Indicating 338 LM

[liseo]

Hey guys.
I'm a weekend gunsmith, installing barrels on my rifles and those of close friends, with relative success. I indicate in the throat area and deeper, as far as the indicator can reach.( interapid 312B-15)
But for calibers like 338 LM, which method do you use, or you recommend?

Thanks

Liseo

 

[SKWERLZ]

On my 338 I just indicated what I can with a long stem interapid, I figure that extra 1/2 inch forward isn’t going to deviate much.

 

[Dusty Stevens]

Get what you can or use a grizzly rod

 

[tobnpr]

^^^
Yep. Don't overthink it on long magnums. We love getting into hypothetical hyperbole- but a LM isn't a benchrest competition rifle.

Your wind call will affect your impact 100 times more than what you're talking about.

 

[762plinker]

^^^
Yep. Don't overthink it on long magnums. We love getting into hypothetical hyperbole- but a LM isn't a benchrest competition rifle.

Your wind call will affect your impact 100 times more than what you're talking about.

wrong...just longer distances....group and score in mt.
talk to alex tom and.......shawn..the gunsmith

 

[LVLAaron]

A mitytoyo tenths with the 1.5 inch indicator should get you into the throat. I think I'd settle with the throat and an inch behind it

 

[DaveTooley]

I chamber them no different than any other caliber. 6PPC to 50 BMG

 

[INTJ]

Ideally, a 3.25" indicator tip would be about optimum for the longer cartridges. You can make one and I may do so for my Interapid. I do have a 5.5" tip but I don't like it.

That said, I think if you have a decent quality barrel and you throat is only a little past where the 2.75" Interapid reaches, you are much better off to just indicate as far in as you can with the Interapid vs using a Grizzly rod.

 

[liseo]

Thank you all guys.
I became more confident with your guidance/suggestions

 

[tobnpr]

wrong...just longer distances....group and score in mt.
talk to alex tom and.......shawn..the gunsmith

Wrong? About what, exactly?

 

[762plinker]

Wrong? About what, exactly?

it is used in BENCH REST...BUT AT 2000 YARDS

 

[tobnpr]

Why shout? Someone piss in your cornflakes?

My point is the same, and still holds. Whether he figures out a way to indicate the throat, or indicates an inch behind it- his wind call is still going to be far more important than some hypothetical difference of microns in location. I'm no stranger to to 2000 yards- you're not changing my mind.

 

[Tucker65]

I just did a 338 Lapua Imp recently using the Interapid indicator to directly dial in the bore. I drill and prebore when I chamber so I just indicated in as far as the indicator would reach. Then I drilled the pilot hole before I prebore. After that the indicator nose would reach in the pilot hole quite a bit farther so I could make any adjustments in the actual throat area if it was off.

 

[gme]

I made a large version of the Starrett 196F I used a pair of abec 7 miniature ball bearings at the pivot, it can reach into the bore +3.5", use my Mitutoyo 1/10th test indicator on the other end, with the 1:1 ratio there's no loss of resolution and no deflection of the contact point

 

[SKWERLZ]

I just did a 338 Lapua Imp recently using the Interapid indicator to directly dial in the bore. I drill and prebore when I chamber so I just indicated in as far as the indicator would reach. Then I drilled the pilot hole before I prebore. After that the indicator nose would reach in the pilot hole quite a bit farther so I could make any adjustments in the actual throat area if it was off.

I really need to pre boring before reaming

 

[762plinker]

Why shout? Someone piss in your cornflakes?

My point is the same, and still holds. Whether he figures out a way to indicate the throat, or indicates an inch behind it- his wind call is still going to be far more important than some hypothetical difference of microns in location. I'm no stranger to to 2000 yards- you're not changing my mind.

lets just say i still disagree with your basic statement, period