Interesting Video on Fitting a Mauser Barrel

[Uncle Grinch]

I'm not a machinest, but when I came across this video, I thought it may be interesting to some of you who are like me. This is a somewhat detailed installation of the steps to fit a barrel to a M48 Mauser.

http://www.youtube.com/watch?v=1Ufes_zrZmg

[kbstenberg]

Very interesting!

[MBTcustom]

Looks like every other barreling video I've seen, with the same misinformation. No offence to the OP, but not everything is as it seems. The guy lost me when he started talking about how barrels are not drilled straight. He only says that because thats the way they look when he's done twisting the blessings out of it with his 4 jaw chuck and spider.
It's much better to use a method that allows the barrel to be held firmly, and accurately, that induces no twisting stress on it.
Honestly, if they don't know how to set up a darn barrel in the lathe, they shouldn't blame the barrel makers for a personal lack of fixturing knowhow.
Sorry, pet peeve.

[aspangler]

Looks like every other barreling video I've seen, with the same misinformation. No offence to the OP, but not everything is as it seems. The guy lost me when he started talking about how barrels are not drilled straight. He only says that because thats the way they look when he's done twisting the blessings out of it with his 4 jaw chuck and spider.
It's much better to use a method that allows the barrel to be held firmly, and accurately, that induces no twisting stress on it.
Honestly, if they don't know how to set up a darn barrel in the lathe, they shouldn't blame the barrel makers for a personal lack of fixturing knowhow.
Sorry, pet peeve.

+1 to goodsteel. As an apprentice to a local gunsmith that builds custom rinfire bench rest rifles, a four jawed chuk is NOT the way to go. Not going to reveal any secrets but a Good three jawed chuck with w spider at the back of the headstock is a MUCH better way. Just my 2 cents.

[B R Shooter]

Where the mistake is with the 4 jaw, is clamping directly on the barrel and not using a collar so the barrel muzzle can be adjusted without the bending. And where does the "twisting" come from?

Tell me the difference in using a 4 jaw, and using a set-true? As long as you use some common sense and tighten the jaws to a similar torque, they are adjusted the same.

Surely you aren't relying on a 3 jaw that doesn't adjust?

[MtGun44]

So, please (briefly) describe the proper way to put a barrel in a lathe.

Bill

[MBTcustom]

I chamber in a steady rest, but the tips of the steadyrest are used to hold a precision bearing assembly that I built myself. It utilizes Barden ceramic hybrid bearings and has a TIR of 78 millionths of an inch.
This bearing has been indicated truly concentric and parallel to the axis of my lathe.
There is a 1.4 diameter hole going through the center of the bearing and it has a small spider on it.

I set up my lathe with an adjustable 3 jaw chuck, which allows me to put exactly the presure I want on the workpiece, and then adjust it in as you would a 4 jaw.
Inside the chuck, rides a fixture that I designed that is basically a spider that is able to be adjusted for pitch and yaw.

The way chamber a barrel, is to put one end in the adjustable spider.
I use the spider bolts to get it within .010 of center.
I then slip my range rod into the opposite (tailstock) end of the barrel, and I adjust it until it is running within .001 just hanging out there. At the same time, I use the adjustable 3 jaw to keep the headstock end of the barrel running true.
Once everything is lined up and the barrel is perfectly aligned with the axis of rotation (much the way it is held by the firearm), I slide the steadyrest with the super bearing in over the barrel.
The barrel will be sagging by about .005-.010 but the spider in the steadyrest will pick it up when it is indicated in.
I then use the range rod to indicate the neck area of the barrel till the needle is as asleep as it can get (usually never stops quivering just .0001 or so)
Then I thread the barrel, verify that the alignment has not changed, drill, bore, and ream (with the truly floating reamer holder that I designed).
I have discovered that aftermarket barrels are drilled much straighter than common knowledge would lead us to believe. Do any of you really think that a Kreiger barrel is drilled 1/16" warped?!?! Do any of these people know how to read light rings?!? I've got news for you, the worst aftermarket barrel I have chambered was running out less than .004 end to end, and was capable of drilling 3/4" groups.

If you want to know why the barrels have to be adjusted so far on the back of the lathe in order to get just 3 straight inches at the front, just turn the spider bolts loose in the chuck, just take the pressure off all the spider bolts at one end of the barrel and give it a spin. You will notice that the free end is not running true. Common knowledge is to fix this by torquing the living blazes out of it until you force the end you care about to be twisted into a straight looking condition.
Hulk not like wobbly barrel! Hulk smash!
My favorite is when they get done twisting the barrel into a pretzel, and then get done explaining how badly it was drilled, they explain the advantages of threading the shank so that the barrel points up in its twisted condition, and they clock the action accordingly.

Sorry, but I have built some of the most precise mechanisms in the the world, and I just don't have any superstitions about it. I know how to indicate things so I can actually see what I am looking at, and I know how to interpret the readings I am getting and understand what is really going on.
All you have to do is observe the evidence, and don't dismiss it.
For instance, next time you get a barrel blank in the shop, look down it, and see if it is straight. Mount it between centers and indicate it. put marks on it in the high spots, and record the readings. Mount it in the lathe, and go through the normal steps. Why not put an indicator on it and see if your fixturing has done anything to it Hmmm? If you are chambering through the headstock, you can't indicate it, but you can look down it and see of it's still straight right? If it's not, why not solve that problem before ramming a reamer in there?

Shoot, I don't know everything. Each barrel is a learning experience for me, but at least I learn! We're all just experts in training.
Check what I am saying on your own equipment, and I'm confident you will see what I am saying is true. Most of us are taught by others and are trained to make the same assumptions, and to have the same blind spots, and this business is loaded with misconceptions.

[MBTcustom]

I'm probably going to regret this, but here is a picture of my system in action.
82105
The only way you get that barrel running truer is in a zero gravity environment.

[UBER7MM]

Beautiful set up, Mr. Malcolm!

No regrets!

[btroj]

Good looking setup Tim. What was that one chambered for?

[MBTcustom]

It was chambered in 500 Jeffery. The client I was building it for decided it was too expensive to shoot, so I sold the barrel to hotguns and for all I know it's now a 50 Hushpuppy or something.
Anyway, it's as good a picture as any of what I think is the right way to do it. (at least for me it is)

[MtGun44]

Tim,

Thanks for taking the time to explain that. I get the gist of it, but unless I was sitting at the
machine actually setting up a barrel, I won't 100% follow it. It does sound like a good way to
make sure all is straight and true.

Bill

[MBTcustom]

Yeah, sorry.
The main thing is that the fact that the spiders impart twist on the barrel, is not ignored. I tried to get away with it with shims, wires, holy water, etc etc etc, and I could get it darn close, but not perfect. I always indicate the middle of the barrel, and I mark where the high spot is, and how var out it is. After I'm done setting the barrel up, that high spot had better not have moved or gotten any worse or better, or I'm going to redo the setup.
If that's what you are truly after, then let me tell you, its enough to make you get so mad that you finally just sit down and beg God for help. I couldn't let it go, and I couldn't get it right, with any traditional setup, and nobody had a better solution that didn't gloss over what I was seeing in my indicators. It was about the most frustrating thing that I have dealt with.
The good news is, I found a way to satisfy my OCDishness to the fullest LOL! You can see much better pictures of the setup in lovelife's thread in special projects:
http://castboolits.gunloads.com/showthread.php?207534-Malcolm-Ballistic-Tool-(MBT)-long-range-rifle

[B R Shooter]

I am curious what the bearing arrangement is in the steady.

[MBTcustom]

The bearing is the key to the thing. My lathe has a TIR on a turned piece of stock of .0002 inches. I wanted better.
The bearing you see there was built by me using Barden Ceramic hybrid bearings. I built it at my day job, and I rejected it because it had a TIR of 78 millionths of an inch, and I expected less than 50 millionths TIR. That's unacceptable for the purpose I was building it for, but I'm confident that it's much more accurate than anything else being used to build rifles with. Because the bearing is far away from the spindle, even though the spindle has .0002 TIR, it has little effect on the other end that I am working on, and I am confident that I am getting less than .0001 TIR on my chambers, and that is reflected by my measurements on the reamer and the chamber as it is being cut.

See I was taught to build bearings and work with steel in millionths of an inch by the best minds in the country. One feller helped write the national standards for US bearings, and the other designed the bearings in the hubbel space telescope. I bugged the living heck out of these two men, and spent hours learning from them, and finding ways to apply their knowledge on a practical level.
I have built bearings that have less than 10 millionths TIR on a 13" diameter......and that was not an air bearing. That was a ball bearing.

So you might ask, what does a rifle have to do with ball bearings? Well, you have a boolit that is spinning as it is driven in a linear motion. Concentricity is absolutely key!!!!
Most smiths get it good-nuff for use with jacketed bullets, but how do you think their rifles will do with cast lead???
The cast lead boolit is so fragile that any misalignment will show up at 100 yards.
I like to think of it like this project I worked on where I had a little 2" cup made of soft aluminum, that needed to be spun at 35,000 RPM. I told the engineer that we were going to have to get that cup running true within a few tenthousandths of an inch, if we expected it to not ring like a bell. Turns out I was 100% right, because they tried to cut corners about 3 times before they did whatever it took to make sure that cup was running perfectly true. Once we got it lined up within .0001 it stopped ringing!
How fast is you're boolit spinning?
How accurate do you think it needs to be?
At these speeds, .0002 will make a noticeable difference, because boolits don't ring like the cup, they just shoot 1" groups at 100 yards instead of bug holes.

Here's an interesting concept to munch on for a second. The cup in my illustration up yonder had a very clear "RPM threshold" below which, it would not ring, but as the speed approached it's limit, it rang louder and louder. Only by getting it to run perfectly true were we able to increase the RPMs. The more perfect the cup was aligned, the faster we could spin it.
Interesting huh?

[Willbird]

Well a normal steady, which is a plain bearing has a runout of .00000000000000000

:-).

I use a 4 jaw, but I make a ring out of copper wire, the ground wire from #12 house (or garage hehe) wiring, and lay it in the serrations in the jaws, and at the other end I use a spider that has gas checks on the ends of the set screws.

But as to barrels being drilled straight, nope they are not, never has been a perfect one in the history of the gun. Tony Boyer has said his most accurate barrel ever was "as crooked as a dogs hind leg". Some makers straighten them which IMHO is not a good thing, better to leave it alone as it was made.

I bought a 34" blank once for a project where I fitted 1/2 and got to keep the other half, the ID and OD ran out probably .03 in the middle of the blank, and it was from a decent barrel maker (all I will say was it was not Shilen, Hart, or Lilja). The OD and ID ran concentric at the muzzle and breech end of the entire blank.




Bill

[MBTcustom]

Bill, that's all dealing with the outside of the barrel. If you had .03 scew on the inside, then I'd say you got a janky barrel.
Also, you're not getting .0000000000 runout. You're getting whatever runout was ground into the outside of the barrel by the manufacturers belt sander, or spinner. Probably about .001
It's true that a normal steady rest is quite accurate, but again, that's the outside if the barrel, and even a Kreiger is only concentric to the inside within about .0015.
I'm talking about the inside of the barrel being perfectly straight and concentric (relatively speaking).
If I look down it, and see any more than .004 scew, I send it back. I don't care what the outside is doing, because I have cancelled it out. However, if it's running out any more than .004 then I re profile it to correct that issue (on a target rifle).

I have never seen a barrel that was drilled .030 scewed. So far the winner goes to a Remington 700 SPS with a heavy varmint barrel and it was about .025 near as I can tell. In fact, I was just in Dicks sporting goods yesterday, and had a look down the barrel of an SPS in 270 and it was the same thing. The outside was straight, the inside was bowed.

So far though, the worst aftermarket barrel I have used was a Green Mountain 35 caliber that was about .004 out on the inside. Ie, I could barely detect the bow by looking at the light rings. So far Kreiger barrels have been dead nuts, and I can't detect any bow at all. There are some fellers out there that might be better at reading light rings than me, but I'm only good to about .004 and even that is more of me just seeing that something is off in there, but it's so slight, I just can't tell where the crest is exactly.

If you want to calibrate your eyeball, just gather up all the pull offs and look down 'em. Make sure the outside is running pretty true (re-profile if you have to) and find the crest of the bow on the inside, mark where it is, and cut the barrel in half there. Then just use a tubing mike to see how much bow you were actually looking at.
Anybody who does this will find out that you can detect the scew of a barrel with remarkable accuracy.

(edit to add)
Please dont take it like I'm trying to offend any of the smiths here. I'm just reading my indicators and doing something about what I see, using the tools I have available to me.
Most of the smiths on this board were building rifles when I was in diapers. So please don't take it like I'm trying to tell you how to do your job. I'm just saying "This is what I see. This is how I do it". No offense is meant in any way.

[B R Shooter]

But how is the bearing mounted, and how is the sleeve held to the bearing? The best bearing in the world has to be mounted, and to be able to indicate a barrel within it, you need a sleeve of sorts with adjusting screws.

I've seen some setups, some homemade, some used the lathe's steady frame. I've never been satisfied on how to mount the bearing. If you used a thick plate as the "frame", pressed a bearing in it, then OK. Now you need a way to adjust. To me, to keep the loading centered, a sleeve would need to be pressed in the bearing's inner race, but you would need adjusting screws on both sides. Not that isn't impossible, but just adds to the setup. So this is the reason I asked. You are Rey confident in your setup, just asking for details if you're willing to share.

I don't agree that going through the headstock induces stress on a barrel, if done right. No stress should be used. Done properly, the barrel will simply be held rigidly on both ends with no forces induced. My interest in this is for two reasons. Short barrels that won't go through the headstock, like an XP, and big barrels larger than the headstock hole. OK, a third reason, real long barrels that would have quite a bit of overhang mounted in the headstock.

Thanks for the post.

[MBTcustom]

You don't understand. That's not a raw ball bearing. It's a bearing assembly.
I ground the housing and the spindle out of solid 416 bar stock. The outer diameter of the bearing assembly is 6". The bearing spindle is hollow and has a spider on the end of it. The bearing assembly is being held by the steadyrest journals. Great care was taken to center the bearing in the steadyrest, and to make sure it has no pitch or yaw in it. The spider tips are only used for positioning, and I have a separate sleeve that rides inside the bearing assembly to provide power to drive the bearing.

Also, if you are holding the barrel "rigidly" then you are steering it with the spiders. Every time you tighten a spider enough to actually provide power to the barrel so it can be turned, threaded, chambered, crowned, etc. You are providing enough power to steer it off center causing a warped condition inside the headstock. The only way to prevent this is to be able to cancel out the pitch and yaw being imparted by one of those spiders, and make it so that the other one doesn't matter (hence the power sleeve in my steady rest).

BTW, Kreiger guarantees their bore straightness end to end as being less than .002 TIR. If any of you are salty enough to see that with the naked eye, then you're a better barrel looker downer than me!

What that means is that if the barrel was mounted in a stress free way, there would be no discernible eccentricity on the ends, or the middle of the barrel, no matter what method is used to measure it.

[B R Shooter]

Well I didn't understand, that is why I asked. Us mortal folks don't have the means or methods to make a bearing from scratch, we rely on purchasing things like this, and making it work. As far as inducing stress in a barrel by using a spider on the outboard side to position a barrel and a 4 jaw chuck with something like a copper wire, or even a spider chuck itself, you will never convince me of that. Or, the hundreds of benchrest rifle smiths that use this method, or the old way of using a steady, and produce the incredibly small groups being shot today.

I submit to you, you should contact one or two of these renowned folks, tell them your method is hands down better and can make a more accurate chambering job that will reduce groups in a measurable way, and I'll stand corrected. If you would like some names, let me know.

[MBTcustom]

Well I didn't understand, that is why I asked. Us mortal folks don't have the means or methods to make a bearing from scratch, we rely on purchasing things like this, and making it work. As far as inducing stress in a barrel by using a spider on the outboard side to position a barrel and a 4 jaw chuck with something like a copper wire, or even a spider chuck itself, you will never convince me of that. Or, the hundreds of benchrest rifle smiths that use this method, or the old way of using a steady, and produce the incredibly small groups being shot today.

I submit to you, you should contact one or two of these renowned folks, tell them your method is hands down better and can make a more accurate chambering job that will reduce groups in a measurable way, and I'll stand corrected. If you would like some names, let me know.

BR shooter, first, let me say that I consider you a friend as I do every one here on the forum (until they convince me otherwise), and I'm not trying to reinvent the wheel here, or belittle anyone.

All I'm saying is that the idea that target barrel bores are more than .002 out of straight end to end, is silly, and would be silly to anyone who actually knows how to look down a barrel.
Also, anyone who tries to tell me (like lots of these certified, bonafide, super duper, bench rest smiths) that this is proven by how far the tail stock end of the barrel is running eccentric has no idea what is really going on with that barrel.
None of my rifles are winning bench rest matches yet, but my work is orbiting the earth if that means anything to anybody.

We are all mere mortals, but some of us have indicators and know how to read them LOL!

I'm just talking about science, and superstition does not enter into it. If you have a smith you trust, then stick to him and his method. After all it doesn't matter if he warps the barrel slightly in the lathe as long as the rifle prints correctly. However, that's the shooters point of view. I'm coming from the gunsmiths point of view, and part of advancing in any field is research and experimentation which is what I have been devoting every shred of my spare time to.

I simply saw a flaw in the video, and it happened to be a pet peeve of mine, so I said something.
Heck, maybe somebody will get something out of my opinion, but if not, no big deal. I think what I have said should be considered, especially the next time you are setting up a barrel in the lathe, but if you think what I have seen in my indicators is heresy, then don't give it another thought! It's nothing to get bent over.

[Willbird]

Believe me Goodsteel it was aprox .03 on the inside.

And honestly when we put a chamber in we for the most part want it parallal to the bore, if you can indicate a few inches of bore and get .0000 and .0000 on each end of that couple inches you are good to go to chamber, any twist or other thing that the holding creates is a temporary situation.

Even a "tight neck" has .002 "slop"....heck one guy I used to type back and forth with on Benchrest central (I think it was) used to chamber his barrels totally by hand, he had a friend who could run the threads and such to fit his Stolle action, and he had a "pit" in his shed out back that he put the barrel down in, and he ran the reamer in with a T handle tap wrench, took him about 45 minutes. The BR shooters make side bets for the little packages of nabisco snack crackers..they call them "nabs" and he wins or won his share of "nabs" with those barrels. He had worked with a reamer maker to get a reamer setup to give him the chamber he wanted using his method.

And when I used the steady as a plain bearing I TURNED the outside of the bearing true to the bore.

I have built a handful of rifles that all shoot into 1/4 moa using several different methods, chambering is NOT rocket science, the reamer has a pilot on it, some of the setups seem to be geared towards ID grinding a chamber with no reamer or pilot involved at all.

I highly doubt you can make any permanent change to a heavy contour barrel with a copper wire hoop in a 4 jaw, and 4 setscrews on the muzzle end, and honestly if the last few inches of barrel are straight when I run the reamer in, all is exactly as I want it to be.

I have worked with a lot of different stuff and I have never been able to bend a part permenantly with some little setscrews and inch lbs of torque...the muzzle spider bolts need to be just snug enough so the barrel does not rattle around....they have the ability to use the barrel as a lever, and could even have delrin noses I bet.

[Willbird]

http://benchrest.com/showthread.php?62297-Barrel-Straightness-Issues

Read over this thread here for some interesting data, some very good well respected people said .004 off center (.008 TIR) is about average, and they MIGHT CONSIDER rejecting stuff that was .03.

[Willbird]

I just grabbed the chunk of barrel I was talking about, might as well say it is a PacNor, it is a 1/8 twist, and measuring at the "muzzle" end I get .286 one side and .311 the other side, which should give us actually .05 TIR runout ?? That was dead center in the middle of a 34" blank. Customer got 17" I got to keep 17" to fit to a 310 martini action.

[MBTcustom]

I just grabbed the chunk of barrel I was talking about, might as well say it is a PacNor, it is a 1/8 twist, and measuring at the "muzzle" end I get .286 one side and .311 the other side, which should give us actually .05 TIR runout ?? That was dead center in the middle of a 34" blank. Customer got 17" I got to keep 17" to fit to a 310 martini action.

Good grief! They don't happen to ship USPS do they? :kidding:

I have never had a barrel that bad come through the shop except a Stevens shotgun barrel I cut off once.
Like I said, Kreiger guarantees .002 end to end.

[Willbird]

Good grief! They don't happen to ship USPS do they? LOL!

USPS cannot (I hope anyway) introduce a runout between ID and OD :-). I just faced it off quick in a 3 jaw and took the ID burr off with an rcbs case neck chamfering tool, and tried my best to get a picture to show what is up.

http://i.imgur.com/pEaWa9W.jpg

This was taken with the camera pretty square to the end, played with angles and stuff, flash and no flash, this was the best I could get easily.

The one guy in the thread I just linked dialed a barrel all in, cut off 4" and had .009 TIR (and that barrel was a Krieger).

Bill

[Willbird]

Just measured it again with calipers making sure I was in a groove. .287 one side, .312 the other. .833 muzzle on a 34" blank, so it was not some skinny contour :-). I cannot remember if it was #7 or #8. I have a 30" Shilen #6 at hand and it has a .671 muzzle.

They may have just had a but too much tailstock pressure when they turned the contour, with it cut in half I have no way of knowing now how straight or crooked the bore was.

Bill

[MBTcustom]

We're these barrels profiled before they were cut?

Just got off the phone with Green Mountian. Guy told me that no one had asked him that question in a long time. He put me on hold and talked to manufacturing. He said they reject everything that is more than .005 TIR on the bore. He also said that has no bearing on what the outside of the barrel is doing. The only way to match the outside to the inside is to carefully profile it after perfect centers have been cut.

[Willbird]

We're these barrels profiled before they were cut?

Just got off the phone with Green Mountian. Guy told me that no one had asked him that question in a long time. He put me on hold and talked to manufacturing. He said they reject everything that is more than .005 TIR on the bore. He also said that has no bearing on what the outside of the barrel is doing. The only way to match the outside to the inside is to carefully profile it after perfect centers have been cut.


The 34" barrel was purchased profiled.

I still am not sure what exactly GM is talking about, sounds to me they mean the concentricity of the muzzle and the breech end to the portion of the ID you can access there, and they are not talking about what the concentricity would be say if you cut the barrel up into 1" slices and checked ID to OD.

In the thread I referenced one poster set a Krieger up with the muzzle end dialed in dead nuts, cut off 4", then had .009 TIR runout from removing 4" of the barrel...leading him to think the bore curved .0045 (to give .009 TIR) in that 4" distance.

Some of it has to do with the steel bar stock barrels are made from.

Bill

[MBTcustom]

Well, just because you slice up a barrel and measure it, doesn't mean it's hot a hook in it (although it could). It simply means that the outside of the barrel does not run true to the inside for whatever reason.
I got curious about this today, and I called Kreiger, Green Mountain, Shilin, PacNor and McGowen.
I asked each of them what their tolerance was on straightness. Then I spent the next 15-20 minutes trying to get somebody from the manufacturing line that knew what I was talking about.
The answer was the same across all companies (except Shilin, who is still getting back to me). .002-.005 end to end straightness is there standard. Some have a machine that uses light to measure this, and some have inspectors at every stage of the barrel making process that look down the barrel's to determine straightness, and they all have a big dumpster out back full of rejects.
Each one told me that if I looked down the barrel and could determine a hook, to send the barrel back to them, and they would replace it.
Each one informed me that the inside of the barrel cannot be measured from the outside of the barrel, and the tolerance they have on the concentricity of the outside of the barrel is looser than what they hold the inside to, and may or may not be perfectly aligned with the inside.

I'm not knocking your experience Willbird, and I'm not arguing at all with what you have presented. I'm just telling my side, and comparing it to your side.
So far, I'm thinking that they all let a few slip by that are not perfectly straight, but they all will replace the barrel if brought to their attention.
Please don't take offense. This is a good thread.

[Willbird]

But the outside is very easily checked with a dial indicator. So to explain the test better, check the OD, even OD grind it if you want it super nice, then slice up in 1" sections and check ID/OD concentricity.

[MBTcustom]

Or you could just look down it? I don't understand why I would want to turn a perfectly good Krieger into a California roll. LOL! (Ok, I cracked myself up a little with that one LOL!)

[Willbird]

Or you could just look down it? I do t understand why I would want to turn a perfectly good Krieger into a California roll. LOL! (Ok, I cracked myself up a little with that one LOL!)

It would not have to be a standalone experiment, you could do "ballistics by the inch" too :-).

But yes looking down them has been used for many many generations but does it give you a value for "crooked as a dogs hind leg" ?? You could also do it once a barrel was shot out. Even 4" or 6" lengths would give you data, and you could still make muzzle brakes out of them :-).

[MBTcustom]

It would not have to be a standalone experiment, you could do "ballistics by the inch" too :-).

But yes looking down them has been used for many many generations but does it give you a value for "crooked as a dogs hind leg" ?? You could also do it once a barrel was shot out. Even 4" or 6" lengths would give you data, and you could still make muzzle brakes out of them :-).

Yeah, I can't argue with that.
However that would be a painful experiment! I don't think any krieger gets trashed if its over 16" long. I'll milk those babies for every shot they're worth.
Wish I had the money to buy barrels from each of the major manufacturers, and just saw 'em up in the name of science, and eyeball calibration.

[Willbird]

Yeah, I can't argue with that.
However that would be a painful experiment! I don't think any krieger gets trashed if its over 16" long. I'll milk those babies for every shot they're worth.
Wish I had the money to buy barrels from each of the major manufacturers, and just saw 'em up in the name of science, and eyeball calibration.

I dunno if you have ever read any articles the guy who tests Sierra bullets has written for Precision Shooting, he would be a good example of somebody who shoots out a variety of barrels (not sure about Kriegers tho) but he did one blind test of about 6 barrels where 3 were cryo and 3 were not. It was a truly blind test, he did not know which was which....he had "gut feelings" over their lifespan which was was which based on how they fouled and cleaned, etc.

But in the end he was totally wrong with his guesses, and in actual results you could not pick the cryo barrels out by looking at ANY of the actual data.

Bill

[B R Shooter]

I recently had a barrel in to chamber and then cut off short and install a brake. Why these military types like and 20" barrels is beyond me. Anyway, this is from one of the top makers. He wanted me to turn the brake to the profile of the barrel, make it look like the barrel. Well, you have to use the bore to install a brake, and the OD was running out so much, I told him I wouldn't profile it. I would have had to cut back into the barrel and somehow try and blend it in. I just left the brake big, made a taper transition.

I'm not sure a maker checks the bore straightness as part of their normal QC. I have noticed that in the past 10 years or so, it seems barrels are drilled much straighter than they used to be. This is by eyeball, once set up through the headstock.

Another point to make, just for grins, I indicate both ends true, even though there is always some runout in the bore. I change barrels often I suppose, and don't want one barrel shooting into next week from one to another. However, there are those that use the drilled "drift" to advantage. One well known and renowned smith, uses the range rods and will move the muzzle end of the barrel wherever it needs to be, to get the first several inches of the breech end in alignment of the bore. then, once threaded, he will "clock"the barrel so it points up. He does most of his work for the 1000 and 600 yard shooters, and that elevation works for them.

I think Brownells used to sell brass bore rods, that you would drop down a barrel, and if hung up, it was drilled too far out. Maybe that was to check for it being bent, don't remember.

Anyway, I've had no intention to criticize here, just ask questions. Everyone seems to be quite defensive on their method to chamber, and I'm in the same boat. I think each needs to try different methods, and adapt the method that produces the best end result for the equipment they have. Not everyone has the same lathe, and equipment. I still want to make a steady bearing fixture for those times through the headstock won't work.

[MBTcustom]

I don't mean to defend anything except accuracy, and I'll apologize right now if I offended anyone. I don't argue that the methods being taught and accepted by the mainstream shooting community work, but sometimes it seems more like superstition than science.
I recently watched a video that cost a friend of mine a pretty penny, and I was shocked at what the smith was teaching. Angie can tell you, I was on the edge of my seat yelling at the TV "NoOOOoooooOOOOooo you fool!" LOL!
I told her look what this guy is doing to this barrel! He's smooshing it! I told her "I'll bet he's not smart enough to put his indicator back in the barrel after he threaded that. I guarantee you it changed!" Well, as it happened, he did put the range rod back in the barrel and calmly explained that "the barrel changes after every operation" He calmly torqued the snot out of it again, and drilled the chamber. I told Angie "look! He did it again!!!"
again, he checked it and it had changed again. This was on video. That somebody paid good money for.

[Willbird]

I recently had a barrel in to chamber and then cut off short and install a brake. Why these military types like and 20" barrels is beyond me. Anyway, this is from one of the top makers. He wanted me to turn the brake to the profile of the barrel, make it look like the barrel. Well, you have to use the bore to install a brake, and the OD was running out so much, I told him I wouldn't profile it. I would have had to cut back into the barrel and somehow try and blend it in. I just left the brake big, made a taper transition.

I'm not sure a maker checks the bore straightness as part of their normal QC. I have noticed that in the past 10 years or so, it seems barrels are drilled much straighter than they used to be. This is by eyeball, once set up through the headstock.

Another point to make, just for grins, I indicate both ends true, even though there is always some runout in the bore. I change barrels often I suppose, and don't want one barrel shooting into next week from one to another. However, there are those that use the drilled "drift" to advantage. One well known and renowned smith, uses the range rods and will move the muzzle end of the barrel wherever it needs to be, to get the first several inches of the breech end in alignment of the bore. then, once threaded, he will "clock"the barrel so it points up. He does most of his work for the 1000 and 600 yard shooters, and that elevation works for them.

I think Brownells used to sell brass bore rods, that you would drop down a barrel, and if hung up, it was drilled too far out. Maybe that was to check for it being bent, don't remember.

Anyway, I've had no intention to criticize here, just ask questions. Everyone seems to be quite defensive on their method to chamber, and I'm in the same boat. I think each needs to try different methods, and adapt the method that produces the best end result for the equipment they have. Not everyone has the same lathe, and equipment. I still want to make a steady bearing fixture for those times through the headstock won't work.

I know a lot of folks just fit the brake, then readjust so the OD of the barrel runs true, and then turn the brake.

And Goodsteeel about guys that do not really know much making videos and writing books, that Krankhausen guy wrote a book on how the 1911 works, cept he got it WRONG. People swear by his books, but why would I buy a book written by a guy who does not even understand how the gun works ?? :-).

Bill

[Willbird]

I have done tons and tons of Pain in the behind setups over the years, on delicate things, odd shaped things with curves and draft angles all over them, then had to hold close tolerances and good surface finishes.

Fitting and chambering a rifle barrel is a walk in the park compared to that kind of stuff, esp when I work for ME and can take 2 weeks at it if I want/need to :-).

Bill

[MBTcustom]

I have done tons and tons of Pain in the behind setups over the years, on delicate things, odd shaped things with curves and draft angles all over them, then had to hold close tolerances and good surface finishes.

Fitting and chambering a rifle barrel is a walk in the park compared to that kind of stuff, esp when I work for ME and can take 2 weeks at it if I want/need to :-).

Bill

Well there is that.....
LOL!

[Willbird]

Well there is that.....
LOL!

I think everybody that has decided on ways to get it done, struggled some with finding what seemed right to them.

I know two smiths who are 180 degree opposite about whether to fit a rem bolt nose .001 fit to the barrel counterbore, I listed to both, but the one guy told me he does not want the bolt nose touching anything ANYWHERE, and it rung true with me and I now use .01 in every direction to make sure it never does.

Reading through Rifle Accuracy Facts by Dr. Harold Vaughn taught me a LOT....has me going NO NO NO when people talk about stiffening up receivers with beefy scope mounts screwed on top. Saw it in reference to a Muzzle loader build on a savage action and reasoning told me "the reciever ring is not in tension when it fires, no issue there".

Anybody that can find a copy of that book is encouraged to read it from cover to cover.

Bill

[MBTcustom]

I think everybody that has decided on ways to get it done, struggled some with finding what seemed right to them.

I know two smiths who are 180 degree opposite about whether to fit a rem bolt nose .001 fit to the barrel counterbore, I listed to both, but the one guy told me he does not want the bolt nose touching anything ANYWHERE, and it rung true with me and I now use .01 in every direction to make sure it never does.

Reading through Rifle Accuracy Facts by Dr. Harold Vaughn taught me a LOT....has me going NO NO NO when people talk about stiffening up receivers with beefy scope mounts screwed on top. Saw it in reference to a Muzzle loader build on a savage action and reasoning told me "the reciever ring is not in tension when it fires, no issue there".

Anybody that can find a copy of that book is encouraged to read it from cover to cover.

Bill

Well that's just common sense! LOL!
Gunsmithing reminds me of a story that was told to me by a friend of mine who runs a sawmill.
He told me that at one time, it was commonly held that if a nut bearing tree wasn't producing, it was because of a lack of iron, so they would pound nails in the trunk of the tree to fix its iron deficiency. The tree would respond by bearing much more fruit, which reinforced the commonly held position. Then comes along the scientists and master foresters who explained that the tree didn't need iron at all! It just needed to be stressed. It thought it was mortally wounded, so it tried to reproduce itself in response to the nails that had been pounded into it's trunk.

Sometimes I think we get the right result, but without a real understanding of why.

[Willbird]

Well that's just common sense! LOL!
Gunsmithing reminds me of a story that was told to me by a friend of mine who runs a sawmill.
He told me that at one time, it was commonly held that if a nut bearing tree wasn't producing, it was because of a lack of iron, so they would pound nails in the trunk of the tree to fix its iron deficiency. The tree would respond by bearing much more fruit, which reinforced the commonly held position. Then comes along the scientists and master foresters who explained that the tree didn't need iron at all! It just needed to be stressed. It thought it was mortally wounded, so it tried to reproduce itself in response to the nails that had been pounded into it's trunk.

Sometimes I think we get the right result, but without a real understanding of why.

Well the one guy loves the idea of the bolt nose riding in the c'bore...after some thought I disagree ;-).

The other guys told me how to bush a bolt which I have done a few of. Now we can just buy the PTG bolts if we wise made to fit.

Bill

[codgerville@zianet.com]

YES!! Willbird, you are right on with that. Before I retired they would bring some odd-shaped piece of worn-out junk in that had no common reference surfaces and was worn so bad there was no way to tell where the original bore had been and say, "we gotta have this by this afternoon." Fitting rifle barrels here in my home shop is relaxing compared to that. I might even take a break and have a mug of coffee and a pipe full of good tobacco.

[MBTcustom]

Well the one guy loves the idea of the bolt nose riding in the c'bore...after some thought I disagree ;-).

The other guys told me how to bush a bolt which I have done a few of. Now we can just buy the PTG bolts if we wise made to fit.

Bill

You don't say?
In the same way, why blueprint a crappy M700 when you can buy a Stiller for cheaper?

[leftiye]

Well, at the risk of getting flamed all the way to the hot place, I gotta say this. Most of this doesn't matter. All praise to Mr Goodsteel's precision and in no way to offend, his setup is probly near perfect. But there are so many places that Mr gun does his act his way, as he desires, that it perhaps makes no difference. I'll start by saying "Yes, Why not do it perfectly? Precision can't hurt." Then I'll say that where the last two inches of the barrel happens to be pointing at the moment the bullet passes through is what makes the difference.

Barrel harmonics for instance - the end of the barrel waving around in unfathomable patterns. Bedding for instance, the barrel moving in the stock. Causing the barrel to be in a different state of flex each time the barrel fires, not to mention pointing somewhere new each time. With today's bedding methods these can be miniscule, but I didn't start the worrying about miniscule here. Action bedding, same story. Action internal stresses built in during production. Scope mounting imperfections, etc. Bullet imperfections. Powder not burning precisely right, nor the same each time. Cases varying in concentricity, and volume. Case neck concentricity. Primer variances. Bore condition changing as firing goes on. Ambient temperature changes, etc.

There's so much else going on after the boo/ullet enters the rifling. Plus that entry depends more on the correct (optimum) dimensions of bore, rifling, freebore, and leade than the precise dimensions of these and the chamber itself further back. Coaxiality of chamber does matter, but tenths of thousandths probly don't.

Exactly how a reamer cuts the chamber is dependent on what? Whether the last two or three inches of barrel are straight. Whether they turn parallel and concentric to the axis of? Of the reamer! Runout of barrel while cutting Should be minimized, But how much runout can happen before it affects a free floating reamer?

This not in any way to advocate sloppy practices, non attention to precision, or any of that. Only to say that you can have a perfect rifle and have one that doesn't shoot perfect one hole groups which are groove diameter.

[tek4260]

Great point! Has anyone ever been able to determine how much a barrel "whips" when you fire it? I know they are all different, but has anyone been able to measure one in particular?

[MBTcustom]

Great point! Has anyone ever been able to determine how much a barrel "whips" when you fire it? I know they are all different, but has anyone been able to measure one in particular?

Near as I can tell, the guy that designed the quickload program did tests that seemed to support his theories. (My own experience seems to lend merit to his theories as well, but I might just be hammering nails into trees LOL!).
I have seen high speed camera footage that seems to clearly show the barrel whip, but that's not an exact measurement either.

I think the most research has been done on the effect of the barrel harmonics (BTW, there are two distinctly different kinds of harmonics that effect the barrel when the trigger is pulled) rather than the physical changes that take place, but I'm sure someone found a clever way to get an exact figure.

I can tell you who I would ask though. Maybe Larry Gibson, or Felix will weigh in here. I'd just bet they can speak more intelligently than me on that subject.

[fouronesix]

Great point! Has anyone ever been able to determine how much a barrel "whips" when you fire it? I know they are all different, but has anyone been able to measure one in particular?

Yes, it's been done within the instrumentation capabilities available including the lateral movement and the on-axis compression waves within the barrel/action. Ends up being far too complex to model predictions about "accuracy on target" outcome though- as leftiye pointed out. Just put rifle and ammo together within the best tolerances that can be done, then see what the target shows. Well known generalities usually apply- but the prediction of results is where most "models" have shortcomings. That's why testing and verification still exists.

[Willbird]

You don't say?
In the same way, why blueprint a crappy M700 when you can buy a Stiller for cheaper?

Well one can go to Maomart and buy a 700 rifle in a popular caliber, pull the barrel and stock and sell them, and if you were to use a PTG bolt sell the orig bolt as well, and maybe have $0 in the action at that time.

Plus I just like 700's, always have. When I trued mine and bushed the bolts I had $0 in all 3 at that point.

Bill

[Willbird]

Yes, it's been done within the instrumentation capabilities available including the lateral movement and the on-axis compression waves within the barrel/action. Ends up being far too complex to model predictions about "accuracy on target" outcome though- as leftiye pointed out. Just put rifle and ammo together within the best tolerances that can be done, then see what the target shows. Well known generalities usually apply- but the prediction of results is where most "models" have shortcomings. That's why testing and verification still exists.

Dr. Harold Vaughn put accelerometers on a rifle barrel then fired the rifle, and documented the results in a scientific fashion in the book "Rifle Accuracy facts"...he did many other scientific things with bullets, barrels, and actions as well.

[Willbird]

Dr. Harold Vaughn put accelerometers on a rifle barrel then fired the rifle, and documented the results in a scientific fashion in the book "Rifle Accuracy facts"...he did many other scientific things with bullets, barrels, and actions as well.

He actually isolated some of the "whips" down to assymetry in the rifle action, one was caused by the gas port drilled in one side, the solution there was to drill a matching gas port in the other side of the action. And the most interesting was that a scope base that stiffened the action caused ANOTHER asymmetry, the cure there was to make a base that did not stiffen the action....many people think stiffening the top of an action with a big beefy one piece "moa" type base would be a GOOD thing, and in fact the reverse is true IMHO and Dr. Vaughns Scientific opinion too.

[leftiye]

Great point! Has anyone ever been able to determine how much a barrel "whips" when you fire it? I know they are all different, but has anyone been able to measure one in particular?

Way back, I heard that to get a 1" (100 yards) group you only need .001" variance in muzzle position. More lately, others have calculated other outcomes, but group size it would seem is a tell tale as to what the barrel is doing. There may be some effect at release from the muzzle (launch), that now, is truly uncalculable.