came in very good with the first shot from a clean bore slightly lower than the next 4, which those 4 came in around 0.2".

After a little more longer range testing, I plan on using this load for LR hunting, but I also plan to load and test a few 105 Berger VLD-H's with hopes they will do as well or maybe even better.

 

[Capt. Oblivious]

Nice, I used 105gr Berger VLDs in a 6SLR at 3350fps for LR hunting and the combo was devastating on animals way out there.

 

[boltfluter]

Excellent! That should be a terror at long range. Is that case just formed and not fireformed yet? Should be a great hunting round.
Paul

 

[Greatgrandad]

Excellent! That should be a terror at long range. Is that case just formed and not fireformed yet? Should be a great hunting round.
Paul

Yes, it is simply formed and turned. Here is a case after firing and loaded with a 95gr NBT for testing.

 

[Greatgrandad]

I just wanted to state that other than experimenting with the hybrid case for higher velocities, I was desiring to create a 243 load that would somewhat substitute for my 6Rem and 6RemAI loads. Those brass have become difficult to find, and I have become rather sparing in their usage.

Since this venture has shown such good promise in velocity and accuracy for a lower volume LR hunting and target load and I have obtained a good stock of cases, it appears this will keep my other larger 6mm's at home for a while.

I am even imagining how this case may also work for 243AI or even 6mm SLR.

 

[46and2]

I just wanted to state that other than experimenting with the hybrid case for higher velocities, I was desiring to create a 243 load that would somewhat substitute for my 6Rem and 6RemAI loads. Those brass have become difficult to find, and I have become rather sparing in their usage.

Since this venture has shown such good promise in velocity and accuracy for a lower volume LR hunting and target load and I have obtained a good stock of cases, it appears this will keep my other larger 6mm's at home for a while.

I am even imagining how this case may also work for 243AI or even 6mm SLR.

Have you full length sized the cases yet?
Just wondering how you plan on sizing the steel base.

 

[Andy Legg]

243 Fury -
I started by resizing the 6.8x51 Sig hybrid case to 243, turned the necks from .017" to .012", worked up a load using RL17 and the old 105gr AMAX, and settled on 45gr of RL17 for a 5 shot average of 3,373fps with an SD of 5.4, 3,367fps low and 3,381fps hi. Indications were I could easily go into the 3,400+fps range, but 3,373fps with the 105gr is well above a 240Bee and my 6-06. After fire-forming, the first 5 shot group came in very good with the first shot from a clean bore slightly lower than the next 4, which those 4 came in around 0.2".

After a little more longer range testing, I plan on using this load for LR hunting, but I also plan to load and test a few 105 Berger VLD-H's with hopes they will do as well or maybe even better.

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I have been using this brass in a .243 Win. AR10 with a 20” 1/7 twist X-Caliber Barrel.

Load Data so far with no signs of PSI….106 A-Tip, CCI#34’s with 38.2 Grains SW Precision seated about 0.150” off the lands. Shotmarker indicates it’s still running just under 1900 fps at 600 and over 1400 fps at 1000 yards.

For brass prep….all I am doing is running well Lubed New 6.8x51 SIG Brass through a .243 Win. FL Sizing Die. I am using a 0.008” Reading Competition Shell Holder, bumping the shoulder back around 0.047”-0.050” (Headspace is set to 0.003-0.005”).

I have reloaded/fired some of these as many as three times full length resizing each time with no issues….. They haven’t needed trimming until the third firing and probably could’ve got away with not doing it then…… just wanted to cut them back so all would be the same length.

 

[Greatgrandad]

Have you full length sized the cases yet?
Just wondering how you plan on sizing the steel base.

Yes. The initial size was FL and some test cases have been FL sized 3 times without any issues. The steel head doesn't expand the same as brass does.

 

[Andy Legg]

I’ve contemplated my next AR10 barrel to possibly be a 7mm-08 “Fury”……or maybe .25 caliber with the new 138 grain A-Tip….

Honestly, I’m enjoying the .243 at the moment. Kinda curious if life will be too short for shooting Mid & Long Range Prone.

 

[Evlshnngns]

Need a bushing die for 277 fury. Its case design is good to go if you want a 243/6.5/7mm/308 improved.

 

[46and2]

I’ve contemplated my next AR10 barrel to possibly be a 7mm-08 “Fury”……or maybe .25 caliber with the new 138 grain A-Tip….

Honestly, I’m enjoying the .243 at the moment. Kinda curious if life will be too short for shooting Mid & Long Range Prone.

How long do you suppose an extractor will last with a steel case rim?

 

[Andy Legg]

How long do you suppose an extractor will last with a steel case rim?

Very good question…. I have broken one, but the Barrel/Bolt already had about 1600 yds down it.

That said, I worked the load up slowly, and as the powder charge it increased, so did the speed of the action. I believe there was still too much chamber pressure for extraction.

I have a new extractor with about 35 rounds on it now. I have also restricted the gas flow and install installed a KAK 9.3 oz Buffer with a Tubbs Spring.

I have my eye on the extractor and we carry an extra bolt with us everywhere we go

 

[Greatgrandad]

Also, I am playing with a 308 Fury load with the goal of simply reaching 3,000fps with a 178/180gr in one of my bolt actions. I did exceed that in my first testing, but I had better accuracy with the 178 ELD at 2,982fps. So, for now, I have settled there. I do plan to test this some more. Also shown is a 168gr load I tested as compared to the 243 Fury.

 

[Straightshooter1]

Also, I am playing with a 308 Fury load with the goal of simply reaching 3,000fps with a 178/180gr in one of my bolt actions. I did exceed that in my first testing, but I had better accuracy with the 178 ELD at 2,982fps. So, for now, I have settled there. I do plan to test this some more. Also shown is a 168gr load I tested as compared to the 243 Fury.

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For your .308 configuration, what case volume are you getting?

I've necked up the .277 Hybrid Fury's for my .308 where one batch had a volume of 57.7 grs H2O and other at 56.3 grs H2O.

I've loaded up some with 46.1 to 47.0 grs of H4895 behind 169 SMK's and will be going out soon to see what I get.

 

[Greatgrandad]

For your .308 configuration, what case volume are you getting?

I've necked up the .277 Fury's for my .308 where one batch had a volume of 57.7 grs H2O and other at 56.3 grs H2O.

I've loaded up some with 46.1 to 47.0 grs of H4895 behind 169 SMK's and will be going out soon to see what I get.

Are you using the same year head stamp? My lot has a mix of 2023 and 2024, so I am separating them by year. I haven't decided to weigh them or not, but like you, I am seeing very similar volumes. So far, I don't think it is enough to really matter this early on in testing, but as things evolve, I may decide otherwise.

The 243 Fury load with the 105's has really impressed me with its groups, low SD and velocity, but I have more LR testing to perform. It should do very well.

When you have completed your 308 testing, I have another post on the 308 Fury in the 30 cal forum, so please post your results.

 

[Straightshooter1]

Are you using the same year head stamp? My lot has a mix of 2023 and 2024, so I am separating them by year. I haven't decided to weigh them or not, but like you, I am seeing very similar volumes. So far, I don't think it is enough to really matter this early on in testing, but as things evolve, I may decide otherwise.

The 243 Fury load with the 105's has really impressed me with its groups, low SD and velocity, but I have more LR testing to perform. It should do very well.

When you have completed your 308 testing, I have another post on the 308 Fury in the 30 cal forum, so please post your results.

I've got some head stamped with 2023 and 2024, which have the lesser case volumes at around 56.3 and the head stamp with 277 SIG FURY has the 57.7 case volume. Also, I've got some with just SIG for a head stamp that also has case volume at 57.7. Yeah, I've got 4 different head stamps from the 500 I bought. I've been been playing with the larger case volume cases to see what I can get.

It was a little surprising to me that I've been getting some low SD's as well, considering I've haven't been making any effort to do so as these are newly fire formed cases.

Will certainly post my results.

 

[Thauglor]

How long do you suppose an extractor will last with a steel case rim?

In the semi autos, the life of the whole bolt head is considerably reduced, and the barrel life will be very short too at 80k psi. Barrel and bolt are consumables.

 

[Greatgrandad]

It seems some people don't understand how the 6.8x51 Sig hybrid case changes loading and what pressures it allows without the same dangers as a simple brass case. My postings on the 308 Fury were deleted, and I was informed it was due to "dangerous pressures" related to velocities. Though in my 26" barreled rifle, it shows no indications of that, as that rifles characteristics have always been fast. The same for my 26" 243. These cases are designed for well above max pressures in even strong brass cases, and on other forums, there are LR/ELR comp shooters loading and using them faster and heavier than I have.

Here are 2 cases from my test batch that have been fired 3 times, and I had just posted this about five minutes before my 308 Fury posts were deleted by admin.

Anyone else remember the old "Steel Head" cases from the 1980's and how those cases changed the velocities we could safely obtain as compared to brass? Those old cases did have an issue with eventual separation between the joint, but the Sig cases are much improved over those.

Heck, even Sig loads their ammo for a 16" barrel 277 bullet at 3,200 fps in a semi and full auto.

 

[Straightshooter1]

It seems some people don't understand how the 6.8x51 Sig hybrid case changes loading and what pressures it allows without the same dangers as a simple brass case. My postings on the 308 Fury were deleted, and I was informed it was due to "dangerous pressures" related to velocities. Though in my 26" barreled rifle, it shows no indications of that, as that rifles characteristics have always been fast. The same for my 26" 243. These cases are designed for well above max pressures in even strong brass cases, and on other forums, there are LR/ELR comp shooters loading and using them faster and heavier than I have.

Here are 2 cases from my test batch that have been fired 3 times, and I had just posted this about five minutes before my 308 Fury posts were deleted by admin.

Anyone else remember the old "Steel Head" cases from the 1980's and how those cases changed the velocities we could safely obtain as compared to brass? Those old cases did have an issue with eventual separation between the joint, but the Sig cases are much improved over those.

Heck, even Sig loads their ammo for a 16" barrel 277 bullet at 3,200 fps in a semi and full auto.

View attachment 1680086

I think the fear is that some novice will take that load information and try to use it in a standard brass case. . .???

But, you're right, these hybrid cases are designed to take well above max pressures that SAAMI publishes. As I recall, they've been tested up to 100K PSI. And Sig initially had the military cartridge's doing 80k psi, though I think it's been reduce a little more for some reason. I wonder where the limit is for how high a pressure has to get to start producing a ring our barrel that aren't really "designed" for such really high pressure???

Am still curious as to how you figured your .308 cartridge with a 178 ELD-X produced less than 80k psi, as my calculation and other poster shows just over 90k psi???

 

[Greatgrandad]

I think the fear is that some novice will take that load information and try to use it in a standard brass case. . .???

But, you're right, these hybrid cases are designed to take well above max pressures that SAAMI publishes. As I recall, they've been tested up to 100K PSI. And Sig initially had the military cartridge's doing 80k psi, though I think it's been reduce a little more for some reason. I wonder where the limit is for how high a pressure has to get to start producing a ring our barrel that aren't really "designed" for such really high pressure???

Am still curious as to how you figured your .308 cartridge with a 178 ELD-X produced less than 80k psi, as my calculation and other poster shows just over 90k psi???

As I had stated in my 308 Fury post just before it was all deleted, QL, which some use, doesn't know what my chamber dimensions are, throat, leade, bore dimensions, lapped vs rough, etc, etc. I have never put any stock in QL, for over the years when I tested it against a few proven loads in MY rifles, it wasn't even close. I am not feeling nor seeing anything from my loads in "MY" 26" rifle that indicates 90k psi. Could it be at 80k psi? It could be, but 90k is out of the question.

I have been on other forums were people are loading the Sig hybrid cases in 308 comp loads and achieving faster vels with heavier powder loads than I and in shorter barrels, and they have fired hundreds of cases without issue.

I've been loading, creating wildcats, experimenting, currently load 54 cartridges, ran an ammo reman business for several years, and much other for nearly 60 years.

Barrels are disposable items in shooting, and I have burned out a lot of barrels in my life. Some in just one season of comp or varmint shooting.