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DanWalker
10-28-2005, 01:40 AM
Hi guys. I just got a 7mmtcu and am trying to reload cast bullets in it. I have a 7mm M die.Unfortunately, even screwed all the way down as far as it will mechanically go, it won't expand the case necks on this neat little cartridge. Do I have the wrong die? What remedies are available to me?
I'm tired of collapsing shoulders trying to load cast .

Oldfeller
10-28-2005, 06:34 AM
Dan,

Try this on one case. Bevel the mouth on the inside -- all the way until it just about hits the outside. One big mouth bevel.

Take this as-sized bevel mouthed case and install a gas checked cast bullet in it with your seating die.

Amazing, ain't it? If you did this to all your cases you would never have to mess with M dies or pliers or anything else again.

The gas check acts as your M die, except it does not require a separate step. Just load and go.

Oldfeller

joeb33050
10-28-2005, 07:21 AM
The 7TCU requires the "short" expander body-there are 2 expander bodies, long and short.
The top screw in thing accepts any "plug", the plug is the thing doing the actual M die ing.
If you have a short expander body, the 7MM plug will fit the top screw in thing and you'll be able to M die the cases.
All we really need is the 2 bodies-and I don't know why just the "short" body wouldn't work for everything, and a set of plugs-available from Lyman.
If I knew that I wouldn't have all those M dies around.
For an even more exciting explanation of this, with table and pictures, go to the CBA web site, then "Forum", then "Files", then 5.8.8 "A Table Of Lyman M Dies" by Norm Johnson.

Bret4207
10-29-2005, 07:43 AM
Oldfellers method works fine as long as you're not dealing with one of those situations where the GC is a tiny bit smaller than the boolit, like with using a 8mm GC on a .331 boolit. Then you'll shave lead. I've got M-dies, the Lee Universal expander and a couple other methods I use. If you press is tall enough the Lee works fine. The M-dies with the long body can be cut off and made shorter. Some times just a twist with a pair of needle nose pliers in the mouth is fine.

Singletree
10-29-2005, 12:13 PM
Dan,
I use commercial 223 cases to neck up to 7mm. Then using the exact method as Oldfeller to bevel the mouth. I am casting with the Lee 130 gr. round nose mold, dropping a .285 diameter bullet and I am using a gas check. In my 10 inch T/C this is a very accurate combination shooting well into one inch @ fifty yards. One word of caution, this is a long bullet and I have to seat it past the shoulder of the case. On occasion there can be a gas check left in the chamber throat from a previously fired round.

DanWalker
10-29-2005, 06:53 PM
Could someone with both long and short M dies please measure them and post the difference in length, so I have a rough idea how much to shorten my die?
Thanks,
Dan

floodgate
10-29-2005, 07:51 PM
Could someone with both long and short M dies please measure them and post the difference in length, so I have a rough idea how much to shorten my die?
Thanks,
Dan

Dan: My .45 Pistol M die has the M-1 body, which the CBA chart says is the "short" one; it calipers 2.880"over the die body. But on this one, the 0.453" expander button does not unscrew from the "top thing", they are in one piece - nor does it have the second step. Must be an older design; I got it several years back for .45-70 reloading. I must have ordered ".45 Pistol" instead of ".45 Rifle" - or maybe they sent me the wrong one. But it worked OK for my reloads. I need to get the long (M-2) one, though, and some of the removable 2-step buttons. Floodgate

DanWalker
10-29-2005, 09:18 PM
Thanks for the info.
Have angle grinder, will travel....

donald duck
11-17-2011, 09:20 PM
I first use Rislone as my lube and with a q tip, lube the inside of the case mouth. Then using a .257 die open the mouth to .257, then use the Lee TCU dies, open to .284 My favorite load is (five)5.0 grains of Unique. I cast my own 120 grain gas checked bullet lubed and seated in my RCBS Lubesizer. Last time I re sized a bunch of cases I lost 2 or 3 out of 50. I prefer Federal .223 cases but use most anything. I think the 7MM TCU is easy to load and very accurate. I even had a rifle rebarreled to 7MM TCU.