Barrel flute timing?

[Edd]

I'll make this as polite as possible.

I'm not a Gunsmith, but if I was I wouldn't chamber a barrel like that. If those that do aren't embarrassed about work like that, I guess I'll be embarrassed for them.

As for the original question, I think the edge of the forend should be aligned with a rib.

 

[MontanaRifleman]

I'll make this as polite as possible.

I'm not a Gunsmith, but if I was I wouldn't chamber a barrel like that. If those that do aren't embarrassed about work like that, I guess I'll be embarrassed for them.

As for the original question, I think the edge of the forend should be aligned with a rib.

Are you saying you wouldn't clock the barrel so that the curve of the barrel is up?

Why not?

 

[J E Custom]

I see this discussed frequently. There are two ways, that I know of, to dial in a barrel through the headstock. One of these methods will likely leave the need to clock the muzzle. That method seems to be the one most commonly used.

Maybe You and JE could describe how you dial in a barrel blank before chambering.

I am sorry some of you guys are having to deal with a crooked bore. "I DON'T" because the barrels
I use are straight.

As I have said before, you have to work off of the bore and it must be straight, if it is not you will never get the barrel set up correct.

You can't just set up on end or the other. You must set up both ends at the same time and once I
set up with no run out on ether end I am ready to cut the tenon, thread it and chamber it. the barrel is never removed until all work including head spacing and timing flutes is finished.

Then when crowning and/or fitting a muzzle brake the barrel is turned around and the hole process of setting the barrel in the lathe with no run out (Or as good as my last word will measure with no
indication of run out). Also by setting up both ends off the bore true I can do a precision job of boring the brake .020 larger true instead of .030 to .040 larger than the bullet diameter like most are.

Simply put ,You pay enough for a premium barrel and should not except anything less than near perfect.

J E CUSTOM

 

[Edd]

JE, are you able to use this method on a 20" long blank that will have a 5/16" breech cylinder length after threading?

 

[Hired Gun]

No disrespect JE. I know you are aware of the different chambering methods but straight barrels are the exception. The method you are using will not reveal the curve in the bore. Chamber run out will not show up either until the barrel is dialed in front of the throat. I guess I look at barrels as if they are all only 2" long.

The technology currently used to deep hole drill barrels just will not produce a perfectly straight bore. I believe EDM would do it but at what expense? If I were to return every barrel that had a curved bore I would be sending 99% of them back, I would spend the rest of my life waiting on barrels and if I kept sending them back I would eventually get black listed. I'm no stranger to sending them back. There are a few companies that I avoid completely now because they just can't seem to be able to get me a decent one.

Unless the barrel has an exceptionally straight bore, the method you are using to chamber I can spot with my bore scope in just a few seconds and on my lathe in a few minutes. Rifles have been built that way for years and do shoot. After bore scoping lots of sub 1/2MOA factory rifles with really crooked chambers I question just how important getting the bullet into the lands perfectly square really is. My experience though a fraction of yours is undeniable that when a barrel is dialed on both ends at the same time a tenth indicator will only run true right where it was dialed. Move in 1" and it will start showing the curve in the bore.

By dialing in one end at a time I can compensate for the curved bore and get my chamber, perfectly in line with the "bore". (throat to 2 inches farther) To overcome the curve in the bore where the chamber is I have to single point the chamber area to bring it inline with the throat and 2" farther in area that the barrel is dialing into. Otherwise the reamer will just follow the curve in the bore and make the point of dialing in on the throat and 2" into the bore pointless.

This gets the bullets straight into the throat as possible and on the crown end I dial in the last 2" and cut the crown and install brakes in line with that. Accuracy wise we are having incredible luck. Look what Tumbleweed has been doing with the 300 RUM we did for him. I believe he is a some kind of long range savant or something. It's along the line of .2 MOA to 1300 yards. http://www.longrangehunting.com/forums/f28/retumbo-h50bmg-32-300-rum-120250/index5.html#post856860

With respect
Shawn

 

[J E Custom]

JE, are you able to use this method on a 20" long blank that will have a 5/16" breech cylinder length after threading?

I have never tried to build a barrel with only 5/16'' shank but have done lots of factory barrels with only about 1/2 '' of shank Just enough to get a good grip on it with the chuck.

On my Lathe I can do 22.5'' barrels with no problems. shorter than that requires a totally different
set up.

J E CUSTOM

 

[J E Custom]

No disrespect JE. I know you are aware of the different chambering methods but straight barrels are the exception. The method you are using will not reveal the curve in the bore. Chamber run out will not show up either until the barrel is dialed in front of the throat. I guess I look at barrels as if they are all only 2" long.

The technology currently used to deep hole drill barrels just will not produce a perfectly straight bore. I believe EDM would do it but at what expense? If I were to return every barrel that had a curved bore I would be sending 99% of them back, I would spend the rest of my life waiting on barrels and if I kept sending them back I would eventually get black listed. I'm no stranger to sending them back. There are a few companies that I avoid completely now because they just can't seem to be able to get me a decent one.

Unless the barrel has an exceptionally straight bore, the method you are using to chamber I can spot with my bore scope in just a few seconds and on my lathe in a few minutes. Rifles have been built that way for years and do shoot. After bore scoping lots of sub 1/2MOA factory rifles with really crooked chambers I question just how important getting the bullet into the lands perfectly square really is. My experience though a fraction of yours is undeniable that when a barrel is dialed on both ends at the same time a tenth indicator will only run true right where it was dialed. Move in 1" and it will start showing the curve in the bore.

By dialing in one end at a time I can compensate for the curved bore and get my chamber, perfectly in line with the "bore". (throat to 2 inches farther) To overcome the curve in the bore where the chamber is I have to single point the chamber area to bring it inline with the throat and 2" farther in area that the barrel is dialing into. Otherwise the reamer will just follow the curve in the bore and make the point of dialing in on the throat and 2" into the bore pointless.

This gets the bullets straight into the throat as possible and on the crown end I dial in the last 2" and cut the crown and install brakes in line with that. Accuracy wise we are having incredible luck. Look what Tumbleweed has been doing with the 300 RUM we did for him. I believe he is a some kind of long range savant or something. It's along the line of .2 MOA to 1300 yards. http://www.longrangehunting.com/forums/f28/retumbo-h50bmg-32-300-rum-120250/index5.html#post856860

With respect
Shawn

None Taken Shawn.

With the range rods in the bore "on each end" if you move the indicator and it changes you are right.
it is not a straight bore and depending how long your rang rods are the barrel run out will be more than the reading.

With the new technology , a good barrel maker can do amazing things with a barrel and produce
consistent quality If he wants to. Straight bores are not as hard to produce now as in the past when barrel straightening was the norm, and an art of it's own.

As far as experience goes you may have more than I do. I just demand the best quality I can get
because it helps me. (As a Sage gunsmith on this site says, "You cant make a silk purse out of a sows ear".

There are many ways to do things and I only use the ones that work for me. I don't claim to be able to take a poor quality part and make it work great, so I don't use them. With this philosophy I have been able to produce sub 1/2 MOA rifles consistently with most shooting under 1/4 MOA and some under 1/10th MOA. (4 of my personal hunting rifles will shoot under 1/10th MOA).

If I had to make a living at this ,I would probably starve because I take so long to set everything
up before I start, but being retired I can afford this luxury.

Enough Said.

J E CUSTOM

 

[Edd]

shorter than that requires a totally different
set up.

Are you talking about between centers or something else?

 

[Hired Gun]

On barrels too short to reach the tail spider we use our action truing jig. My only reservation about this method is we can't use our high pressure flush system.

 

[Edd]

On barrels too short to reach the tail spider we use our action truing jig. My only reservation about this method is we can't use our high pressure flush system.

Since JE likes to indicate both ends of the barrel, I don't think he is using that method.

 

[foreign]

"By dialing in one end at a time I can compensate for the curved bore and get my chamber, perfectly in line with the "bore". (throat to 2 inches farther) To overcome the curve in the bore where the chamber is I have to single point the chamber area to bring it inline with the throat and 2" farther in area that the barrel is dialing into. Otherwise the reamer will just follow the curve in the bore and make the point of dialing in on the throat and 2" into the bore pointless.

This gets the bullets straight into the throat as possible"

HG, i was wondering if you find any measurable curve in the 2" of bore that you dial in? it make sense to me to dial in the area where you are working as that is where the bullet will seat.
what doesnt make sense to me is the need to single point cut. id imagine that the curve in 2" would be at unmeasurable so the bore should be running true to the lathe spindles center. that should mean that you could just ream the the chamber with reamer and it should turn out square.
The other question i had was when you single point cut how deep do you go. if you went the full chamber depth (minus a little for the reamer) then the shoulder of the reamer will be the first thing to bear as you insert it instead of the bushing on the end in the bore.couldnt that lead to some miss alignment?

thanks for sharing your knowledge and thoughts guys

 

[Hired Gun]

I can measure over 6" up into the bore and do it in tenths. When you measure in tenths any amount of curve looks like a lot considering I hate to see the indicator moving at all. So measuring in tenths it depends on the barrel but most every barrel has quite of bit of curve in 2". I have never seen one perfectly straight. To do the Chey Tac based rounds we have to be able to single point close to 2.5". Cutting to the base of the shoulder to .010" under gets the pilot into the bore long before the body gets much cut. The bushing is close to 1.5" beyond the shoulder on a 338 LM.

 

[foreign]

what dti do you have with a 6" stylus??? or do you use a grizzly type rod?

thanks HG. read something you have written on slugging barrels. very helpful!

 

[Hired Gun]

It's a Grizzly rod supported in a loose lubricated O-ring in the tailstock with a Starrett indicator as close to the barrel as possible.