Dialing-in Dystopia

[Henryrifle]

So, I've been hanging out in this forum for a while and have picked up some things from y'all. I have a cool new chamber flush system that has saved several hours during the reaming process. This was a great thing to copy!!!

I recently picked up an inboard spider for my lathe and thought I'd try it out this weekend. I've been out of town all week for work and could really use some down time focusing on something I normally enjoy.

Until this weekend, I have "dialed-in" using a range rod. I've had good results using that method--high master at midrange in both F-TR and F Open and several state mid-range championships and a regional championship along the way.

Like many here, I've learned from watching Gordy Gritters videos and reading his books. Bob Pastor has a few very helpful videos on chambering that show the entire process--and he's a lot of fun to talk to.

In my mind, I think the range rod gives you an average of the runout over the distance you are measuring and let's you split that in half. Unfortunately it is not very repeatable. I usually withdraw the rod, turn it 90 degrees and re-zero. I keep doing this until I get consistent results. This is probably not really changing much.

Direct indicating seems like a better approach--something y'all have been talking about lately. After installing the inboard spider, I loaded in a new barrel, got it close with the range rod and drilled it with a 3/8 drill a little more than an inch. I am chambering this barrel as a .284 and wanted the pilot to engage the lands as I only have floating reamer holders.

I put the freebore area underneath the inboard spider and dialed in with a Mitutoyo 513-504 DTI with the mid-length 1.33" contact point understanding that any deviation was a little over twice what the gauge was reading. That wasn't to hard to get to zero after cleaning the barrel with alcohol several times...

I changed to the longer 2.65" contact point and indicated on a point approximately 1.5" ahead of the freebore area. Using the outboard spiders I can get it close but every .0001 on the gauge is really .00045! I can not get the gauge to zeros in all grooves. The the best I can do is about .00005 on the gauge which is about .00023.

The Mitutoyo is a small gauge and I am using magnified headsets to make sure of the readings. I've kept both inboard and outboard spiders relatively loose trying to minimize any distortion of the area I want to indicate. I am guessing that I'd have better luck If I drilled further and used the shorter contact point. Is this about right are are y'all able to get both positions reading dead zero?

I am not so happy about copying this technique at this time...

I am glad I am not doing this for a living--my family would be very skinny!

Thank you for any feedback positive or negative,
Hank

 

[Dusty Stevens]

Try to use deltronic pins. They fit better than a bushing on a rod. I use the rods to find the correct bushing size i want, use deltronic pins for the outboard and direct indicator for the throat. Just find a method that checks out in the end. If a flush ststem saved you hours in reaming you werent doing it right to start with. A flush system saves me 10mins worst case. I dont even mess with the mess anymore.

 

[LVLAaron]

I follow Gordy's process so hopefully, I can help.

- If using rods, hang a small weight on them to take up as much slack as possible. I don't generally use them other than to find the right bushing or look for a tight spot. I'll dial the outside of the barrel and switch to the bore.
- The mity tenths indicator seems fine with the 1.5 inch, but is a total mess with the ~3 inch. Avoid.
- Don't be afraid to pre-bore more out. You want to dial at the start of the throat, and in front of that (if following gordy's method, not here to start a flame war on methodology). If you pre-bore straight the reamer will go in and stay straight. If it's all dialed correctly. You don't need the pilot.

I recently got the interapid long reach indicator... and it's much more suited for the long stem. It doesn't fit in the pre-bored chamber the way the little mity does so some adjustments to method need to be made... but that's another topic.

edit:
I'll put a mark on the barrel where the start of the throat will be. Make sure that's your inboard pivot point, or you'll chase your tail.

 

[INTJ]

Get one of these:

Interapid Test Indicator 312B-15V, Vertical, 0.060" Range, 1-1/2" Dia., 0.0005" Graduation - 12-015-4

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I stopped using Grizzly rods a while ago. Tolerance stacking, rod bending, and all that. I have never used range rods since they don't dial in the throat. While there are lots of ways to get there, with whatever you do, dial in the throat with a direct reading indicator.

I start by dialing in the outside of the barrel first with a plain .001" dial indicator. I first dial in the outboard portion of the barrel using the outboard spider, then I dial in the inboard part of the barrel with the inboard spider. I get it to .001", with the goal being getting the barrel fairly straight though the headstock.

I then go to the Interapid, a 312B-15V. It has a 2.75" tip. This is the VERTICAL version that rotates the correct way--clockwise for increasing height. The horizontal version rotates backwards.

I position the throat area of the chamber at the pivot point of the inboard spider. Using the Interapid I dial as tight as I can using the inboard spider. Then I go back to about 1/2" in from the breech and dial in using the outboard spider. I go back and forth until I am happy with the dial in.

If the breech is especially ugly I'll ream out the rifling using a chambering reamer before completing dial in. I don't prebore here as I don't want to correct anything yet. I just want a smooth surface to finish the dial in. Some carbon barrels seem to have different rifling heights at the breech, and the the chamber reamer fixes that so I can get a good dial in.

I can have a good fairly straight barrel dialed in quickly this way and because I am direct reading I know it's true. A bad barrel takes longer......

 

[Henryrifle]

Starting with what I think I understand:

• Get the bore straight enough to start the following steps (several ways to accomplish this)
• Put a mark on the barrel where the throat will be
• Barrel pivot point should be at marked freebore location
• Dial in freebore section using inboard spider
• Dial in area ahead of the freebore toward the muzzle with outboard spider - I used about 1.5 inches.
• Recheck both for zero - several times...

I did the above things after getting the bore straight with a range rod - very imperfect tool, no argument.

Dialing in the area ahead of the freebore (toward the muzzle) is not as easy with the outboard spiders as it was with the range rod. If the grooves are lined up with he inboard spider at the throat, they aren't further forward and I ended up having to loosen and tighten two of the outboard spiders at a time. Took a while to get the hang of that...if you really can.

I cut and threaded the tenon and profiled for the coned bolt followed by a recheck of zero with the Mitutoyo. I had to make some small adjustments to bring it back to perfect.

I agree that the Mitutoyo does not feel as precise with the longer contact point but is repeatable though it takes a lot of patience to carefully read that tiny gauge face...

Don't understand:

Ream the chamber without a pilot bushing? Are y'all doing that with a floating reamer holder? I could see doing that with a fixed and trued holder. I use a Manson floating reamer holder and to this point would not dream of chambering w/o a bushed piloted reamer. Why would anyone do that? What harm could come from the pilot?

Grey Area:

I did not pay any attention to the bore between the freebore and breach other than when I centered it up with the range rod to start -- sounds like that might have been a mistake?

That Interipad is expensive (!!!) and looks like a .0005 gauge. So, it's a lot bigger but with much less resolution. How is it used to indicate the freebore and beyond on a cartridge like a .284? The case is about 2.20" long so, you have about 1/2" to play with.

I locked the Mitutoyo in my Jacobs chuck and was able to easily gauge depth with the tailstock. How do you hold the vertical Interipad?

Thank you all for the long read(s) and for sharing your knowledge. I appreciate the learning and sharing here...

Hank

 

[INTJ]

Starting with what I think I understand:

• Get the bore straight enough to start the following steps (several ways to accomplish this)
• Put a mark on the barrel where the throat will be
• Barrel pivot point should be at marked freebore location
• Dial in freebore section using inboard spider
• Dial in area ahead of the freebore toward the muzzle with outboard spider - I used about 1.5 inches.
• Recheck both for zero - several times...

I did the above things after getting the bore straight with a range rod - very imperfect tool, no argument.

Dialing in the area ahead of the freebore (toward the muzzle) is not as easy with the outboard spiders as it was with the range rod. If the grooves are lined up with he inboard spider at the throat, they aren't further forward and I ended up having to loosen and tighten two of the outboard spiders at a time. Took a while to get the hang of that...if you really can.

I cut and threaded the tenon and profiled for the coned bolt followed by a recheck of zero with the Mitutoyo. I had to make some small adjustments to bring it back to perfect.

I agree that the Mitutoyo does not feel as precise with the longer contact point but is repeatable though it takes a lot of patience to carefully read that tiny gauge face...

Don't understand:

Ream the chamber without a pilot bushing? Are y'all doing that with a floating reamer holder? I could see doing that with a fixed and trued holder. I use a Manson floating reamer holder and to this point would not dream of chambering w/o a bushed piloted reamer. Why would anyone do that? What harm could come from the pilot?

Grey Area:

I did not pay any attention to the bore between the freebore and breach other than when I centered it up with the range rod to start -- sounds like that might have been a mistake?

That Interipad is expensive (!!!) and looks like a .0005 gauge. So, it's a lot bigger but with much less resolution. How is it used to indicate the freebore and beyond on a cartridge like a .284? The case is about 2.20" long so, you have about 1/2" to play with.

I locked the Mitutoyo in my Jacobs chuck and was able to easily gauge depth with the tailstock. How do you hold the vertical Interipad?

Thank you all for the long read(s) and for sharing your knowledge. I appreciate the learning and sharing here...

Hank

The Interapid is a very high quality indicator and it's easy to see .0001" of movement. IIRC, @DaveTooley found the Interapid was accurate to .0002", which is my personal standard for dialing in. Much easier for me than with the .0001" Mity, which I have but almost never use anymore. You don't need to go a lot past the throat area when dialing in. The goal is just to have the bullet start straight. I do have a 5.5" tip for my Interapid, and it's kind of a pain to use. I wish I could get one that was about 3.25" long--might have to make it. Still, I think direct reading off the rifling is the most precise way.

The way you dialed in at the breech then forward of the breech is a very good way. It does require that you drill and prebore, which you are doing. If I ever start drilling and preboring, and I probably will, that is how I will do it too. Since I am nor drilling and preboring than its critical I get the breech end straight as well.

I am not undertsanding the difficulty you are having manipualting the spider. I also don't know what you mean by "two outboard spiders". I have one outboard and one inboard spider. I used to use a 4-Jaw, but when I started chambering barrels for customers last year at work I went to an inboard spider. The other day at home I started to dial in a abrrel with my 4 Jaw. I hated it so much that I pulled the barrel, yanked the 4 jaw, and built an inboard spider for home.

The spider is so easy to manipulate. At first I use two Allen wrenches because the initial adjustments are bigger. After that it's one Allen and it goes fast.

 

[LVLAaron]

Regarding no pilot... I use a JGS that keeps the reamer centered-ish. If I understand the manson might not do that... in which case I can provide not comment.

 

[Shawnba67]

Don't understand:

Ream the chamber without a pilot bushing? Are y'all doing that with a floating reamer holder? I could see doing that with a fixed and trued holder. I use a Manson floating reamer holder and to this point would not dream of chambering w/o a bushed piloted reamer. Why would anyone do that? What harm could come from the

Thought exercise. What good can it do?
You indicated to 0.0001 now your guide only holds 0.0003 and the reamer IS going to follow your prebore. Your bushing IS going to follow your elliptical bore. So why add extra tolerance and a crooked path to all your aligned work?
Cut one with out tge bushing on a scrap barrel stub see if it impacts your results

 

[Henryrifle]

@Shawnba67 - I like the way you think. In that thought experiment, how is the reamer being held? And a follow-on question. How is a reamer supposed to be held? It would seem that if pilots are less useful than I imagined that you'd have the choice between reamers as I know them today and those that have no pilot and stop at the end of the ramp.

For clarity, I am only focused on HSS reamers.

Thank you,
Hank

 

[Dusty Stevens]

@Shawnba67 - I like the way you think. In that thought experiment, how is the reamer being held? And a follow-on question. How is a reamer supposed to be held? It would seem that if pilots are less useful than I imagined that you'd have the choice between reamers as I know them today and those that have no pilot and stop at the end of the ramp.

For clarity, I am only focused on HSS reamers.

Thank you,
Hank

Dont get too far into the weeds. Just start chambering and ask questions as you go and test your results. Youll get so far out into left field on here youll never be able to start

 

[LVLAaron]

^ 100 percent. You learned from Gordy. Do what he taught you until you're comfortable to experiment with making changes.

 

[sdean]

^ 100 percent. You learned from Gordy. Do what he taught you until you're comfortable to experiment with making changes.

All these discussions just make you buy more tools. There aren't enough feet and toes to count the winning rifles just indicated throat and muzzle. Just as many Gordy way. Although they were doing it that way before him. Pushers,floaters and solid all can work too. How many you think won just running the reamer in with a steady. If you don't prebore you just as well use a steady in my humble opinion. There is no way to prove any of this. Moral of the story to me is there is a lot more to a winning rifle the how you indicate or chamber a barrel. I don't hear anyone talking about what they do to an action. As Butch says, whatever makes you warm and fuzzy.

 

[LVLAaron]

All these discussions just make you buy more tools. There aren't enough feet and toes to count the winning rifles just indicated throat and muzzle. Just as many Gordy way. Although they were doing it that way before him. Pushers,floaters and solid all can work too. How many you think won just running the reamer in with a steady. If you don't prebore you just as well use a steady in my humble opinion. There is no way to prove any of this. Moral of the story to me is there is a lot more to a winning rifle the how you indicate or chamber a barrel. I don't hear anyone talking about what they do to an action. As Butch says, whatever makes you warm and fuzzy.

I said to do what Gordy taught because that is what that individual knows best. No one wants to argue who's method is best.

 

[sdean]

I said to do what Gordy taught because that is what that individual knows best. No one wants to argue who's method is best.

That's my point. I don't think there is a best. I spent 3 private days with Gordy and we didn't chamber all my barrels HIS way. Best money I have spent was on Gordy.

 

[Henryrifle]

@sdean - Good points. Some of this is learning and some of this is playing but all of it is experience. I don't love the lathe but I do appreciate being in full control of the rifle building process and when match results are good, then I know that a lot of things went right -- very rewarding.

It is informative to hang out with y'all and learn new stuff. One day I will contribute back some of the stuff I will have no doubt learned from you guys and stuff I learned on my own.

Thank you and many others for the good, realistic, practical and informative feedback...

Hank

 

[LVLAaron]

That's my point. I don't think there is a best. I spent 3 private days with Gordy and we didn't chamber all my barrels HIS way. Best money I have spent was on Gordy.

If it's the way he knows, it's the best way for him, at the moment.

 

[tobnpr]

• Barrel pivot point should be at marked freebore location
• Dial in freebore section using inboard spider
• Dial in area ahead of the freebore toward the muzzle with outboard spider - I used about 1.5 inches.

Basic stuff:
Indicating is based upon getting two- and ONLY two- points running true, to each other and the axis of rotation- the concept is extremely simple, though this gets over-complicated somehow.

Which two locations you choose are subjective. Some choose the muzzle end and throat, I choose the throat and the breech because I don't much care what the muzzle end is doing (some "clock" the muzzle end- but that is unrelated to the barrel setup). You're indicating two points- not a two or three inch section of barrel. It's worth noting that premium barrels are air-gauged- Shilen advertises .0001 uniformity. Uniformity of diameter, isn't straightness tho... which is why we choose to do this to begin with.

INTJ mentions Bruce Thom- his rigid setup is different/doesn't use an outboard spider- but he stated that he indicates the throat area over roughly the length of a reamer bushing.

As LVLAaron stated, the point at which your barrel pivots on the inboard spider needs to be the furthermost "in" point you choose to indicate. I choose just inside the breech for my second point, to get the area from the throat back lined up. Once pre-bored, any variations that might be there are made true between those two points. Visualize what you're doing (or trying to do)- When you work the inboard spider (your pivot point), you're moving THAT specific location. When you work the outboard spider, you're moving the ass end of the barrel- (your throat at) the pivot point is not moving. Make sure you're indicator is set up in-line with the direction of movement. If your spiders screws are oriented at 12:00, 3:00, 6:00, and 9:00- and your indicator tip is at 4:30, you'll be frustrated in very short order.

I found that modifying the brass screw tips with ball bearings in V-blocks allows much more freedom of movement. With the screws moderately tight- I can still freely pivot the barrel breech from the muzzle end with minimal effort. This assures that the barrel WILL move, rather than fighting against resistance and lightly bending the barrel.

We all overthink this, but you said yourself that you've been winning with the Grizzly rod method.
Keep in mind that 20 years or so ago, that method WAS state-of-the-art...
Now, some are trashing it? Gimme a break.
It works just fine when done correctly as you've found out. Is direct indicating better? I believe it is, or I wouldn't have switched to it. Before through-the-headstock came about, everyone chambered in the steady rest- which is still a very viable method for all but the most demanding accuracy requirements.
To be candid- chambering in the steady will be MUCH better than a barrel that's been improperly set up in the headstock. You'll see borescope pics of non-concentric leades that are horribly crooked to the bore done through the headstock- it's impossible for that to happen in the steady rest. Not as precise as dialing- but it's certainly not "hackery".

Getting into the weeds makes for interesting theory/discussion- and some very good ideas. At the end of the day, there's many different ways to get "there"- and regardless of the method used the barrel will shoot better than 99% of those driving the rifle can realize.

 

[LVLAaron]

^ Well said.

I need to give the v-block thing a try. I might try and make some soft jaws, cross-drill and install some brass rods in there. I really like that setup.

 

[INTJ]

If it's the way he knows, it's the best way for him, at the moment.

I think that is an important point. Our method of dialing in will change as we gain experience chambering barrels. What is best when we start probably isn't best at 50 or 100 barrels in, and the 100 barrel method probably isn't best when we are at 1000 barrels.

Some here have and elsewhere have talked about how many championship barrels have been chambered just by dialing in the throat and muzzle. That is yesterday's news.

A better evaluation of dialing in methods would be how have recent top shooting BR barrels been chambered. BR, both SR and LR, is where very little differences do indeed make a difference and show up on the target. That is the discipline where this mystical 1% of the shooters exist that can shoot a barrel to its potential.

That said, I--like many here--have chambered barrels that are so straight it probably wouldn't matter how you dialed them in. I have chambered others that were so crooked it probably didn't matter how you dialed them in. And my best two shooting LRBR barrels so far were dialed in with Grizzly rods, but checked with an Interapid.

 

[Larry Boers]

Basic stuff:
Indicating is based upon getting two- and ONLY two- points running true, to each other and the axis of rotation- the concept is extremely simple, though this gets over-complicated somehow.

Which two locations you choose are subjective. Some choose the muzzle end and throat, I choose the throat and the breech because I don't much care what the muzzle end is doing (some "clock" the muzzle end- but that is unrelated to the barrel setup). You're indicating two points- not a two or three inch section of barrel. It's worth noting that premium barrels are air-gauged- Shilen advertises .0001 uniformity. Uniformity of diameter, isn't straightness tho... which is why we choose to do this to begin with.

INTJ mentions Bruce Thom- his rigid setup is different/doesn't use an outboard spider- but he stated that he indicates the throat area over roughly the length of a reamer bushing.

As LVLAaron stated, the point at which your barrel pivots on the inboard spider needs to be the furthermost "in" point you choose to indicate. I choose just inside the breech for my second point, to get the area from the throat back lined up. Once pre-bored, any variations that might be there are made true between those two points. Visualize what you're doing (or trying to do)- When you work the inboard spider (your pivot point), you're moving THAT specific location. When you work the outboard spider, you're moving the ass end of the barrel- (your throat at) the pivot point is not moving. Make sure you're indicator is set up in-line with the direction of movement. If your spiders screws are oriented at 12:00, 3:00, 6:00, and 9:00- and your indicator tip is at 4:30, you'll be frustrated in very short order.

I found that modifying the brass screw tips with ball bearings in V-blocks allows much more freedom of movement. With the screws moderately tight- I can still freely pivot the barrel breech from the muzzle end with minimal effort. This assures that the barrel WILL move, rather than fighting against resistance and lightly bending the barrel.

We all overthink this, but you said yourself that you've been winning with the Grizzly rod method.
Keep in mind that 20 years or so ago, that method WAS state-of-the-art...
Now, some are trashing it? Gimme a break.
It works just fine when done correctly as you've found out. Is direct indicating better? I believe it is, or I wouldn't have switched to it. Before through-the-headstock came about, everyone chambered in the steady rest- which is still a very viable method for all but the most demanding accuracy requirements.
To be candid- chambering in the steady will be MUCH better than a barrel that's been improperly set up in the headstock. You'll see borescope pics of non-concentric leades that are horribly crooked to the bore done through the headstock- it's impossible for that to happen in the steady rest. Not as precise as dialing- but it's certainly not "hackery".

Getting into the weeds makes for interesting theory/discussion- and some very good ideas. At the end of the day, there's many different ways to get "there"- and regardless of the method used the barrel will shoot better than 99% of those driving the rifle can realize.

I agree with all statements above except chambering on a steady would be less accurate. If you go to the NBRSA site under world records (unlimited records) you will see 5 records set with barrels chamber with a steady rest.

Larry