Contender .444 Marlin barrel

[Machado]

Gentlemen:
I was given a TC Contender 14-inch .44 mag barrel somebody modified to .444 Marlin. I fired this thing once and have no intention of shooting it again. I fired .44 magnum loads in this barrel - cast RCBS 240 grainers clocking 1,300+ fps from a 10" barrel. The 14" modified barrel tipped open every time I fired it, and I cannot find a reasonable explanation. The cases did not bulge. Cases show no evidence of excess pressure. Cases did not stick in the chamber. This happened with this same barrel installed in other Contender pistols, also. Would anybody have any idea? Thank you.
Antonio

[Mokwaw]

It's been many years since I messed with Contenders, but here's a maybe. Since the barrel was originally a .44 mag the spring for the locking bolt may not be strong enough, now this is just a maybe, but perhaps a spring for the 45/70 Contender may work, or a spring for one of the other hard recoiling calibers. One place to look might be SSK industries they have taken the Contender above and beyond.


A friend of mine has a 45/70 Contender and as you said I shot it once and don't intend to shoot it again.

[Machado]

Thank you, Mokwaw. However, the barrel is tipping open when I fire .44 magnums in it. The previous owner did not report any event of this kind using .444 loads. By the way, I also have a 45-70 barrel I've never fired. It came with the gun package, I only own 15 45-70 rounds (virtually non-existing in my country) and truly believe in the stories I was told about being kicked to next week by the big .45.

[Hobie]

With the Contender it is sometimes simply the locking bolts on the barrel that need replacing. I expect that your barrel as the "split" bolt, i.e. it is really a left and right bolt, is this correct? Is there a number on the bolt? TC did sell different bolts at one time.

[harry]

You may have funky things going on with the excessive free bore caused by the 444 chamber, like the bullet trying to turn sideways, that is causing the barrel to unlatch.
Harry

[Machado]

Yes, there's almost 1-inch free bore. But the .444 lateral dimensions exceed those of the .44 mag only by 0.0128 nominally - .44 mag bullet may wobble some, but enough to unlatch the barrel? Also, I noticed no gas leaks - supposing a gas leak could unlatch the barrel. But the fly in the ointment is that functioning with the .444 barrel is perfect. By the way, the barrel is new, was modified in the United States and was fired only 11 times.

[bigbore442001]

The .444 Marlin chambered for the older style Contenders is a topic of great debate. The issue is that the original Contender frame was designed to handle cartridges that do not exceed a certain pressure. I want to say the limit is 45K. Some Contender fans state that the .444 marlin produces too much pressure and will stretch the frame. Others say it isn't a problem and that with careful handloading you have a winning combination.

Right now Thompson Center is in the process of moving from Rochester New Hampshire to Springfield Massachusetts. I have heard from some sources that any warranty work may have a delay of 3 months until they settle in. So you may want to get some new locking bolts and fix those on your own if possible.

[Hobie]

I would guess that Antonio is on his own in Brazil...

I was wondering about the cartridge fit of the .44 Mag in the .444 Marlin chamber. However, the rim diameters are supposedly the same and the case head (forward of the rim) for the .44 Magnum is only .020" smaller. That large freebore should DROP pressures by quite a bit. I just can't come up with an explanation of this.

[harry]

I would guess that Antonio is on his own in Brazil...

I was wondering about the cartridge fit of the .44 Mag in the .444 Marlin chamber. However, the rim diameters are supposedly the same and the case head (forward of the rim) for the .44 Magnum is only .020" smaller. That large freebore should DROP pressures by quite a bit. I just can't come up with an explanation of this.

Just a guess but the head thrust from the 444 cartridge was keeping barrel in place just long enough to keep the barrel latched. The 44's lower pressure with out the head thrust allows the barrel to come unlatched, wore out lugs or a weak spring.
Harry

[Machado]

Right you are, Hobie. I'm wondering whether even such a minuscule difference im rim thickness would justify the .44 case accelerating backwards enough to drop the barrel. Nothing else comes to mind. Harry may be right, too. But the barrel is like new.

[harry]

Right you are, Hobie. I'm wondering whether even such a minuscule difference im rim thickness would justify the .44 case accelerating backwards enough to drop the barrel. Nothing else comes to mind. Harry may be right, too. But the barrel is like new.

A couple of things you can check:
Shelf engagement, color the lugs and see how far they engage the shelf
Spring, if you have a scale (trigger pull gage) measure the spring weight and compare to your other barrels.
Harry

[2X22]

I have a .444 Marlin barrel that SSK did for me 20 years ago. They put a much stronger aftermarket spring it in to keep it locked up better. I shoot 300gr cast at 1900fps with no problems. In fact, that is the only load I've shot through it since I had it rechambered and I bet I've went over 2K rounds through it.

[Mokwaw]

I misunderstood, I thought it was unlocking with .444. That is a mystery. Still I would look at the locking bolt and spring, or the locking shelf on the frame.

One other thought, is the pivot pin that holds the barrel to the frame a reasonably tight fit (no wobble, etc.) maybe the hole thru the frame is stretched a bit..??

That's the only areas I can think of that may cause a problem.

One thing you could try, if you have plenty of .444 cases, trim a few back to .44 mag length and load them, see if still have the problem. If it still unlocks, then you will know it's not due to case size.

[Hobie]

The first thought is ALWAYS the locking bolt and spring OR the frame is stretched. That it doesn't do this with the .444 barrel or other barrels eliminates the stretched frame theory. I'm pretty certain it is in the locking bolt spring. At least a stronger spring would alleviate that... HOWEVER, how do reduced loads in the .444 case behave?

[Machado]

Hobie, I've just cooked up a half dozen rounds using the cast RCBS 240 grainers ahead of 16 grains of Blue Dot. This is a little below my long-standing load of 17 grains of Blue Dot under the same bullet for the .44 Magnum load. I'm off to the range now; let's see how the gun behaves.
Antonio