resizing tmm tcu

rrp · July 18, 2010, 01:56 PM

I just finished making and fireforming some 7mm tcu from 223 rem cases. I had no problem sizing up to 7mm from 223 using plenty of lube inside and out. However, after firing these from my contender and trying to resize them I had a hard time. With more than enough lube, they still wanted to stick in the die about 1/2 way in. I then relubed them, and then I could completely size them. It happened with every case. I took the die apart and checked and cleaned everything and relubed it. Still the same thing, I have to take two pulls to resize them. The die I am using is a Lee die, marked Lee-7mm tcu-17.

Jim243 · July 18, 2010, 02:16 PM

Interesting cartrage, you learn something new each day.

One of two issues I can see.

A. the 223 rem is a tapered case from .376 down to .354 at the shoulder and with all brass there is some memory as to the original dimensions. Especially if using hard brass.(military cases).

B. The 223 rem is 1.760 long and the TCU is suppost to be 1.740 long. Are you sure you have trimmed to the right length?

Jim

rrp · July 19, 2010, 09:10 AM

Thanks for the responce Jim. The brass is military brass and is trimmed to the right length for the 7mm TCU. What is baffeling me is why, when I resized the cases for the first time, before shooting them the process went just fine. It's only after I fire formed the brass, that I am having this problem. I'm wondering if it is because the die is equipped with a very long and tapered expander ball to acommadate sizing the neck to 7mm from 223. The cases do seem to be just fine after I go through the extra motions and finish sizing them.

SVO · July 19, 2010, 09:45 AM

Strange that you can form the cases but not resize them. In my experience with the TCU cartridges, after forming and then fire forming, the case will come out just a bit short of the minimum length. I always used .222 magnum cases and trimmed to the required length, so I doubt that case length is the problem. Are you lubing the inside of the neck before running then into the sizing die? Do you happen to know any one else that might have a set of dies that you could borrow so that you could try a different sizing die? You may want to try a different case lube also. To be truthful, I'm just shooting in the dark trying to think of what the problem might be.

Magnum Wheel Man · July 19, 2010, 11:31 AM

I was having serious issues with the 5.7 X 28 ( BTW... I also load for 7mm TCU, as well as the 6mm TCU/ SSK, & the 30 & 357 Herrett cartridges ), along with a host of others

my local loading mentor told me to throw away that RCBS case lube... if I'm lubing on a pad, his recommendation was STP Oil Treatment, & it works remarkably well on tough cases... I also use Frankford Arsenals spray lube, & Imperial Sizing Wax, depending what I'm doing...

could be that your chambers dimensions & the dies dimensions are different... maybe just try neck sizing... it can make your cases last much longer, & you can get better accuracy, if it works for you

rrp · July 19, 2010, 05:33 PM

Thanks for the replies guys. It might be that the chamber is a tad oversized. I've got quite a few TC barrels and have never had an issue with any of them. I did try to contact Lee by phone, but they don't answer. I have a hard time thinking it is the RCBS lube, but I will give another brand a try. I'm not a fan of spray lubes, but I have some one-shot here, so I can try that too. These cases are definately going to stick in the die, if I force them. They are that tight on the first pull.

Magnum Wheel Man · July 19, 2010, 06:03 PM

I'd try just neck sizing 1st...

July 18, 2010, 01:56 PM	#1
rrp Senior Member Join Date: February 18, 2006 Location: west central Wi Posts: 300	resizing tmm tcu I just finished making and fireforming some 7mm tcu from 223 rem cases. I had no problem sizing up to 7mm from 223 using plenty of lube inside and out. However, after firing these from my contender and trying to resize them I had a hard time. With more than enough lube, they still wanted to stick in the die about 1/2 way in. I then relubed them, and then I could completely size them. It happened with every case. I took the die apart and checked and cleaned everything and relubed it. Still the same thing, I have to take two pulls to resize them. The die I am using is a Lee die, marked Lee-7mm tcu-17.

July 18, 2010, 02:16 PM	#2
Jim243 Senior Member Join Date: January 6, 2009 Location: Just off Route 66 Posts: 5,067	Interesting cartrage, you learn something new each day. One of two issues I can see. A. the 223 rem is a tapered case from .376 down to .354 at the shoulder and with all brass there is some memory as to the original dimensions. Especially if using hard brass.(military cases). B. The 223 rem is 1.760 long and the TCU is suppost to be 1.740 long. Are you sure you have trimmed to the right length? Jim Last edited by Jim243; July 19, 2010 at 12:29 AM.

July 19, 2010, 11:31 AM	#5
Magnum Wheel Man Senior Member Join Date: July 26, 2006 Location: Southern Minnesota Posts: 9,333	What are you using for lube ??? I was having serious issues with the 5.7 X 28 ( BTW... I also load for 7mm TCU, as well as the 6mm TCU/ SSK, & the 30 & 357 Herrett cartridges ), along with a host of others my local loading mentor told me to throw away that RCBS case lube... if I'm lubing on a pad, his recommendation was STP Oil Treatment, & it works remarkably well on tough cases... I also use Frankford Arsenals spray lube, & Imperial Sizing Wax, depending what I'm doing... could be that your chambers dimensions & the dies dimensions are different... maybe just try neck sizing... it can make your cases last much longer, & you can get better accuracy, if it works for you

July 19, 2010, 09:10 AM	#3
rrp Senior Member Join Date: February 18, 2006 Location: west central Wi Posts: 300	Thanks for the responce Jim. The brass is military brass and is trimmed to the right length for the 7mm TCU. What is baffeling me is why, when I resized the cases for the first time, before shooting them the process went just fine. It's only after I fire formed the brass, that I am having this problem. I'm wondering if it is because the die is equipped with a very long and tapered expander ball to acommadate sizing the neck to 7mm from 223. The cases do seem to be just fine after I go through the extra motions and finish sizing them.

July 19, 2010, 09:45 AM	#4
SVO Senior Member Join Date: December 21, 2009 Location: Texas Gulf Coast Posts: 728	Strange that you can form the cases but not resize them. In my experience with the TCU cartridges, after forming and then fire forming, the case will come out just a bit short of the minimum length. I always used .222 magnum cases and trimmed to the required length, so I doubt that case length is the problem. Are you lubing the inside of the neck before running then into the sizing die? Do you happen to know any one else that might have a set of dies that you could borrow so that you could try a different sizing die? You may want to try a different case lube also. To be truthful, I'm just shooting in the dark trying to think of what the problem might be.

July 19, 2010, 05:33 PM	#6
rrp Senior Member Join Date: February 18, 2006 Location: west central Wi Posts: 300	Thanks for the replies guys. It might be that the chamber is a tad oversized. I've got quite a few TC barrels and have never had an issue with any of them. I did try to contact Lee by phone, but they don't answer. I have a hard time thinking it is the RCBS lube, but I will give another brand a try. I'm not a fan of spray lubes, but I have some one-shot here, so I can try that too. These cases are definately going to stick in the die, if I force them. They are that tight on the first pull.

July 19, 2010, 06:03 PM	#7
Magnum Wheel Man Senior Member Join Date: July 26, 2006 Location: Southern Minnesota Posts: 9,333	I'd try just neck sizing 1st...