Measurements for GM 32" IBS barrel .50 caliber

[khaga]

I could use some help! If anyone has a Green Mountain 32" IBS barrel (1:70 twist) for a .50 caliber T/C Hawken, can you provide a couple of measurements for me?

I need to replace the 28" barrel in my 1979 T/C Hawken, and I don't see a 28" for the traditional 1:70 twist. I use a round ball and patch, so I don't want to get one of the LRH barrels with the 1:28 twist.

I haven't been able to see an image of this GM 32" barrel anywhere either - so I can't tell if it has 1 or 2 wedges to anchor the barrel down... the 28" barrel has only 1. Finding specs on these barrels seems tough!

In this diagram, I'm simply looking for the distance between points (A --> W) and points (A --> R). Any help would be greatly appreciated!!

 

[dbutch]

Green mountain drop in barrels only have one wedge key--the only adjustment you might have to make is shorten the under rib ...GM barrels shoot great!

 

[khaga]

ok, thanks! Yeah, I'm curious about the distance from points A-->R, since I'm going from a gunstock designed for a 28" barrel (original) to a 32" barrel... I would hope that the underrib on the 32" is just 4" longer (28 -> 32), but the same distance from the breech of the barrel (point A).

If anyone can confirm this distance, it would really help. I don't need a $220 paperweight...

Thanks

 

[Tom Compton]

Confirmed.

 

[Semisane]

It will fit fine.

The A-W measurement is 7 & 1/2"

The A-R measurement is 13 & 7/8" (after I trimmed about 1/16" off of the rib)

I have five GM IBS barrels, four on Renegades and one on a Hawken. Had to trim the under rib on every one.

 

[khaga]

Yep - its a perfect fit!!

Thanks - now I can look forward to getting one and teaching my boys how to shoot it! :hatsoff:

Hopefully I can find one in stock... I've been amazed at how low the availability of many blackpowder barrels has been. Must be some healthy demand out there.

 

[Leatherbark]

I hope the 79 model Hawken fits better than a 4 digit model from the early seventies...............I had to modify mine out the ying yang. New tang and deepen the wedge mortise then glass bed the mortise and then file the underlug some.............Defininatly not a drop in for my old Hawken...............But never the less it shoots a ragged hole at 50 yards for three shots rested with a .530 Lee cast ball wrapped in a drill cloth spit patch all over 70gr of fffg...............Bob

 

[longcruise]

All of the above is based on ordering the barrel for a TC hawken. If it's made for the TC it will fit even though the barrel is a bit longer. If you mistakenly order a drop in for a Lyman, it will not fit.

 

[khaga]

OK, thanks for the advice. The serial number for my Hawken is in the K121xxx range. The T/C booklet I have is dated August of 1978 and I got it shortly after that - back when you really had to work at those kits to get them to look good. I hate to replace the barrel... it was very accurate when it was new. I swapped it to a buddy of mine for many years and the barrel wasn't cleaned properly, so it needs replacing - at least the breech plug does.

I thought about trying to remove the breech plug and seeing if just that could be replaced ??? How likely is that to be something easy to do? I'm guessing after 30 years, its probably bonded pretty good to the barrel...

 

[Pete44ru]

It's easy enough to find out - A fellow forum member has a T/C breechplug wrench in our classifieds @ $30, IIRC.

.

 

[khaga]

Thanks for pointing out that breechplug wrench - I went looking in the Classified section but didn't see it... which sub-section was it under?

 

[Rogue River]

Firearm parts for sale!

 

[longcruise]

As far as the breech plug area goes, I guess you could spend $30 on a tool that will allow you to take a look at it, but it might be better spent to sending the barrel to be re-rifled or smoothed. The smith doing the job will be automatically looking the breech plug over. If it's bad he may be able to re thread the barrel a bit larger and replace the plug.

If you are pretty sure it's bad, just commit it to jack handle status and get the IBS barrel. The IBS barrel is much better suited to shooting round balls and (sticking my neck out here :shocked2: ), is a better quality barrel than the TC.

 

[jan buck]

i bought several gm barrels and my latest, a .58 cal which dropped right into my renegade stock. 4- digit serial #. as stated you may have to cut a little bit off the under rib. set into the stock, measure, take off rib then cut to fit. some filing may be needed. i had to do this with one of my hawkens.
that [k] in front of your serial# probably means it was/is a kit gun. barrels are shooters for sure. have fun.