Headspace/Sizing problem

[BBarn]

If you have access to a larger caliber die you could also neck the case up to 33 or 35 caliber and then neck back down to 30 caliber, adjusting your 06 die so that the case chambers with only a couple of thousandths of clearance. That would produce a small partial “shoulder” that would reduce the case slop in the chamber, and should reduce the web stretch upon firing.

[Paul B.]

"If you have access to a larger caliber die you could also neck the case up to 33 or 35 caliber and then neck back down to 30 caliber, adjusting your 06 die so that the case chambers with only a couple of thousandths of clearance. That would produce a small partial “shoulder” that would reduce the case slop in the chamber, and should reduce the web stretch upon firing."

I'll second that motion. Also, if you have access to say a 180 to 220 gr. cast bullets with a tight bore riding nose you could load those with the bullet jammed into the rifling when you fireform. The expanded neck plus the tight bullet insures a good tight fit for forming.
Paul B.

[Unclenick]

Vettepilot,

In general, case forming is done with just the cereal and a paper wad to retain it and no bullet. It will be gentle and is unlikely to contribute to stretching the case just in front of the head. Putting some case lube or grease on the body of the cartridge will further ensure stretching is avoided, whether you do this with a bullet or with cereal.

It used to be a lot of cast bullet shooters put cereal filler between a light powder charge and a cast bullet. However, enough examples of gradual chamber ringing resulting from this practice were observed so that most people have dropped it. There are safe fillers to use, like Puflon and polyester pillow ticking to hold powder back over the flash hole, but they are much less dense than cereals. For case forming without a bullet, you need the cereal mass, though, and it also seems to cause the brass to fill out with more uniform thickness distribution. I don't know why, but that has been reported repeatedly for Cream of Wheat, in particular.


Hounddawg,

No disrespect back at you, but your example compares apples to oranges to a degree (pun intended). Brass doesn't have just one set of annealing temperatures and times. It obeys the law of recrystallization which says that as the potential energy stored as stresses in the worked brass go up, the time and temperature combinations needed to initiate recrystallization go down. Case necks about to split are at near 100% work hardening, as proved by the small percentage of stretch that splits them. At that stress level, oven temperatures do, indeed, have a measurable effect, so the oven warning remains valid, especially for the OP's military brass which has extra hard heads.

It's unusual that someone has put their cases in an oven, but something has to explain the extreme amount of resizing the OP got. I don't believe I own a die that would push even a dead soft case back that far, though I think I will do the experiment just to be sure.

I can give you a reference to look at for the annealing stuff, but let's take it to PM's, as we are pulling the thread OT.

[tangolima]

I second unclenick's suggestion to grease the casing. I learned that from slamfire and it works. Load the round with mild charge if you worry about excessive bolt thrust.

-TL

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[Unclenick]

No need to worry about excessive bolt thrust. Grease doesn't offer a low enough coefficient of friction to raise it appreciably. But it is a low enough Cf to spread the stretching out over a great enough length of brass so the thinning is negligible.

[tangolima]

Originally Posted by Unclenick

No need to worry about excessive bolt thrust. Grease doesn't offer a low enough coefficient of friction to raise it appreciably. But it is a low enough Cf to spread the stretching out over a great enough length of brass so the thinning is negligible.

I agree and I don't worry about it myself. It was to preempt someone from lamenting; there should be nothing but air between his brass and chamber wall.

-TL

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[F. Guffey]

It was to preempt someone from lamenting; there should be nothing but air between his brass and chamber wall.

I did not say I thought it was not cute to grease your bullet. I did say it was necessary to grease your bullets in the old days when using streak-er ammo.

And then removing the streaks was a different problem.

And I said I do not want anything between the case and chamber but air, clean air because the case is embeddable. Mix the dirt, grit and grime with the grease makes that greasy mess honing/lapping compound.

F. Guffey

[Unclenick]

Clean cases are presumed. Slamfire has been successfully extending case life this way for some time, though having had excess grease and oil fly back and coat my glasses from a Garand and later creep down into bedding, I am less keen on lube for regular use than for special purposes like the OP's. Varmint Al's analysis showed of mirror polishing the chamber should do the same thing and appears promising and I've got a couple of Criterion barrels I am trying this on.

[F. Guffey]

I am less keen on lube for regular use than for special purposes like the OP's.

Again, I did not say packing all that grease into the chamber was not cute. And then there is the space between the case and chamber. I have no curiosity about how fast that grease squirts out from between the chamber and case but I am convinced the exit velocity speed is fast enough to penetrate the skin. And then consideration has to be given to the possibility the spray can not be good for the lungs.

F. Guffey

[higgite]

I’ve never greased a round for fire forming, so please pardon my ignorance, but:
1. When the case expands in the chamber, does the grease dent the case like an overly lubed case in a sizing die?
2. When a greased round is chambered, especially when heavily greased like some of the pics I've seen in other threads, I’m sure some of the grease gets scraped off the side of the case and back to the case head/bolt face area. Does any of it get squeezed into the firing pin channel when the bolt closes or when the case expands?

[Unclenick]

I don't think oil can get around the bolt face to squirt you directly. What I got seemed more to be the small residual pressure as the case extracted blowing loose bits of accumulated lube off the outside edges of the opening bolt. There is some history of cartridge lubing between the WW's. The Thompson Autorifle used magazines with oiling pads. Pederson's design required applying hard wax to cartridges during manufacturing, and, IIRC, there was a German weapon that used magazines with oil lube pads for reliable ejection, but I don't recall a model so don't take that as gospel.

The trick is the oil or light grease coating film has to be thin, just like sizing lube, and if it isn't it can dent a case just like sizing lube and it won't squirt directly back, just like sizing lube. A little space exists around the part of the case head that doesn't expand, so whatever wipes off during chambering or might try to squirt back can go there, so an accumulation of grease at the mouth of the chamber is a concern to watch for and wipe away between firings if you get any.

Thinking of the Pederson waxed cartridges, it is possible applying some paste wax to cartridge cases would work, too, and would be dry and not tacky and would not produce spray or dents. But I haven't tried it, so I can't attest to its efficacy at eliminating pressure ring thinning.

Search for Slamfires posts on the subject. He's got photos and everything.

[hounddawg]

never did this myself but....

https://gundigest.com/gear-ammo/relo...eforming-cases

[F. Guffey]

1. When the case expands in the chamber, does the grease dent the case like an overly lubed case in a sizing die?

Someone would have to get into fluid and flow, I do not grease my bullets but in the old day the case was not lathered-up; in the old days they tried to lube the bullet to prevent it from streaking the bullet. As with all the best of 'laid plans' the shooter got careless, it was about that time he had grease up to his elbows.

It should be explained by the slide and glide shooters in the big inning the streak-er bullets left streaks of material in the barrel that would build up. Cleaning the barrel was no normal choir; the streaks left in the barrel could not be remove my normal means.

The fix? Change the material bullets were made of. The bad streaker bullets were called Cupro-nickel bullet .

The last information I have found/seen was published in 1954 complete with recommendations and solutions. This information can not be of interest because you have decided to lather those things up. Not because of streaker bullets but because you can not size a case to off set the length of the chamber from the datum/shoulder to the bolt face.

Cupro-nickel bullet: I found a deal? in Mauser ammo, I called Cheaper than Dirt for clarification; they claimed the bullets could not be picked up with a magnet so I took off. And then? I went to the checkout register, I asked the employee behind the counter if he had a magnet. He was so sure he responded with "Of course, right here on the pole". It was about that time I asked him to slap a clip of 5 rounds of 8mm57 ammo against the magnet just to see if the ammo would stick. And sure enough. like magic the ammo stuck to the magnet and then he ask me if he had talked to me earlier in the morning.

The ammo was Turkish, they also had Romanian 8mm57 ammo for the same money. The Romanian ammo was packed like the Turkish ammo the Romanian ammo was good stuff. The Turkish ammo reminded me of a box of chocolate, I did not know what was going to happen until I pulled the trigger.
Streaking my barrel was the least of my problems.

F. Guffey

[F. Guffey]

No need to worry about excessive bolt thrust. Grease doesn't offer a low enough coefficient of friction to raise it appreciably. But it is a low enough Cf to spread the stretching out over a great enough length of brass so the thinning is negligible.

Fluid and flow: Oil and lube are fluid because they both flow. Air is fluid because it flows and then there are other factors like time. Back to the joke about choosing nothing between the case and chamber but air. I prefer air between the case and chamber because it gets out of the way in a hurry; I like that because I like the ideal of my cases locking to the chamber. If the slide and glide shooter examines the case after firing and finds the case is still lathered up with grease there is a big chance the grease did not get out of the way in time. And then there is the time factor or not.

F. Guffey