How much Red Dot do I need for fire-forming?

[HumptyDumpty]

I just ran a few 8x57 cases through a 7.7 Jap sizing die, and I want to fire-form with a mild loading first, before developing some full-power loads. I've got some 115 grain boolits (originally for a 32-30), and was thinking about a modest charge of Red Dot, but of course I don't want it to be too lite.

[racepres]

Fairly large case.. I would go with 6 grains for one and See!!!!
I would use corn meal, tho,... it is Not recommended with Bottleneck cases, under a Projectile...

[pworley1]

I would go a little higher, maybe 8 or 9.

[HumptyDumpty]

Well, it looks like I'll have to put this part of the project on hold; rounds will not fully chamber, whether they are factory Norma or my own reformed cases, the head protrdes about 1/8" back into the action I did load one of the reformed rounds into an 8mm Mauser (it still chambered just fine), and 6 grains did not generate enough pressure to full re-form the shoulder, so I think I'll bump it up, as pworley suggested. But first I have to figure out what is going on with my Arisaka's chamber. It is absolutely NOT in 6.5 Jap, or any other of the various odd-ball cartridges that I have laying about. I've already tried a few things, I'll post more about it later (perhaps in a new thread, not sure).

[15meter]

May want to read this:

https://castboolits.gunloads.com/sho...Rifles-Article

Doesn't necessarily reference Red Dot but it give you some pointers on light loads for military rifles. There is reference to drilling flash holes, then never using these cases for full house loads.

There has been testing some testing done here:

https://castbulletassoc.org/blog/art...-Test;-308-Win.

Good luck, and one of the weirdness's with fireforming is firing vertically gets better results then horizontally. That works with the cream of wheat style forming. Not so much with real projectile type loading. Used to do it before the farm got sold but there was better than a section of open ground behind the barn that I could visually check that I wasn't dropping an unexpected gift into a neighbor's lap.

Now it's just inert filler and annoy the wife with little bits of toilet paper spread all over the back yard.

[JonB_in_Glencoe]

I fireform reformed 257Rob cases for my Custom T-38 6.5 x 257Rob using a typical cast boolit load (like a 1700fps load). I found that is the way to go for thorough forming, instead of anything lighter.

[Cap'n Morgan]

the head protrudes about 1/8" back into the action

1/8" protruding from the base of the barrel seems about right for most rifles I've seen.

[Mk42gunner]

The barrel may have been set back and rechambered for the .300 Savage. Seems like that was fairly common in the post WWII years.

Robert

[HumptyDumpty]

The barrel may have been set back and rechambered for the .300 Savage. Seems like that was fairly common in the post WWII years.

Robert

It's funny, me and a buddy were just discussing that possibility. He's going to see if he can find a round of 300 Savage in his stockpile somewhere, so that I can try it. If this was re-chambered, the smith did one heck of a job retaining the rifle's original appearance.

[lar45]

You might consider doing a chamber cast. Then measure and know what you have.

[405grain]

^ I second this. A chamber cast will answer all your questions. Also, way safer than trying to chamber live rounds (of possibly the wrong caliber) in order to attempt to figure out what you have.

[wesson357]

6gr is not enough for fireforming. Use at least 10gr with a 115gr bullet. A heavier bullet would generate more pressure.

[HumptyDumpty]

I found the problem.

I then increased the charge of Red Dot to 10 grains, and now have usable brass. What a valuable learning experience this was. I wonder if the seller knew about this?

[JonB_in_Glencoe]

WOW, that surely would do it.

[stubshaft]

WOW, that would make forming brass difficult.

[Texas by God]

That “Case Extractor” requires a gentle touch……
But I’ll bet you knew that!
Way to go, now things will go better.


Sent from my iPhone using Tapatalk

[HumptyDumpty]

WOW, that would make forming brass difficult.

I suppose this was my opportunity to create a new wildcat, lol.

And as Texas By God alluded to, it was definitely a delicate operation; that case segment was held in by the hand of Zeus!