Boyd Allen
Active member
Hint: "Rifle Accuracy Facts"
Al's Perfect LR BR action???
- Thread starter alinwa
- Start date
Hint: "Rifle Accuracy Facts"
I'm not sure what you're intimating here Boyd..... I think everyone agrees that glued and screwed is most stable. I just ordered a BRM from Jim this week and he reiterated your words basically verbatim
As you know, and you and I BOTH know you know,
I know.....
as in "I agree"
But I've stopped ref'ing RAF here because a bunch of folks on this board think little of his work, making statements like "his testing was done at such gross levels that the stuff we're discussing is lost in the noise" and "what matches has he won ennyways" and even "his stuff is irrelevant because we have much higher resolution maths and measures now"
snap 'd is not hand tight.
maybe some basic education in threaded fasteners and torque would help.
maybe some basic education in threaded fasteners and torque would help.
Butch Lambert
Active member
try a local junior college.
maybe a 4yr with a good engineering program.
join the mil and select a mechanical specialty.
mine goes thru basic steam plant , automotive, launch vehicles(space) remote controlled submersibles, and nuclear power.
proper torque education/use in all three.
when you quit learning you are dead, just breathing other peoples oxygen.
maybe a 4yr with a good engineering program.
join the mil and select a mechanical specialty.
mine goes thru basic steam plant , automotive, launch vehicles(space) remote controlled submersibles, and nuclear power.
proper torque education/use in all three.
when you quit learning you are dead, just breathing other peoples oxygen.
FBecigneul
Member
And what have you ever positively contributed here?
jackie schmidt
New member
Fitted this new barrel to my Panda project today. The first witness mark is where it comes up tight by hand. The second mark is 100 lbs. lbs/ft. of torque.
Good shootin'. -Al
That is about what I come up with.
jackie schmidt
New member
By the way. Everybody gets hung up on the seemingly brutal recoil of the overly large chamberings and just assume that the barrel and action are seeing the same thing.
They don’t.
The only thing that the barreled action sees is the amount of pressure placed on the bolt face upon ignition. The pressure exerted against the base of the bullet is trying to shove the barrel one way, the pressure exerted by the case head against the bolt face and lug abutments is trying to push the action the opposite way.
If you shoot an old 6.5 REMINGTON Magnum at 62,000 psi, and a 338 Winchester Magnum at 62,000 psi, the actual load on the bolt face is identical. Your body will feel the difference, but what you feel, what the scope and it’s mounts feel, and what the stock feels is entirely different than what the actual pressure exerted against the bolt face and directly transferred to the barrel shoulder joint.
They don’t.
The only thing that the barreled action sees is the amount of pressure placed on the bolt face upon ignition. The pressure exerted against the base of the bullet is trying to shove the barrel one way, the pressure exerted by the case head against the bolt face and lug abutments is trying to push the action the opposite way.
If you shoot an old 6.5 REMINGTON Magnum at 62,000 psi, and a 338 Winchester Magnum at 62,000 psi, the actual load on the bolt face is identical. Your body will feel the difference, but what you feel, what the scope and it’s mounts feel, and what the stock feels is entirely different than what the actual pressure exerted against the bolt face and directly transferred to the barrel shoulder joint.
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Bill Gammon
New member
I guess that I had been doing things wrong all of these years. The working pressure in a PPC is like 70,000 lbs MIN. And I have been tigthing barrels at 50 lbs, 75 when I use a long internal receiver wrench, I guess I must be wrong!
FBecigneul
Member
You’re doing things right, Bill. Man, it hurt to say that.
mwezell
Mike Ezell
I think you can calculate the force trying to open the joint by calculating thrust, which is chamber pressure x Pi R squared. R being the radius of the case ID. Is that right, Jackie?
PSI is an abbreviation, it stands for pounds per square inch.
I don't know how to illustrate this clearly but simple fact is that the same pressure over more square inches does more work as in "exerts more force"...... like you step out into the wind with a box in your hand, you'll feel a push. You step out into the same wind carrying a sheet of plywood you might get blown over.
Same wind, same psi, larger surface area.
Increasing the surface area of a rifle chamber while exerting the same psi on it DOES NOT mean the stresses on the boltface, the bolt lugs and the chamber walls are somehow magically equal because "exact same pressure"..... a rudimentary working knowledge of hydraulics may be useful here.
The term for the force against the boltface is "bolt thrust" and it's not imaginary. It's the reason people who understand this stuff make larger bolt lugs, more stout abutments...... and it's the reason for larger tangs being required when moving to larger diameter chamberings.
In actual fact this is basic, fully quantified stuff straight from the engineering handbook.... rifle action designers and carttridge designers run the numbers every day.....the simple FACT is that Jim and Jim and Ralph and Jerry and Greg and Harold and Henry and many many others have long since stopped arguing here on this board with people who can't separate fact from opinion........and the REAL problem here is we've folks who've never tested this stuff spouting opinions simply because "alinwa is wrong"
fascinating character study, but opinions don't change facts.
some facts regarding the force exerted against the joint on some cartridges;
-6PPC=10,740lb
-.308 Win=12,000lb
-300WSM=17,000lb
-338LM=19,000lb
speaking of character studies....... and since this is my thread...... I think I've found I've a third "mode" in my life.
I gener'ly operate in two modes, "Work Mode" and "Home Mode"..... each of which offends a different set of people but generally "Work Mode" is the one which rubs folks "feelings" raw the quickest. So I try to wind down into "Home Mode" before getting on BRC.
But this morning I'm finding it even harder than usual to sort out folks' viewpoints. My mode this morning is "My Dad died Thursday, I just lost a good friend and mentor, my Mom just lost her BEST friend Mode" and altho I've been working down in the shop where my Mom and Dad have spent Dad's last few weeks.......experimenting and building guns and in-and-out checking on Dad until the wee hours of the morning all week......and it's been very therapeutic...... and I'm well-rested and feeling blessed that Dad finally Went Home.......
And while I'm not looking for condolences nor "understanding"......
I'm seeing an almost snarky side of me
who'da'thunkit!
ME!
SNARKY!!
Think it might be best I hare my lanky butt back down to the shop and grind up another action.....get off the social media.....
later
al
I gener'ly operate in two modes, "Work Mode" and "Home Mode"..... each of which offends a different set of people but generally "Work Mode" is the one which rubs folks "feelings" raw the quickest. So I try to wind down into "Home Mode" before getting on BRC.
But this morning I'm finding it even harder than usual to sort out folks' viewpoints. My mode this morning is "My Dad died Thursday, I just lost a good friend and mentor, my Mom just lost her BEST friend Mode" and altho I've been working down in the shop where my Mom and Dad have spent Dad's last few weeks.......experimenting and building guns and in-and-out checking on Dad until the wee hours of the morning all week......and it's been very therapeutic...... and I'm well-rested and feeling blessed that Dad finally Went Home.......
And while I'm not looking for condolences nor "understanding"......
I'm seeing an almost snarky side of me
who'da'thunkit!
ME!
SNARKY!!
Think it might be best I hare my lanky butt back down to the shop and grind up another action.....get off the social media.....
later
al
mwezell
Mike Ezell
Al, that's what I was referring to and posted how to calculate bolt thrust....pi r squared x pressure in psi. R being the radius of the cartridge case ID. So I agree with you that the bolt thrust at a given pressure does change a fair amount with different case diameters.
Now, find an online clamping force calculator or chart and I think you'll find that the clamping force can relatively easily surpass the thrust force. If that's the case, then you can calculate from those two figures how much torque applied to the barrel is needed to prevent the joint from unloading. I'm not looking to argue. I'm either right or I'm wrong but either way, I think it's calculable....err, verifiable. I'm not an engineer so I'll defer to you or someone that is. I may be leaving something out that is needed in calculating the necessary torque.
mwezell
Mike Ezell
speaking of character studies....... and since this is my thread...... I think I've found I've a third "mode" in my life.
I gener'ly operate in two modes, "Work Mode" and "Home Mode"..... each of which offends a different set of people but generally "Work Mode" is the one which rubs folks "feelings" raw the quickest. So I try to wind down into "Home Mode" before getting on BRC.
But this morning I'm finding it even harder than usual to sort out folks' viewpoints. My mode this morning is "My Dad died Thursday, I just lost a good friend and mentor, my Mom just lost her BEST friend Mode" and altho I've been working down in the shop where my Mom and Dad have spent Dad's last few weeks.......experimenting and building guns and in-and-out checking on Dad until the wee hours of the morning all week......and it's been very therapeutic...... and I'm well-rested and feeling blessed that Dad finally Went Home.......
And while I'm not looking for condolences nor "understanding"......
I'm seeing an almost snarky side of me
who'da'thunkit!
ME!
SNARKY!!
Think it might be best I hare my lanky butt back down to the shop and grind up another action.....get off the social media.....
later
al
I'm very sorry for your loss. I recently lost my dad too, who was also my best friend. Still working out a mess with the estate and this whole thing has been the hardest time in my life. So I can and I do sympathize with you and I offer you my deepest condolences. Prayers, my friend!
Jackie, I broke the barrel loose and went back on with it. Using a fine point surgical marker to make the reference points, I took it from as tight as I could make it with my hand and then torqued it to 100 lbs/ft., just like before.
The reference marks are right at .080 apart.
For kicks, I grabbed three Stan Ware chambered Panda barrels, one chambered by Ron Hoehn, one by Manley Oakley and one done by Dan Lilja....from back when they did chambering/fitting.
Each of them are virtually dead on for reference marks, as compared to this one.
Good shootin'. -Al
mwezell
Mike Ezell
It's not ALL about the action and barrel face compression. There's also the angular compression of the threads, to one another.
jackie schmidt
New member
Al, I said in my post comparing the 6.5 REM Mag to the 338 Weatherby,, I meant to say 338 Winchester as it and the 6.5 REM Mag share the same rim diameter.
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