fire forming

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Kenny Wasserburger
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Joined: Tue Sep 24, 2002 3:53 pm
Location: Gillette, Wyoming

Re: fire forming

Post by Kenny Wasserburger »

I anneal after every firing.

The chronograph says it makes a difference. Proved it years ago, plus at one mile was able to maintain 1 MOA of vertical on the steel. That pretty much closed the deal for me.

KW.
We'll raise up our Glasses against Evil Forces, Singing, Whiskey for my men, Beer for my horses.

Wyoming Territory Sharps Shooter
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Lumpy Grits
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Joined: Tue Jan 28, 2003 7:58 pm
Location: Springfield, Missouri-U.S.A. Earth

Re: fire forming

Post by Lumpy Grits »

Kenny Wasserburger wrote: Wed Nov 20, 2019 3:02 pm I anneal after every firing.

The chronograph says it makes a difference. Proved it years ago, plus at one mile was able to maintain 1 MOA of vertical on the steel. That pretty much closed the deal for me.

KW.
The target says the same thing to me. :wink:
Gary
"Hav'n you along, is like loose'n two good men"
mdeland
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Joined: Mon Nov 20, 2006 1:47 pm

Re: fire forming

Post by mdeland »

I was curious as to how hot brass has to be to anneal and found one report that says it begins at a bit under 500 degrees F. At 600* F brass will anneal in one hour at 800 it only takes a few seconds.
I had accidentally heat dried some wet brass at about 400 degrees and was concerned I may have annealed the heads but apparently not.
I don't see how it would make much difference when all the cases are treated the same as the bullet tension would also be the same in each batch of reloads, shot to shot that is. It would make sense if part of the batch of reloads was annealed and the rest not.
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kenny s
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Location: Venice FL

Re: fire forming

Post by kenny s »

I just bought 100 ,40 70 SS BA cases and thy do not fit the shiloh chamber without full length sizing in my lyman die. the last 1/4 inch is too large. and while this works, they are sized too small.

I called Kirk and he said the RCBS dies are what he uses.
The cases fit after sizing , but hold less powder and are not accurate. after FF,they fit perfectly and hold the correct amount of powder and are accurate
I never size them again, and had first annealed and beveled the cases in and out.

I wish BA and or Shiloh would offer cases the truly fit the Shiloh chambers. or at lease, Shiloh should sell a die that matches their chamber .

lot of work, but the BA cases will be fine . 30 40 craig base case is fine.
mdeland
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Re: fire forming

Post by mdeland »

There are at least two fixes I have used for your situation Kenny. One is to lap out the sizing die a bit with a charged, sized, case ( the safer method) or lap the chamber a bit bigger with a fire formed case. Either will get you there but would no doubt nix the Shiloh Warranty using the later method.
I simply threaded a sized case through the primer hole for a 3/16s steel rod for the case axle held in a drill motor. Lube the case and get it moving freely in and out of the sizing die then apply a very thin lap charge at first until it is cutting over the full case exterior. You will only need to remove a couple of ten thousands to get the job done. I start with 220 grit and finish up with 400-600 then a polish with some rouge.
You may need to find a tighter sizing die to form the lap case small enough for use in the die you which to enlarge. The lap compound will increase the lap case size a bit.
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kenny s
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Location: Venice FL

Re: fire forming

Post by kenny s »

ok mdland, neat idea. but I've got them all sized now and I'm fireforming.
this is the type of idea Shiloh should use to offer a die to fit their chambers.

especially on a round like the 40 70 ss that brass has to be used from craig or such shells.

I' don't think I'd do it to the chamber though....the fired cases fit perfectly, in any direction, and never have to be sized again.

and I have a 'history'.......HA....Ken
lefteye
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Joined: Tue Nov 23, 2010 7:06 pm
Location: Grand Junction

Re: fire forming

Post by lefteye »

Some very good comments.
It does depend how serious the shooter is and where he wants to finish the match.
Consistency is the holy grail in our game. New brass will not be consistent. Brass that was fire formed, trimmed to length, weighed, annealed and flash hole deburred will give you the confidence needed to win matches. :D
keep smiling :D
mdeland
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Re: fire forming

Post by mdeland »

In my opinion fire forming brass initially, for black powder cartridge loads, should be under taken with smokeless powder at medium pressure levels to accomplish full chamber forming. My reasoning for this is I have observed BP bottle necked cases with shoulder lube dents that were not formed out fully while using duplex loads which always develop more pressure than does straight BP loads even when compressed. I never noticed this with straight walled case as there is never any lube dents to reveal it.
I think one would be well served to form BP cases with a good smokeless load then you will have a fully developed case capacity from the get go that will not be changing on you as the low pressure BP loads gradually , if ever, full hammer out the case to fully fit the chamber.
I'm wondering now if this observation may be the reason I have noticed gradual case shorting over time as my case were slowly using up brass thickness to gradually fill up the full chamber dimension. My chambers have always been full SAAMI specked not the tighter match type.
My guess is this is where a lot of inconsistency occurs in early load development for any BP load and especially in the larger SAAMI specked chambers. One mans opinion.
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