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View Full Version : 45-70 Thompson Contender Problem



madman
08-05-2006, 10:20 PM
While shooting 350 grain hornadyHollow Point Bullets after firing a round the breech opens up by itself and the casing flys out. I like shooting it cause it kicks kinda nice but i think theres something wrong with it. What do you guys think. Thanx Madman

JRouche
08-05-2006, 10:49 PM
Ok... Thompson is a great gun and company.

The breech should not open after shooting, as you know. And I would not shoot it again till fixed.

Question, you probably are not but,,,you are not wrapping your fingers around the outside of the trigger guard are you? Just had to ask, that will open the breech.

It sounds like you have a mechanical failure. Thompson will fix it for free (or they may I should say). Very good company.

I also shot the 45-70, power house round. The .375 maximum is also a nice chamber. JRouche

Nother question: Does it happen with other barrels? I think it might be the spring which pushes the locking lug on the barrel outward. Check that spring if you dont have any other barrels handy.

http://img.photobucket.com/albums/v366/Jrouche/HSM/barrellrevised.jpg

johnhurd
08-05-2006, 11:00 PM
It's probably just the new semi-auto single shot

jmm360
08-05-2006, 11:20 PM
semi-auto single shot:D
I like it

IOWOLF
08-06-2006, 08:19 AM
Single shot, Open Bolt?

JRouche
08-06-2006, 11:30 AM
Single shot, break open action ..JRouche

MTNGUN
08-06-2006, 11:56 AM
There are several issues.

One, the TC has a Rube Goldberg internal safety device that is supposed to block the hammer unless the barrel locking lugs are engaged. This gadget has gone through several design changes because it has never worked reliably. Sometimes it would block the hammer even if the lugs were engaged, other times it would let the hammer fall even if the lugs were not well engaged. It's not common, but it does happen.

Second, the TC's frame is pretty wimpy and definitely stretches when the gun is fired. The stretch changes the locking lug engagement.

Third, there is no positive mechanical lock keeping the TC locking lugs in position, only spring force and friction. Because the lugs have a angled shape, the cartridge thrust tries to push the lugs forward. If there is enough cartridge thrust, the thrust will overcome the spring and the friction, the lugs move forward, and the action unlocks, spitting the brass and hot gas in your face. Nothing is broken -- it's an inherent design characteristic.

Four, due to the interchangeable barrels on the TC, no two barrels will lock up exactly the same on any given action. One barrel may lock up solidly, while another may not lock up so well, or not at all. Tolerances are a fact of life.

If you seperate a case in the TC, you can pretty much bet it will open up and spit in your faces. It has happened to me many, many times, with several different barrels, different frames, and different cartridges. Nothing was broken -- it is a inherent design characteristic.

The same sort of thing often happens on the NEF/H&R Handi-Rifles, for all the same reasons.

The TC was originally designed for the 22LR and the 22 Hornet. The designer never envisioned that it would be used for large, high pressure cartridges. Personally, I don't think the TC is suitable for the 45/70. Yeah, I know, thousands of them have been sold, and most don't have any problem, but how many times does a TC have to blow stuff in the shooter's face before we admit that it is not a safe design?

The TC is to guns what the Corvair was cars, except there is no Ralph Nadar in the shooting world. No "Consumer Reports" magazine for guns. Gun magazines will never come out and say that one of their advertisers makes a defective product that should be pulled off the market. The NRA will never come out and say that one of their corporate members is irresponsible.

If you return it to TC, they will likely put new parts in the locking lugs and maybe the Rube Goldberg safety interlock, and the new parts may improve the fit enough to solve your problem. Or not.

gizmo2
08-06-2006, 01:55 PM
Madman, I had a frame that did this too. Sorta like a 1911, it used the recoil energy to cycle itself. Most unnerving. Anyway, I happened to be at the IHMSA Nationals at the time, and Ken French (from T/C) looked at the gun. First we tried a couple different bolts but no luck. THis was an early model with the split bolt, we tried the newer solid, split, etc. Ended up sending frame back to factory for replacement. Had to do with the bolt shelf not being quite as square as it needed to be. Only had the problem with this one particular barrel, but the frame turned out to be the culprit. No charge of course, their warranty is one of the best. That was over 20 years ago, so my memory might have a little mold around the edges, but there you go.

JIMofalltrades031
08-06-2006, 02:09 PM
Thank the dear lord there is no Naybob for the gun world. People should be responsible for their own actions. I would ask if the gun is being used with handloads or factory ammunition? If handloads then you are most likely seeing excessive pressures! Stop shooting the load. If it is with factory ammo then the gun IS broken and needs to be returned to the factory for repair. If it is possible to repair it. According to a article in Guns and Ammo Warren Center initially chambered the original contender for calibers .22lr to 45-70. The G-2 is somewhat larger in design and chambered for magnum pressure cartridges.
I find your statement as to the safety of the design to be erronious.

IOWOLF
08-06-2006, 07:43 PM
Single shot, break open action ..JRouche

Someone made a few single shot open bolt pistols after the Ban, no magazine but it cocked itself after ejecting the spent case. I was making a joke.:)

Leigh
08-06-2006, 07:59 PM
I don't think the TC is suitable for the 45/70.
I have a T/C chambered in .444 Marlin and have never had any problem with it. And I shoot pretty heavy handloads. Much more powerful than the .45/70.

JRouche
08-06-2006, 11:34 PM
Someone made a few single shot open bolt pistols after the Ban, no magazine but it cocked itself after ejecting the spent case. I was making a joke.:)

Yeah, kinda figured that but didnt quite know without the :D i know you are gun-fluent so I figured :D JRouche

pcarpenter
08-07-2006, 04:33 PM
This is a commonly encountered problem with Contender shooters and can be caused by several different issues. Lug engagement is one issue, but the most common problem is caused by case length (typically with bottleneck cartridges). In short, if a round is too long by even a thousandth or two, the barrel never goes closed far enough to let the locking lugs snap into place without dragging on the locking table on the frame.
I had this back when I thought that full length sizing was to be avoided. With a tip-open action like this, you must full-length resize each time. Brass that is too long will actually lead to degraded accuracy in these guns.

Mike Bellm harps on this quite a bit and a lot more info can be had here, so I won't repeat things.

http://www.bellmtcs.com/FAQ/barrels_that_unlock.htm

madman
11-30-2006, 10:29 AM
I think im gonna trade it for one of those marlin guide model levers, Then i can pour a little xtra powder into er for some real oomph. Should knock the socks of a moose at 50 yards pretty good.

pcarpenter
11-30-2006, 12:52 PM
Don't trade it in because you think it is broken...it's not. However, counter to what I read in at least one post, it is not some sort of design problem and certainly not one that cannot be overcome...usually pretty easily. Read the link I posted on Mike Bellm's site. Loaded cartridge length or brass that is not resized completely are the most common causes. Case head protrusion of more than a thou or so will keep the gun from locking up and as a handloader you have control over that. Locking lug fit which can be adjusted easily is a secondary cause but should only be messed with after the other causes are eliminated. I had the problem with my .300 Whisper barrel years ago when I was trying not to full-length size to improve accuracy. There is no place for that in a break open action like this. I now full length size and drop my brass in the chamber with the barrel off to check fit. Any case protrusion above the face of the barrel gets fixed before the round is loaded.

At least one posting implied that Contenders pop open all the time and that it is because case pressure attempts to open the locking lugs. Hogwash. Show me how case pressure is applied to the locking lugs in a direction that will unlock them (only toward the muzzle). Same with the frame stretch argument. It does stretch and if you are not doing something stupid, it is only within the elastic limit of the metal. The frame does *not* stretch the maybe 1/8-1/4" of lug engagement, allowing them to disengage. The same poster talked about how case separation always results in an open action. If you are getting case head separations on a regular basis, I know what your problem is...and it ain't the gun.

It's really frustrating to read disinformation that leaves people thinking there is something inherently wrong with something....when it is most commonly caused by handloading practices and can easily be fixed. If you want the guide gun, get it, but don't do it because you think your Contender is broken.

Paul

japcas
11-30-2006, 01:07 PM
I'm sure the contender is more than adequate to handle the 45-70 round as long as it is not over loaded. If there was any doubt about it I doubt JD Jones would be chambering some of his infamous rounds in it. I would think several of them operate at a lot higher pressures than the 45-70. But I'm no expert.

gundog
12-01-2006, 02:47 AM
Madman,
I had an old model TC that would blow open with a 7TCU barrel. Old model TC's have a serial number less than 295,000.

By the way all 7TCU are hand loaded it is a factory wildcat barrel. A 7TCU is a .223 case necked out to 7MM and fire formed to fit the chamber.

This was my only barrel that did this. I called them and told them about it and they said for me to send it too them for repairs with the barrel. They sent me back a brand new frame no charge. The gun was manufactured in the early eighties and I bought it used in around 1998. I was amazed how they handled it.

I used to shoot IHMSA matches and was thining a sear spring in my garage on the grinder with a nail the spring went flying and I lost it. I called them to order a replacement and they asked my address and sent me 3 new ones again no charge even though it was all my fault.

I wish they made machine tools I don't think you could do business with a better company give them a call.
Mike

dp
12-01-2006, 03:06 AM
I have a Marlin model 336 45-70 lever action rifle that flat wants to break my shoulder when I shoot it (well, i reload, and most times the cases split...). I can't imagine a 45-70 hand gun. I'm aware of the old 45 Casull wheel gun but damn, what's the point? I remember reading about a 30-30 TC and thinking the same thing. I like big bores but there's a pragmatic limit to practicality that aught to be firmly in the realm of common sense.

There was a time when all my handguns were .45 cal. Some were .45 acp, some .45 Long Colt, what ever. I think, in hind sight, that the most accurate i could have gotten with them is if I'd have thrown them overhand with a bit of CCW spin.

The one piece I miss the most is my .41 mag Blackhawk single action. It was a tack driver. Probably the most perfect ballistic projo ever conceived. It was stolen and I hope the bastid is rotting in hell. Next is my .45 combat commander, also stolen. Such a sweet gun... And my .44 Mag S&W model 29 stolen before I had put a box of rounds through it. FYI, burglar alarms are imperfect.

madman
12-01-2006, 08:40 AM
My Native friend was watching me touch off rounds up north at his cabin. I was surprised when he didnt want to try it. I told him id put the girlie 30-30 barrel on it for him but he just wasnt interested. Im round 250 pounds 6 foot 4 or so and i do have to admit that thing had a whomp to it. After 40 to 50 rounds you were kinda getting a bit recoil shy.

meho
12-01-2006, 11:01 AM
GunDog,
I'm not surprised by your 7TCU problem. They were farmed out another shop to be chambered and they used a drill press to ream the chamber. Needless to say there was a lot of chamber problems with 7TCU's. I had one that I shot in a match once and got beaten so bad by a XP100 the TC didn't make it home.

James