Author Topic: Contender chambering question  (Read 828 times)

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Offline flatlander

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Contender chambering question
« on: June 11, 2003, 02:50:48 AM »
Can the Contender be safely chambered in 300 Savage or 30-40 Krag? It seems from looking at some of the past posts that this subject, that there is a difference of opinion. Can any of you shed some light on this?

Offline PaulS

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Contender chambering question
« Reply #1 on: June 11, 2003, 07:38:37 AM »
Flatlander,
While it is possible to cut a chamber to fit these rounds in the Contender, the internal area will, at maximum pressures, produce too much thrust for the action to handle over time. The breach thrust will eventually destroy the action and probably injure the shooter.

PaulS
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Offline flatlander

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Contender chambering question
« Reply #2 on: June 12, 2003, 02:17:28 AM »
That is what I was thinking, but there sure are a lot of guys shooting those things!

Offline RonF

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Contender chambering question
« Reply #3 on: June 12, 2003, 02:51:37 AM »
Gentlemen, I respectfully disagree - in part.  The .300 Savage has a little over 4% greater case head (not rim) area than the Krag, so it should exhibit a bit more back thrust than the Krag if operated at equal pressures.  Pressures are not equal, however.  The pressure standard for the Krag is 40,000 CUP, and if memory serves it is 45,000 CUP for the .300 Savage.  This is 12.5% greater than the Krag.  An estimate for the increased backthrust of the Savage over the Krag would be 1.04X1.125, or 1.17 - 17% greater.  I think the Krag is safe, but with a small margin, and I think the Savage exceeds this margin if operated at maximum pressure specs.  Most of the folks using the Savage in a Contender are careful to state that factory loads should not be used and that only milder reloads should be used.  I agree, and don't own a Contender chambered to either the .250 or .300 Savage.  I do own one in .30-40 Krag, and I have shot lots of near maximum loads to NO ill effect.  So, in summary, and supported by some data, I say the Krag is safe and the Savage isn't.  My half nickel....

RonF

Offline flatlander

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Contender chambering question
« Reply #4 on: June 12, 2003, 06:16:36 AM »
Good info. So what are the pressure limits that a contender will handle? I remember seeing this somewhere, but don't recall that number at the moment. I just did a search on the TC pistol forum and this was listed on a post:

"I contacted Tim Pancurak at T/C, who gave me these CUP Limits The small diameter .223 Rem has a CUP of 52,000. Larger case diameters such as the 30/30 Win have a CUP of 39,000. 44 mag CUP of 36,000 and the 45/70 CUP of 28,000."


Wouldn't this leave the 30-40 right on the edge and maybe just a little over? Granted TC would give conservative numbers for liability reasons.

Offline RonF

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Contender chambering question
« Reply #5 on: June 12, 2003, 08:49:31 AM »
I agree the Krag is near the edge:  I said "with a small margin," after all.  A long throat chambering helps.  Yes, it's close, but probably not close enough to be catastrophic.  It could lead to frame stretch, but my experience with a good many near max loads hasn't led to that.  I'm comfortable with it.  You may not be.  If that's the case, stick with something a bit less.  I'm NOT comfortable with the Savage, as I think it's enough more than the Krag (which I think is on the edge, mind you) to be dangerous.  In my view, if it's chambered to a factory round, then it needs to be safe, even if just barely, with factory ammunition.  I personally believe that to be the case with the Krag and not with the Savage, hence my choices.  I do have some engineering background (over 35 years) which helps me feel confident in these decisions, but I do NOT specialize in firearms, nor do I recommend you do something you don't feel comfortable with.  I do not know the Contender limits versus case head size.  I would expect the data attributed to Tim Pancurak to be a bit conservative for the reasons you indicate, and that a careful person could stretch them some without stretching a frame.  How much is open to question.  All engineering requires some assumptions, which would be classified by many people as a leap of faith, since we can never be absolutely sure the assumptions are valid.  All I can say for sure is that so far it (the Krag) has worked for me on more than one Contender frame in both handgun and carbine configurations.  If you decide not to accept the risks, that's fine.  If you do decide to give it try, be careful and good luck.

RonF

Offline flatlander

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Contender chambering question
« Reply #6 on: June 12, 2003, 01:54:43 PM »
Agreed.  Also coming from an engineering background, I understand your points entirely and probably would consider one if I had an extra frame layin' around. There are enough guys shooting them that you know it has to be on the working side of things. BUT, for me "Oops, I guess I'd better order a new frame." just isn't something that would go over well at home. I guess I'll have to keep it off of that line and err on the safe side.  Thanks for the info.

Offline Graycg

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Contender chambering question
« Reply #7 on: June 17, 2003, 05:26:54 AM »
Gentleman,
  Krag is fine in the contender if you stick to loads designed for the Krag Military rifle, stay away from loads tailored to the Ruger number 3.  I have a pair of contender barrels in 30-40 and have never had any problems in many years and several hundred rounds through the barrels.  If you measure the diameter of the Krag case forward of the rim, you will see that it is fairly much in line with other rounds chambered in the contender that are in the 40,000 psi range.  The Krag is one of the best cast bullet rounds in the contender, long long case neck really helps with big 200+ grain bullets.

my opinion only,
 Regards,
 Graycg
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