Indexing a rifle barrel...

[Hal]

It wouldn't make any difference what caliber you used to shoot for indexing. You would go by the center of the group.


Didn't Pope talk about shooting a group ,out of a machine rest,while rotating the barreled action 360*. The group as I recall was a smaller one and Pope stated the hole in the end of the barrel must be in the center.

Hal

 

[STS]

Guys
I finally found the answer to my question,
How far does the POA and POI change,
due to indexing the bbl.

Per info from Mike Ross's articule,
POA and POI can change as much as 2" or more at 50yds,
due to bbl indexing around the clock face positions.

Tia,
Don

I'm way late in this discussion and have not read all the posts but will offer my experience with indexing a RF barrel. I turned a straight section on a straight taper blank between centers with the blank at finished length to isolate the curvature of the bore relative to the outside of the barrel. After chambering I placed the barreled action in my rail gun and fired 2 shots at every 45 degrees until I completed a full rotation. The resulting 'group' was about 3.25 inches at 50 yards.

 

[Nvreloader]

STS

Did you by any chance notice at which index setting/point,
that the group dimensions changed from round to vertical impacts etc,
realizing that a 2 shot group would not show much,
as a 3-5 shot group per index point?

At what index point where the POA and POI closest to each other?

Tia,
Don

I'm way late in this discussion and have not read all the posts but will offer my experience with indexing a RF barrel. I turned a straight section on a straight taper blank between centers with the blank at finished length to isolate the curvature of the bore relative to the outside of the barrel. After chambering I placed the barreled action in my rail gun and fired 2 shots at every 45 degrees until I completed a full rotation. The resulting 'group' was about 3.25 inches at 50 yards.

 

[STS]

I marked the barrel with a sharpie marker relative to the barrel block on the rail gun so I could go back and shoot groups at each 90 degree position. In my case the 6 o'clock position yielded vertical groups with the smallest amount of dispersion. After my testing I set the barrel back the few thousandths necessary to put the barrel in that position when the action was oriented correctly.

 

[Nvreloader]

STS
Thank you for that info,
I have a 17 WSM RF case/bbl I am testing right now,
to see the indexing difference, on a very light bbl size of .625" x 19.5" long.

Can't wait to see the results, if the cross wind ever STOPS blowing long enough.
Have sorted 3000+ cases for rim thickness and Datum lengths, and ammo makes to run several tests.

Tia,
Don

I marked the barrel with a sharpie marker relative to the barrel block on the rail gun so I could go back and shoot groups at each 90 degree position. In my case the 6 o'clock position yielded vertical groups with the smallest amount of dispersion. After my testing I set the barrel back the few thousandths necessary to put the barrel in that position when the action was oriented correctly.

 

[madderg]

As you rotated the barrel and the point of impact changed, do you think that stopping at any given point, that your group sizes would be any different from any other point? I think it's a waste of good time that could be used learning to shoot in the wind. You can tune any variance in the barrel with load development, maybe even a barrel tuner.

 

[okie]

No use in talking in facts around here are they. Below has to do with the OP's question in an email that I just received from Gene Beggs.

Hi Butch

Yes, I found a way to index barrels using a diffrentially threaded bushing between the receiver and tenon threads. It worked perfectly and was invisible in place. The only drawback was that the tenon diameter had to be reduced to accommodate the bushing. I always knew it was safe but the rifle would not shoot the loads I used before without the cases tightening up.

It was an interesting project but I decided it was not worth the extra effort and you sure would not want to place that system in the hands of an amateur who wouldn't leave it alone. I finally decided it was best to simply locate the natural droop of the barrel to the six o'clock position and let it go at that.

Later
Gene

was there a PS article on this?? seems like i remember this?? maybe in a warehouse??

 

[okie]

Have you ever seen a gun owner that isn't?
Just as the Bern Or Hilary Larry

something about the loose screw behind the trigger????

 

[JasonT]

The OCD side of me makes me index straight up (12) or down (6). I can't rest easy if I know the barrel is at 1:00. That's why I index more than anything else

 

[butchlambert]

was there a PS article on this?? seems like i remember this?? maybe in a warehouse??

You have a PM.