T/C Contender 357 Mag Chamber

[Josh]

In today's economy I think I got an excellent deal on an octagon T/C Contender barrel and forend. The gentleman bought it new "over 40 years ago" and fired "about a box" of ammo through it.

That sounded great until I got it in the mail and discovered a forcing cone throat. Me thinks this barrel never shot well and that's why it was regulated to the back of the safe.

Without lengthening the 357 Mag chamber, what options do I have to get this barrel a real throat? Should I shoot it first before worrying? What's the general consensus?

 

[CWLONGSHOT]

First off why are you trying to fix something that may not be broken? With the advent of these borescope cameras more problems have been found that never existed. It may will be a problem and it doesn't look correct but go shoot it and see what it does.

As far as making a better lead or throat, but not lengthening the chamber, in other words, changing the caliber. You just throat that barrel, which increases lead, and smooths out the lead. Yes nit changes, the dimension slightly, but does not lengthen the chamber.

CW

 

[Rick H]

Clean it well and try it. If there is a problem do a chamber cast to get a good look at what you have before doing anything radical. Like CW says the throat can be cleaned up if needed but you should find out if its broke before investing the time and money to fix it.

 

[Ben]

I have a factory 12" round barrel in 357 Mag.
My chamber looks a lot like the pics in the OP.
Mine shoots cast bullets just fine.

Ben

 

[300BLK]

A tapered leade is a forcing cone.

 

[Jeff H]

Heck, I'd shoot it.

I had a Ruger No.3 in 223 that shot half-inch, five shot groups at a hundred yards, a Ruger Mini 14 that would shoot an honest inch and a Ruger Mini 14 Ranch Rifle that reliably shot just under an inch and they were all box-stock and not supposed to shoot according to the people in the three different shops from which I acquired them.

All jacketed handloads, but still...

 

[Bret4207]

Heck, I'd shoot it.

I had a Ruger No.3 in 223 that shot half-inch, five shot groups at a hundred yards, a Ruger Mini 14 that would shoot an honest inch and a Ruger Mini 14 Ranch Rifle that reliably shot just under an inch and they were all box-stock and not supposed to shoot according to the people in the three different shops from which I acquired them.

All jacketed handloads, but still...

I wish my Mini 14 had done that! I tired all sorts of factory ammo and 3-4" groups at 50 yards was the norm!

 

[CZ93X62]

I think I understand the O/P's concerns regarding the apparent short or non-existent throat and/or abrupt leade.

Similar conditions exist in most levergun chambers and many autopistol chambers as well. Bullet designs for these chamber/throat scenario cater to this environment by virtue of ogive forms like Lymans #311041 (30/30 WCF) and #452374 (45 ACP).

The problems I have encounters with these throat forms were all caused by bullet designs not meshing with these throat forms--specifically full-caliber drive bands seated to extend past the cartridge case mouth.

The classic example is the Keith SWC like Lymans #358429. #429421, or #452424. These can pose feeding problems like overlength in levergun actions and chambering when the exposed full-caliber drive bands encounter short throat/abrupt leade situations. You can seat bullets more deeply, of course--but that gives up the increased powder space in the Special cases that Keith had in mind from the git-go. No free lunch, IOW.

Years ago NV Curmudgeon (RIP, Bill.....) and i were both playing around with Marlin 25/20 WCF leverguns. Lymans #257420 and #257312 both shoot very well in our 1894CL variants, but they wouldn't chamber smoothly or fully due to this short throat/abrupt leade scenario. Our 'fix' was to trim cases back from 1.302" to 1.275" lengths, and it was smooth sailing going forward.

Adjust--adapt--overcome. There is more than one way to skin a cat.

 

[Josh]

First off why are you trying to fix something that may not be broken? With the advent of these borescope cameras more problems have been found that never existed. It may will be a problem and it doesn't look correct but go shoot it and see what it does.

As far as making a better lead or throat, but not lengthening the chamber, in other words, changing the caliber. You just throat that barrel, which increases lead, and smooths out the lead. Yes nit changes, the dimension slightly, but does not lengthen the chamber.

CW

There's a good bit of documentation about this style of throat not being conducive to great accuracy with cast. I know one barrel maker had some articles on it. Mike something I believe. I'm more wondering if it would be better to source a chamber reamer with a correct throat or a 0.358" throat reamer. Both have merits.

I do plan on shooting it, I'll load up some jacketed and cast to see what it does. I hope to be pleasantly surprised.

 

[Rick]

There's a good bit of documentation about this style of throat not being conducive to great accuracy with cast. I know one barrel maker had some articles on it. Mike something I believe. I'm more wondering if it would be better to source a chamber reamer with a correct throat or a 0.358" throat reamer. Both have merits.

I do plan on shooting it, I'll load up some jacketed and cast to see what it does. I hope to be pleasantly surprised.

That would probably be Mike Bellm . . . But I don't think he was barrel maker.

T/C Contender-Encore Accuracy by Mike Bellm - Specializing in Precision Chamber Work and Co-Ax Throating

www.lasc.us

 

[Jeff H]

There's a good bit of documentation about this style of throat not being conducive to great accuracy with cast. I know one barrel maker had some articles on it. Mike something I believe. I'm more wondering if it would be better to source a chamber reamer with a correct throat or a 0.358" throat reamer. Both have merits.

I do plan on shooting it, I'll load up some jacketed and cast to see what it does. I hope to be pleasantly surprised.

Mike Bellm.

The supposed problem is that SAAMI duplicated the throat/forcing cone geometry in a rifle chamber when it was totally unnecessary, because there is no cylinder to barrel transition. I believe H&R did similarly, but I had decent accuracy from a couple. Bellm also seemed to indicate that MGM does a decent job (almost as good as his - my words, not his), but that MGM would send your barrel to him so he could do it better.

OK, Rick beat me to it...

 

[Bret4207]

There's a good bit of documentation about this style of throat not being conducive to great accuracy with cast. I know one barrel maker had some articles on it. Mike something I believe. I'm more wondering if it would be better to source a chamber reamer with a correct throat or a 0.358" throat reamer. Both have merits.

I do plan on shooting it, I'll load up some jacketed and cast to see what it does. I hope to be pleasantly surprised.

100% agree! Always, always ALWAYS shoot and see what it does before considering surgery! I' the dummy that jumped to a conclusion more than once and did something unrepairable. Don't be like Bret!!!!

 

[Rick]

This article by Mike Bellm could answer several questions posed by Josh. Scroll down for photo's of different chambers.

Firearm chamber casts (cerrosafe), what they tell you and what it means for accuracy potential

From the pages of The IHMSA News, Shooting sports, hand gun, ammo, cartridges, xp 100, reloading, firearm, cast bullet, bullet casting and more information articles

www.lasc.us

 

[CWLONGSHOT]

100% agree! Always, always ALWAYS shoot and see what it does before considering surgery! I' the dummy that jumped to a conclusion more than once and did something unrepairable. Don't be like Bret!!!!

Well, I don't know about being like Brett part… But that's all I was trying to say, don't be fixin on stuff ya dont know if its broken. Like the carpenter that cut twice, but the boards STILL SHORT! Its easy ta take a lil more, all too often, hard ta add back.