I'm spinning up a 6 TCU barrel for a handgun. It's for a barrel stub, so it doesn't take much to make a barrel. I'm planning on fire forming with cream of wheat, which based on my past experiences won't leave me with fully formed brass with a sharp shoulder until I've fired a couple bullets. I'm thinking about using some of the excess barrel blank to make a second barrel specifically for fire forming and cutting the chamber with slightly longer headspace than the one I plan to shoot. Since it's a handgun I can make the barrel as short as I want. My thought is I'll be able to push the shoulder back a little and get closer to complete forming before loading a bullet. Has anyone tried something like this before? Did it work well?
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Fire forming barrel with extra headspace
- Thread starter biednick
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Rich Coyle
Well-Known Member
Cleaver.
been using that method for years with hydraulic forming dies. you will need to play a little bit with the length of the chamber, I use .012-.015 but the die doesn't have the pressure of the COW method. use a good false shoulder to prevent case stretch and adjust the powder to just get just what is needed but don't try to get to 2-3 times fired all at once.
let us know how it works and how the fireform barrel is set for headspace. I am guessing you will need less than half the extra headspace than I use with the die.
Thanks for the input. I'll definitely keep this thread updated with my results.
It sounds like we're on the same page with our assumptions. I'll chamber the main barrel to just close on a go gauge, and plan to chamber the fire forming gauge to just close on a no go gauge. That should put me right around .005" longer, but I'll need to check the length of the gauges.
.005 might be a little light depending on your COW charge. .005 + .002 shoulder bump = .007. it might give you sharp shoulders, maybe a higher charge or no go plus masking tape will be .007 on headspace.
i have had better luck when reforming brass if i use lower pressures to move brass at a slower/ smoother rate than high pressures which seems to stretch instead of moving the brass.
Nimrodmar10
Well-Known Member
I once used a T/C Contender 14" in 6mm TCU for shooting Handgun Silhouette and deer hunting. As far as fire forming cases goes, I simply fired Lake City 5.56mm rounds through the TCU barrel. Cases came out completely fire formed and ready to be reloaded. As far as I can tell, it did no damage to the barrel.
I figure there's going to be a good amount of experimentation to get it right. I bought a reamer instead of renting it this time so I can play around if I need to, and could use shims between the shoulder to make adjustments if I want. I suppose I could do a barrel nut too, but that's more work. I appreciate the input.
I thought about doing that, but I have a surplus of virgin Starline 223 brass to work with. My dad has the same reccomendation, he did that for 6.5 TCU in a contender when he was shooting silhouette.
Fire formed brass thats longer, head to datum, may not get pushed back far enough to chamber, using a standard fl die.
When forming brass in a standard die, the shoulder may spring back more.
When i loaded 7mm TCU, i just sized 223 in the standard 7mm fl die.
But not a normal fl die. If the bottom of the die contacted the shell holder, the shoulder was pushed back way to much.
Interesting to see how your process works.
When forming brass in a standard die, the shoulder may spring back more.
When i loaded 7mm TCU, i just sized 223 in the standard 7mm fl die.
But not a normal fl die. If the bottom of the die contacted the shell holder, the shoulder was pushed back way to much.
Interesting to see how your process works.
Axl
Well-Known Member
I don't think a cleaver would be too clever for chambering a barrel!
Rich Coyle
Well-Known Member
Not to high jack a thread on purpose, 'cause I ain't smart enough to do that.
But this very day I used duct tape to get the plastic wrap off linoleum I rolled up twenty years ago. In frustration I tried the tape and it worked!
What were we talkin' about?
But this very day I used duct tape to get the plastic wrap off linoleum I rolled up twenty years ago. In frustration I tried the tape and it worked!
What were we talkin' about?
UncleDano
Well-Known Member
Not sure that I understand why you want to go to so much trouble for such a small gain; a little sharper shoulder?
I think that some of you guys just like to tinker with new/bigger projects.
Here's another thought you might consider: I noticed that the Win. LC brass was much harder than some Norma brass that I had, and it took longer to get that sharp shoulder with the harder brass.
So maybe if you had some softer brass around, you might get that sharp shoulder. But, of course that would destroy your plan for the extra barrel project.
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I definitely do like to tinker. To me machining is a hobby as much as shooting, so it's great when I can combine them. That said, it's pretty trivial to make a barrel for this use case. I'll probably have it done in 45 minutes or so seeing as I don't need to profile a barrel or dial the barrel in as well as I would for a barrel I'm actually shooting. If it works out the way I think it will I'll have brass close to fully formed without shooting a bullet. My previous experiences with COW lead me to the conclusion it's not worthwhile as I still had to fire form with a bullet to get the shoulder properly formed. With the price of bullets and minimal choices for inexpensive 6mm bullets compared to something like 224 I'd like to avoid blowing through 500 bullets to make brass.
Now that I've thought about it more I can probably use a shim with my main shooting barrel to achieve the same thing, so I may not even need to make a second barrel. The concept is still the same if I go that route.
That's a good point about brass hardness. I'm going to use Starline, but if I didn't already have thousands of pieces of 223 I might try other brass.
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