7TCU Primer choice

[lead Foot]

I'm using Remington 7 1/2 s'. They seem to be to a little hard for my Thompson. Hard to strike ~ 20% don't go off. What do you use. Your help will be most apprecited.
Lead foot;

[7br]

Hmm, I usually use the same primer and can't remember having a misfire. Weak Springs? Locking lugs not fully engaging?

[JSH]

I have used about every primer out there for the TCU's. I settled on the 7 1/2's for them, now it is when I can find them.
I would suspect improper sizing myself on the misfires. If you bump the shoulder back to far it will just drive the case into the chamber, rather than transfer the energy to the cup. Also it would not be out of line for the chamber to be deeper than it should be, another TC glitch at times.
When fireforming I seat out against the lands to hold the case against the breach face. Makes the brass grow up front rather than at the rear where you could get head seperations.
FYI, to really see how your brass fits the chamber, you need to take the extractor out, as it will give false readings/indications that your brass is long enough. Yes the extractor will hold the case rearward, but it shouldn't, that is not it's job.
jeff

[6.5 mike]

I use cci's in a 6mm tcu with no mis-fires. Getting ready to use them in a 7mm tcu.
Case fit is the trick.

[lead Foot]

I have used about every primer out there for the TCU's. I settled on the 7 1/2's for them, now it is when I can find them.
I would suspect improper sizing myself on the misfires. If you bump the shoulder back to far it will just drive the case into the chamber, rather than transfer the energy to the cup. Also it would not be out of line for the chamber to be deeper than it should be, another TC glitch at times.
When fireforming I seat out against the lands to hold the case against the breach face. Makes the brass grow up front rather than at the rear where you could get head seperations.
FYI, to really see how your brass fits the chamber, you need to take the extractor out, as it will give false readings/indications that your brass is long enough. Yes the extractor will hold the case rearward, but it shouldn't, that is not it's job.
jeff

Thanks Jeff ~ This did cross my mind. I haven't had the gun long. The gun came with a set of good looking Pacific three die set. I must of had the seating die a little low and squashed the necks on a few. I'll try neck sizing next and seat the boolit out further. The first time I tried the gun out I put five shots into .7" @ 50 meters With the RCBS 145-sil ~ very happy with that,
Lead foot;

[JSH]

As mentioned above by Mark, make sure the little flat bar saftey is dropping and the hammer is going all the way down on the frame, when it misfires. You didn't say but it sounded like maybe there was at least a small dimple on the primer?
I got the same mold and it doesn't want to work in my XP in 7BR? Another project I need to get moving on.

[7br]

As for fit on your xp100, try casting a little hotter. For years, I could not get the RCBS to work for my xp woth the original factory barrel. Got an encore in 7br and loaded some rounds for it with the RCBS. Those worked fine in the xp also. Go figure.

Not sure if I changed alloy or what.

[Jon K]

lead Foot,

Fed 205 will work good for the T/C.

JSH/7br,

The RCBS worked great in everything I put it in 7BR(factory)/7 Merrill/7TCU(XP-100)/7 Rocket(Merrill).
The only one I had trouble with was a 7x30 Waters w/muzzle brake, only worked going REAL slow????

Jon

[lead Foot]

Thanks guys I'll have to investigate a bit more. And yes there is a small dimple on the primer. I can get fed + win primers. As far as spare parts here wound be near impossible.
Thanks lead foot;

[JSH]

LF, sounds like a brass issue to me.
Mark, actaully I forget what the issue was exactly. I will try and run it down this long weekend and see what it was.
jeff

[lead Foot]

I think I have found the problem. I was full length resizing a few cases last night and most were getting jammed in the die. After looking at a fired case and a resized one ~ the shoulders looks different ( pushed back).. If the shoulder is pushed back the case will be pushed forward when the hammer falls. Neck sizing the fired cases should fix the problem.~ I hope.
Lead foot.

[DragoonDrake]

I use cci small br's. I only have a problem when I forget to clean the breech end of the barrel and the front face of the frame. I open and use a paper towel and close again and bam it works.

Adam

[6.5 mike]

Lead Foot, I set my 6 & 7mm tcu dies up at first to full lengh size, after they are fireformed I use a spacer or two (depending on case) made from a plastic tub lid. Just screw it onto the die under the locking ring & screw it down like normal. One works well for small, or cases with a short neck (7mm tcu), 2 will work for 30-40 krag, 30-30, or anything with a longer neck. It keeps the die from hitting on the case shoulder, & with it between the lockring & press frame it makes necksizing very consistent. I also use this if the brass is only going to be used in one rifle only, makes necksizing a snap. Mine are made from the lids on wally world ice cream tubs.

[lead Foot]

Thanks guys I'll try those ideas. It seems the case is not the problem. After fire forming the case's, the loaded rounds were firm to chamber. I noticed the gun dosen't cock in a few case's and the hammer fall is still lite. The trigger is very lite also. What do I do now. I bought some Feds 205's ~ might try those.:drinks:
Lead foot;

[JSH]

Thanks guys I'll try those ideas. It seems the case is not the problem. After fire forming the case's, the loaded rounds were firm to chamber. I noticed the gun dosen't cock in a few case's and the hammer fall is still lite. The trigger is very lite also. What do I do now. I bought some Feds 205's ~ might try those.:drinks:
Lead foot;

Firm to chamber?
Did you ever start over? I mean remove the extractor and use the barrel as a case checker? If you FL sized the brass before FF, the case may have slid back, and expanded wrong <at the web>. This can and will cause lock up problems. If the hammer sear is set to lite and you have to really snap it hard to get it to shut, it may be tripping the sear and not let the hammer set.
Mike Bellm has some thoughts on these and a quick search should produce some info. HOWEVER, his thoughts are no written in stone as he would like to think. His sizing info on FL sizing and bumping shoulders has a lot of merit WHEN a full tilt load is used. With a good standard CB load or a IHMSA type load is used, neck sizing does give good results. You will have to bump the shoulder sooner or later though as the case continues to grow.
There should also be some info on how to set your trigger so it doesn't trip when closing and still have a good trigger. A .050 allen wrench is all that should be needed.

When you say the hammer won't cock, I am huessing that the hammer won't set when pulled back? If that is the case, when you let it down does it go all the way down and contact the frame 100%? Or, does it go down and stay back from the frame about 1/16" from the frame?
If it doesn't conatact the frame, the little saftey bar is not dropping. This is a sign that the locking bolts/lugs are not doing their job of tripping the lever in the frame.
Can be caused by a few things. Case being to long and not letting the barrel slide all the way in to battery.
The saftey bar could be gummed up and not dropping from gunk binding it up. I have also seen them "squished" a bit from repeated use and not dropping. and from there not being enough lube on them, I use a thin grease and just a small bit, but only after a good cleaning.
LOL, if I had a good boat, I would row over and give you a hand and get it running.
jeff

[Ramslammer]

G'Day Lead Foot
I've got a 7TCU in a rifle and I've never full lenght sized for it yet. It's been around our brown country shooting silhouette of and on for about 6 years now and I'm still on the 250 cases I started with (Rem). Also I use federal 205m's with no problems.
Juddy

[lead Foot]

LOL, if I had a good boat, I would row over and give you a hand and get it running.
jef
That is a very kind offer Jef ~ Shame you have'nt got a good boat. Thanks for the time in writing a lenghy reply. I shall endeavour to fix the problem with your help.
I see how the Thompsons are addictive and it would be good to have it running smoothly. When you have miss fires it feels like you have shot more that 40 silhouettes.
Lead foot;

















































































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