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Old March 22, 2013, 12:52 AM   #1
Newton24b
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case life, lever action

people tell me that a case from a lever action needs to be checked carefully for case head seperation. because the mechanism is supposedly torquing the case when the action is operated.

now what is happening to pistol calibers in the lever action? is is subjecting the little 44 mag case to the same death enhancing strain, or is it different?
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Old March 22, 2013, 02:38 AM   #2
dmazur
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The bolt moves in-line with the chamber, lever-action or not.

Any extractor which grabs one side of the rimmed case will create an unequal force during extraction, on the rim.

The rim is as strong as the material and dimensions allow.

Maximum loads will stretch the case ahead of the "web" area. As I understand, this is rare in most pistol calibers, but with .44 Mag and up it is possible.

However, this area of the case isn't subject to "torque" during extraction.

Can you explain the torque concern in a little more detail?
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Old March 22, 2013, 09:16 AM   #3
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Quote:
people tell me that a case from a lever action needs to be checked carefully for case head seperation. because the mechanism is supposedly torquing the case when the action is operated.
They are right and they are wrong.

Yes, bottle necked cases fired in lever actions need to be checked for case head separation, but it is because lever action rifles (most of them) are rear locking mechanisms. Given that steel compresses around 0.001” per inch (I don’t remember the exact number, look it up in your Ottesen) given a three inch long bolt, supported at the rear, that bolt is going to compress 0.003” during firing, and your case will therefore stretch 0.003” . This is the reason case life is so short in Lee Enfields. Lee Enfields are weak actions, the cartridge operated around 40,000 psia and they were rear locking. Cases get stretched something awful in these actions. Lee Enfields are so weak and stretchy that the British NRA recommends not firing them in the rain!

I have not had case separation issues with straight walled 44 Magnum cases in my M1894. Might be due to the fact they are not bottlenecked, or it might be due that I don’t fire the thing all that much.
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Old March 22, 2013, 09:17 AM   #4
chiefr
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First time I heard that one. Interesting to know what lever action supposedly causes this problem.
Max load do cause cases to stretch in any action. Bolt & auto included.
Torque is defined as any twisting force exerted on an object.
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Old March 22, 2013, 10:42 AM   #5
buck460XVR
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Many reloading manuals recommend using only new or once fired brass when loading handgun caliber lever carbines to max or near max loads. It has to do with the bolt of levers locking at the rear and the resulting flex causing the case itself to stretch. Repeated max or near max loading of brass can lead to case separation with half a case stuck in the chamber. With my lever carbines, hunting type loads go in new or once fired brass......after that, those cases are used for plinking loads and use in the revolvers.
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Old March 22, 2013, 11:22 AM   #6
david_r
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You could measure your brass and know. Resize, measure, load, fire, resize and measure. If it gets longer, that length has to come from somewhere.
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Old March 22, 2013, 11:25 PM   #7
Newton24b
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im useing a 336 in 30-30, but it was explained to me that in order for the bolt to unlock, the rear end has to pivot, and that created torque on the case in the chamber, leading to a shortened case life. i was wondering if that would apply to pistol cases
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Old March 23, 2013, 01:45 AM   #8
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Newton,
I do not believe there is any pivoting in the bolt. Doesn't your bolt come out the rear and cock the hammer?

Scroll way down on this page to the parts diagram for a 336. Part number 24 is the bolt lock. You can see that it engages the slot at the rear of the bolt during lockup. The distance between the bolt lock and the face of the bolt is why people say a bolt can "spring" on firing.
http://www.freerepublic.com/focus/f-chat/2928005/posts
and go here for the operation of a lever action. I'm not seeing any pivoting
http://www.hunter-ed.com/washington/...5001_700046633
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Old March 23, 2013, 01:51 AM   #9
Boomer58cal
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Also... 30-30 cases aren't overly thick either. When fired from my friends Rem 788 bolt action the cases last much longer than my 94 wins do.

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Old March 23, 2013, 07:19 AM   #10
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I shoot .45-70 Gov't. In a Marlin Guide Gun. I have 10 loadings on most of the brass that have. They are still going just fine. I anneled the brass after 5 reloads to help extend the life of the brass from cracking at the case mouth from the expander. If the brass were cheaper I would never worry about it.
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Old March 23, 2013, 12:16 PM   #11
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I know full length resizing of belted cases ruins the case after one or two reloadings. my brothers #1 Ruger 375 did anyway. they would seperate about 1/3rd of the way past the belt. Neck sizing cured the problem, I wonder if this could be related since they both headspace at the rear of the case.
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Old March 23, 2013, 01:16 PM   #12
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I never noticed any problems with case seperation with my Winchester 94. Maybe it has to do with the 336 side ejection? The Winchester is top ejection. Head separation I thought had to do with to much head space and after time and case expansion you would get separation. Maybe the 336 puts some twist on ejection and on a case that has already been stretched a couple of times splits?
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Old March 23, 2013, 06:45 PM   #13
zeke
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BlR bolts rotate like a bolt action. Regular levers come straight back, not sure how that could "torque' anything. Rear locking bolts allow more case stretch, more so in higher pressure cartridges. if the fired case is not relaxing enough to easily be pulled from the chamber, something is amiss.

And yes, straight walled pistol cases can stretch in lever actions, when loaded to full power. Best not to mix them with revolver fired loads if ya can avoid it.
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Old March 23, 2013, 07:20 PM   #14
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Quote:
im useing a 336 in 30-30, but it was explained to me that in order for the bolt to unlock, the rear end has to pivot, and that created torque on the case in the chamber, leading to a shortened case life.
Marlin 336 bolt head does not rotate or torque when unlocking or extracting. It has a small locking block at the rear that locks the bolt. When the lever is opened, the locking block drops and the bolt travels rearward in a straight line. The cartridge is pulled straight out of the chamber.

One issue with lever action rifles and ammo is that with the locking block at the rear of the action, the action stretches minutely and springs back when the rifle is fired. This can eventually lead to excessive headspace if the rifle is fed a steady diet of elephant loads. The increase in headspace may cause the brass to be weakened at the web, causing head separation if you are not careful about how you full-length resize your brass.
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Old March 23, 2013, 11:21 PM   #15
Boomer58cal
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My 94 100th anniversary is a angle eject and has no real issues my older 94's don't. Really I think it's much improved. I did have the unfortunate experience of buying a new 336. Since they moved factories quality it hit or miss. I am admittedly a winchester guy but marlins used to be better in some ways. The new marlin stripped brass from the cases better than my die grinder.
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Old March 24, 2013, 04:11 PM   #16
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You need to check your fired cartridges and make sure you are not oversizing them. Case head separation is heavily influenced by improper head space. Yours would not be the first lever gun with an excessively large chamber. Your micrometer is your best friend when figuring our how much (or little) to bump the shoulder back.
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Old March 24, 2013, 05:04 PM   #17
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Quote:
I know full length resizing of belted cases ruins the case after one or two reloadings. my brothers #1 Ruger 375 did anyway. they would seperate about 1/3rd of the way past the belt. Neck sizing cured the problem, I wonder if this could be related since they both headspace at the rear of the case.
Could. Shoulder locations on belted magnums are all over the place since headspace is measured off the belt. The best way to size belted magnums is with the cartridge headspace gage found in this article:
http://www.realguns.com/Commentary/comar46.htm

I think 30-30 Winchester is more standardized.
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