Your gun, your choice. Obviously the concept of proof for guns is lost here. Someday this gun will be offered for sale, probably passed to another owner. Then another and another, etc. Not to me, if I want to shoot 3” ammo I’ll buy a gun that is made and proofed for this.
reaming a 12g chamber to 3 inch
- Thread starter Evanguy
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Londonshooter
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He doesn't get it, Jim.
that is true, I don't get it, I'm new to working on shotguns, ill admit.
I'm just use to centerfire rifles, where people are working with 60k psi pressure and rechambering them is very common. happens al the time and I've personally done it many of times. loads of rifles built on actions that did originally come in that caliber from factory
a 1970's gun as far as steel goes is brand new, if this shotgun was made in say 1880's when they were just changing over to smokeless and changing from Damascus id full agree, I have lee metford from 1890's that fires smokeless factory with loads no issue, I don't believe there is any mild steel that can be bought that canT handle 11.5k psi, even old black powder brass framed rigs can handle those pressures.
I doubt there is a lower pressure centerfire round then 11.5k psi, and some of those barrels are a few mm thick and made in the 1800's
I'm just use to centerfire rifles, where people are working with 60k psi pressure and rechambering them is very common. happens al the time and I've personally done it many of times. loads of rifles built on actions that did originally come in that caliber from factory
a 1970's gun as far as steel goes is brand new, if this shotgun was made in say 1880's when they were just changing over to smokeless and changing from Damascus id full agree, I have lee metford from 1890's that fires smokeless factory with loads no issue, I don't believe there is any mild steel that can be bought that canT handle 11.5k psi, even old black powder brass framed rigs can handle those pressures.
I doubt there is a lower pressure centerfire round then 11.5k psi, and some of those barrels are a few mm thick and made in the 1800's
One of the guys that was actually in a position to pay for the pressure testing rigging, over in the Double Gun Journal, actually looked pretty hard at the use of 2 3/4 shells in 2 1/2 inch chambers, and came away pretty happy that it would not cause you the prophesied "World of Hurt" that was the general attitude at the time. Dunno if they followed up with data on 3 inch in 2 3/4 chambers.
All else being equal, I would shop for a long forcing cone reamer, provided that the original carcass had enough meat on it to not cause any other issues.
madtrapper143
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A lot of guessing here. You cannot compare a centre fire rifle cartridge effect to a shot shell. As for shooting long cartridges in short shotgun chambers the key element of that experiment was pressure rise due to the opening crimp into the forcing cone causing a pressure spike. IF the the longer shell was loaded to a level the gun was proofed for most times very little increased pressure was noted. These experiments were only conducted using 2 3/4" standard (not magnum) cartridges in short chambered guns i.e. 2 1/2" and 2 9/16" NOT 3" in 2 3/4". The only way the OP can do what he wants to do safely (known not guessed) is to have the barrel wall thickness determined by a competent smith in the area where the chamber is to be reamed. If the smith determines there is enough material to do the operation safely it can be done. Any other way is guess work and could cause injury or at least damage to the gun. Now go ream it out a see what happens......
Darryl
Darryl
You obviously don't know the Merkle SxS
When you think about it... the ammunition factories must have given it a lot of thought when they manufactured the 3 inch Magnum that easily fit in a 2 and 3/4 inch chamber... and I think they erred on the side of caution ... they made the ammo so it would not blow a 2 & 3/4 gun up.
I’m not an engineer or anything fancy like that, but I do possess some not so common, common sense. Extending the chamber to accept longer shells sounds like a bad idea to me. Even if the shells were the same pressure, you’re spreading it out over a longer area. Im sure plenty of barrels are over built and will take the added stress, but I personally wouldn’t chance it. I work with metal and pressure every day and have seen first hand what happens when you “try something” that hasn’t been tested properly.
I’m probably wasting my time here but one more try.
Firearms are proof tested to verify that they withstood a specific charge without material damage - once. In some cases twice. These ‘proof’ loads are a very specific overload and a gun that passes this test is stamped with proof marks to attest that it has passed this severe test. You may then purchase this gun and use it confidently with normal factory ammunition designed for the gun. A gun that has been altered in a manner which could compromise safety is as hazardous as using ammunition that is manufactured or reloaded beyond the pressure standard for that cartridge. If the gun is altered in a manner that could compromise safety it will always be an unknown issue until it is reproofed to establish it’s integrity.
All new guns are proof tested before sale to verify strength and safety. In most of the civilized world including all of Europe there are government operated proof establishments ( proof houses) that proof test guns to a predetermined international standard. Used guns are also sometimes reproofed and all guns must meet the proof standard or they can not legally be sold. Across most of the world an out of proof gun has little true value because it can’t be sold. This also applies to military firearms, they are also proof tested and marked as in compliance - check your old Mauser , Webley or Lee Enfield. USA and Canada are outliers, they do not have proof laws or government proof houses - except for military firearms in time of war. Here each manufacturer is responsible to do their own proof testing to a prescribed government standard which approximates but doesn’t exactly duplicate the European standard (CIP). Each manufacturer such as Winchester, Remington, etc has their own proof marks which they apply to their own guns. If these guns are sold in Europe they must also pass European proof and be marked accordingly.
Yes in Canada and USA, gunsmiths, hobbiests, tinkerers and plumbers commonly modify guns to suit their own whims with no concern about adequate measured safety testing of the result and no thought about the future beyond their control. Many of these gentlemen are very knowledgeable and very conscientious but also many are way over their heads, they all leave a legacy. A good gun can and will give excellent service for 100 years or more, any potential safety compromise is there forever. Do what you want, just remember that what you do leaves a legacy and you are responsible for it.
Firearms are proof tested to verify that they withstood a specific charge without material damage - once. In some cases twice. These ‘proof’ loads are a very specific overload and a gun that passes this test is stamped with proof marks to attest that it has passed this severe test. You may then purchase this gun and use it confidently with normal factory ammunition designed for the gun. A gun that has been altered in a manner which could compromise safety is as hazardous as using ammunition that is manufactured or reloaded beyond the pressure standard for that cartridge. If the gun is altered in a manner that could compromise safety it will always be an unknown issue until it is reproofed to establish it’s integrity.
All new guns are proof tested before sale to verify strength and safety. In most of the civilized world including all of Europe there are government operated proof establishments ( proof houses) that proof test guns to a predetermined international standard. Used guns are also sometimes reproofed and all guns must meet the proof standard or they can not legally be sold. Across most of the world an out of proof gun has little true value because it can’t be sold. This also applies to military firearms, they are also proof tested and marked as in compliance - check your old Mauser , Webley or Lee Enfield. USA and Canada are outliers, they do not have proof laws or government proof houses - except for military firearms in time of war. Here each manufacturer is responsible to do their own proof testing to a prescribed government standard which approximates but doesn’t exactly duplicate the European standard (CIP). Each manufacturer such as Winchester, Remington, etc has their own proof marks which they apply to their own guns. If these guns are sold in Europe they must also pass European proof and be marked accordingly.
Yes in Canada and USA, gunsmiths, hobbiests, tinkerers and plumbers commonly modify guns to suit their own whims with no concern about adequate measured safety testing of the result and no thought about the future beyond their control. Many of these gentlemen are very knowledgeable and very conscientious but also many are way over their heads, they all leave a legacy. A good gun can and will give excellent service for 100 years or more, any potential safety compromise is there forever. Do what you want, just remember that what you do leaves a legacy and you are responsible for it.
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madtrapper143
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Yep. And though I am not that interested in trying it personally, lots of guys shot cut shells over the years, with vary few consequences that anyone has heard of.
So, if cutting a shell and stuffing the shot load AND the external portion of said shell case down the bore works out without much to-do, there is like to be not much to worry about save a little extra recoil and maybe worse groups.
At one point, I recall reading an article in a gun book, there were shotguns being made with aluminum barrels, that were thin enough (IIRC.015 inch) that the guys that tried, were able to dent those barrels with thumb pressure. They were made solely as a promo, and factory reps took them to matches to demo them. They pulled a dent remover through the barrels and carried on when the barrel was dented.
Which is to say, shotgun pressures are pretty low to start with, and almost any modern steel chosen for a barrel, is liable to be WAY overkill for the purpose.
Moving the start of the choke an extra quarter of an inch down the barrel is not like to cause a great deal of difference in the overall view, I think.
That doesn't mean it can't be done.
madtrapper143
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OK, I will let Bear hunter get the last word ( in regards to how strong a Merkel is). Maybe we need a "Bubba" sub forum for the Gunsmithing forum. An undertaking like reaming a shotgun chamber needs to be approached cautiously not with "should be OK" and guessing. But it is the OP's shotgun and he can do whatever he wants with it.
Darryl
Darryl
madtrapper143
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Dennis was the purpose of your work on those guns to reduce recoil and improve patterns or did the owners say they wanted to shoot longer cartridges? I agree a properly altered forcing cone is no issue if the same ammunition the gun was proofed for is used.
Darryl
madtrapper143
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Always something else to consider. Congrats on your retirement, enjoy it.
Darryl
Darryl
