Neck Down 308 Win to Create 7mm08??

[jds holler]

Is this do-able without neck turning, or not. How about military brass? jd

 

[Someoldguy]

I have made 260 Rem brass from .308 Lake City brass. Neck clearence was not an issue. However, I would take measurements to make sure it is not a problem in YOUR rifle with YOUR dies.
I would also recommended annealing the necks after sizing but before fire forming.

 

[SSL]

Unless you are having problems finding brass, I would just buy the correct brass and not have the work involved sizing or the chance of grabbing the wrong ammo based on head stamp It probably isn't a big problem where you live, but in areas that might be caliber-specific, having the wrong head stamp might cause difficulties with authorities.

 

[Albany Mountain]

I've made lots with commercial brass. Neck turned a certain lot for long range accuracy.

 

[chop house]

Yes. LC brass is different and requires different treatment, than other brass.

could you elaborate on this? thx

 

[Toolbreaker]

Is this do-able without neck turning, or not. How about military brass? jd

JD, I've ran LC '67 NM brass in my 7mm-08 for a few years now. That is some seriously tough, long-lasting brass. The necks on mine measure right at .015" after necking down, so if you have a minimum spec SAAMI chamber, you would have about .002" neck clearance. I turn mine .002" (.001"/side) for full cleanup.

 

[fyrewall]

I have done that - neck .308 down to 7mm-08. It makes for a shorter necked 7mm-08. It would be a good idea to check out case/bullet clearance as the neck walls will be slightly thicker on the new reformed 7mm-08 brass. I am a big fan of Lake City brass both 7.62 X 51 & 5.56 X 45. Before necking once fired brass down like .30 to 7mm & .30 to 6.5mm I anneal; brass is then turned after neck down. I also neck down 5.56 X 45 to .20 making .20 Practical ammo. Coffee cans full of real nice brass.

I will check out Joe R's findings.

 

[alf]

Is this do-able without neck turning, or not.

The only safe way to answer that is to do a chamber cast of your chamber.

Everything else is speculation.......

 

[ebb]

Caution should be used, as some have eluded to when necking down necks can get thicker and longer. If you check neck clearance (diameter) and length (oal) and cut to trim length all should be good. I had trouble a few years ago finding 260 brass for my AR10. Lapua was around but I didn't want to use it for the gas gun to throw all over the range. I necked up 243win brass. As the neck is stretched it gets thinner and I cut all for OAL, no issues at all.

 

[Prose]

To ensure you don't size the neck into the shoulder, sizing of the neck and body should be done separately if you want fully sized cases that require no fire forming.

First, size the body with no bushings.

Second, utilizing bushings, unscrew the die .044 -.050 depending on your individual measurements. This will allow precise neck sizing while accommodating for the different shoulder junction.

 

[brokeasajoke]

Joe R is this dwell time in the sizing die? I have never let the brass set in the die. Just in then back out. I am slowly learning. Should this be done on all brass or just when neck in down.
Thanks

 

[jds holler]

Thankyou fellers, for the response. This is for a bud of mine who is going to our local gun show with me tomorrow. He is needing 7-08 brass, and I thought if we can't find any, why not just do the neck down thing. Rifle is a Ruger Hawk-eye.

I've got neck turning equipment and experience if it is necessary, just don't know how roomy his chamber is yet. This is a sweet handling, light weight hunting rifle, not a bench rest rig.

After reading what somay'all think about the LC brass, I'm probably gonna get myself some for my little 308 bolt gun. We could then try some for his 7. jd

 

[fyrewall]

"dwell times" are apparently part of the process of measuring hardness of brass and other metals using the Rockwell thing. 10-15 seconds is provided. Working brass in a die vs. embedding a small steel ball into a brass surface using a measured force has some commonality. Looks like I won't be so hasty when necking down or necking up brass but annealing would be a good step in limiting spring back.