Forming 7mm TCU brass

[jason280]

So, I've decided to get a carbine length 7mm TCU.  I've stocked up on standard .223 brass, and I picked up a set of Hornady Custom 7mm TCU dies.  First question.  Can I simply run the lubed .223 cases into my full-length sizing die, or do I need a special expander die?  Second, after fireforming, should I only neck size or full length size the cases on subsequent reloading?  Third, what fireform loads do you recommend?

Thanks!

[ted]

I have a 10 " 7 tcu barrel and have the same hornady custom dies. You simply lube the case and lube the inside of the neck and run the case through. I have tried the dry grahite lubes and do not like them as I have had several cases bulge on me. With the regular case lube inside the neck (I am using a Lee brand case lube) I have had zero cases dent on me. As far as the fireform load, I use 26 grains of imr 4895 with a 130 grain speer btsp bullet. This is my silhouette load. You will notice that after fireforming, the case will be able to hold about 2 or so more grains of powder. This is not a max load but, about 90% of the max load which is what most people say you should fireform cases with. You should find it very accurate even with the fireform loads. As far as the neck v. full length sizing. I full length size simply because then I don't have to invest in more stuff and the 7tcu is very accurate with no need to neck size as is. I do back off my full length die approximately 1/16 of a turn after the cases are fireformed. This is called 'partial re-sizing and does alomost the same thing as neck sizing. Hope this info helps. I have thought about getting a carbine barrel and just might someday! Let me know what loads/velocity you are getting and how everything turns out!

[jason280]

Ted,

I tried running a case through my full-length sizing die, and it worked fine.  I never realized it would be so simple!  Now all I have to do is fire form, and I'm ready to go.

[Steve P]

When I am sizing the brass the first time, I use a Q-tip with imperial sizing wax on it.  I run it inside the neck only.  I use Dillon spray lube (or my own recipe of alcohol and lanolin) on the outside of the cases.  They size pretty easy.  After sizing the military brass. I get rid of the primer crimp, hand prime with a lee priming tool, then load up with 8.0 grains of Unique, WSR primer, and RCBS 145 sil cast bullet.  Accurate load and does a great fireform job.  

After fireforming military brass, I full length size it, trim it, debur the case mouth and flash hole, then I would anneal the case necks.  Don't over do it on the annealling as the cases will buckle when loading.  I like to use a boattail bullet if using jacketed, or a minor bell from belling die if loading cast bullets.   After about 5 firings, anneal again.  Otherwise, you may start to get split necks with the military brass.

Good Luck,


Steve