Help please?

[DonH]

I have need to know ACTUAL diameter of currently produced unfired 8mm Mauser or .30-06 cases as measured just ahead of the extractor groove. What I'm after is (without having to buy brass just to find out) which brand as currently produced has the smallest ACTUAL diameter

[Conditor22]

I convert military 30-06 in 8MM (8x57) and they work fine
ACTUAL 8mm SIZED AND LOADED .4685
military 06 CONVERSION SIZED AND LOADED .4675 LC 69

[Blackhawk357]

According to Sierra....https://uploads.tapatalk-cdn.com/20191020/980609c105b9d7ecae4c31c0e998c462.jpg

Sent from my SM-G950U using Tapatalk

[Bazoo]

Well, you could take your calipers to the local academy or similar and measure some.

I measured some 30-06 winchester above the rim and it measured .4645 across 3 cartridges. All the factory ammo I have for that caliber.

[DonHowe]

[QUOTE=Bazoo;4747404

I measured some 30-06 winchester above the rim and it measured .4645 across 3 cartridges. All the factory ammo I have for that caliber.[/QUOTE]

Thank you. Exactly the kind of info I am looking for.

I know what the specs are but no 06 brass I have is as large as specs. However all 06 brass I have is at least 25 yrs old. The only 8mm brass I have is .4675 in front of extractor groove. It is PPU.

[44Blam]

8mm Mauser is a tricky one - there are two that are similar. But one is rimmed and the other is not.
The JS is not rimmed, the IRS is:
249981

[Thin Man]

I suspect you could create smaller base 8mm brass from 30'06 by first sizing your brass in a 30'06 small base sizing die. Expand the neck with a tapered neck expander, then size with a conventional 8mm Mauser sizing die to establish the shoulder. Trim, chamfer and load. Worth a try at least.

[DonHowe]

Thanks for the responses.

One response was helpful: "I measured som .30-06 Winchester..." This what I had hoped for re: different brands. I know all about 8x57 J, Js, JRS (who has 8x57 rimmed); I wrote 8mm Mauser because that is the headstamp...

I need to buy 8x57, 8mm Mauser, brass from which to form cases in a small base die and would like start with the smallest diameter cases that are readily available. Experimenting, I have formed cases from
8mm brass that measured .467" and it worked tho I lost some. Smaller dia. would be easier. If need be I can and will use 06 cases but 8mm simplifies the process. I could go to a store and measure cases but do not know where to find 8mm brass in stock locally. That is why I asked here.

I know what PPU 8mm brass measures. I had hoped someone might have some Win/Rem/Hornady they might quickly measure?

[44Blam]

I measured one. It is a PPU 8mm Mauser Match 200 grain bullet. Here are the stats:
Neck: 0.347
Neck end: 0.347
Shoulder: 0.433
Base: 0.468
Case Length: 2.235
OAL: 3.170

250073

EDIT: Missed that you know what PPU measures... But will leave the post for others.

[DonHowe]

I measured one. It is a PPU 8mm Mauser Match 200 grain bullet. Here are the stats:
Neck: 0.347
Neck end: 0.347
Shoulder: 0.433
Base: 0.468
Case Length: 2.235
OAL: 3.170

250073

EDIT: Missed that you know what PPU measures... But will leave the post for others.

Thank you. I have made a few cases from 8mm PPU but would prefer a smaller base if possible.

[oconeedan]

I'm curious, what are you forming cases for? Some brass, has thicker walls and this may be the factor that determines ease of forming.

[tankgunner59]

I don't have a Sierra manual, but in the Lyman 50th Edition it says the dimensions are max and if your reloaded ammo brass is at or over this measurement they will likely not chamber in most firearms. I had a 22-250 case stick in my rifle the other day. After I got it out I checked it and it was .005 over the measurement in my Lyman manual. It also says the measurements are max and cases shouldn't be at or over these measurements in most guns. I don't know if it is the same with the Sierra manual but I thought it may help to know this info.

[DonHowe]

I have learned to use specified diameters for mostly for reference.
Thirty + years ago I was developing loads for a .338-06and encountered a problem with brass bulging excessively. The problem turned out to be mostly due to a chamber that was wallowed oversize. In tracking down the problem I started measuring base diameter of various makes of .30-06 brass.., LC, Ww, R-P, Federal. I do not recall all dimensions but I do recall the largest being LC at .467 and the smallest being WW at .464. Not one even close to spec.
In reloading for factory rifles normally there would be no reason to be concerned about case diameters. It is when you get off the beaten path (or encounter a really tight chamber) that it pays to know what you are dealing with. In this case I need to form cases using what amounts to a "snug" small base die meaning that finding new brass with the smallest diameter will greatly reduce time and effort in forming cases. Not to mention expense should I buy a quantity of brass only to find it unusable.