I've read different instructions on forming 6.5 TCU brass for use in a Contender and wondering what everybody does. Some say to neck it up with the FL die, load up and shoot. Some say that the shoulder is moved forward enough that you have to seat the bullet into the lands. I agree with Mike Bellm that neck tension will not reliably headspace the cartridge when blowing the shoulder forward. When I formed my first batch I expanded to 7mm and then sized it to give me a tight headspace. On the 2nd firing after the fireforming I'm getting about 20% split necks. I'm beginning to believe that the first method is the best and then only FL size to the point that the lugs fully lock. In other words, put up with a little stretch when fireforming and minimize it from there on.

First a comment about split necks, I don't think that your split necks are a result of a headspacing issue with your gun. Rather I think it has to do more with your method of expanding the brass mouth and hardness of your brass. Excess headspace and consequently brass stretching will result in head separations (in my experience). If you're not using a tapered expander to neck up your brass then you might try that. If you are, then you should probably consider annealing your cases before opening up the case mouth.

As for my method of fireforming TCU (regardless of caliber) brass, I prefer to just load up the round after opening up the case mouth to the appropriate size and shoot away. Keep in mind that I'm NOT shooting anywhere near maximum loads so I can get away with a bit more than someone trying to push the cartridge to its limits. Using this technique along with neck sizing only I have reloaded my 7TCU cases 5 times now without any issue (including misfires or difficulty closing my Contender) or even any case stretching.

I've tried three different methods of fireforming my brass. 1) Not seating the bullet in the lands with my regular charge of powder (usually around most books starting loads or even lower). 2) Seating the bullet in the lands with normal charge of powder. 3) Seating the bullet in the lands with a compressed load of very slow powder. Externally I have been unable to measure any differences between the three methods. Granted, the first two methods have the potential of causing a bit of thinning of the case web due to brass stretching but it has not manifested itself in the form of cracked cases or separated cases. Your mileage will vary so be careful and all should be fine.

I have formed many of these over the years, and only once did I get split necks. That happened when I used some once-fired .223 commercial brass (W-W). If I remember correctly, I may have lost 10% to splits back then with that particular batch. But in using new brass, case loss is usually zero.

I simply run the brass into the FL die, choose a powder that will give a compressed load while still creating sufficient pressure to fully form the case -- and then seat the 140 grain bullet out as far as I can. In the 6.5 TCU, there is no need to first run it into a 7mm die and then size down again. You are only creating unnecessary work for yourself.

Extra work and quite probably split necks due to overworking. I missed the fact that the cases were being opened up to 7mm then sized back down to 6.5mm. I feel very confident in saying that is a major contributor to split necks.

What a timely thread. I just received my 7 TCU barrel, dies, new brass and 140 grain projectiles. I was hoping to use Winchester 748, since that's what I already have on hand for .223. I have RCBS dies - no idea what particular style of expander it has. The box just says "FL die set - 7MM TCU". I assume that I need to lube the inside and outside of the case necks, run them through the die, then clean them to get the lube off. How close should the shell holder get to the bottom of the die to acheive best shaping? Thanks.

Ferdinand-
The die will not shape the case but will simply neck it up to 7mm. You will essentially have a 7mm/.223. Fireforming will take it out to TCU dimensions.

I allow the shellholder to barely contact the die on the first go-round.

I spray the cases with Hornady One SHot and lube the inside of the necks with Dillon sizing (aerosol) lube. I simply dip a clean Q-Tip into it and run it into the necks of 8-10 cases before refreshing it. This method works like a charm...

From then on (once the brass is fireformed), I simply use the Hornady One-Shot spray. Enough of it gets inside the case necks to facilitate easy sizing.

Thanks guys; when it's time for more brass I'll run them through the FL die, load with a lighter load, shoot, and them do the usual case uniforming tasks.

Top,

Seems I've come to the topic late and I don't shoot a 6.5 but I do have 2 7mm TCUs.

Properly sized cases can be loaded with nearly maximum loads the first time (if safe in your barrel, of course). I form and do all the normal case treatment and shoot the "fireforming" loads in normal use. there seems to be no difference in accuracy with the 7mm TCU.

Ferdinand,

The W748 will work pretty well. Accuracy was good in mine but velocities with the 130 gr. Sierra SSP was not has good as it should have been so I switched to H4895 for 2450 instead of 2250 fps. I am now trying H335 but have not run these over the chronograph.

Hobie Have you tryed any Reloader# 7 I was it in my 12" Bellm 7mm TCU and get 2356fps with 26.2gr and 120gr Nosler BT. This one of my best hunting loads

In the 10" barrel I had, I used the heaviest cheap (Remington Bulk) bullet I could and seated them touching the lands. 80-85% formed full and perfect on the first try. The others still had slightly rounded corners, but worked fine with full loads the next time and got squared away nicely.

I'm having a hard time figuring out how deep to seat the bullet. The first round (140gr. Rem) was seated so that the top of the case was about half way between the bottom of the bullet and the cannelure. It dropped right into the chamber - no resistance indicating that it is touching the rifling. Seems like if I seat the bullet out any further, the case isn't going to have much of a hold on the bullet. What should my OAL be? Or what is the minimum amount of bullet that I should have inside the case? Thanks.

ferd i had the same worries with my factory 6tcu. i could not reach the lands with the 80gr bullets i had on hand. i was worried that accuracy would be hindered by the long throat.
sdhandgunner advised that he used a standard of trying to have a caliber's depth of bullet seated into the neck. such as .243" of bullet into the case on a 6mm. i just kinnda used that as a guide and relied on my own judgement when seating the bullets no where near touching the lands. the forming loads turned out great and were very accuarate. maybe seating close to the lands is somewhat overrated i'll not worry with it now, unless one just refuses to shoot to my satisfaction.