7mm-08 die set help

[Fletcher/AAC]

I am used to a Redding Type S full length sizer die, but am new to 7mm-08. I will be necking down .308 Lapua brass and firing the 162 AMAX. My gunsmith is using a "no turn" chamber.

My question is, do I just buy a standard Redding type S 7mm-08 die and run the brass strait through it, do I need anything else to size it down? Also, if anyone has any suggestions on what bushing size to get, I'm all ears.

Thanks

 

[Hummer]

Re: 7mm-08 die set help

Make sure to use a good case lube. I use Imperial Sizing Die stuff.
If you have new 308 you can go like that. If it is once fired you might clean it and stress relieve the neck/shoulder before you start sizing.

On fired cases after cleaning I remove the decap pins and first run them in 308 die to take neck down a little bit then into the 7/08 die.

If you have a no turn chamber all you are looking for is bullet grip then. It helps to have a tubing mic so you can measure neck wall thickness. On bolt gun I want about .001" grip on bullet. On gas guns I want .002". This is going to be iffy to calculate and can get expensive buying bushings as there are several variables.

The biggest variable besides case manufacturer is how uniform the necks are. They are not the same thickness all the way around. For instance on 7.62 M118 Match they vary .005" on neck wall. Another variable is you don't know how big your chamber neck is.

The easiest way to do it is get a standard 7/08 FL size set and size them. Measure the neck diameter before seating bullet and after seating and you can get a idea on how much "grip" you have.

I vary my grip by using expander buttons that expand the necks to the inside diameter I want. That seems to have better repeatablity in seating bullets and trying to squeeze the neck down and it spring back for me.

Someone wrote all about this on another thread about a month ago but I forget the title. As you were, it was in Precision Shooting magazine.
Hope this helps.

 

[Victor N TN]

Re: 7mm-08 die set help

The problem is going to be the interuption between the bushing and the die. I'm afraid you are going to have problems using a bushing die for necking down. I form 25-06 brass from mil 30-06. But I made a die close to a 270 neck for a halfway step. If I were you, I might get a cheap regular full length sizing die and use it to run the 308 cases through to start with. Be sure to use plenty of lub in your case forming steps.

Another thing to be aware of is that the case necks will thicken when you neck down the cases. Be sure and measure everything really well before actually loading live rounds. I would cast the chamber and measure it to make sure I had room for the thickened case necks. If not and you still want to use 308 brass, you'll have to turn the case necks.

As for the bushing size, that depends on the thickness of the case necks and just how much neck tension you want on the loaded rounds.

 

[Fletcher/AAC]

Re: 7mm-08 die set help

So I would be better off not using a bushing die at all for the initial sizing due to the junction of the die and bushing.

Since there is only one step down from .308 to .284, I thought that I wouldn't have to use an additional die like I would forming .260 brass from .308 brass.

Any reccomendations on the standard full length sizer?

Thanks,
Fletch

 

[Victor N TN]

Re: 7mm-08 die set help

The cheapest thing you can find will do fine as long as it has been reamed fuul length. I have a LEE F/L die for things like that. Less than $20...

 

[Hummer]

Re: 7mm-08 die set help

I agree, the Lee dies for the money are fine. They are not as pretty as others but have yet to find one that did not work.

Victor, that is a very good idea using a 270 die for intermediate step down. Did you just cut off a 270 FL die or happen to have a reamer and make the whole thing from a blank?

It just dawned on the a 270 case trim die would be just the ticket for a intermediate step down. I have used case trim dies to form cases for other calibers.

 

[BobinNC]

Re: 7mm-08 die set help

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hummer</div><div class="ubbcode-body">I agree, the Lee dies for the money are fine. They are not as pretty as others but have yet to find one that did not work.

Victor, that is a very good idea using a 270 die for intermediate step down. Did you just cut off a 270 FL die or happen to have a reamer and make the whole thing from a blank?

It just dawned on the a 270 case trim die would be just the ticket for a intermediate step down. I have used case trim dies to form cases for other calibers. </div></div>

Hummer,

Victor is using a 270 die as a step down because he is forming 25-06 brass. Your forming 7mm (.284) brass from 308 brass. Using a 270 die (.277) would be two steps down, and below a 7mm.........

Bob

 

[427Cobra]

Re: 7mm-08 die set help

Whats wrong with Win 7-08 brass, I think the little extra prep work that Win brass needs over Lapua is no biggie because the price of the brass is .33 cents cheaper per piece(MidwayUSA prices per thousand), and I doubt you or most of the rest of us can shoot the difference.

 

[Fletcher/AAC]

Re: 7mm-08 die set help

I only ask because I have a ton of lapua brass, no one here shoots 7-08 with the 162 amax and lapua hulls that can take a measurement?

 

[sobrbiker883]

Re: 7mm-08 die set help

I shoot FC 308 necked down, but I just use a Redding FL die both to step it down and to reload. I ain't fancy enough for bushing dies, so I can't help there. I get .002-.003" neck tension with my simple setup.

I will probably switch to Win 7-08 next batch, because I'm man enough to admit that no, I probably can't shoot the difference....