Is this possible and why??

[Pops5683]

Good morning all. I recently bought a new Savage Axis in .308. I did the expected cleaning pror to shooting and then took it to the range. It functioned well as I had expected. After I got home I started looking at the cases to see if there were any issues with them. All was good.

I'm just getting back into reloading after many years away. Now here is the problem, if it is one. I fully intend to reload these and neck size them. I have 150gr FMJBT 308's I bought from Grafs. All of these bullets will go into the necks of the fired rounds before neck sizing. Is this normal?

I also have a 100 or so Hornady 150gr SST's that I was going to use in a Mosin Nagant. These guys are .311 and also go into the 308 cases. I expected the 308's to fit into the fired cases but not the .311's. Because these .311 rounds fit into the necks of these cases can they be used or am I missing something?? Ed

[stangfish]

Yes. If your brass is new and not hard it will expand and seal to the chamber and only shrinks back a few thousands if that much. If you check your neck wall thickness is probably between .015 and .016 thick. Multiply that times 2 (once for each side) and subtract that from the id of the chamber in the neck area which will be around .344.

So lets say .344(Chamber neck diameter) -.031(total neck thickness on diameter) is .313(Id of fired brass neck) and it shrinks .002 to .311. the outside diameter of the projectile is very close to .308. that leaves .003 +or- clearance between the neck bore of fired brass to the OD of the projectile.

[Pops5683]

Thanks alot Stang. I put calipers on them and I'd swear you were right here cause that's what I got. Amazing. Now the other issue is can I put the .311 bullets into these .308's cases since the necks are .311 or would the neck sizing prohibit that.??

[JCalhoun]

No.

You will need to use the .308 diameter bullets for the .308 diameter bore. The resizing of the case will make the necks smaller to allow for a slight interference fit. That is, after resizing, the bullets won't slide into the case.

The .311 diameter bullets are 7.7mm and fit the .303 British, 7.62X54R Russian and 7.7mm Jap Arisaka.

[stangfish]

JC is correct. Once you size the brass the id of the neck can be anywhere from .304 - .307.

You might be able to push the .311 projectiles through a cast bullet sizing die and use them if they come out at 308. I think they would probably expand back to .309 though...not good enough.

[eddiesindian]

couldnt of said it better.............

[Pops5683]

Thanks to all that replied. I got the answers I was looking for. This forum is certainly knowledgeable and helpful. Great members and glad I registered.

[JCalhoun]

We're glad to have you.