Multiple Impact Barrels: POI differences between them

[LeadFinger]

What zeroing process do you guys go through when you change calibers on the Impact?

At 15 yards, it takes 20 elevation clicks (up) and 57 windage clicks (right) to zero the .25 barrel after I pull the .30 out.
I understand the elevation being off, but the windage difference sounds insane.

 

[RJGTA]

Just thinking out loud but It might be your cant. Are you using a level? 

 

[Willie14228]

Is the rifling twist rate different in the two calibers? It does sound a bit extreme 

im assuming that the barrel is indexed and can only be installed one way? Almost sounds like it is being installed 180deg off 

 

[LeadFinger]

It's dead level. And there is only one way to insert Impact barrels. 

I looked for a thread on this and couldn't find one. 

 

[T3PRanch]

If I recall according to Ernest the thumb screw that secures the barrel can be over tightened giving a pretty significant windage shift.

Thurmond

 

[weatherby]

It is very hard to align different barrels in the same gun.
Barrels are just about never machined in such a way that the poi is about the same.
I machined a .25 cal barrel for my impact, and the poi between the .25 and .30 barrel is only a couple of clicks away. I guess I'm just lucky
Record the poi shift like you did, and work from there. The grouping is way more important anyway, just dial in the difference and let it rip

 

[LeadFinger]

"T3PRanch"If I recall according to Ernest the thumb screw that secures the barrel can be over tightened giving a pretty significant windage shift.

Thurmond

Thanks, yeah I saw that. I just snug it on both barrels. 
Anyone else have it wildly off like this? 

 

[LeadFinger]

"weatherby"Record the poi shift like you did, and work from there. The grouping is way more important anyway, just dial in the difference and let it rip

I haven't shot groups at 50 yards with the .25 yet, but yeah that's ultimately what I'll do. I just hope it's not flat out bent...

 

[sniperlabyo]

I would chuck the center of barrel on a lathe and dial it in -- if You can, you can further trouble shoot if not you can't. 

When I get a batch of barrels i spin then all and grade Mark 1-5, one deing the straightest 

 

[LeadFinger]

"sniperlabyo"I would chuck the center of barrel on a lathe and dial it in -- if You can, you can further trouble shoot if not you can't. 

When I get a batch of barrels i spin then all and grade Mark 1-5, one deing the straightest

That sounds like the next thing in line to do at this point. Thank you.
Have you heard or run across many barrels that far off?

I'm assuming my buddy with a lathe will know what you mean by "dialing it in", but if it's not too whacked, what ideas did you have in mind for troubleshooting?

I just received the barrel kit 2 days ago from AOA, it's absolutely a candidate for an exchange. I just wanted to pass this issue by you guys to see how common it is. 

 

[sniperlabyo]

On a none wind day, zero gun at 75y, then shoot a group at 75y, 50y, 30y, 20y now look at the groups is it moving to the left or right?? Or staying center??

Now zero at 20y and shoot 4 more groups at all 4 distances to confirm. If the group stay about center Then go to the next test. 

 

[Maineiac]

"LeadFinger"

"sniperlabyo"I would chuck the center of barrel on a lathe and dial it in -- if You can, you can further trouble shoot if not you can't. 

When I get a batch of barrels i spin then all and grade Mark 1-5, one deing the straightest

That sounds like the next thing in line to do at this point. Thank you.
Have you heard or run across many barrels that far off?

I'm assuming my buddy with a lathe will know what you mean by "dialing it in", but if it's not too whacked, what ideas did you have in mind for troubleshooting?

I just received the barrel kit 2 days ago from AOA, it's absolutely a candidate for an exchange. I just wanted to pass this issue by you guys to see how common it is.

Keep us posted! I've got a barrel kit coming this week and now I'm nervous. ;-)