Colt Trooper MKIII Rebarreling

[KS1911]

Hello all,

Bought a Colt Trooper MKIII a while back that had a 4" barrel on it. I was wanting to look at changing it to a 6" for some hunting. I found a nice barrel for little of nothing. Now the big question, how hard is it to change it. I see the barrel has threads, but how does one setup the gap between the barrel and the cylindar?

Thanks again.

 

[Old Fuff]

The barrel screws off and on ....

But they're is a lot more to it then just that. If you make a mistake you could warp the frame and ruin the revolver. Professional pistolsmiths use a heavy barrel vise and special blocks that support both the frame and barrel. If it is necessary to set the barrel back to correct the gap they usually use a special lathe set-up, and after making the final adjustment may recut the throat, or cone at the back of the barrel.

It would be best to leave this job up to someone who is experienced and tooled up too do it. I suggest you contact Colt.

Hint: it is often less costly to sell a revolver that has the "wrong" length barrel, and buy another one that has the "right" length then convert the former with a new barrel, particularly a take-off that may or may not work out.

 

[KS1911]

Thanks for the info. I have some nice vices good and heavy. I also have the ability to make some blocks to support the frame. Now, can I remove the old one with out screwing anything up. I mean can I remove it and put it back on with no problems? Second questions, what is the gap I'm looking for between the cylindar and barrel?

Thanks,
Troy

 

[Old Fuff]

If you remove the present barrel you should be able to put it back. Be sure to scribe a witness mark on both the barrel and frame so it goes back to the same position. Measure the present barrel/cylinder gap with feeler gauges to determine what the gap should be. (Most likely between .003 to .007 inches).

From here on you're on your own ...

 

[medmo]

This isn't something for someone to do who has never done this before. It is also isn't something for someone to do with some info on a website. Tweaking the frame will ruin the gun. It is REALLY easy to tweak the frame without the right tools. Let's assume that lady luck is with you and you pull the factory 4" bbl without tweaking the frame. Then what? Most likely the 6" bbl isn't just going to screw into the frame giving you proper sight alignment and correct bbl/cylinder gap. Now you have to relieve the shoulder of the bbl to index the sights. Next you may have to turn the bbl for the correct bbl/cylinder gap and recut the forcing cone. I'm sure there is someone out there wanting a 4" bbl'ed Colt as much as you want a 6" bbl'ed Colt. Safest bet would be to pick up another gun.

If it isn't broken..........

 

[KS1911]

Thanks for the info. I'm probably not gonna undertake it. I feel confident in my machining skills, but it's something new to me so I thought I would ask. You never know until you ask. Just thought I would get the proper process by asking.

Thanks Guys.

 

[Old Fuff]

I don't doubt your skills, but the cost of getting the necessary tooling to do the job RIGHT is far more then the job's worth, and the consequences of doing someting wrong could be a ruined gun. If you want to see what's involved in the way of tooling go to:

www.brownells.com

They also offer a free technical service that will answer any questions.

 

[dfariswheel]

Many people just assume that gun barrels are just pieces of threaded pipe that can be screwed on and off at will.

They aren't, and require a LOT more knowledge and tooling than you might think.

Here's a condensed explanation of how to re-barrel a revolver:

The old barrel is locked into a special set of aluminum, brass, or tough plastic blocks that are custom fitted to the specific barrel.

The frame is gripped with a special frame wrench, which has a pair of inserts that fit that specific model of gun.
This wrench and inserts properly grip AND support the frame to prevent bending it or cracking the frame in the thin section that's threaded for the barrel.

The barrel is removed.

A new barrel OR a used barrel that is capable of being used is selected. (Not all used barrels can be used due to damage or other factors that are not readily apparent).

The barrel is test fitted, and the amount of metal that must be removed to allow the barrel to torque up with the front sight at 12:00 is judged.

A lathe is used to cut that amount of metal off the barrel shoulder.

The barrel is installed and torqued properly using the frame wrench and barrel blocks.

The rear of the barrel is now trimmed to establish the correct barrel-cylinder gap, using a special cutting tool that works down the bore.

Finally, the forcing cone in the rear of the barrel is re-cut to the proper spec, using another special cutting and lapping tool set and gauge.
The forcing cone is a CRITICAL item, and the only way it can be properly set is with the cutting tool and a special gauge.
The spec is a VERY narrow range, and the critical dimension is the OUTER mouth of the cone.
If the outer mouth is too big, accuracy is gone. Too small, accuracy is gone AND the gun will spit bullet material.

The difference between too big and too small is TINY.

All these tools are expensive.

Attempting a barrel job by using "expedient" tooling has ruined many fine guns.
The old "hammer handle through the frame" trick is about the fastest way known to destroy a gun.

Bottom line: Even many gunsmiths don't have the right tooling, and don't know the correct methods.
An amazing number of local gunsmiths have no idea the forcing cone is so critical, and fewer still even have the tools to cut it properly.

When a revolver needs to be re-barreled, find a PRO pistolsmith with the knowledge and tooling to do it right.

 

[KS1911]

Looks like I might keep my 4" Trooper and buy another revolver!

Thanks guys!

 

[Standing Wolf]

The good folks at http://www.cylinder-slide.com have rebarrelled several revolvers for me. I didn't say they did it cheaply or quickly. I said they did it well.