timing barrel

[Randfal]

Missing the point.....
Say you dial in the barrel with a range rod at the muzzle. Not in one position, but in two along the length of the rod. Granted there can be some discrepancies in how well the range rod fits but let’s say for sake of argument that it’s running true. Now you have the chamber bore line running true to the centerline axis of the lathe. It’s only accurate AT THAT LOCATION. The muzzle end can be pointed somewhere else. Most really good quality barrels will be very straight and only slight deviations will be measured. Let’s say the OP has a medium quality barrel or one that got past inspection with less than perfect world straightness. If you take that “dialed” in range rod and put it in the muzzle and check with indicators along it’s length you can easiliy have a barrel bore that is not running true to the chamber end. And to be clear I’m talking about a barrel being held stress free at both ends of the lathe(No “bending” of the barrel to make it dial in). If you have one that is bad and you time the high or low side pointing either to the right or left (I just had a Krieger that was off .035” and I’ve never had one from Krieger be that bad, so it even happens to the good barrels on occasion) it doesn’t mean it won’t group at 100 or 500 yards, but there’s other issues. If it’s really bad and you site in the rifle at 100 yards then dial up to 500, 700, 800, or 1000yds etc the path of the bullet is not going to follow the vertical plane it’ll be traveling either left or right and won’t be tracking truly vertical. Think about double rifles(side by sides) they are “regulated” or “timed” to have both barrel’s point of impacts meet at a specific distance. Bullets paths will “cross” after that point and begin to grow apart after that “intersecting” point.

If all you do is shot point blank 100yd or one specific distance where you site in and forget it, then who cares about it. Just shoot it. But if you dialing everywhere in between 50 and 1500 yds. You should time it vertical. After all, it’s all about removing the variables if you can. You benchrest guys should know all about removing variables and not knock a guy for trying to remove a variable.

In answer to the original question: There’s no “fixing” it. You’ll have to move the shoulder back to get the barrel to index and then re-headspace the chamber. Hopefully you threaded the shank enough so you don’t need to lengthen the threads too.

 

[tobnpr]

I remain unconvinced...
Were it not for the effects of barrel harmonics- the very real -and visible- deflection of the muzzle as the shock wave travels back and forth the length of the barrel in milliseconds- "timing" the muzzle end would make sense to me.

We're talking mere ten-thousandths of an inch for a quality barrel.

In this video, you can SEE the muzzle whip- not in ten-thousandths of an inch- but in hundredths:

Now, if anyone can convince me that a muzzle is at exactly the same point in space when that bullet exits, as when it's locked down in spindle, I'll be a convert. For now, high-speed video has me believing that muzzle "timing" is hocus-pocus and not worth the additional labor cost.

As we say on the 'net, JMO.

 

[Randfal]

I remain unconvinced...
Were it not for the effects of barrel harmonics- the very real -and visible- deflection of the muzzle as the shock wave travels back and forth the length of the barrel in milliseconds- "timing" the muzzle end would make sense to me.

We're talking mere ten-thousandths of an inch for a quality barrel.

In this video, you can SEE the muzzle whip- not in ten-thousandths of an inch- but in hundredths:

Now, if anyone can convince me that a muzzle is at exactly the same point in space when that bullet exits, as when it's locked down in spindle, I'll be a convert. For now, high-speed video has me believing that muzzle "timing" is hocus-pocus and not worth the additional labor cost.

As we say on the 'net, JMO.

So what you are saying is, “if you push the muzzle of barrel sideways. It has no effect on point of impact”. Lol
Or put another way.....if I deliberately machine and thread a barrel tenon crooked .030-040” and “time” it so that the barrel when tightened is pointing to the left in the barrel channel it will have no effect on where the gun shoots?
It will shoot to the left and continue to shoot to the left along the entire path of the bullet flight. If you zero your scope at 100yds and then dial elevation for 600yds and shoot at a target at 600yds, the point of impact will be to the left. It would continue to get worse the farther you shoot from your zero.
Group sizes will stay the same. That’s not the point. The point is the point of impact of the group will be off either left or right from your original zero as you move out it range. This is not taking into account any wind influence. I would bet most of us have had a rifle that you could dial in to shoot little bug holes dead center on a target at 100yds and then when you move out to 400-500 yds in perfect calm conditions and find you are grouping to left or right of center without explanation. Then we of course blame the scope, the bags, triggers, tracking etc. and the real problem may be the gun is doing just what it’s supposed to be doing...shooting right where you pointed it.
I tried to draw it up quick on paper for illustration. Lines are exaggerated to try show point.
Timing/indexing the barrel does nothing for group size, it just lines everything up in the vertical plane to try eliminate growing horizontal impact errors when dialing to longer ranges. Makes it a little easier to dial on target at various distances.
This isn’t generally a noticeable problem for higher end barrels but the mid range and factory barrels, they may have enough deviation that Not timing it in the vertical plane can mean the difference between the barrel hitting the side of the barrel channel or not. I tinker a lot with take off barrels and see the extremes in those often enough.

 

[Doug Beach]

So what you are saying is, “if you push the muzzle of barrel sideways. It has no effect on point of impact”. Lol
Or put another way.....if I deliberately machine and thread a barrel tenon crooked .030-040” and “time” it so that the barrel when tightened is pointing to the left in the barrel channel it will have no effect on where the gun shoots?
It will shoot to the left and continue to shoot to the left along the entire path of the bullet flight. If you zero your scope at 100yds and then dial elevation for 600yds and shoot at a target at 600yds, the point of impact will be to the left. It would continue to get worse the farther you shoot from your zero.
Group sizes will stay the same. That’s not the point. The point is the point of impact of the group will be off either left or right from your original zero as you move out it range. This is not taking into account any wind influence. I would bet most of us have had a rifle that you could dial in to shoot little bug holes dead center on a target at 100yds and then when you move out to 400-500 yds in perfect calm conditions and find you are grouping to left or right of center without explanation. Then we of course blame the scope, the bags, triggers, tracking etc. and the real problem may be the gun is doing just what it’s supposed to be doing...shooting right where you pointed it.
I tried to draw it up quick on paper for illustration. Lines are exaggerated to try show point.
Timing/indexing the barrel does nothing for group size, it just lines everything up in the vertical plane to try eliminate growing horizontal impact errors when dialing to longer ranges. Makes it a little easier to dial on target at various distances.
This isn’t generally a noticeable problem for higher end barrels but the mid range and factory barrels, they may have enough deviation that Not timing it in the vertical plane can mean the difference between the barrel hitting the side of the barrel channel or not. I tinker a lot with take off barrels and see the extremes in those often enough.

If your barrel is pointing left at an angle, say 5 minutes (1/12°), and you adjust your scope to compensate for this at 100 yards, it will also compensate at 200, etc, because the angle remains the same. You may well experience left / right movement of your group as you get farther from your target, but it’s not due to your barrel angle.

 

[natdscott]

Competitive shooters need to time their barrels. Particularly the Highpower crowd.

 

[Dusty Stevens]

If the bullet exits when the barrel is in motion passing exactly 12:00 all you gotta do is wait til it gets 5 deg hotter and itll exit at 11:45.... or maybe 12:40. Yall keep on timing. I do it but i know what really happens. High speed video never lies.

 

[natdscott]

Competitive shooters need to time their barrels. Particularly the Highpower crowd.

Come onnnnn....

nobody is gonna take me up on my little trrrolllllll ?

 

[jrm850]

Come onnnnn....

nobody is gonna take me up on my little trrrolllllll ?

I'll time them all. Just send a note saying which direction you want them pointing and I'll make it happen.

We actually had one of these in gunsmith school 30 years ago but I never saw it used on anything.

 

[natdscott]

hahahaha

 

[Stan Taylor]

I'll time them all. Just send a note saying which direction you want them pointing and I'll make it happen.

We actually had one of these in gunsmith school 30 years ago but I never saw it used on anything.

That works real well trying to straighten the old muzzleloader barrels but if you attempt that on a button rifled barrel it will go right back where it was soon as you turn it Yes you can get by on cut rifled barrels to a minimum.We took a reamed hole that was crooked about 27 inches long an ground 3 places on it each end an the middle with a cylinder grinder between centers until it was a zeroes on each spot that was ground an put in this barrel straightener until the hole was straight an set it up on the dial indicator that hole from one end to the other was only out .0004 thousands in 27 inches.

 

[jrm850]

View attachment 1128604
That works real well trying to straighten the old muzzleloader barrels but if you attempt that on a button rifled barrel it will go right back where it was soon as you turn it Yes you can get by on cut rifled barrels to a minimum.We took a reamed hole that was crooked about 27 inches long an ground 3 places on it each end an the middle with a cylinder grinder between centers until it was a zeroes on each spot that was ground an put in this barrel straightener until the hole was straight an set it up on the dial indicator that hole from one end to the other was only out .0004 thousands in 27 inches.

Sweet! Spongebob and Fred Flintstone. I like your style. Is the barrel straightener yours?

 

[Stan Taylor]

No that belongs to the company I work for at Douglasbarrelsinc we used to make oodles of muzzleloader barrels back in the day it's part of the establishment hasn't been used in 25 years ago been here 30 yrs myself.

 

[Alex Wheeler]

I have chambered between centers, dialed both ends in the headstock, as well as dialed only the breach end. So I have experience with each method. In my opinion the most important part of the barrel is the throat. I want the throat concentric with the bore at the throat and in front of it. I do not want the section of bore that the bullet is going to enter running on a different plane than the chamber even if they both meet at the freebore, so I dial that section of the barrel. You will naturally have runout at the muzzle end. Thats the lesser of 2 evils in my opinion. In my experience I find throats come out better for me in this fashion. No matter how crooked the bore, the throats all look the same, and I have not been able to see any difference in accuracy between the straightest vs the ones that run out the most. I have tracked some of the extremes to see if I could find something there. Heres a good way to check your work. A dial indicator point will leave a faint line in the surface finish of a bore. You can see it in the bore scope. If you dial in the barrel just in front of where the freebore ends you will see a faint line in the bore very close to the end of the cut. That line is your reference point, a perfect throat will have the same gap from the end of the cut to that line. As to indexing, theres more than one way to do it depending on the section of bore you want to control. No doubt these are small things and guys have had success with all methods. My advise is to decide what is important to accuracy in your mind, then learn how to check your work and develop a method to give you the most consistent results.

 

[dmoran]

Sweet! Spongebob and Fred Flintstone. I like your style. Is the barrel straightener yours?

Might as well call it his, for @Stan Taylor has worked at Douglas barrels for like 100-years....

 

[jrm850]

No that belongs to the company I work for at Douglasbarrelsinc we used to make oodles of muzzleloader barrels back in the day it's part of the establishment hasn't been used in 25 years ago been here 30 yrs myself.

My first blank was a Douglas almost exactly 30 years ago. I was a student at CST then and pretty sure we all used a Douglas that year. I still have that rifle today.

 

[PWS]

....
Now, if anyone can convince me that a muzzle is at exactly the same point in space when that bullet exits, as when it's locked down in spindle, I'll be a convert. For now, high-speed video has me believing that muzzle "timing" is hocus-pocus and not worth the additional labor cost.

As we say on the 'net, JMO....

Is it not that the barrel is "exactly the same point in space when the bullet exits" but that the barrel moves in the same way every time the bullet exits?

Since movement is unavoidable, it would make sense to orient the barrel in a direction that encourages the most consistent movement.

Granted, the direction the barrel is pointing is probably well "within the noise" of factors influencing consistency and, in most instances, not worth the additional labor

 

[sdean]

Might as well call it his, for @Stan Taylor has worked at Douglas barrels for like 100-years....

I thought he owned the place

 

[tobnpr]

Is it not that the barrel is "exactly the same point in space when the bullet exits" but that the barrel moves in the same way every time the bullet exits?

Bingo.
For those that subscribe to OCW theory, that's exactly it.
Finding the bullet/load combination that results in the most consistent barrel harmonics. We all know accuracy is nothing other than consistency.

All I'm saying is that I do not believe in most cases we can control- by " timing", where the muzzle is pointing when the bullet exits. I completely concur that dialing the throat area can be beneficial if dialing in a chamber as that's a different issue of sending the boolit precisely into the center of the bore.

We all do what we think works. It's also different for DIY where maybe time isn't as critical, and you reason "it can't hurt" to spend the extra time.
Different considerations are in play when it's paid work.

 

[dmoran]

I thought he owned the place

He might... .... or he at least comes with the place...

 

[Dusty Stevens]

He might... .... or at least comes with the place...

Like a cat out by the dumpster.