264 Win from 7 Rem

[Laguna Freak]

Asking for load counsel to move/fire form the shoulder on 7 Rem Mag brass in 264 Win Mag chamber.

Thanks in advance.

 

[Zero333]

I thought 7mm RM and 264 winmag are the same except neck diameter and shoulder length... shoulder being longer in the 264wm.

Looking at cartridge prints, it looks like the base to shoulder datum should be the same.

If I'm wrong I hope someone corrects me.

 

[Laguna Freak]

I should probably say that I will be pushing 130’s with Retumbo and would like to obtain some seating depth data while fire forming the shoulder. Obviously, after FL sizing. Typically I back off max load 2 or 3 grains when testing seating depth but I have zero experience with 264 Win Mag.

With that in mind, any suggestions /experience with initial powder charge and case length?

 

[jackieschmidt]

I assume you are going to just push the 7mm Rem Mag case into a full length 264 Win Mag die
If it will chamber, it will fireform fine. The necks are similar in thickness. As you know, the belt will guarantee the headspace.

Just my opinion, but trying to ascertain useful data while fireforming is unproductive. I would concentrate on getting the cases where you want them and then work on critical areas such as seating depth, neck tension, load, etc.

 

[jackieschmidt]

I assume you are going to just push the 7mm Rem Mag case into a full length 264 Win Mag die
If it will chamber, it will fireform fine. The necks are similar in thickness. As you know, the belt will guarantee the headspace.

Just my opinion, but trying to ascertain useful data while fireforming is unproductive. I would concentrate on getting the cases where you want them and then work on critical areas such as seating depth, neck tension, load, etc.

I had a 264 Win Mag back in the 70’s. I bought it out of a pawn shop. It was a beautiful Rifle.

I am surprised that it hasn’t made a resurgence.

 

[Laguna Freak]

I assume you are going to just push the 7mm Rem Mag case into a full length 264 Win Mag die
If it will chamber, it will fireform fine. The necks are similar in thickness. As you know, the belt will guarantee the headspace.

Just my opinion, but trying to ascertain useful data while fireforming is unproductive. I would concentrate on getting the cases where you want them and then work on critical areas such as seating depth, neck tension, load, etc.

Yes. So, you would recommend picking a middle of the road powder charge? Pressure not likely any issue?

A thought I had was to trim the cases a little longer than spec to provide extra brass for the shoulder movement. Assuming I have chamber space to do so.

 

[Laguna Freak]

I had a 264 Win Mag back in the 70’s. I bought it out of a pawn shop. It was a beautiful Rifle.

I am surprised that it hasn’t made a resurgence.

I think its resurgence began about 15 years ago. The chambering has a loyal growing following. It just doesn’t get the press that cartridges like the 6.5 Needmor gets because its always been more of a sporting round than a benchrest round and it got a bad rap as a barrel burner. I think its a bit of a niche cartridge for those who value 220 Swift type velocity in a much larger-heavier bullet.

 

[hammerjack]

You can run them through sizing die load and shoot unless you have a tight neck chamber.
About the same as 6.5 X 47L to 6x47L.

 

[TheOtherZilla]

I had a 264 Win Mag back in the 70’s. I bought it out of a pawn shop. It was a beautiful Rifle.

I am surprised that it hasn’t made a resurgence.

It has. The young generation now call it a 6.5.

 

[Laguna Freak]

You can run them through sizing die load and shoot unless you have a tight neck chamber.
About the same as 6.5 X 47L to 6x47L.

Cool. I’m glad you said that. I just got to thinking that annealed necks & shoulders should get formed exactly right in the FL sizing die. End result; neck ends up a little shorter narrower and the neck : shoulder is 0.017” longer than the 7mm.

Thanks for straightening my brain out.