I heard of this proceedure and I to was unsure. I have a 6mm TCU that I got from Billy Marr so I asked him about it. He said the same thing as the others just did. No way do you want to shoot 223 cartridges through a TCU barrel of any caliber.
Guys, this thing of throwing a .224 slug down a .284 pipe goes against everything we're taught about reloading safety from the word go. Now I suppose you can do whatever you like with your own barrels but rest assured it will never happen to one of mine.
To begin with I quit trying to use previously loaded 223 brass even if it hasn't been fired as I could never get it to last. For me it's virgin brass only. I lube them up just enough to size them properly while being careful not to set the shoulder back. All you want is for the action to close freely with no binding.
My pet load is the 139gr. Hornady soft point over 26.5grs. of H322 with a CCI 400 primer in Winchester brass. This is not only my hunting load but my fireforming load also. I see very little difference in accuracy between fireforming and fired and reloaded rounds. When I first started loading for this round years and years ago, I used reduced loads to fireform. Big Mistake! I saw more than my share of blackened and pressure dented brass until I warmed up the load. Even with cheap slugs, you're wasting powder, primers, and time. Make your forming loads count. You'll be suprised how well they work.
For anyone who cares to try the above mentioned load, Back it off a bit and work it up to match your own firearm. Be safe.
tahnkyou old syco you've answered a question ive been thinking about asking, full loads to fireform brass although i'll most likly statr a little lower and form the brass then load a bit at a time till pressures stat to show and back down and shoot for accuracy been doing
that in my .44 mags and 357 mags just starting to get into botlnecks recently, as far as shooting .223's out of the barrels ive been told it works but that could get a little dangrous seems like an accident waiting to happen.
7MM TCU brass in the books is 1.750" long, trim to 1.740". I make 7TCU from 222 Rem Mag because 1. Brass made from 223's ends up 1.725" long after firing and trimming, and 2. My contender is very long throated.
Prime 222 Rem Mag, add 12/Unique, almost fill with well-settled Cream of Wheat, smear wax on the mouth to hold it together, and fire. Haven't lost a case yet. Open up the nek with an M die, and tim until a belled case mouth goes in the gun without closing the bell. For my gun, 1.780". Then trim another .005" for safety-for my gun case length is 1.775" Anneal the necks and you're done.This is .025" over spec, and .050" over cases made from 223's, seems like a little, but it allows 140gr bullets to be seated almost to rifling.
:toast: Wow, almost as many ways to fireform brass as there are different kinds of beer at the local market. You choose one pending on the taste you are craving and the amount of time (or money) you have to spend.
I have done most of the methods mentioned above, except firing .223 ammo in my 7mm barrel. My opinion it is a dangerous waste for what you get from it. Just my :money: .
I am a silhouette shooter. A good standing load is 8 grains of Unique and an RCBS 145 sil cast bullet. Very mild with minimum recoil. Take a .223 brass, run it thru the RCBS 7TCU sizer die, trim to about 1.730 (this is about average for RP, Win, and PMC brass), debur case mouth and flash hole, then shoot the above load for silhouette practice. This load will form 90% of that shoulder, and is good for plinking, practice, and my standing silhouette matches. I then load the brass with my one of my silhouette loads and use them in one specific barrel for chickens and pigs out to 100 meters. These steel critters just don't realize the difference when hit with a 3" load vs a 1" load. After this second firing, my brass is fully formed, and ready for use in this particular barrel for silhouette turkeys, rams, shoot offs, hunting, etc. Using this method, I am continuously building my supply of 7TCU brass for each of my 7TCUs.
I have heard the argument yes-no about firing .223 in a 7 TCU to make brass for 20 years.
I have heard the statement about neck splits being more prevalant. From my experience it doesn't matter which method you use you are going to get neck splits just deal with it.
Not one single person here has said why you shouldn't fire .223 to form 7TCU, they just say you shouldn't. If you go back to the HeyDay of Wildcatting that is exactly how a lot of wild cats were formed.
Everytime over the past 20 years some one has told me that doing it was unsafe, I have asked WHY/HOW? There own logic ususally told them that they were wrong. No one yet when they thought about, other than the iherent danger of a firearm has been able to prove it's dangerous.
Last year for the first time some one told me a reason why it's not a good idea that made me think they are right. Did you know thay you can peen steel with brass. Did you know you can use lead to bend steel.
When you fire a .223 down a 7mm bbl the bullet is expelled with force unsupported to bounce with force down your barrel banging back and forth against the rifling. A .223 diameter 55 gr. brass and lead ball peen hammer.
That is the only reason for not firing .223 down a 7TCU. That said, I still do it in my own non competition guns.
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