I'm just a hobbyist at this point so a slow process doesn't correlate any lost income. I would, however, like to do things the best I can and appreciate any advice and help. First barrel took me three days but I've got it down to a single busy but relaxed day now. Also, being a consumptive hobby, I've tried to minimize costs in equipment while producing an acceptable level of quality. So far, my results have been as good as typical factory rifles in my hands, that is 1-2moa with a variety of loads is normal. Nevertheless, I would like to improve and refine what I'm doing.

Being limited in space and with the cost of shipping, I bought one of Grizzly's recent "South Bend" 8K model. A few selling points for barrel work were the 1 1/8" spindle bore and a minimum rpm of 45. As you can see from the pic, there's just enough space to chuck a barrel through the spindle and have room to work the breech end. It's tight but I can test fit an action with the reamer left in the tailstock holder. Unfortunately (or not?), it precludes any technique using centers or a steady rest so I'm trying to refine my through-the-spindle technique.



What I've been doing to setup a barrel is to chuck it in the four jaw chuck with a piece of aluminum wire between the jaws a barrel. Torqueing down the jaws flattens the wire to about a .200 wide contact point on each jaw. I would assume the single contact point minimizes tension on the length of the barrel. I then eyeball the muzzle end in the outboard spider with just finger tension on the screws. I then use a Gritter rod with the bushing located in the bore at the point of wire contact. Then, by spinning the chuck by hand, dial in that point to the best of my ability and equipment - which seems to be about .0005". That's also the best I'm able to get on the naked spindle nose so I'm not convinced the lathe is any more accurate.



Once the breech end is dialed in, I'll use a tight fitting tapered/bushed pin in the muzzle end (first addressing burrs or irregularities there) to dial in the muzzle end while lightly snugging up the spider screws. The pin is turned on a mini lathe from brass and features a short section that, from my experience, I would estimate somewhere around .0002" clearance, and then a taper from under bore diameter to just above. The thought being that it would provide an accurate external representation of the last few inches of the bore. Once this is dialed in, again to the best of my ability, I pull the rod and pin, run the lathe at ~100-150rpm and look down the bore. So far, only two barrels of the 10 I've fitted have NOT looked like a jump rope swinging (ironically, one was a $30 Remington junker, the other a Midway $150 6.5 Shilen.



At this point, I would go ahead and cut the tenon and threads to fit the receiver, do a quick check to confirm I haven't knocked things out and finish the chamber with the same setup using a Manson floating reamer holder, running in close to final headspace and use feeler gauges to finish.

Some of you guys post over on Practical Machinist and I've read a lot of the barrel setup threads there. With all the different techniques, I've tried a few refinements on the above steps.

For whatever reason, my indications are not repeatable to less than about .001" in my "big" lathe. That is to say if I swing #4 chuck jaw into position and take a reading, the next time it might be anywhere from +/-.0005" from where it was. My indicators cost about $100 each so they're not super fancy. Still, they're dead nuts in my stupid little 7x10 mini lathe (love/hate that thing... $350 ten years ago and if I do my part, I can hold to a 10th on it...) What I'm now doing for a final check is to run the lathe at the threading and chambering RPM with the rod and indicator setup and dotting the barrel with a marker every time the indicator reads a certain position. Initially, the dots locate in one spot consistently so I repeat the process until the dots scatter around the circumference. Then I assume the barrel is as centered as the system will allow.


Another thing I've tried is skipping back and forth, dialing in the muzzle on the pin then the breech with a Gritter rod at the wire ring. THEN, I run the Gritter rod in 3" and loosen the spider screws and redial the +3" location by moving the floating muzzle by hand in the spider. The chuck wire holds the barrel in position and I've been able to nudge it to .0005"RO with no tension on the muzzle end whatsoever. Not sure what gravity does on the hang of the barrel but once it's running "true" at the wire and +3", carefully snug up the spider screws without disturbing the location of the muzzle. This usually results in a muzzle end anywhere from true to swinging .035" with the breech end running true.

Then, with the breech end running "true" and ignoring the muzzle, I'll cut the tenon and fit the barrel to the action. Then, I'll install the reamer in the holder and set the compound to the taper of a flute on the reamer with a dial indicator and bore the body of the chamber to .010" undersize with a mini boring bar. Then, finish the chamber with the reamer, doing the final fit with feeler gauges.

Needless to say, that muzzle flopping around is a bit disconcerting. But, the three barrels done this way still shoot as well as me and my circumstances allow (1-2moa from sporters in typical Kodiak weather on rough benches).


It bugs the crap out of me that I'm not consistently able to get a barrel turning visually true in the lathe. I've tried to learn how to "read" a barrel visually in-hand and successfully identified two of the worst I've fitted. But, the others are not so obvious. One method I used to check for straightness in-hand is to align the barrel on a power line outside the shop window surrounded by clear sky. The straightness of the reflection of the power line on sidewall of the bore is used as a reference. This also seems to work on the edge of the 4' fluorescent light fixture above the lathe when it's too dark outside. Either way, I still wasn't able to see any crookedness in 13 of the 15 barrels I've looked through. The two worst were another Remington junker and a Midway Green Mountain 35 cal and the bore reflections in both were obviously bowed but the rest appeared ok until I got them "dialed in" in the lathe.

I would love to use centers and a steady rest. Coupled with a floating reamer holder and a properly fit bushing, the reamer has to follow the bore no matter where either one goes. I can't on my little lathe however.

I've been turning my own bushings from brass and strive for the tightest fit that allows easy movement, again, from my experience I would guess about .0002" clearance. The same bushing is used on the Gritter rod and reamer. I don't have the ability to grind steel bushings like PTG but brass is so nice to machine that so hope it's a viable material and isn't doing any harm in the bore.

I'm also using the Manson floating reamer holder and have noticed it float on only one barrel (with an undersized piloted reamer - throat was obviously eccentric when finished so I redid it). I think the floating feature is good but it wonder if, by design of having a flat floating surface, that if the bore is not centered and the pilot floats to follow it, what would that do to the chamber dimensions?


Any insight, suggestion, tip, or thing to consider for a better method is greatly appreciated! Thanks!

Search for Les Brooks posts, he showed how to chamber on a lathe that I think is smaller than yours.

That sure is a lot of information.

Speerchucker will be along here any minute and
give you some ideas. Kenny

For many years I threaded between centers and chambered in the steady. About fifteen years ago, I started doing everything through the headstock and methodology is not a lot different than yours. I have no trouble dialing in to within a couple of tenths at the breech end and if the muzzle end is within a thou, I'm happy enough. For match rifle barrels, I dial in at the location of the throat and rough with a boring bar. I have also started chambering then threading on the center afterwards. I stared gunsmithing professionally in 1977, Since then, I have watched a dozen different 'smiths fitting and chambering and have seen about a dozen different techniques employed. None are totally wrong but some are better than others.
Reamer holders susch as the one you are using don't really float much laterally but tend to center up under load. As long as this "center" is coaxial with the bore, everything is good. If not, not so much. If your reamer is cutting to size, you are probably just fine. Most tailstocks are made to be a bit high when the machine is cold. Once the headstock warms up, everything lines up. If the tailstock is centered vertically when the machine is cold, it may well sit low when the machine is warmed.
All in all, I see nothing really wrong with your technique but I would be inclined to use a different holding system for the reamer. I start chambers with the reamer held on the tailstock center then switch to a flat "pusher" once I've reamed an inch or so.
I can take a rifle out of the rack, fit, chamber, cut&crown, stamp, polish and re-assemble in two hours unless I have to cut an extractor cut (add a half hour for that). One day I did five barrels in eight hours and two of those had extractor cuts and two needed the barrel channel opened up.
Now that I no longer make a living at it, the procedure goes more like this: Set-up then have a coffee. Rough the chamber, coffee. Ream mostly, lunch and read a book for a while. Finish reaming, walk the dog. Cut and crown, coffee. Polish, stamp, and final polish, re-assemble. I'm not nearly so quick anymore! Regards, Bill.

I would work on my benchrest skills and equipment before changing your chambering method.

Maybe coffee should be used for cutting fluid whilst chambering? Seems like an ample supply is generated in gun shops!

quote:

Originally posted by WoodHunter:
Maybe coffee should be used for cutting fluid whilst chambering? Seems like an ample supply is generated in gun shops!

No kidding! I didn't drink quite so much when I was actively gunsmithing but, for whatever reason, I had quite a few customers/friends who liked to drink coffee and watch me work. In order that they not interfere with production, I habitually ignored their presence and moved as if they were not there. As a result, if they were not paying attention, there was some spillage. Eventually, the more talented could anticipate my every move and it became like a well-practiced dance with nary a drop spilled.
Wouldn't work today since, quite often, even I don't know what my next move might be. In a case like this, the default move is to the coffee pot. Regards, Bill

One vice I never acquired.

I've chambered several hundred barrels in the headstock. I found that it always took a lot of time to set up and there were some problems with the technology that could not be worked out so I eventually dropped it. That said, as long as you use a good reamer holder that floats both lineally and axially to take care of any misalignment and take light cuts at low RPMs you should have few if any problems.

dpcd - How did you manage to stay in the Army 28 years? I only had 6 years total and some was reserve and I developed a taste that lasts till today. Of course I was not in Armor I was in the Artillery - CW radio operator. I suppose you had no place for a coffee pot in those metal boxes.

On the setup you show, I would put your ring out to the end of your 4-jaw, set the barrel in further so the shoulder is closer to the chuck for more rigid setup. I essentially use the same setup and on the outboard side I turned the tips of my screws rounded and use a strip of copper sheet bent round the barrel to prevent dings. You really have to be carful how tight the screws are on both ends as you can induce bowing.

Ideally, on the muzzle end, one should just push the barrel around by hand until it floats true; being held only by the wire on the front. The front is, at this point, dialed in and running true and the muzzle ebd is running true but unsupported. Then, you turn the screws in until they just touch. Keep an eye on the dial while doing this. Then, while still watching the dial, tighten the screws up. When the screws are reasonably snug, the barrel should be aligned and stress-free. Regards, Bill

quote:

Originally posted by matt salm:
On the setup you show, I would put your ring out to the end of your 4-jaw, set the barrel in further so the shoulder is closer to the chuck for more rigid setup. I essentially use the same setup and on the outboard side I turned the tips of my screws rounded and use a strip of copper sheet bent round the barrel to prevent dings. You really have to be carful how tight the screws are on both ends as you can induce bowing.

And by setting the ring closer to the chuck jaws you will eliminate a lot of back and forth with the indicator due to the breech end not moving around so much when you indicate the muzzle end. Also with only a 1.125 spindle bore you will be handicapped when trying to get the normal 1.250 breech end barrel set up.

Thanks for the tips guys, I figured I was in the ball park but it's all new and exciting for me and it's great to get some professional feedback.

I did the trig concerning runout at the breech, 3" beyond (the throat), and the muzzle of a 24" barrel and got the ratio of approximately 1:8 between +3" and muzzle if the breech is true. That is to say, .001"ro at the throat would be .008" at the muzzle. Unfortunately, my muzzle runout is often .010-.020" with the throat "zeroed". I really hope I'm not misreading .002-.003" at the throat!

It does bring up the question of just how straight is the average $200 barrel and how straight are the $300-400 top brands? I haven't done a top quality tube yet, figuring it wise to practice the basics on take-offs first.

My chambers do seem to be coming out within spec as all the '06 based cases have mic'd less than .470 at the web after firing. That said, is there a reamer holder that floats both lineally and axially? I think the Manson I have is only axial as the reamer only moves parallel to the ways.

I'll move the chuck ring further out in the jaws. The previous idea was to keep it where the jaws are more supported but it makes sense to maximize the distance between barrel supports and move the pivot as close to the end of the barrel as possible. Jim is right about being limited by breech diameter but I'll try to run the barrel in as far as reasonable and put the wire ring as far out as possible. I'll keep using the method of dialing in the breech first then dial the throat with the muzzle floating and only snug up the muzzle to keep it in position when finished.

I drilled and tapped the screw tips in the spider and installed smaller brass screws. Saves me a lot of butterfingering shims in the bore of the spider.



Any thoughts yea/nay about using self turned brass bushings for the reamer pilot and Gritter rod pilot?

You kind of have to keep it in the back of your head that barrels are generally not bent. Because of the way they are drilled barrels actually have a very long, very slow helix to them.

As it was explained to me by guys supposedly in the know. The deflection is about .006 to .020 inch over a distance of 6 to 10 feet depending on the diameter of the drill. So there is no such thing as a perfectly straight barrel. But they are pretty damned straight. Some years back I sat down with one of the guys from Hart and he candidly told me that they cull out anything that was visually cocked off.

I also know a guy that used to work for Apex and he had the same story. Their logic was that after a barrel got close to .004 inch of deflection at 29 inches it was obvious to anyone with a half a brain who rolled the barrel over V blocks. 98% of the barrels that come out of the drill are under .004 which also happens to be the amount of deflection needed to be picked up by the naked eye.

Without telling him what I already knew, Dan Lilja also corroborated with exactly the same story and said that his people culled out any tubes that came out with any visual deflection. So, you can rest assured that any tubes coming out of the big names, are going to have less than .004 inch deflection over 29 inches. Or, if you care to do the math .004÷29=0.000137 deflection per inch.

Contrary to what people think, It's impossible to make an off center throat. The reamer has a pilot on it and the pilot runs on the lands. The lands are a perfect circle. They were formed with a drill which cuts perfect circles and reamed with reamers which cuts perfect circles. As long as you use the correct size pilot it is impossible to cut a throat off center. So trying to dial in a throat is sort of a lost cause to my way of thinking. I have found that those rotating pilots on the end of the reamers don't cut that well. Maybe I need to sharpen my pilots a bit?

The back end of course can have run out after the chamber is cut. But if you figure your deflection per inch in a worst case scenario is 0.000137 and multiply it by the 3 inches of your chamber you only get 0.000411 inch of run out at the back end of the chamber. I have a $300 Mitutoyo needle type indicator that is graduated in tenths of thousandths. I read Mitutoyos specs for that indicator and they claim a repeatability of +-.0002 so with a possible variance of .0004 just in the indicator itself I have to think with that and the .0005 slap in the bearings of my machines I really couldn't honestly and accurately measure 0.000411 if I wanted to. So I don't try.

I would have to say that if you are getting .010 to .020 run out on the muzzle end then something is probably askew. I don't think I can ever recall seeing a new barrel that was ever that bad. I pretty much gave up on that technology years ago because I just had to many problems with it and I couldn't get any repeatability out of it. If I have to use it now I always dial it in at the chamber and at the muzzle using a double cat head or a four jaw and an outrider 4 jaw.

But as I said in an earlier post, if you are using a good reamer holder that floats both lineally and axially all of that dialing in is just a waste of time. It could be out 1/64th of an inch at either end and the floating holder will still allow the reamer still go straight down the bore. Unless of course it hits a hard spot in the steel.

quote:

Originally posted by speerchucker30x378:
You kind of have to keep it in the back of your head that barrels are generally not bent. Because of the way they are drilled barrels actually have a very long, very slow helix to them.

As it was explained to me by guys supposedly in the know. The deflection is about .006 to .020 inch over a distance of 6 to 10 feet depending on the diameter of the drill. So there is no such thing as a perfectly straight barrel. But they are pretty damned straight. Some years back I sat down with one of the guys from Hart and he candidly told me that they cull out anything that was visually cocked off.

I also know a guy that used to work for Apex and he had the same story. Their logic was that after a barrel got close to .004 inch of deflection at 29 inches it was obvious to anyone with a half a brain who rolled the barrel over V blocks. 98% of the barrels that come out of the drill are under .004 which also happens to be the amount of deflection needed to be picked up by the naked eye.

Without telling him what I already knew, Dan Lilja also corroborated with exactly the same story and said that his people culled out any tubes that came out with any visual deflection. So, you can rest assured that any tubes coming out of the big names, are going to have less than .004 inch deflection over 29 inches. Or, if you care to do the math .004÷29=0.000137 deflection per inch.

Contrary to what people think, It's impossible to make an off center throat. The reamer has a pilot on it and the pilot runs on the lands. The lands are a perfect circle. They were formed with a drill which cuts perfect circles and reamed with reamers which cuts perfect circles. As long as you use the correct size pilot it is impossible to cut a throat off center. So trying to dial in a throat is sort of a lost cause to my way of thinking. I have found that those rotating pilots on the end of the reamers don't cut that well. Maybe I need to sharpen my pilots a bit?

The back end of course can have run out after the chamber is cut. But if you figure your deflection per inch in a worst case scenario is 0.000137 and multiply it by the 3 inches of your chamber you only get 0.000411 inch of run out at the back end of the chamber. I have a $300 Mitutoyo needle type indicator that is graduated in tenths of thousandths. I read Mitutoyos specs for that indicator and they claim a repeatability of +-.0002 so with a possible variance of .0004 just in the indicator itself I have to think with that and the .0005 slap in the bearings of my machines I really couldn't honestly and accurately measure 0.000411 if I wanted to. So I don't try.

I would have to say that if you are getting .010 to .020 run out on the muzzle end then something is probably askew. I don't think I can ever recall seeing a new barrel that was ever that bad. I pretty much gave up on that technology years ago because I just had to many problems with it and I couldn't get any repeatability out of it. If I have to use it now I always dial it in at the chamber and at the muzzle using a double cat head or a four jaw and an outrider 4 jaw.

But as I said in an earlier post, if you are using a good reamer holder that floats both lineally and axially all of that dialing in is just a waste of time. It could be out 1/64th of an inch at either end and the floating holder will still allow the reamer still go straight down the bore. Unless of course it hits a hard spot in the steel.

Gosh, I don't know where to start.
In the first place, it is plain that you have spoken to some barrelmakers who just flat out lied to you! I don't know how many barrels I've spun in the lathe but it's been quite a few in the last forty years and I'll tell you, it is a rare barrel indeed which does not exhibit a certain amount of curvature in the bore. Frequently it's a significant amount. I know I have not seen many straight ones and I have yet to see a perfectly straight one from any Montana maker! Apparently, the ones Dan Lilga culled out ended up in my shop. By the way, when a barrel is spinning in the lathe, I think it is possible to see considerably less than .004. I can recall two barrels which were visibly, perfectly straight. One was a Clyde Hart barrel and the other was from Ron Smith. I told Ron I wanted all of my barrels to be just like that and he said, "Dream on". That any barrelmaker can say all of their barrels are straight within .004" and say it with a straight face is just amazing to me.
As far as eccentric throats go, there is always enough clearance and enough flex to allow a reamer to be pushed off enough to cut a throat which is visibly eccentric. If the throater is cutting at .0005 over groove diameter or less, it doesn't have to be far off to see it. If it was impossible to cut an eccentric throat, there wouldn't be so many of them out there.
I have not seen a reamer holder/driver which will float axially when it is under load. The holder sold by Clymer looked like it would float axially but when under load, it was forced to center. The flat faced holders which are just a pusher with a sleeve to keep the reamer from falling out can let the reamer move a little but even they don't allow much float when they are pushing. For this reason, it is beneficial to try and set up as straight as possible; within reason of course. In my yet-to-be-completed book, I describe a half dozen different techniques and set-ups and advantages and disadvatages of using them.
It often seems like the more I learn, the less I know. For this reason, I constantly try different techniques in hopes that I can prove I've been doing things right but often end up proving I've been doing it wrong. Of course, as I get older and more forgetful, I can just keep learning the same thing over and over and it's still new! Regards, Bill.

I actually can't remember who showed me this trick. Might have been Ron Smith, but I disremember now. If you're just puttering around in the shop some time try this. Stick the first tenth of an inch of the chamber end of a barrel in your three jaw and lock the steady rest down on the tip of the muzzle. Just enough to hold it snug. Then use the use your tool post to push the barrel over at about the mid point. Use a dial indicator sitting on the bed with the needle beside the tool post to accurately track the movement and move it .001 at a time and peep through the barrel with a flashlight in the spindle if needed. .004 inch is actually one hell of a bend. .010 or .020 inch looks like it's gonna come around and shoot you in the ass.

I always wanted to build a strained wire gauge to measure bore deflection and map barrels. I think I even tried to talk old Butch Lambert into building one once. Every time I think about building it, the grim reality that knowing how much deflection is in a barrel won't make it shoot one iota better hits home, so the device would be useless as lipstick on a pig and I put the project on the back burners. I will make one some day though. Just cause.

Like you, I have seen throats cocked off in barrels too. But I have never seen the problem in one that I have chambered. I have always equated the bad ones I have seen to loose fitting pilots. It's up to the guy doing the work to select a proper pilot and if necessary order or grind a new one. I just cut them out of a chunk of hardened drill rod in my Cuttermaster grinder. But as long as the pilot fits the reamer and bore right, it's pretty hard to screw em up. Well, I haven't been able to yet anyway and I do squint at them, pet them and whisper sweet nothings at them when I'm done. Maybe that helps, I dunno.

I have also seen a lot of throats that looked cocked off but weren't. If one or two grooves happen to be of differing depths it will give the false impression that the throat is off. If you follow all of the lands forward to the end they look great. If you follow all the grooves back to where they start they look like hell. But there isn't much you can do about that. Other than send the barrel back.

You're right on the Clymer style floating holders. They won't float lineally under pressure. Pushers like the bald eagle will and so will the really good commercial ones that have the planetary balls inside. For the last 5 years I have been holding the reamers in ER32 or ER40 collets and floating the barrels. That's about 150 to 200 chambers and so far, no problems. It has eliminated chatter 100% too. Even the old Clymers, Hendricksen and Hartford reamers I have with no relief angle don't chatter in the ER's. The only trouble I had was with a couple old Guild reamers. After chucking them up I found that they were off by a few thou and I had to put them between centers and regrind the shanks true. I guess they were meant to be driven on centers.

Great exercise, Speer'! I just did what you suggested and I couldn't see the deflection until it was around .005". Once it got to .010", though, it's pretty darn obvious.

This was by observing the straightness of the in-barrel reflection of a black coated cleaning rod hanging on the wall the barrel is pointing at.

From the few other barrels I've eyeballed, I'd have to say that most of them were within my ability to see a .005" or more curve (whatever that's worth...)and only two were beyond that.



So, if my eyeball can easily recognize a barrel with .010" of curvature and I zero the muzzle and breech of that barrel, the maximum deflection at the 3" throat on a 24" barrel will be .00125". That still seems like quite a bit of runout. Of course, with a properly piloted reamer in a floating holder... it's going to easily follow the bore and cancel that much runout.


Hmmmm.... So perhaps I'll try this:

1. Look through the barrel and see if I can detect any curvature. If none detected, go to step #2. If a curve is observed, go to step #5.

2. Chuck barrel in 4-jaw with minimal stickout and zero.

3. Zero muzzle

4. Fit to action, prebore and ream. Done

5. Skip #3 and zero throat area with Gritter Rod and let muzzle "float". Snug spider screws when zeroed and ignore final location of muzzle.

6. Fit to action, prebore and ream. Done.

With a barrel sitting still, .005 truly is about as little as one can see in a rifled bore; maybe a little better than that in a smooth bore. I know that when straightening a barrel in a press, I would be pretty happy to end up at five thou. If a barrel is spinning, you can see a lot less than that.
If you want to align the initial portion of the barrel and let the muzzle be where it wants, you are better off to cut your chamber then center both ends to cut the thread. Otherwise, you may end up with the barrel pointing off further than you can adjust. This is the thing, with a curved barrel, somewhere, there is a compromise.
Dialing in at the throat then roughing with a boring bar allows a chamber that is concentric with the throat but, if the barrel is very curved, it might not be co-axial with the bore ahead of the chamber. Also, one is limited in the length of cartridge. Tough to dial in the throat area on an Ultra Mag but easy on a PPC. The further in you have to reach, the less accurate the measurement. Like I said, with a crooked barrel there is always a compromise. Regards, Bill

It's actually kind of amazing. People will stare at barrels for hours and can't find any deflection. But put it in the lathe and push it over an actual .004 thousandths and the deflection is immediately apparent to the naked eye. Push it over .010 and it looks like its bent 1/4 inch. Yet you look back at the indicator and it really has only moved a tiny bit.

Mind you .004 deflection is .008 inch center to center. Once you begin to see what to look for, ,004 center to center deflection is also easy to see if you roll it on V blocks. As I said, .010 inch looks so badly bent that it might come around to hit you in the ass if you shot it. Most all of the quality barrels we look through these days are so straight that you really have to know what to look for to perceive any deflection at all.

It's kind of a simple, dumb experiment. But it does teach you what .004 deflection really looks like. Not that it does any damned bit of good at all. Knowing how much deflection it has, will never make a barrel shoot any better and straightening barrels just generally makes things worse. After you straighten them they just want to walk back to their original bent state when they heat up and your groups start walking across the target. Barrels with deflection shoot a lot better if they're just left the way they are.

As far as chambering goes. You try to get the barrel and reamer as straight in the machine as possible with the equipment at hand and use a close fitting pilot on the reamer. Beyond that. Something has to give a bit to compensate for human and mechanical error. If you lock the barrel solid, like in a double cats head setup, its best to float the reamer somehow. If you don't float the reamer, then you have to float the barrel so that it can move and flex and slide up the reamer like pulling a sock over your foot. Something has to give a bit somewhere.

When dialing in a barrel through the headstock, one tip that WILL save you a buttload of time is to leave the screws loose on the inboard side and support the barrel with the tailstock center. Dial in the outboard end then snug up the inboard screws and pull your tailstock back and dial in the bore. Many times you will be so close there's no need to go 'back and forth'. I dial in the chamber end, drill out the chamber (undersized), dial in the throat and muzzle one last time and bore the drilled hole true. My finish reamers take 10-15 thou to cleanup the chamber. I typically step bore to ensure the reamer can be inserted far enough to engage the pilot in the bore before the body cuts as I use a pusher and w/ 2 points referenced the reamer will track straight. If I can't get the pilot in due to a long case and minimal taper I'll initially feed in with the tailstock center to ensure a 'fairly' true entry. As soon as the pilot is in the bore the Bald Eagle pusher is used.

quote:

Originally posted by matt salm:
When dialing in a barrel through the headstock, one tip that WILL save you a buttload of time is to leave the screws loose on the inboard side and support the barrel with the tailstock center. Dial in the outboard end then snug up the inboard screws and pull your tailstock back and dial in the bore. Many times you will be so close there's no need to go 'back and forth'. I dial in the chamber end, drill out the chamber (undersized), dial in the throat and muzzle one last time and bore the drilled hole true. My finish reamers take 10-15 thou to cleanup the chamber. I typically step bore to ensure the reamer can be inserted far enough to engage the pilot in the bore before the body cuts as I use a pusher and w/ 2 points referenced the reamer will track straight. If I can't get the pilot in due to a long case and minimal taper I'll initially feed in with the tailstock center to ensure a 'fairly' true entry. As soon as the pilot is in the bore the Bald Eagle pusher is used.

Man I like that setup tip!

quote:

Originally posted by speerchucker30x378:
Some years back I sat down with one of the guys from Hart and he candidly told me that they cull out anything that was visually cocked off.

I don't know about US barrel makers, but in Europe it is pretty common to inspect barrels visually for straightness and to straighten them on manual spindle press. I have personally seen this at Heym and I know other European makers routinely do the same. If done properly, this has no impact on accuracy.

A lot of the USA barrel makers grade down barrels that don't come off to a certain standard. I think at least Shilen, Douglas and Hart grade down barrels to cheaper status when they don't quite come out right and reserve the best as match grade. I'm pretty sure that a lot of their buzzard grade barrels, have been straightened. I'm pretty sure they don't just throw them out.

We really don't know why some barrels shoot well and others don't. If we did, everyone would be making one holers. I have seen picture perfect barrels what were good for little more than holding up tomato plants. I installed a barrel for a regular customer last year that for all intent and purpose looked like it was whitworth threaded instead of rifled. The lands were also backward to what a ratchet rifled barrel is supposed to be. The idea was to use it ass a fire forming barrel so he didn't care as long as it got up to 55,000 PSI. I stuck it on and the thing shoots right up there with his other stuff so go figure.

The old horse racers adage applies to barrels too: "You breed the best to the best, and you pray for the best."

Dang! More great tips. Thanks Matt and Bill!

I'll definitely follow your setup procedure, Matt, as the dinking around, back and forth from one end to the other sure takes a lot of time.

And, I'll do like you suggest, Bill, with the really wonky ones; that is use separate setups for the chamber and the tenon. You're so right about so many things in general in that there's always a compromise somewhere.

I have no problems with curved barrel as long as I can get it to shoot, it's just been a head scratcher on how to get them setup. It would be nice if they were all dead nuts straight though. That'd be easy!

Thanks again for the great tips everyone!

PWS
To start with. I love your new lathe.

I have a small Monarch with a 1 & 1/8"
thru hole and have not had a barrel that
wouldn't go thru the spindle yet. Good Luck Kenny

I have seen some VERY crooked bores shoot VERY well. My take on it is that the barrel itself is just more of a PITA to chamber, but it will likely perform as well (or much better in a couple enlightening cases) than any other quality barrel that borescopes well and dials in straight. I do have one 6mm barrel blank I've been sitting on that the bore has some severe run-out through the middle. I've marked the direction of run-out and one of these days I'll install it indexed to 12:00 for a varmint rifle and see how it shoots just out of curiosity. I'm pretty certain it will shoot very well, but we will see.

One thing with dialing in a crooked bore, if you are trying to get the throat area centered and concentric, be sure to pay attention to where the pilot of the reamer will be vs. where the throat is. If you dial in where the throat will be, the pilot will be 1/2" ahead of that and may start to pull the reamer off your 'perfect' dial-in. I usually split the difference and dial the bore in 1/4 way up where the pilot will be riding at full-depth. This is most critical on the real funky ones.

quote:

When dialing in a barrel through the headstock, one tip that WILL save you a buttload of time is to leave the screws loose on the inboard side and support the barrel with the tailstock center. Dial in the outboard end then snug up the inboard screws and pull your tailstock back and dial in the bore. Many times you will be so close there's no need to go 'back and forth'.

I chambered a barrel last night using this setup method.......so simple and fast that i felt really stupid for not figgrting iy out myself!

Many thanks for posting!



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JTEX,
I'm glad it helped. I can't claim the idea either as I watched a good friend of mine do it that way and I thought the same thing...why the hell don't I do it that way????