Indicating Barrels to chamber

[urbanrifleman]

here's a couple of pics of the 223 chamber. Opposite sides of the throat.View attachment 1235007View attachment 1235008

Considering the math of the angle of the throat showing even the tiniest run out (as Alex Wheeler stated), these chambers are effectively at zero run out. Not truly zero, but effectively zero.

I would think at this point, the chamber would be a non factor.

 

[dnellans]

here's a couple of pics of the 223 chamber. Opposite sides of the throat.View attachment 1235007View attachment 1235008

Dave is that a 5R barrel with the R only on the "left" side of the the land? it looks asymmetric to me

 

[dnellans]

I would find it very hard to believe the chambers shown in your video would be the limiting factor in your groups.

Those look pretty darn incredible to me.

If only I could find out what the limiting factor is without testing 1000 things independently... I'd be the best shooter in the world

 

[urbanrifleman]

If only I could find out what the limiting factor is without testing 1000 things independently... I'd be the best shooter in the world

The shooter.

Amazing how the same guys keep ending up at the top no matter the equipment.

 

[DaveTooley]

Very seldom do I pull out my bore scope. Inspecting a throat takes about 10 seconds using one of these. Shadows provide depth perception. I can see concentricity and finish. It's easy to see a tenth or two misalignment in the throat.
You don't want more power as the higher you go the shorter the focal length gets.

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[ridgeway]

The only thing that I may add, be careful practicing on worn barrels. If you do, cut a healthy amount off to get ahead of the fire cracking. Reason being, that area can have the hard carbon embedded or a harder metal surface. You can toast a HSS reamer in a second.

 

[dnellans]

The shooter.

Amazing how the same guys keep ending up at the top no matter the equipment.

I don't mean to sound like an *ss, but that is the most tired line in shooting and also completely untrue. The guys who end up at the top are using the best equipment -and- have skill. Factory 700's would be fine for everyone and hold all the records if the equipment didn't actually matter. Buy as many points as you can, earn the rest.

 

[urbanrifleman]

I don't mean to sound like an *ss, but that is the most tired line in shooting and also completely untrue. The guys who end up at the top are using the best equipment -and- have skill. Factory 700's would be fine for everyone and hold all the records if the equipment didn't actually matter. Buy as many points as you can, earn the rest.

That is NOT what I said. I never said they don't use the best equipment. But most likely is the same equipment as most everyone else, for the most part. By lots of gunsmiths. Over many years. Lots of different barrels, lots of chambers, lots of bullets, etc etc

 

[dnellans]

Here is chamber on my first 223 mentioned earlier. I haven't shot it yet.

 

[tobnpr]

As we drift off topic...
IMO it depends on the discipline.
Different types of skills involved.
We have a newly-opened 2000 yard range a reasonable drive away. Recently hosted a PRS match.
Barricades were still up when we were there a couple of weeks ago, so I figured what the hell...

Of course- I didn't have the "right" equipment- bags, etc.- even a correct rifle for the task- but for a guy that can bang steel pretty consistently out to 1200 I was quickly humbled by trying to hit steel at 700 balancing a rifle on an unstable barricade. Of course- an accurate rifle is needed for this type of shooting, but nothing near the level of accuracy to compete in benchrest. Far more about the shooters' technique, ranging skills, and physical shape from what I gathered in my little "experiment"- than whether the rifle can shoot one hole off a bench.

Definitely generated enough interest on my part to do some research and build myself a PRS rifle...

 

[Alex Wheeler]

Here is chamber on my first 223 mentioned earlier. I haven't shot it yet.

That looks great. You can always get away with good enough. But once you know how well you can do something why would you ever do it to a lesser level? Usually we say we want every groove to look the same. Thats true. But I have seen barrels that had ratchet in only one groove. These have not been top grade barrels. Im not even sure how a cut barrel could have ratchet in just one groove but I have seen it more than once. Nothing you can do to make those look right. Just pay attention to everything you see.

 

[DaveTooley]

As we drift off topic...
IMO it depends on the discipline.
Different types of skills involved.
We have a newly-opened 2000 yard range a reasonable drive away. Recently hosted a PRS match.
Barricades were still up when we were there a couple of weeks ago, so I figured what the hell...

Of course- I didn't have the "right" equipment- bags, etc.- even a correct rifle for the task- but for a guy that can bang steel pretty consistently out to 1200 I was quickly humbled by trying to hit steel at 700 balancing a rifle on an unstable barricade. Of course- an accurate rifle is needed for this type of shooting, but nothing near the level of accuracy to compete in benchrest. Far more about the shooters' technique, ranging skills, and physical shape from what I gathered in my little "experiment"- than whether the rifle can shoot one hole off a bench.

Definitely generated enough interest on my part to do some research and build myself a PRS rifle...

"Only accurate rifles are interesting" Townsend Whelen

 

[DaveTooley]

That looks great. You can always get away with good enough. But once you know how well you can do something why would you ever do it to a lesser level? Usually we say we want every groove to look the same. Thats true. But I have seen barrels that had ratchet in only one groove. These have not been top grade barrels. Im not even sure how a cut barrel could have ratchet in just one groove but I have seen it more than once. Nothing you can do to make those look right. Just pay attention to everything you see.

And after everything.
The target tells all.

 

[DR_2297]

Here is chamber on my first 223 mentioned earlier. I haven't shot it yet.

the last 22 cal Bartlein 5R I did (for myself incidentally) had the same “sawtooth” profile on each groove. There was no discernible difference between any land or groove. Don’t think I could cut a chamber any more coaxial. Shoots fairly well too - .3 moa (10 shot groups @ 200).

 

[338 Mollett]

All this Nth degree dialing in boils down to the gunsmith covering his butt if the barrel does not shoot !!

 

[Alex Wheeler]

I do not agree. I do the best I can to make sure the barrel has the best chance. Barrels that do not shoot are very rare. I dont understand the resistance to doing the best possible work? Seems like I see this often.

 

[DaveTooley]

the last 22 cal Bartlein 5R I did (for myself incidentally) had the same “sawtooth” profile on each groove. There was no discernible difference between any land or groove. Don’t think I could cut a chamber any more coaxial. Shoots fairly well too - .3 moa (10 shot groups @ 200).

The sawtooth look is the intersection of the freebore diameter, a finite line, and the groove diameter, an irregular surface. Thus the saw tooth appearance. Remember we're talking in millionths here.

 

[DR_2297]

The sawtooth look is the intersection of the freebore diameter, a finite line, and the groove diameter, an irregular surface. Thus the saw tooth appearance. Remember we're talking in millionths here.

What I was speaking of I guess is better termed a ratchet. Not the irregularity across the groove intersection. The squiggly line isn’t parallel to the axis.

 

[Alex Wheeler]

Ratchet is when the cut looks angled, indicating one side of the groove was cut deeper. When you see a concave or convex cut I call that radius error, the cutter radius is off a little and cuts deeper at each edge or in the middle. Yours has a tiny amount of each, overall its pretty good. I dont find that small amounts of either have an effect on accuracy. They do make it harder to dial the barrel in as well. I dont like an excessive amount of ratchet. I do feel those barrels have been under performers. Not terrible but enough that I have noticed it. That could just be that it would be much harder to control the volume of the bore with a lot of ratchet. Fitting the barrel's volume the bullet size does have an effect on velocities achievable and accuracy. Theres a line in the sand. Seems that you can make very fast barrels but at some point the accuracy starts falling off. You can go bigger than Id have thought though.

 

[DaveTooley]

Dave is that a 5R barrel with the R only on the "left" side of the the land? it looks asymmetric to me

Yes it is 5R. Not the best pics but there is a difference in the angle used on either side. One side drives and the other follows.