forming 7TCU

[Nobade]

I have a 14 inch 7tcu contender barrel on the way should be here Monday . was going to ask about forming brass . It seems I always find my answers on here with out asking . I really like this group learned a lot since I joined .

You'll love it. Wonderful cartridge to work with.

[Three44s]

My first Contender barrel that I acquired in the 7mm TCU is a 14” Super. My second is a 21” carbine. Still have and like both of them. I really like the carbine!

The one thing I have been disappointed with is the fact that the chambering is throated for heavier longer slugs. I nearly pulled the trigger on a 6.5 TCU barrel when I discovered that it also is long throated. I would like a little shorter throat for light for caliber bullets (j words) as I am a varmint shooter.

A long time dearly departed Cast Boolits member Junior1942 was a huge fan of this cartridge and he also wrote articles online about his work and experiences with it. A bullet he had good experiences with was the Hornady 154 gr. spritzers. My barrels liked also. I recall a ground squirrel I shot with my carbine barrel loaded with this bullet. No expansion but one very dead grey digger indeed.

Junior 1942 went to work and set up a mini chop saw and lopped the nose off a bunch of those Hornady 154’s and found a resulting slug that DID now expand at 7 TCU velocities.

VIVA the 7mm TCU!

Three44s

[Mr_Sheesh]

Getting set up for this round again.

My new Size/Expand/Decap die seems to INSIST on screwing the decap / expander stem in tighter, I have to watch out or it will get bent! Going to use a wrench on the darn thing, and, I think, find a short wrench to fit in the die set's box. And going to degrease the die's parts.

I found that graphite doesn't work too well for expansion (new Starline Brass), on my setup at least; So I use a regular case lube, then tumble the cases after.

I just wish I could fire form those here on the place I live but the local PD would get upset, so, nope... I'll go camping or something and form them

I plan to try the 7mm "Soup Can" bullet out. Should work on various targets well

[mike69]

Getting set up for this round again.

My new Size/Expand/Decap die seems to INSIST on screwing the decap / expander stem in tighter, I have to watch out or it will get bent! Going to use a wrench on the darn thing, and, I think, find a short wrench to fit in the die set's box. And going to degrease the die's parts.

I found that graphite doesn't work too well for expansion (new Starline Brass), on my setup at least; So I use a regular case lube, then tumble the cases after.

I just wish I could fire form those here on the place I live but the local PD would get upset, so, nope... I'll go camping or something and form them

I plan to try the 7mm "Soup Can" bullet out. Should work on various targets well

I'm thinking of trying the 7mm soup can or this one from noe 288-135-FN-F1 RG4 cavity GC (7mm Thor)
[288-135-FN-F1-112] haven't really decided which to get first

[Mr_Sheesh]

Nice meplat on that one! I suspect both will do well.

[marshall623]

My 10" 7TCU likes the 160 Lyman Sil. boolit over 20.5 gr of RL 7 . Wanting to try the RCBS 145 Sil. or the 150 Hunter from NOE in it .

Sent from my SM-G930V using Tapatalk

[3856imp]

7 tcu is easy size, fireform trim, keep like brass together

[Walks]

I used 7X30Waters FN in mine. Got great expansion, had good luck with the Discontinued HORNADY 7mm SSP bullet too. Just seated them out a bit.

I used once fired F-C & R-P .223REM cases, formed them with a full power load. Cases last 5-6 firings, trim after 3-4 firings, used Imperial sizing Lube. Worked great inside and out.
Military brass was harder to form, some splits, wrinkles. Not worth the effort.

[JSH]

I used and prefer LC brass. Annealing is not a must but solves a lot of problems. I actually had more issues with FC brass than any others.
The long throats were not really as much for heavy bullets as they were to keep pressure down.
IMHO to get the most and the best from this cartridge a custom barrel and a proper throat will make a huge difference.

[frankmako]

i started shooting 7tcu in the 80 for nra pistol silhouette matches. the only brass i used is military 5.56 brass.

[Eamonn]

What a thread to stumble upon just when I'm in need of a bit of kind experience
Sorry for going a bit OT but I just bought a 6x45 non TCU rifle built on a Sako L461 and I'm planning ahead and picking upp stuff here and there while waiting for the licence to go through.
I'm expecting it to be great little bird rifle.

So, are there any issues with the cheap Lee aluminium press (of recent vintage) with quick die bushings as to expanding the neck?
I can't really find any reliable info online. Just opinions that the press can do anything with ease or that it will explode when looked at.

[Nobade]

If you can find a better press I'd recommend it. But that one won't have any problems opening the necks to 6mm.

[Mr_Sheesh]

Eamonn - Going 223 to 7mm is indeed easy - I use regular case lube to do so, it just works better for me than graphite. I've been using a Lee Hand Press for this step so it's indeed very easy, as Nobade says. 6mm will be easier I'd think. It's good to have a VERY good press, I have several (used to have 5 RockChuckers but a family member "helped himself" -.-) - I use the weaker presses for depriming, and other very light work. The RC IV I have now is the only way to go for heavy case swaging, compound leverage helps there a LOT. (6mm forming from 223 tho is not going to require that )

Enjoy your new caliber

[415m3]

I can fireform .223 into my 7TCU cases?? ******! I've been using a RCBS die for that

[Nobade]

I can fireform .223 into my 7TCU cases?? ******! I've been using a RCBS die for that

Sure. Just fire 223 in your 7 tcu barrel and they'll form most of the way.

[Iowa Fox]

I can fireform .223 into my 7TCU cases?? ******! I've been using a RCBS die for that

You can but anytime I tried it I had crooked necks on the fired brass, plus it seems like a lot of extra work to me. Forming TCU brass on the expander in the sizing die is so easy plus it leaves you with brass that is ready to load and shoot at a match. Just remember lots of GOOD lube on the inside of the neck before you expand it. I purchased the first barrel I could get my hands on when Thompson Center first started chambering for the 7 TCU.

[Eamonn]

If you can find a better press I'd recommend it. But that one won't have any problems opening the necks to 6mm.

Eamonn - Going 223 to 7mm is indeed easy - I use regular case lube to do so, it just works better for me than graphite. I've been using a Lee Hand Press for this step so it's indeed very easy, as Nobade says. 6mm will be easier I'd think. It's good to have a VERY good press, I have several (used to have 5 RockChuckers but a family member "helped himself" -.-) - I use the weaker presses for depriming, and other very light work. The RC IV I have now is the only way to go for heavy case swaging, compound leverage helps there a LOT. (6mm forming from 223 tho is not going to require that )

Enjoy your new caliber

Thanks, I'll keep an eye out for a used one. I regret passing on a Forster Co-Ax with a really nice price tag a short while back =)

[Mr_Sheesh]

Oh. Also. The expander stem on the 7mm TCU CAN or WILL, if you don't lock it down thoroughly, unscrew itself until it rams into the case web and bends itself out of shape; You will want to degrease the stem's threads and be sure to lock it down WELL with the lock nut, or you get stuck waiting for a replacement part. Or at least I did when I first formed these.

[JSH]

The Hornady tapered expanded balls work well for expanding.
My first 6x45, the only die I had for a while to size with was the Hornady 6mm neck die.

[mike69]

When I got my 7tcu barrel it cam with a set of redding dies . I've formed and loaded about 150 rounds for it for when weather gets better . Used my lee turret press think I only had maybe 3 necks split . I'm using the NOE 288-135 fn (thor) have flat nose and hallow points cast and loaded for it . Justing waiting to do some shooting with it .