.308lap brass to 7-08ai

[acooper1983]

Good morning gentlemen, ive recently taken possesion of my new 7mm-08ai built by Jim Kobe. The chamber was throated for some dummy rounds that I made up @ 2.350 to the ogive on a berger 168g. My question is. I found a couple hundred bran new 308 lap brass, and with my redding neck die, I was playing around with a few building some new dumming rounds simply neck sizing the brass from .308 to .284 and seating a VLD. The rounds chamber and extract find, maybe a tad snug but nothing that i would be worried about. Is there anything else i need to be mindful of? this is my first "AI" and I was planning on having to turn the necks, but if its chambering the dummy round fine, everything should be go to go to load some fire forming rounds correct? Thanks for your time, and sorry for the "newb" question

-Adam

 

[acooper1983]

Anyone?

 

[MudRunner2005]

Good morning gentlemen, ive recently taken possesion of my new 7mm-08ai built by Jim Kobe. The chamber was throated for some dummy rounds that I made up @ 2.350 to the ogive on a berger 168g. My question is. I found a couple hundred bran new 308 lap brass, and with my redding neck die, I was playing around with a few building some new dumming rounds simply neck sizing the brass from .308 to .284 and seating a VLD. The rounds chamber and extract find, maybe a tad snug but nothing that i would be worried about. Is there anything else i need to be mindful of? this is my first "AI" and I was planning on having to turn the necks, but if its chambering the dummy round fine, everything should be go to go to load some fire forming rounds correct? Thanks for your time, and sorry for the "newb" question

-Adam

If you get a snug bolt close, then your brass fitment should be just perfect for fireforming. If the shoulder/neck junction isn't tight like that, you will want to run a reduced load (about 75% of book starting load) of your powder of choice, and seat the bullet press-fit into the lands, that way it keeps the head of the brass seated firmly against the bolt face and when the brass expands it will properly fill the chamber and properly form to your chamber.

But, since your brass closing has some resistance, I would say you wouldn't have to worry about that. Personally, I still use cheap bullets (Hornady Interlocks) and powder I don't use for anything but fire-forming for my Ackleys (RL19), and cheap CCI primers, and if it's a non-belted caliber, I always use the reduced load with the bullets seated to the lands method. If it's a belted case, then I still use a reduced load, but I don't have to seat them into the lands, because belted cases headspace off the belt, and non-belted cases headspace off the shoulder, which is why you have to seat the bullet into the lands and use a reduced load while forming brass for them.

Also, if your dummy rounds fit in the chamber just fine, then I see no reason to turn the necks.

 

[acooper1983]

Thanks mudrunner, your post confirmed what "made sense" to me I appreciate your time

 

[AZShooter]

If you have a large quantity of brass to fireform you could take the time to find an accurate load and use those forming loads for hunting or target work.