Outlaw6.0
Well-Known Member
Yes, that is what I meant but it sounds like you have a better plan running
Don't forget to keep us updated on your build progress.
t
6mm ai too long for savage short action?
- Thread starter tbrice23
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Yes, that is what I meant but it sounds like you have a better plan running
Don't forget to keep us updated on your build progress.
t
Engineering101
Well-Known Member
Edd,
Why do you think not chambering a Savage small shank barrel for a WSM is smart? The diameter of the Savage small shank barrel is 1.060" which is the same as a Rem 700. The large shank Savage measures 1.117". The large shank thus increases the metal wall thickness of the chamber by 0.0285" or 11.29% (assuming the chamber is cut to WSM dimensions). I have no expertise regards metallurgy. Is there anyone out there that can comment on this subject?
Why do you think not chambering a Savage small shank barrel for a WSM is smart? The diameter of the Savage small shank barrel is 1.060" which is the same as a Rem 700. The large shank Savage measures 1.117". The large shank thus increases the metal wall thickness of the chamber by 0.0285" or 11.29% (assuming the chamber is cut to WSM dimensions). I have no expertise regards metallurgy. Is there anyone out there that can comment on this subject?
First off, let me say that i am not going to argue with any gunsmith before he has started work for me, either he will or he won't.
But the answers I've gotten were along the lines of "Savage won't do neither will I"
The answers were insufficient but don't argue.
But the answers I've gotten were along the lines of "Savage won't do neither will I"
The answers were insufficient but don't argue.
Engineering101
Well-Known Member
tbrice23
I understand that Savage made a change from small shank to large shank for the WSMs and such. I also know that they and the 300 RUM work fine for me in a small shank. I was just trying to get the "adequate answer" you mentioned that you didn't get.
I am certainly not advocating that anyone do what I have done. I like to tinker so I gave it a try suspecting that I would not blow myself up since there are Savage WSM rifles out there with the small shank. Also, rifles are proof tested 30% above rated pressure (that would be 84,500 psi for a WSM). I'm guessing that Savage wanted more margin but who knows?
I understand that Savage made a change from small shank to large shank for the WSMs and such. I also know that they and the 300 RUM work fine for me in a small shank. I was just trying to get the "adequate answer" you mentioned that you didn't get.
I am certainly not advocating that anyone do what I have done. I like to tinker so I gave it a try suspecting that I would not blow myself up since there are Savage WSM rifles out there with the small shank. Also, rifles are proof tested 30% above rated pressure (that would be 84,500 psi for a WSM). I'm guessing that Savage wanted more margin but who knows?
If you look at the thread minor diameter there will be about a 14% increase. If you wanted to continue the process, there is only about a 6% increase to take another step up from a WSM cartridge to a Lapua sized cartridge. Some people, and some rifle mfgs, will use a 1.062" thread for that large case too. You have to draw the line somewhere. I choose to draw the line for 1-1/16" threads at the standard belted case size.
Trickymissfit
Well-Known Member
small shank, large shank is the question. But not really in the long run. The first figures of this equation is simply the distance from the root of the thread to the I.D. of the chamber. Then somewhere along the way, it's just how dangerously one wants to live. The next piece of data is the O.D. of the bridge of the action. We usually think it's just out there doing nothing. Or is it? Then we have to deal with the threads per inch (more important than one might often think. Then we have to sort out where the weakest point of the action is. Not usually the bridge I might add here.
What happens when you pull the trigger on a 63,000 psi bolt thrust that is also pretty large in square inches. Ah! But you it's only .55" in diameter verses the .47" of the Mauser case. Not much, or is it? Out of the top of my head, that's close to 33% more bolt thrust area in square inches. With no other factors plugged in, and simply working off chamber pressures alone; your going to see a 33% increase in recoil alone. Lots more to it as we'll learn later. But what is the chamber pressure in the first place? Mostly resistance. The barrel is nothing more than a pneumatic chamber just like the chamber we put the case in before firing. You fire the round, and what happens (most folks have zero ideas). Assuming we have about .015" bullet jump, and have good ignition. We have several pressure spikes. The actually pressure of the gas build up in the chamber is first. The bolt thrust backwards actually relives the pressure for a micro second at the most, but it does. The bullet moves into the throat and strikes the lands, and we then se a serious pressure spike. The greater the diameter of the bullet, the greater the surface area striking the lands. Bingo! More pressure. The bullet now is trying to turn with the twist +of the lands inside the barrel, and we see another spike. This stuff is the easy part.
The chamber pressure spikes do a lot more than simple bolt thrust, and this is the hard part to prove out, unless you have a mechanical CAD program with the ability to insert factors into it. Bet most us didn't know that the barrel acts like a coiled spring when the bullet passes thru it. Taking into fact the physics axiom that an action always creates a like reaction. The bullet actually causes some barrel stretch just ahead of it as it passes. Behind the bullet the barrel is twisting in the opposite direction (to the left). Creates two small problems that few ever knew. The shoulder (Remington or Savage) of the barrel or nut leaves the receiver seat, and tries to turn left. Thus making an effort to also unscrew the barrel. The receiver behind the bolt seat also tries to twist in the opposite direction of the rifling. Under high chamber pressure the barrel threads expand and then contract (this is extremely important). They then push the threads inside the bridge outwards the same amount. Nature of the beast. Ever take a piece of metal and keep twisting it? What happens? Of course it breaks due to metal fatigue. Yes we know we are not pushing the metal past it's yield point, but we are inducing fatigue.
Now we get into metal itself. Two basic metals are used in fire arms. Chrome Moly steel and stainless steels. On paper the average stainless steel looks better, and in some cases it can be. Virtually all C/M steels are superior in the end. They tend to endure fatigue better, and almost always have a better granular structure. Most stainless steel barrels are made of 416 SS steel, because it machines much easier than things like 410 and 420. 440 would probably be too brittle in the end. These steels were designed to be used in a compressive state, but of course a lot of folks have taken them into other uses. Some good and some very bad. C/M will work in either way just fine. Most all 4xx SS steels are known to be "martensitic", and this is the last thing you want in a piece of heat treated steel. There are forms of stainless alloys that don't have these issues, but are harder to work with and cost wise are far greater. So where does retained martensite come into play here? Simply said; it's cracks due to a poor granular structure. Now figure this in with the expansion and contraction of the bridge and barrel threads, and you may or may not have a beast in your hands. Extreme cold weather tends to magnify these issues. There is no perfect way out of this unless you opt for one of the exotic series. You factor in the square inches of area between the chamber and the thread root, and you just don't have a lot of metal to work with. And I might add that I have not factored in the heat. Honestly a C/M barreled action wouldn't be a lot better other than the martensite issue. This is why the large shank is better to a certain extent. Too bad they didn't make the bridge .156" larger in diameter.
gary
What happens when you pull the trigger on a 63,000 psi bolt thrust that is also pretty large in square inches. Ah! But you it's only .55" in diameter verses the .47" of the Mauser case. Not much, or is it? Out of the top of my head, that's close to 33% more bolt thrust area in square inches. With no other factors plugged in, and simply working off chamber pressures alone; your going to see a 33% increase in recoil alone. Lots more to it as we'll learn later. But what is the chamber pressure in the first place? Mostly resistance. The barrel is nothing more than a pneumatic chamber just like the chamber we put the case in before firing. You fire the round, and what happens (most folks have zero ideas). Assuming we have about .015" bullet jump, and have good ignition. We have several pressure spikes. The actually pressure of the gas build up in the chamber is first. The bolt thrust backwards actually relives the pressure for a micro second at the most, but it does. The bullet moves into the throat and strikes the lands, and we then se a serious pressure spike. The greater the diameter of the bullet, the greater the surface area striking the lands. Bingo! More pressure. The bullet now is trying to turn with the twist +of the lands inside the barrel, and we see another spike. This stuff is the easy part.
The chamber pressure spikes do a lot more than simple bolt thrust, and this is the hard part to prove out, unless you have a mechanical CAD program with the ability to insert factors into it. Bet most us didn't know that the barrel acts like a coiled spring when the bullet passes thru it. Taking into fact the physics axiom that an action always creates a like reaction. The bullet actually causes some barrel stretch just ahead of it as it passes. Behind the bullet the barrel is twisting in the opposite direction (to the left). Creates two small problems that few ever knew. The shoulder (Remington or Savage) of the barrel or nut leaves the receiver seat, and tries to turn left. Thus making an effort to also unscrew the barrel. The receiver behind the bolt seat also tries to twist in the opposite direction of the rifling. Under high chamber pressure the barrel threads expand and then contract (this is extremely important). They then push the threads inside the bridge outwards the same amount. Nature of the beast. Ever take a piece of metal and keep twisting it? What happens? Of course it breaks due to metal fatigue. Yes we know we are not pushing the metal past it's yield point, but we are inducing fatigue.
Now we get into metal itself. Two basic metals are used in fire arms. Chrome Moly steel and stainless steels. On paper the average stainless steel looks better, and in some cases it can be. Virtually all C/M steels are superior in the end. They tend to endure fatigue better, and almost always have a better granular structure. Most stainless steel barrels are made of 416 SS steel, because it machines much easier than things like 410 and 420. 440 would probably be too brittle in the end. These steels were designed to be used in a compressive state, but of course a lot of folks have taken them into other uses. Some good and some very bad. C/M will work in either way just fine. Most all 4xx SS steels are known to be "martensitic", and this is the last thing you want in a piece of heat treated steel. There are forms of stainless alloys that don't have these issues, but are harder to work with and cost wise are far greater. So where does retained martensite come into play here? Simply said; it's cracks due to a poor granular structure. Now figure this in with the expansion and contraction of the bridge and barrel threads, and you may or may not have a beast in your hands. Extreme cold weather tends to magnify these issues. There is no perfect way out of this unless you opt for one of the exotic series. You factor in the square inches of area between the chamber and the thread root, and you just don't have a lot of metal to work with. And I might add that I have not factored in the heat. Honestly a C/M barreled action wouldn't be a lot better other than the martensite issue. This is why the large shank is better to a certain extent. Too bad they didn't make the bridge .156" larger in diameter.
gary
Engineering101
Well-Known Member
Gary,
Now my head hurts. But I think I learned something. Thanks.
Now my head hurts. But I think I learned something. Thanks.
We know a lot of our barrels are stress relieved, are our actions stress relieved?
Makes me wonder. If so much accumulative movement over time in our barrels also re-work hardens them also changing harmonics through out its useful life.
Makes me wonder. If so much accumulative movement over time in our barrels also re-work hardens them also changing harmonics through out its useful life.
This discussion motivated me to check one of my old gear boxes today. I haven't looked in this box in probably 25 years. There is at least 200 rounds of 6mm Remington ammo in it. Most of it is reloads and I can't find my notes to tell what what they are. They are at least 30 years old and, in my opinion, they should have the bullets pulled, the powder dumped, the primers snapped, and then ran thru the reloading process. If they have any value to you, PM an offer to me.
Barrel just arrived.Yes, that is what I meant but it sounds like you have a better plan running
Don't forget to keep us updated on your build progress.
t
Savage Model 10BA action ,trigger tuned by me to 10oz.
McGowan 26" SS 8 twist varmint.
Northland Shooters supply trued oversize pinned recoil lug and trued barrel nut.
H-S presision stock Devcon bedded and Snakeskinned by me.
8-32 pine ridge scope is being replaced soon.
May be FFing brass tomorrow.
With bullets seated to the lands;
With 95 gr NBT I have .080" room in the magazine.
95 gr VLD has .005" room
105gr Amax has.047" room
105 HPBT has .050" room
105 VLD target just fits , I still need to find some 105 VLD hunting to measure.
105 gr Hybrid targets forget about using the magazine!
Every other caliber I have been able to find a decent jump that works. My 7mag Sendero likes .078" jump. So overall , I'd say I'm in the clear.
Thanks to y'all for the info.
Accuracy/ velocity updates later.
