I just bought a 6 TCU barrel and I am not that familiar with fireforming and have a few questions. I was given an accurate load for this barrel and was wondering if it was safe to use it while fireforming brass. If so, will the point of impact be close to the same load with fireformed brass?

I am using a set of full length dies for the first sizing. Most books say to neck size on fireformed brass. Is this necessary and can I do it by backing the sizing die out or will I need a neck sizing die? Any help and pointers will be appreciated.

Maybe I can help you a little.

I do not own a 6TCU, but have been shooting a couple of 7TCU barrels in silhouette pistol competition for over 10 years now.

When I need to make up a batch of new brass for the 7TCU I just take .223 Rem brass and run it in the full length 7TCU die set to fully size the case. This opens the neck up to take the .284 bullet. The shoulder at this point is still pretty round and needs to be formed to the chamber.

To fireform I shoot pretty near full power loads, but not quite. Quite often, I just subsitute 139 grain Hornady's for the 154's I usually shoot, and use the same powder charge. The point is, you want to reduce the pressure a little, but not too much. You still want sufficient pressure to fully form the shoulder to the chamber.

These loads shoot darned near the same point of impact in my barrels and I often shoot silhouette matches with them. No problem with accuracy, to be sure.

In regard to sizing after you have fireformed the brass, you can just use your full length die. Just do not screw it in all the way. I have a washer that is about the thickness of a nickel that I place on top of the shell holder on the reloading press. I run the ram all the way up the screw the die down to hit that washer. I then tighten the lock ring and remove the washer, I am all set to size only the necks and not hit the shoulder.

Hope this is of some help.

R F

point of impact may be pretty close, but you'll only know by shooting and comparing. you can back the full length die off to size, but if the case grows later, you will have to adjust it down to lightly bump the shoulder back. check out www.bellmtcs.com.
my super 14" 6tcu likes 80gr sierra sspb's with 26.5gr h335, and cci br-4 primers,in rem brass for a forming load. 5 shots averaged 2700fps, and very accurate. i will be working with formed cases soon, i hope. i have close to 200 formed. generally speaking, back off about 2gr from max listed 6tcu loads to form. i formed about 20-30 rnds of 6tcu, by firing a factory .223 REM. UMC 55gr thru it. it works, but sucks out loud. they are very inaccurate. i just had em laying around, so i experimented and added a few cases to the collection.
h335 gives good velocity and super accuracy from my observations, along with info i've recieved from others. imr 4198 is another good powder to experiment with, i just havn't found velocity to be to my liking so far. h322 is worth a try also, but again i get best velocity with h335.

did i fail to mention, you're gonna love the 6tcu. i love it with all my heart!

Thanks for the advice guys. I loaded a few and went shooting yesterday,nothing serious, just mostly fireforming brass. I had a good friend with me who had never been around a Contender before.He is a big rifle man. I sighted it in at 100 yards, then moved out to 150 yards. It was easily grouping MOA and at 150 yards two shots were touching with the third less than an inch away. If I had only had a good rest.

My friend just scatched his head and said, "I never dreamed one of those things would do that."

I believe I'll like the 6 TCU.