jackieschmidt
Gold $$ Contributor
I make bullets. Pretty decent ones.
I just wish I could make as good of a bullet as that Federal National Match.
I just wish I could make as good of a bullet as that Federal National Match.
Barrel TQ and Headspace Crush Measurements
- Thread starter dnellans
- Start date
- Status
Dusty Stevens
Shiner
Edd
Gold $$ Contributor
Buy one of them and shoot it. If it doesn't live up to it's guarantee, return it for a refund.
butchlambert
Site $$ Sponsor
Lucky Shooter
Gold $$ Contributor
We've been through some wild stuff lately-----ranging from
trashing a Jewell trigger to machine work tolerances that
leave some fine machine guys shaking their heads.
Does anybody think maybe a leg-puller might be funning
us ?
A. Weldy
trashing a Jewell trigger to machine work tolerances that
leave some fine machine guys shaking their heads.
Does anybody think maybe a leg-puller might be funning
us ?
A. Weldy
Dusty Stevens
Shiner
Mark told me a couple of times to check this thread out. So I finally did.
After a few chuckles to myself along with Mark.....here are my random thoughts and most of my thoughts will mimic some others here who have already posted so I apologize for any duplication.
500ft lb's torque on the barrel/action assy? Not with out damaging something! Even if you do....how are you getting it a part?
Not poking at Krieger (we use to work there) but I'm pretty sure they don't have equipment to measure to the millionths that has been mentioned. Unless they have some new miracle machine that we don't know about...I call BS! This has been brought up before in some other forums as well.
We have both mechanical and air gauging equipment for checking the inside of the bore of the barrel. Our air gauge unit does show numbers and theoretically measure to the 5th decimal place...so .xxxxx". I will tell you this....you can easily move that wand/probe off center of the bore and you can even watch the 4th decimal place change by .0001" to 0002".
The difference in reading from the mechanical to the air gauge is .0001" if you do it correctly. So we use the mechanical gauges more than anything else as they are more versatile. Also not a huge fan of the air gauge probes is that they can scratch the bore of the barrel. We only use the air gauge probes when it's only required by a contract. Again doesn't guarantee you a better shooting gun/barrel.
To measure in the millionths as has been mentioned....you would need a clean room/controlled environment. Krieger doesn't have one. Neither do we.
Bullets/box ammo and ..000's and .1xx's for groups. Possible? Yes. Consistently....I say no. You show which bullet ammo maker will even guarantee anything close to that. None will. I know of bullet makers that will guarantee 1/3moa and the bullets will shoot 1/4moa at times but will not guarantee that. So if the bullet/ammo is a variable....your going to go thru a shit ton of lots of ammo to find a lot that will shoot if possible just in the .2xx's let alone .1xx's
For box ammo I've shot a lot of Federal (any Federal employee reading this I'm not knocking you guys) but I've seen lots that would only shoot .8xx's to 1moa and other lots that would shoot in the 1/3moa range in the same gun. So the ammo is going to be a variable.
GA Precision did a order for 200 guns for the FBI/HRT a while back. George test fired every gun before it left his shop. We made all the barrels. He started the builds just prior to a shot show one year and at shot show he had a board made up of targets and the test groups with the first 40 rifles built. The 40 rifles averaged a .190". Some shot a smidge better some shot in the .3xx's with box ammo.
To routinely guarantee a .0's or a .1" gun with box ammo and on the first target at any given time...I'd like to witness that.
Later, Frank
Bartlein Barrels
After a few chuckles to myself along with Mark.....here are my random thoughts and most of my thoughts will mimic some others here who have already posted so I apologize for any duplication.
500ft lb's torque on the barrel/action assy? Not with out damaging something! Even if you do....how are you getting it a part?
Not poking at Krieger (we use to work there) but I'm pretty sure they don't have equipment to measure to the millionths that has been mentioned. Unless they have some new miracle machine that we don't know about...I call BS! This has been brought up before in some other forums as well.
We have both mechanical and air gauging equipment for checking the inside of the bore of the barrel. Our air gauge unit does show numbers and theoretically measure to the 5th decimal place...so .xxxxx". I will tell you this....you can easily move that wand/probe off center of the bore and you can even watch the 4th decimal place change by .0001" to 0002".
The difference in reading from the mechanical to the air gauge is .0001" if you do it correctly. So we use the mechanical gauges more than anything else as they are more versatile. Also not a huge fan of the air gauge probes is that they can scratch the bore of the barrel. We only use the air gauge probes when it's only required by a contract. Again doesn't guarantee you a better shooting gun/barrel.
To measure in the millionths as has been mentioned....you would need a clean room/controlled environment. Krieger doesn't have one. Neither do we.
Bullets/box ammo and ..000's and .1xx's for groups. Possible? Yes. Consistently....I say no. You show which bullet ammo maker will even guarantee anything close to that. None will. I know of bullet makers that will guarantee 1/3moa and the bullets will shoot 1/4moa at times but will not guarantee that. So if the bullet/ammo is a variable....your going to go thru a shit ton of lots of ammo to find a lot that will shoot if possible just in the .2xx's let alone .1xx's
For box ammo I've shot a lot of Federal (any Federal employee reading this I'm not knocking you guys) but I've seen lots that would only shoot .8xx's to 1moa and other lots that would shoot in the 1/3moa range in the same gun. So the ammo is going to be a variable.
GA Precision did a order for 200 guns for the FBI/HRT a while back. George test fired every gun before it left his shop. We made all the barrels. He started the builds just prior to a shot show one year and at shot show he had a board made up of targets and the test groups with the first 40 rifles built. The 40 rifles averaged a .190". Some shot a smidge better some shot in the .3xx's with box ammo.
To routinely guarantee a .0's or a .1" gun with box ammo and on the first target at any given time...I'd like to witness that.
Later, Frank
Bartlein Barrels
Please see above info on buttress thread connections and let us know how much torque a 1.080” Buttress can take without damaging something. You get it apart the reverse of putting it together. That’s the joy of threads.
jelenko
Gold $$ Contributor
Wait, Are you saying that Tac Ops uses buttress threads?
jelenko
Gold $$ Contributor
Could someone explain this statement from the linked thread:
Simple math will make it clear to any mechanical engineer, that
.0001 misalignment in the rifle equals .100 spread at 100 yards
I.e., what is being misaligned and how does that result in a 'spread' on the target?
Simple math will make it clear to any mechanical engineer, that
.0001 misalignment in the rifle equals .100 spread at 100 yards
I.e., what is being misaligned and how does that result in a 'spread' on the target?
Have you been reading the thread?
butchlambert
Site $$ Sponsor
Must be a Democrat, moving the thread to buttress threads and away from claimed accuracy. If you have been around the turnip patch once or twice you would know it ain't happening. You're beating a dead skunk.
The threads are what provide the ability to generate the torque, which is part of the package and the 1/4 minute accuracy guarantee. I’m not moving the thread. The thread started with 500lb/ft…
Keith Glasscock
Gold $$ Contributor
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...
jackieschmidt
Gold $$ Contributor
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.
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.
butchlambert
Site $$ Sponsor
Feller, the OP mentioned 100ft lbs and not 500ft lbs as you say the thread started with. Lets get away from the fluff. This BS ain't happening regardless of the thread or torque. As stated, Kreiger is not capable of the measurements mentioned.
jackieschmidt
Gold $$ Contributor
As I stated in a previous post, a buttress thread does exert force in the linear plain and very little in the radial.
I believe you stated they were using a “modified buttress”. Since the major diameter is only increased to .1.080, they must be simply squaring the load bearing side of the thread as there would not be enough metal to generate a true buttress with the clearance, or non load bearing side being at 45 degrees.
Last edited:
butchlambert
Site $$ Sponsor
Yes sir, now let's get to the meat of this.
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