I have 6TCU on a Win 70 w/20" that Bullberry rebarreled about 15yrs ago. I started with 300 Fed Gold 223Rem brass that are now starting to shoulder crack. Looks like the whold batch is bound for the brass recycler. What are you usesing to reform and how did they work out?

First let me say I've never been a big fan of Federal rifle brass. I found it lacking compared to other brands. On the other had their pistol brass is very good. With that said have you drawn the shoulder/necks? That's like annealing except you don't heat the case nearly as hot as in annealing. I feel total annealing changes the neck tension on the bullet too much and it doesn't come back until you've fired and resized it enough to work harden it again. I have 6x45 and I'm using military brass with very good success and not much case lost.

Albert, those TCU cases are persnickety bastards!

The 6mm, 6.5, and 7mm TCUs are all based on the .223 Rem. case, but when you've expanded the neck and blown up the shoulder to match the TCU dimensions, you've created a case that is streching that poor .223 case thin in some areas. There's just not enough brass in the .223 to be stretched out like that.

The necking up from .224" to 6mm is not the problem (necking to 7mm is another story). But the TCUs also blow out the case to create more powder volume. The fire formed case has less body taper and a sharper shoulder than the original.

Have you noticed how the TCU case seems to shrink in OAL from the original .223 Rem. case?

The cure for your premature shoulder separation problem? Start with a .222 Rem. MAGNUM case.

You won't get that violent stretch in the shoulder area that you get when using .223 Rem cases.

.222 Rem Mag cases are expensive and hard to find.

But a better solution....... is to just use 5.56mm military cases and discard as problems arise.

I load the 7mm TCU and it's the most persnickety of the bunch.

FA,

I'm using Lapua 223 brass in my Contender carbine 6 TCU. I've not had any problems with mine. My initial thought is that you are over working your brass when resizing. You would be well served to neck size your brass until it will no longer chamber in your rifle. Then, just "bump" the shoulder with the FL die until the bolt will close again.

It is possible that there is a miss match between the dimensions of your sizing die, and your rifle's chamber.

How many firings do you have on this brass now, that it is starting to crack?

I also have a 6x47 that I use 222 Rem mag brass for, in another Contender carbine barrel, (and I have a stash of virgin 222 Rem mag brass tucked away for it). BUT, for the TCU, use 223 brass. That is the whole point to having the chambering, and why it was developed in the first place. To use the cheaper and more plentiful 223 brass.

EDIT-

I have often thought of putting together either a 6x47 or a 6 TCU bolt gun myself. I still may do the same, for a larger walking predator rifle than my Stevens 223. Tell us more about your Winchester, it sounds interesting.

I had a terrible time with Hornady dies making 6 TCU brass, it over worked the cases like crazy. RCBS dies solved that. I also neck up and just bump the shoulder to chamber. I have one in a mini MKX I built for my nieces and nephews to start deer hunting with. 80 grn rem bullet at 2900 fps or so, has dumped 11 deer with one shot each. That load will exit broadside shots and end up a perfect mushroom just under the skin of the off shoulder after breaking it if angled that way.

DaMan (or is it obamas man): I would not call geting 30plus reloads out of cases that has never been an annealed "premature shoulder separation problem". Now back to the real world. Slowpoke Slim: I would not make a bolt gun into a 6TCU unless it was going to be a deadacated single shoot because of the shoulder turning into a speed bump. A 6x45 or 6x47 should be much better on feeding. My gun was a LW short action Win 70 223 Rem that Bullberry rebarraled with a 20" 1/12" LW barrel contour so that it would fit into factory stock. I didn"t tell him that I wanted to uses it feeding out of the magazine(my falt) and he cut the throat as if it was Contender. Becauses of the longer throat if bullets are loaded to be near rifleing (0.020") they are to long to work through the mag. I they are loaded to work through mag there is about a 1/4 mile jump. I tried to use the short loads in a Running Deer match (5 shots at a deer target pulled across a 70yrd opening at 140yrds) and it was like working a Boys 55cal antitank rifle. The Win short action is way to short to work out of the mag w/6x47 rounds. I have had no probles with short 80gr .243 bullets in my 1/12"(2950fps) out to 250yrds and have shot short 87's at 100 but don"t know how much they will be going sideways at 250? All the charts say FB 80's are the longest that will work in 1/12". Thank about the info on the Lapua brass. If I win the LOTO I might get some. theback40: the Rem 80's are the ones that work worked for me in my gun. Thanks for the info on deer. When I had the gun made I bought the dies from LOCK STOCK AND BARREL. They are Redding (bushing neck die-body die-seater)and are all marked "Redding". I paid regular price for the dies as if they were (308win-223Rem-243Win). They sent me the dies in a week. I talked to Reeding acouple years ago and they say they had to be custom made dies, should have taken 16 weeks to make and cost 4 times as much. I guess I lucked out. H335,V133 and the 4198's (twitley dee and twitly dom) have worked the best I my gun.

quote:

Originally posted by Fat_Albert:
DaMan (or is it obamas man): I would not call geting 30plus reloads out of cases that has never been an annealed "premature shoulder separation problem".

Neither would I. But you initially failed to mention how many times you fired these cases. All you stated in your initial post was that you were having "shoulder separation".

So, Fat_Albert, I guess there really is no problem........ except your ability to express yourself accurately in English.

On my 6 TCU barrel I started out with 100 new Remington brass. I have plenty of 1x fired military brass but i'm too lazy to anneal. So far have fireformed 30 pcs and shot them a total of 4 times each for load developement. Tried to trim them but only 3 needed any trimming at all. Hopefully i'll have a shot on a decent buck this year.