Extending the throat in a 338-06AI

grry10

Handloader
Dec 7, 2007
464
326
I had LRI install an M16 extractor with dual ejectors in the bolt of my 700 Remington 338-06AI. The work that they did to the bolt face has changed my seating depth. My 210 gr NPTs are now pushing into the rifling. I can either seat them deeper or extend the throat/free bore. Since the rifle already has a fairly short throat I would like to extend the throat. The Precision Reamer Kit can be rented from 4D Reamer Rental and I believe it should be fairly straightforward, but have any of you done this yourself? If you have a 338-06AI can you share what your throat length is?
 
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I did one a couple years ago . it turned out good , shoots well . I'd do it again . I have a couple of the before and after measurements goofed up , but it's not important for the how to . hope it helps .
 
I know a guy who attempted to do it himself on a 338 edge. Ended up with about 3” of freebore!

Just go slow because you can’t add metal back.


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that's right Bear , it cuts extremely fast . if I was to do it again , I'd buy the hornady seating depth tool and the brass case . this way you can cut a little and check your progress easy . I kept seating a bullet out a little longer , a little longer , a little longer , and checking different bullets as I went . until I got to where I wanted . one other thing to watch . the two brass nuts on the reamer are the depth stop . I had them come loose one time . if I wasn't paying attention I would have been in trouble .
 
I'm unsure why extractor & ejectors would affect seating depth. Has the headspace changed too?

In my 338-06 Ackley just touched the rifling is at 3.705" with a Davidson seating depth checker from base to ogive. Alvin is long gone as are his tools so this will probably mean nothing to you. I also have a barrel stub chambered to the shoulder with my reamer & anything longer than 5.340" means the bullet is jammed into rifling. This wont do anything for you either.

My reamer was made for the 210 Ptn. For reference, at about 3.260" OAL the bullet base is at the neck/shoulder junction. I seat the 210s to approx. 3.340" OAL which was just about a blond CH short of touching rifling when the chamber was new. As you may know this is an inexact dimension because of tip deformation & the usual bullet variance, but about the best I can give you.

Because I'm cheap, er frugal, Speer 200 spitzers were used for development seated .020" shorter than the 210s. These 2 bullets are almost internal ballistic twins in my rifle... at least with the lot #s I have.

The 200 CT Ballistic Silvertips work nicely in my rifle too but magazine length limits them to 3.370" OAL which is about 1/10" from touch. They shoot very well with a little jump.

Hoping this makes sense. It's late & the bed is calling.
 
358 WCF , I agree with you . nothing done to the bolt should change seating depth . depending on what was done , it could change headspace
 
Friend of mine had a bushing job and new firing pin done on a 6Br and it changed the head space. Had to have it reset. Dan.
 
Knowing LRI, whatever they did I’m sure it was done right. I have been very impressed with the speed and quality of their work


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