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7mm mag takeoff bbls to 7x57?


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Old 09-13-2017, 05:04 AM   #11
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Simply put: There is not enough metal on any factory take off barrel, other than a bull barrel, and perhaps a heavy target, or heavy varmint profile, to allow such a cut and rechamber to be done safely. The vast majority of take off barrels you find are either "sporter", or "light sporter" profiles, because outside of the target and varmint world, lightness is a highly desirable quality in a rifle, and metal costs money. So, a manufacturer will not put any more weight into the barrel than they have to, unless it saves them money somehow.

Almost every barrel manufacturer's barrel profiles are available on their website.
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Old 09-13-2017, 07:24 PM   #12
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what Mr. Jiggs and i are trying to point out is that once you remove enough material from the breech, to rechamber the barrel in 7x57, there isn't enough barrel material left to safely contain the pressure when the round is fired.

the only way, as pointed out, is if the barrel is a blank, or heavy varmint style barrel. which in 7mm Rem. Mag. would probably be non-existent except for a barrel that was specially ordered in that barrel contour. and finding such a barrel on Ebay is probably not going to happen.

study this information to gain a better understanding of what we are trying to convey to you.

http://saami.org/specifications_and_information/publications/download/Z299-4_ANSI-SAAMI_CFR.pdf#page=13

http://stevespages.com/jpg/cd7remingtonmagnum.jpg

http://stevespages.com/jpg/cd7mauser.jpg

http://www.armoryblog.com/firearms/rifles/barrel-chamber-cutaway-after-4000-rounds/
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Old 09-13-2017, 08:39 PM   #13
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I have known this stuff for decades. All I wanted were actual DIMENSIONS of the barrel diameter if cut back 2-1/4". You are both probably right that the barrel would be too small. I never said it wouldn't. I just wanted numbers. I have since checked my 700's '06 barrel, and unless the 7mm mag is bigger, it indeed would not be wise. I could take my calipers to the local gun dealer and measure, but at this point, maybe I'll just put a 7.65mm barrel back on it.

I know one thing, I'll be more specific with my questions here in the future.
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Old 09-13-2017, 09:03 PM   #14
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Originally Posted by jdsingleshot View Post
I have known this stuff for decades. All I wanted were actual DIMENSIONS of the barrel diameter if cut back 2-1/4". You are both probably right that the barrel would be too small. I never said it wouldn't. I just wanted numbers. I have since checked my 700's '06 barrel, and unless the 7mm mag is bigger, it indeed would not be wise. I could take my calipers to the local gun dealer and measure, but at this point, maybe I'll just put a 7.65mm barrel back on it.

I know one thing, I'll be more specific with my questions here in the future.
the 7mm R.M. case is bigger in diameter than the 30-06 case.

i looked at my M700 in 7mm R.M. and it has the heavier magnum barrel, and trying to cut off about 2.25" from the breech, puts the new chamber starting in the portion of the barrel where it begins to taper down. again, it would not leave enough material to safely contain the firing of the round.

now how many rounds it would take before catastrophic results happened, is anybodies guess, since who knows exactly what would give first, the barrel or the action. but i just about guarantee you one will eventually. IMO a time bomb.

this is why it would be better to buy a Mauser barrel in 7x57. if $87 is too much, keep looking for one cheaper. they may be out there. IMO. $87 is pretty damned cheap for a barrel for the project you are trying to undertake and make a safe shooting rifle. i have seen too many people hurt over the years because they tried to cheap out on something, instead of just spending the money on something that would work, because it was more expensive.
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