7-08 Brass Question

[JTB]

I have a good supply of once fired .308 Lapua Brass. When I resized a few to 7mm the brass length ranged from 2.010 to 2.012 inches.
My hornady book shows the case trim length to be 2.025".
Is this brass to short or will it "stretch" to the chamber when fired? (700 Rem) Is it safe?
Thanks
JB

 

[fguffey]

A 308 necked to 7mm08 will result in an increase in case length, the length of the case is of little importance, the length of the case from the head of the case to it's shoulder is more important, not something I can do nothing about but when necking 30/06 cases up to 35 Whelen the case shortens .035 thousands + or - a few.

When crimping a bottle neck case the length of the case must be the same, again, if the case is not going to be crimped, the length of the case is not critical, unless the case is too long.

F. Guffey

 

[snuffy]

A 308 necked to 7mm08 will result in an increase in case length

It MAY be longer than it was when it was a .308, BUT it will be shorter than the minimum 7-08 SHOULD be. One of the concerns is the tiny bit of chamber exposed to the flame and heat of the shell firing. Another concern is the case mouth will not be square. The last concern is the neck brass will be thicker, and may not be a consistent thickness.

A factory chambered rifle will accept overly thick case necks without pinching the bullets. The cases will grow eventually to reach normal length.

I would find the shortest case, then trim them all to that length. That would square them up and allow a good uniform chamfering to aid in bullet seating without scraping the heck out of the driving surface.

When the 7-08 first came out, there was almost no factory ammo available, and certainly no new cases. EVERYBODY formed it from .308 just to get that new rifle shooting. Some smart ones did the above uniforming, and SOME turned necks to get them to a uniform thickness.

 

[GP100man]

Yep it`ll work !! shot my 708 with 308 formed for 4months before recieving any "factory"loaded brass .

& when I tried my loads in the 708 brass they did`nt work as good ,so formed 308 it was !!

 

[JTB]

Thanks to all for the insight.
I just wanted to make sure it was safe. I have plenty of 7mm08 factory brass, but with all the buzz about the quality of Lapua brass I thought it might be an "up grade".