Barrel relining

[Beekeeper]

OK, I read the post by Gearnasher and it made me think about a project I have wanted to do for a couple of years.
I have a Gahendra Martini that I got as" untouched " from IMA and have rebuilt it (not restored , rebuilt as it was in pretty bad shape cosmetic wise)
The furniture was almost non existant.
Any way the problem is the barrel ( I know nothing about old time BP barrels) and was thinking of relining it using a pristine 43 Mauser barrel I have.
The 577/450 cartridge of the Gahendra and the 43 Mauser cartridge are about the same when using BP.
What is entailed in doing a barrel reline and a ball park price to have one done?
I know it is beyond the capabilities I have (equipment wise) and would have to have someone do it for me.



Jim

[John Taylor]

Bullet diameter for the 577-450 is .455". The 43 Spanish is .439" . You can get a new liner in .458" which is a lot closer and the pilot on the chamber reamer will fit, it won't fit the 43.
Normally the cost in my shop to reline is $320 if I have the reamer. I don't have the reamer for the 577-450.

[Beekeeper]

John,
Maybe I do not understand relining a barrel.
You drill out the old barrel, turn down the new barrel and mate the two parts using epoxy or as someone said superglue, right or wrong?
I have the 43 Mauser barrels and had thought of completely changing the Gahendra out to 43 Mauser.
Would have to spud the Gahendra barrel and bore it to fit the Mauser barrel as the threads are not ever going to match.
Would involve rebuilding the extractor to extract the smaller 43 Mauser cartridge.

Was reading a post on another forum where someone wanted to do it.Caught a lot of flack from some one who felt he should not even be allowed to own one as he had no concept of the "Historical Value" of the Gahendra so I shelved the idea until now.

The only reason I am considering it is I want to shoot the Gahendra and have no knowledge of the barrels and bores but do the 43 Mauser as I have 2 and shoot them often.

But what do I know ,I sure am not an expert on them by any means.
I have taken the time to check ballistics on both and the 43 is almost but not quite as powerfull even tho the 43 is a 1000 yard cartridge.

Jim

[John Taylor]

I misunderstood, I thought you were going back to the original caliber of 577-450. What you want to do is doable but may be a bit of fun getting the head space right unless you have a chamber reamer for the 43. I don't use epoxy and never heard of anyone using super glue. I have been using the high strength red loctite. The trick is to have a close fit, I try for .002" clearance. This requires the use of a reamer and the equipment to run it full length with oil pressure to clear the chips.

[Bent Ramrod]

Beekeeper,

Generally a "reline" means drilling out the old barrel to some standard diameter and gluing or soldering in a "liner," which is a steel tube, generally no thicker than it absolutely needs to be, which has been bored and rifled to the caliber one wants to change over to. The pressure is taken up by the combination of the old barrel and the thin metal of the liner.

The advantages are mainly in being able to keep the original barrel contour and markings and not having to do anything to the forend to get it to fit. The disadvantages are that relining gets more complicated and expensive as you move to calibers greater than .22, since properly piloted drills of the required size are harder to find as stock items and usually have to be ground to suit. Also, the average reline job is good for low-to-medium pressure cartridges only. Finally, the process is limited in the larger calibers, as a barrel in a really large caliber seldom has enough meat on it to drill out for a liner to the same caliber.

You seem to want a .43 caliber barrel turned down to liner size and fitted into a drilled-out .577 barrel. This is a lot of work, making a custom liner drill and especially the turning down of the larger barrel. You would have to leave enough meat on the .43 barrel to include the chamber, which may require a "step" drilled in the .577 barrel. Subject to Mr. Taylor's correction, I would say this would be a much more expensive job than a standard reline, or even a rebarrel job.

An alternative is to cut the threaded portion off the old barrel, drill and thread it and turn and thread the chamber end of the .43 barrel to fit and screw and solder it in. Done right, it would index properly, and might blend in with the contour of the .43 barrel if the outside diameters matched. (I would guess this what you were talking about when you were saying to "spud" the barrel.) Here you would probably have to cut two extractor grooves in the new barrel (I assume the Gahendra has the fork extractor of the Martini) and weld extensions on the extractor and dress them down to fit. This again would be strictly a low pressure proposition, and the forend would probably have to be remade to fit.

[John Taylor]

Bent Ramrod has brought up some good points. I forget that there are not many piloted drills out there because I make my own. I also understand that not all shops want to turn a barrel down to liner size. For me it's no big thing, just time consuming. Leaving a step in the liner for the chamber is a common thing and I do it quit often, especially with bottle neck cartridges and thin barrels.
Using the chamber end of the original barrel as a stub for the threads can be done and I have seen it done more than a few times. Draw backs are having the head space right and the barrel timed to the action. Normally the alignment or timing would be done first then a chamber reamer used to get proper head space. When doing something like this I never use the old barrel, just thread a chunk of cutoff barrel blank for the new barrel, screw it on with Loctite or solder it and then thread it to fit the action. Basically making a threaded bushing.
I have done liners on some of the higher pressure rounds, usually with a step in the liner for the chamber. The step makes sure there is enough metal for a clean chamber and also give a mechanical advantage to hold the liner from moving. I have never had one of my relines come loose.

[Beekeeper]

Thanks guys,
I thought the idea was feasible.
As I said it is beyond my capabilities as I have no machining equipment.
Before I decide I think I will find a BP shooter here localy and cajole him into going over the gun with me.
As I said it was made more than 150 years ago when they didn't have the boring and rifling equipment we have today.
It may be safe to shoot as is and someday I will find out one way or the other.
Other than the barrel it is mechanically perfect or as near perfect as one can be and still be 150 years old.
The furniture on it was toast and I had to make new stocks but everything else is good.


Jim