Reloading the 277 Fury 6.8x51 SIG Hybrid Case

[A382DWDZQ]

Wanted to just start a thread on these hybrid cases.
I’m working up some of these resized to 7mm-08 for a Ruger American action. One of my challenges with identifying loads up around the 80k Psi is that most retail powders aren’t made for this, so options seem to be too bulky or very little increase in velocity for the added pressure. I’m also not going to run 80k in the Ruger, but just looking at the load dev in Quickload for that for now. The realistic loads that I’m looking at are < 70k and will give a bit more velocity than normal. CFE223 seems to be a good candidate so far. Curious to hear any other thoughts and experiences with these.

 

[wind gypsy]

There's a dude with the handle 45-70 on snipershide that has done a bunch with these in various cartridges and has mentioned that powder selection is important. I'm not sure I want to mess with it but was tempted to see if he wanted to sell 50 6.5 creed cases at a premium for me to play with in a 18" barrel to get some velocity back.

 

[deerhunter628]

I bought some of the hybrid cases. Im planning to convert them to 308

 

[Mike D Texas]

I have converted these to both 260AI and .308 Win.

Super simple to do either and Fireform to your chamber.

260AI 24” barrel, 140 match burner, RL26, fed 210 - blew primer at 3236fps.

308 Win, 20” barrel, 155 TMK, H4895, CCI41 - 3077fps and still easy extraction.

 

[deerhunter628]

I have converted these to both 260AI and .308 Win.

Super simple to do either and Fireform to your chamber.

260AI 24” barrel, 140 match burner, RL26, fed 210 - blew primer at 3236fps.

308 Win, 20” barrel, 155 TMK, H4895, CCI41 - 3077fps and still easy extraction.

What is your process to convert to 308?

 

[Mike D Texas]

What is your process to convert to 308?

Anneal and then 1 pass with a mandrel.

 

[deerhunter628]

Anneal and then 1 pass with a mandrel.

Great. Thanks. What length barrel did you get 3077 fps out of? Has accuracy deteriorated as the pressure went up?

 

[Mike D Texas]

Great. Thanks. What length barrel did you get 3077 fps out of? Has accuracy deteriorated as the pressure went up?

20” Tikka Roughtech.

I would say no on accuracy degeneration. This is from ladder testing, dots are 1”.

 

[deerhunter628]

20” Tikka Roughtech.

I would say no on accuracy degeneration. This is from ladder testing, dots are 1”.View attachment 856816

Awesome. Im looking to load develop for my Bergara 18”. So you are annealing and expanding with a mandrel. Do you need to full length size after that or do the cases have the same dimensions other than the neck?

 

[Mike D Texas]

Awesome. Im looking to load develop for my Bergara 18”. So you are annealing and expanding with a mandrel. Do you need to full length size after that or do the cases have the same dimensions other than the neck?

I don’t resize until after the first firing.

 

[z987k]

Anneal and then 1 pass with a mandrel.

That shouldn't chamber. The shoulder on the 277 is way further forward and a sharper angle then 308.

I resize them to 338fed. Mandrel to 308 then to 338. But that brass does not chamber. I have to full length size to move the should back enough.

I mean even without doing anything a 277fury case will not chamber in a 308win.

 

[z987k]

Wanted to just start a thread on these hybrid cases.
I’m working up some of these resized to 7mm-08 for a Ruger American action. One of my challenges with identifying loads up around the 80k Psi is that most retail powders aren’t made for this, so options seem to be too bulky or very little increase in velocity for the added pressure. I’m also not going to run 80k in the Ruger, but just looking at the load dev in Quickload for that for now. The realistic loads that I’m looking at are < 70k and will give a bit more velocity than normal. CFE223 seems to be a good candidate so far. Curious to hear any other thoughts and experiences with these.

Lever evolution is a good option.
Accurate LT30 is what I'm using in the 338. Varget will work.

 

[deerhunter628]

That shouldn't chamber. The shoulder on the 277 is way further forward and a sharper angle then 308.

I resize them to 338fed. Mandrel to 308 then to 338. But that brass does not chamber. I have to full length size to move the should back enough.

I mean even without doing anything a 277fury case will not chamber in a 308win.

It does not chamber in my Bergara 308.

 

[A382DWDZQ]

This is an unmodified 6.8x51mm next to one that was run through an RCBS 7mm-08 FL die and loaded with a 150 TTSX.

 

[z987k]

This is an unmodified 6.8x51mm next to one that was run through an RCBS 7mm-08 FL die and loaded with a 150 TTSX.
View attachment 857114

Exactly. The brass on the left wouldn’t come close to chambering in the gun for the right.

 

[Mike D Texas]

That shouldn't chamber. The shoulder on the 277 is way further forward and a sharper angle then 308.

I resize them to 338fed. Mandrel to 308 then to 338. But that brass does not chamber. I have to full length size to move the should back enough.

I mean even without doing anything a 277fury case will not chamber in a 308win.

You are correct, I must have been thinking about my 260AI.

I wasn’t thinking about the shoulder angle/position difference between them.

I’ve even molested one down to 22-250AI but it wasn’t fun at all.

Sorry for the confusion.

 

[deerhunter628]

You are correct, I must have been thinking about my 260AI.

I wasn’t thinking about the shoulder angle/position difference between them.

I’ve even molested one down to 22-250AI but it wasn’t fun at all.

Sorry for the confusion.

Its certainly easy to get cartridges mixed up.