Misfiring cases

24 April 2023, 17:31

jeffeosso

Misfiring cases

quote:
Originally posted by The Lord of Lawn Chair:

Would you opine on how a 7.62 X 51 would head space in a .30-06 chamber?

the question is inaccurate - how does a 308 fire in a 30-06 chamber is a different question.. it COULD jam fits into the chamber OR the extractor COULD hold it well enough.. and the base is the same diameter - but cases are usually undersized and the chamber oversized .. and I've picked up lots of 308 AND 300 savage with very short necks at the range ...

24 April 2023, 19:30

dpcd

Yes, those are how it works; again, no forming or sizing by the bolt. Which was my point all along. It works very easily and yes, I have done it more than anyone on earth. Probably.
Guys also shoot 50 BMG out of 12 gauge shotguns; I have not done that. But well documented and they lived.
Another example; ever heard of shooting 9mm Luger out of the longer cased, 9mm Largo? Same principles involved. Headspace? As in the 308 in the 30-06 or 7.65: immaterial.

25 April 2023, 09:23

The Lord of Lawn Chair

quote:
Originally posted by jeffeosso:
quote:
Originally posted by The Lord of Lawn Chair:

Would you opine on how a 7.62 X 51 would head space in a .30-06 chamber?

the question is inaccurate - how does a 308 fire in a 30-06 chamber is a different question.. it COULD jam fits into the chamber OR the extractor COULD hold it well enough.. and the base is the same diameter - but cases are usually undersized and the chamber oversized .. and I've picked up lots of 308 AND 300 savage with very short necks at the range ...

How can a question be "inaccurate" ?

25 April 2023, 17:28

jeffeosso

you asked if it could headspace - the (off)topic is about firing a 308 in a 30-06 chamber - headspace isn't relevant to the case firing

27 April 2023, 19:38

F. Guffey

quote:
you asked if it could headspace - the (off)topic is about firing a 308 in a 30-06 chamber - headspace isn't relevant to the case firing

The 308W/7.62NATTO ammo headspaces when chambered. Many reloaders have fired 308W/7.62NATO ammo in 30/06 chamber without knowing it. And if they are not in the habit of examining their fired cases they will not be aware of the short necks. If they notice the short necks they never notice the long case bodies.

I said I built 3 8MM06 rifles out of 8MM57 chambered rifles. I fired 100 8mm57 rounds through the 8mm06 chambers. After firing I ejected the the fired cases, all were ejected with very short necks, all of the case bodies increased in length between the shoulder to the case neck; what does that mean? It means the firing pin did not drive the case forward when the firing pin struck the primer. If the shoulder was driven forward to the shoulder of the chamber the fired case would have a neck, instead, the neck became part of the shoulder and part of the shoulder became part of the case body. Reloaders do not measure before and again after firing, the reloader does not know how much the case stretched between the case head and case body. (that is, they do not know if it did stretch or if it did not stretch)

Headspace/clearance: When the bolt is closed on a 308W round in a 30/06 chamber the clearance is .000. Again, the 308W at the case body/shoulder juncture is larger in diameter than the case body of the 30/06 chamber by as much as .012". Meaning a 30/03 chamber reamer will not clean up the 308W chamber.

When I chamber a 308W round into a 30/06 chamber I crush the 308 case to fit when I close the bolt and that eliminates all of the clearance.

I was at the Market Hall gun show in Dallas, Texas when a Mauser owner handed me his Mauser with a problem. He had a 7.62 NATO rifles THAT WAS CONVERTED TO 30/06. He WANTED IT CONVERTED BACK TO 7.62 NATO. I suggested he take it to the smith that chambered it to 30/06. And then I asked him who chambered his rifle to 30/06. He told me and I said "that is him over there, and then I told him it would cost him more to go back to 7.62 NATO than to purchase another 7.62 NATO rifle.

I offered to chamber his rifle to 8mm06 Ackley improved to clean up his chamber, he did not like the ring left in the case and I told him I would have applied the leaver policy; 'leaver the way you found her'.

F. Guffey

28 April 2023, 04:29

jeffeosso

quote:
Originally posted by F. Guffey:
quote:
you asked if it could headspace - the (off)topic is about firing a 308 in a 30-06 chamber - headspace isn't relevant to the case firing

The 308W/7.62NATTO ammo headspaces when chambered. Many reloaders have fired 308W/7.62NATO ammo in 30/06 chamber without knowing it. And if they are not in the habit of examining their fired cases they will not be aware of the short necks. If they notice the short necks they never notice the long case bodies.

I said I built 3 8MM06 rifles out of 8MM57 chambered rifles. I fired 100 8mm57 rounds through the 8mm06 chambers. After firing I ejected the the fired cases, all were ejected with very short necks, all of the case bodies increased in length between the shoulder to the case neck; what does that mean? It means the firing pin did not drive the case forward when the firing pin struck the primer. If the shoulder was driven forward to the shoulder of the chamber the fired case would have a neck, instead, the neck became part of the shoulder and part of the shoulder became part of the case body. Reloaders do not measure before and again after firing, the reloader does not know how much the case stretched between the case head and case body. (that is, they do not know if it did stretch or if it did not stretch)

Headspace/clearance: When the bolt is closed on a 308W round in a 30/06 chamber the clearance is .000. Again, the 308W at the case body/shoulder juncture is larger in diameter than the case body of the 30/06 chamber by as much as .012". Meaning a 30/03 chamber reamer will not clean up the 308W chamber.

When I chamber a 308W round into a 30/06 chamber I crush the 308 case to fit when I close the bolt and that eliminates all of the clearance.

I was at the Market Hall gun show in Dallas, Texas when a Mauser owner handed me his Mauser with a problem. He had a 7.62 NATO rifles THAT WAS CONVERTED TO 30/06. He WANTED IT CONVERTED BACK TO 7.62 NATO. I suggested he take it to the smith that chambered it to 30/06. And then I asked him who chambered his rifle to 30/06. He told me and I said "that is him over there, and then I told him it would cost him more to go back to 7.62 NATO than to purchase another 7.62 NATO rifle.

I offered to chamber his rifle to 8mm06 Ackley improved to clean up his chamber, he did not like the ring left in the case and I told him I would have applied the leaver policy; 'leaver the way you found her'.

F. Guffey

Tom, you got this one? i am laughing too hard

28 April 2023, 08:04

dpcd

I actually had to get back to work; I made a 275 Rigby barrel today. I can only stir the pot so much.

28 April 2023, 22:06

jeffeosso

just to keep it simple = a 308 physically CAN'T "headspace" in a 30-06 chamber. doesn't mean it can't be fired in a 30-06 gun, but it literally can't match the datum. This is a cold, hard fact.

29 April 2023, 01:26

dpcd

Exactly, which is why what I said happens, is happening; it either is held by the extractor and fires, or hits the 06 chamber wall, and is held back, especially on a push feed action. And in the case of my friends Savage, no way would it even begin to work; his chamber being tighter. (In 1974) 30-06 chambers vary widely. But certainly no reforming or sizing, is taking place (not enough force for that) nor is there any head spacing as we know it, happening. Also realize that pressures are really low because the bullet has to jump a long ways, and the expansion ratio is greatly increased.
Just a gimmick; although when the balloon goes up (you know, the Chinese one), it might come in handy.

01 June 2023, 02:10

Atkinson

If you want to simplify this whole silly thread, especially a newbe then do this.

using a kitchen match blacken a resized case neck and shoulder and run it into your chamber half way up the neck closing the action to a sloppy fit, then increase that procedure a tad at a time until you get a slightly snug case fit, taking note of the smoked line will getcha a well Ill be damn..lock your die at this point. Basically a neck sized case. Go a bit more for a FL resize, on a belted or not belted case, load them the same on the shoulder and neck not the belt.

It would be a lot easier to have an old worn out reloader show you this than figure out my explanaton.