Author Topic: Need Help with 7mm TCU (Read 1723 times)

jw4570 · « **on:** November 05, 2005, 03:04:43 PM »

Just went out to garage and tried loading some 7mm TCU.

Here's the setup:

RCBS dies (got with barrels)
223 R-P Brass reformed (but not by me, came with gun, looks unfired)
139 gr HPBT Hornady bullet
Winchester Small Rifle Primer (but probably doesn't matter for this)
IMR 4895 Powder
OAL 2.625 (from Hornady Manual)

All load data from the Hornady Manual.

I first tried 28.5 gr IMR 4895. Fills the case. Compresses too much (ie bullet pushes back out). Can't seem to crimp case to hold bullet. Took a little off the bottom of the seat die with disc sander (die was hitting shellholder, I have done this before on other cartridges and there's no ill effect, you are only removing a little).

This becomes a disaster.

I back down to 26.5 gr IMR 4895. Things go much better, but I can still easily wiggle the bullet out by hand.

I'm a pretty seasoned reloader. I have formed and fireformed brass previously (though I hate fireforming).

I suspect the brass isn't formed properly. It appears some (but not maybe all?) appears to have been neck turned on closer inspection.

I will tried to reform some once-fired R-P I have maybe tomorrow. I quit for tonight (better than being frustrated).

I not "married" to IMR 4895, it's what I had on hand that the manual mentioned. Most (if not all) my rifle powders are IMR, I have most of the common ones. I do have a good supply of AA 2200 data powder (yes, from way back when I shot a lot of 223).

I prefer not to get yet another powder in my inventory, I have been trying to cut down to a handful of different ones over the last few years.

Any suggestions would be most welcome.

Would it be best to obtain some properly fireformed brass to start off?

Thanks

Jason

Steve E · « **Reply #1 on:** November 05, 2005, 07:20:20 PM »

My advice which usually doesn't amount to much is to toss the brass and start from virgin brass or from known once fired brass of your own. Best thing probably would be to do is fireform some for yourself. Brass is cheap, I usually use some of the cheaper bulk bullets from places like Midway and Graf's for fireforming.

Steve E........

Gregory · « **Reply #2 on:** November 06, 2005, 01:03:23 AM »

Have you seated any bullets in an empty case to see how snug they are?
I'm assuming you've examined the case carefully for any small neck splits.

Steve has a good point, try forming your own new brass.

Reed1911 · « **Reply #3 on:** November 06, 2005, 01:11:14 AM »

We have factory made 7mm TCU brass from federal. Cost is 5.20 per box of 20 pieces it is nickel

braud357 · « **Reply #4 on:** November 06, 2005, 04:58:32 AM »

If the previous owner neck-turned the necks - this is probably the problem. I have used the 7 TCU in several Contenders and an XP-100 and have never had any of the problems you describe. I use R-P brass, Hornady New Dimension dies. I simple full-length the cases to expand the neck, load, and fire. I also do not go through the trouble of a fire-forming load. They are match accurate "as is". I would try some new brass, and if the problem persists - you probably need to look at the dies next. Don't give up yet - the 7 TCU is a versatile and accurate round.

jw4570 · « **Reply #5 on:** November 06, 2005, 05:14:27 AM »

I tried reforming one of my once fired Remington 223 Cases. It went well, and I was able to seat a bullet in it with 26.5 gr of IMR 4895 with an overall length of 2.625.

Neck tension seems to be much better.

It was still a compressed charge. I don't like compressed charges personally.

I'm gonna measure and see if the bullet crept out any.

I found an old partial box of Sierra 140gr that the tips are oxidizing, I'll probably use those for forming.

But I might just buy 100 pieces of that Federal Brass if it's all formed and ready to go. It's not that expensive.

I dont' want to give up, looks like a great round for one of my children to use to deer hunt when they get old enough.

Jason

jw4570 · « **Reply #6 on:** November 06, 2005, 06:33:11 AM »

I measured my bullet after sitting 3 hours, it did not creep out (the others were almost instantly). So I went to load more.

Back in from the Garage.

I now have 20 good loads with bullets I can't wiggle out by hand. The brass was the problem.

I took once fired R-P cases (from yellow box 55gr ammo), lubed them with Imperial sizing wax with a tad on the inside with a Q-tip. They formed beautifully, very easy in the RCBS sizer die. I Q-tipped out the lube from the case neck and then deburred inside and out.

I then loaded them normally using:

Reformed cases above
Winchester Small Rifle primer
26.5 grains IMR 4895 powder
139 gr Hornady BTSP
2.625 OAL

I have 20 nice cartridges that go into the chamber easily and all bullets are nice and tight.

Moral of the story is check the brass. I suspect the neck turning (though all the brass didn't indicate it, but none seemed to work) was too much and the bullet wasn't held tight enough.

Oh well.

Now to go sight it in sometime.

Jason

Reed1911 · « **Reply #7 on:** November 06, 2005, 06:59:26 AM »

Jason,

A couple of tips. If you want to really use fireforming loads, grab some cast and GC bullets it will make it much less expensive. Personally I use my normal load and have not had any problems. That being said, my normal load is very mild. You will want to make sure you get ALL the lube out of the case. Even just a little of it left on the neck or interior shoulder will contaminate the powder and cause very erratic results. I would at least tumble them or clean them with a solvent that will cut the lube you are using. I use ethanol based break cleaner (the methanol base will burn your skin) and it works great. Obviously do not use in an enclosed environment the fumes will harm you.

jw4570 · « **Reply #8 on:** November 06, 2005, 08:27:37 AM »

Reed,

I've never had any problems with imperial sizing wax, and it's just a tiny amount, literally almost none. and I do clean it througly, though you are correct, some solvent would be better. I would never say to use any other kind of case lube as it would be a mess.

I will try Mica on these next time (inside the neck). I have not had good luck with Mica in the past, but I was forming much larger rifle brass.

These I'll shoot pretty soon, I'll tumble the cases when I do a 100 or so next time just to be safe.

Thanks for everyone's input.

I think it's going to be a great little gun, especially the carbine 7 TCU.l

braud357 · « **Reply #9 on:** November 06, 2005, 11:39:45 AM »

A powder that you may consider is Accurate XMR-2015. I use 23 grains behind a Sierra 150 Matchking for my silhouette load. Not a compressed load - very accurate - and and non-max load. I have shot many 40's in IHMSA with this load - including 3 perfect scores in 1/2 scale. I shot 3 40's this past year while fire-forming brass. Glad that you figured out the problem -- good shooting !

Steve P · « **Reply #10 on:** November 07, 2005, 04:31:17 PM »

I am glad to see some of the experts dropping in and giving some great advise. If it were me, I would first take some pliers to the crap brass sent with the barrel. You don't want it mixed up with your good stuff. Next keep up with the WSR primers. In my guns (7 or 8 tcu's) they work the best. If you want to use your 2230 to fireform the brass, you can. About 10-12 grains with a cast bullet will do the trick. If you have any unique pistol powder, 8.0 grains is THE fireform load with the RCBS 145 silhouette cast bullet, It is also one of the most accurate load used by a lot of standing shooters, myself included. For standing unlimited, I use this load in new brass, fireform it while shooting silhouette. Cheap way to fireform and watch the animals fall. The xmp2015 load is a good load, as is 27 grains WW748. I have one compressed load with 748 using a cast bullet. It is near max in my gun, but shoots 3-4" groups at 200 with open sights.

Good luck with your gun. Don't get discourage, get a bunch of new RP .223 brass and start out right. I am at work and dont have my numbers with me. Seems like once the brass if fireformed, my trim length is 1.740 or 1.720 pending on the brass.

Have fun with that gun.

Steve

scgunsmith · « **Reply #11 on:** January 19, 2006, 01:52:23 PM »

I have a set of hornady new deminsion dies and about 500 formed brass(from commercial ) I make you a deal on all of it

jw4570 · « **Reply #12 on:** January 22, 2006, 11:49:12 AM »

scgunsmith,

Thanks for the offer, I got my problems worked out, it was the preformed brass that I got.

Let me think about it a few days, I might still take you up on it.

Jason

jw4570 · « **Reply #13 on:** January 22, 2006, 11:51:34 AM »

scgunsmith,

Thanks for the offer, I got my problems worked out, it was the preformed brass that I got.

Let me think about it a few days, I might still take you up on it.

Jason

scgunsmith · « **Reply #14 on:** January 29, 2006, 03:19:59 AM »

I've noticed the hornady dies make a tighter neck then rcbs on the 7mm tcu, the shoulders don't crush as easy either. when I did these I fire formed , then backed out to neck neck size only, and the hornady dies worked better then any dies I ever uded

jw4570 · « **Reply #15 on:** January 31, 2006, 03:43:44 PM »

I too like the Hornady Sizing dies. I am not that fond of their seat/crimp die which drives me nuts with that junky rubber washer to lock on top.

I think I'm ok right now, I'm kinda broke too.

Jason