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Barrel TQ and Headspace Crush Measurements

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jackieschmidt said:
As I stated in a previous post, a buttress thread does exert force in the linear plain and very little in the radial.
I believe you stated they were using a “modified buttress”. Since the major diameter is only increased to .1.080, they must be simply squaring the load bearing side of the thread as there would not be enough metal to generate a true buttress with the clearance side being at 45 degrees.
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I don’t know the exact dimensions of Mike’s exact threat. That was just an example I tossed out.
 
Lets recap: a gun shop in beverly hills builds $7000 remingtons. The barrel is put on with 500lbft with a secret thread. The owner shoots every one secretly in the zeroes and ones with federal factory ammo but the customers cannot duplicate this (but thats ok). They measure things to tolerances the finest machine shops in the world would be jealous of. Im sure they are very nice custom sniper rifles- i can sure appreciate the level of detail they have, but this is all pretty rich.
 
Dusty Stevens said:
Lets recap: a gun shop in beverly hills builds $7000 remingtons. The barrel is put on with 500lbft with a secret thread. The owner shoots every one secretly in the zeroes and ones with federal factory ammo but the customers cannot duplicate this (but thats ok). They measure things to tolerances the finest machine shops in the world would be jealous of. Im sure they are very nice custom sniper rifles- i can sure appreciate the level of detail they have, but this is all pretty rich.
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Where was it ever reported the customers can’t achieve the 1/4 minute guarantee?
I posted a link of happy customers routinely shooting sub 1/4 minute groups.
 
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butchlambert said:
Yes sir, now let's get to the meat of this.
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Butch i think the meat is that he's already bought into the marketing and decided to spend his money on it, and there's no amount of logic and reasoning from barrel manufacturers, and top tier gunsmith's/ shooter's thats gonna change his mind.

I'm completely lost at the statement about using factory ammunition.
I know for a fact that keeping a rifles load tuned is a constant dance, and there is no way this side of hell that 1 of these "SPECIAL" rifles are gonna shoot with our run of the mill rifles.
I'm still searching for .0's in mine. Lol
 
Tokay444 said:
Where was it ever reported the customers can’t achieve the 1/4 minute guarantee?
I posted a link of happy customers routinely shooting sub 1/4 minute groups.
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Every review and testimonial ive ran across. Some guys do shoot 1/4” groups on occasion but theres always a reason they cant duplicate that cardboard sub .100” group that comes with it. Maybe theyre just not close enough to the target
 
Dont get me wrong, i got full respect for anybody that can build a rifle like that and get that much for it. If i ever run across one that will actually shoot like advertised (which is 1/4” or better) ill be the next on the list to get one
 
I'm no engineer, by a LONG shot, but I know for an absolute fact that a high strength structural bridge bolt (A325, 3/4-10) will pull apart like it is made of snot at 500 lbs of torque. A490's will definitely stretch at that torque. Me thinks the builders of said rifles run them up that tight to hold the Kool-Aid in.
 
Mausers use buttress threads on the bolt shroud.

Maybe old Peter Paul was on to something other than not wanting the firing pin assembly winding up embedded in a solders head.
 
If there is a Buttress thread involved the need for more torque makes sense. Theres two ways we need to align a barrel, radial and axial. The axial part comes from the shoulder and face of the action. The radial part comes from a v threads natural tendency to center itself. A square thread has no tendency to center itself so radial movement has to be controlled by friction in the thread joint. From a rifle accuracy stand point I prefer a v thread to any others I have worked with on various actions for this reason. Every Br rifle out there is using a v thread, they dont even need to be pretty to work well. I had a picture of some pretty nasty ones that broke a group agg record and won a National match, some of the nastiest you have ever seen. With normal torque that rifle did in fact shoot quite a decent amount of 1s... at 1000 yards. And the best group agg ever shot at a 1k nats. No I didnt chamber it but I wish I did :)
 
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I have a couple of rifles that will shoot in the 0's and 1's with federal match ammo. (One shot groups!!)


I have a couple of rifles that can't shoot 1's with federal match ammo. ( One shot groups!!!)
 
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After having watched Matt Owens measure and develop clearances of 100 millionths and personally torquing main bearing Cap bolts on an 844 Cummings crankshaft with a 6ft torque wrench and praying for the click, something is coming back to me about some guy convincing a bunch of people to do something really stupid,,,, thinking it was somewhere around the Panama Canal maybe... OH, and it had something to do with Kool-Aid..... John
 
jackieschmidt said:
Frank, as you might know, I have been in the machine shop business for 50 years and have machined parts that did require tolerances in the .0005 range. What most “lay persons” do not understand is when dealing in sizes below that level of accuracy, you have to be in a controlled environment where temperatures are regulated to the term “room temperature”, or in specific cases to an engineered specification.

if You read the link furnished in post #105, you probably noticed that remark about recoil lug squareness in conjunction with the receiver threads and receiver face. The author stated that .0001 out of true square would equate to a much larger .100 number if triangulated out to 100 yards.

It was implied that this would cause the rifle to automatically be locked into a .100 capability, or “spread” as he called it. That statement is simply asinine. Just because a barrel is pointed out of square with the receiver does not equate to the rifle’s ability to agg. Granted, you do want things as square as possible, (I say “as possible” because the author was once again tossing out that .0001 tolerance), but having everything machined perfect still does not guarantee sub .200 performance unless the bullet/barrel/powder/tune combination is equal to the task.

Any competitive Benchrest Shooter can attest to that.

You are probably like me in that you do take many of these discussions with a grain of salt. It is only when they cross over into the unrealistic realm, usually in an attempt to sell a product to a gullible clientele, will I get involved.
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I watch a few people on YouTube with the capability to measure in millionths.
reall amazing to just what the warmth of you hand can do at that level.
Keith Glasscock said:
Let's just for a moment consider the remaining metal in a barrel joint. The remaining cross sectional area is significantly reduced from what a solid bolt would be.

In my pea brain, that means that less total force would be required to achieve yield of the barrel steel.

The tensile strength of 416R isn't too hard to find on the interwebs. You'll need that and the Young's modulus to determine how much the barrel stretches from thread to shoulder when you torque it.

Just a 10,000 foot view for the conversation...
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Along with a much smaller shoulder.
 
jackieschmidt said:
Frank, as you might know, I have been in the machine shop business for 50 years and have machined parts that did require tolerances in the .0005 range. What most “lay persons” do not understand is when dealing in sizes below that level of accuracy, you have to be in a controlled environment where temperatures are regulated to the term “room temperature”, or in specific cases to an engineered specification.

if You read the link furnished in post #105, you probably noticed that remark about recoil lug squareness in conjunction with the receiver threads and receiver face. The author stated that .0001 out of true square would equate to a much larger .100 number if triangulated out to 100 yards.

It was implied that this would cause the rifle to automatically be locked into a .100 capability, or “spread” as he called it. That statement is simply asinine. Just because a barrel is pointed out of square with the receiver does not equate to the rifle’s ability to agg. Granted, you do want things as square as possible, (I say “as possible” because the author was once again tossing out that .0001 tolerance), but having everything machined perfect still does not guarantee sub .200 performance unless the bullet/barrel/powder/tune combination is equal to the task.

Any competitive Benchrest Shooter can attest to that.

You are probably like me in that you do take many of these discussions with a grain of salt. It is only when they cross over into the unrealistic realm, usually in an attempt to sell a product to a gullible clientele, will I get involved.
Click to expand...
Watched a few videos of people capable of measuring into the millionths
It’s amazing what the heat from the hand can do.
 
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