Some good replies and some not so good replies above. I have thousands of TCU rounds at home in 6mm, 6.5mm, and 7mm TCU. I started shooting 7mm TCU in 1986. I have a few hundred rounds to load in the next week and a half for another match coming up. My reply will be based on 25 years and 10s of 1000s of rounds loaded and fired.
Learn to load what you have. Don't go out and guy a bunch of brass if you have a bucket full. (The barrel you are shooting with cannot read the headstamp.)
If you want accurate loads, you have to prepare the brass. Whether military or commercial, you have to do some work to get good accurate loads. (Sub MOA at 100 yards) If you have a bucket of brass, go sort it by head stamp. I don't mean WCC, LC, TW etc in a pile. I mean LC 68 in a pile, LC 72 in a pile etc. EXACT headstamp in a pile. Use brass with exact headstamp when working up your loads. DO NOT MIX IT.
Clean the brass very good. If you have a universal decapping die, or depriming unit, remove primers before cleaning.
After cleaning, debur the inside of the case neck. Remove any burs so the sizing pin in your sizing die does not have a rough area to catch.
Use imperial sizing die wax or similar good lube on the inside of the case neck. I use a Q-tip to apply it. I also like the imperial sizing die wax on the exterior of the case. You don't need much, if any, on the case neck. It is too small for the die right now anyway. Inside the case neck is the important spot to have lubed and cleaned.
Size all of your brass and inspect every one for split neck. If you have cleaned, deburred, and used good lube, you shouldn't have any. Remove any primer crimp with swage or cutter. You can also debur inside of flash hole if you wish.
I now trim my brass to same length. I like RP brass for competition and I size it to 1.720 because that is usually the sweet spot (all cases are that long or longer). A lot of the military brass is near 1.725-1.730. Use a good trimmer if you have one to make all the same length. If you dont have a trimmer and pilot, order one of the Lee trimmers with lock stud. That is what I started with years ago and I still use it.
8.0 grains of Unique and a good cast bullet is accurate and makes a fine fireform load. This is easily within book specification and is actually a load I will shoot in a few weeks in competition (I use RCBS 145 Silhouette bullet).
Once the brass is fireformed, you can work up to heavier loads. If using military brass please ensure you are at least 10% under book max. The brass is often thicker and has less capacity than commercial brass.
I often check length again after fireforming. If using military brass, I will anneal them after that fireform step to soften them a little. You don't have to anneal, but you could start seeing necks split in as soon as 5 reloads.
I have a lot of nickel plated brass that Federal made years ago. 98 of 100 are still in use. I lost 2 to split necks on the 16th reload.
You don't have to spend the big bucks with the 7TCU to make it shoot. Uniformity in brass and loading techniques will usually produce near MOA accuracy if barrel or gun is capable.
Good luck. Hope all goes well.
Steve
