I have an M98 rifle chambered in 308. I want to rechamber for 30/06 as the throat is now too long to load with decent accuracy.

Can I simply use a pull through finishing 30/06 reamer and plenty of cutting oil and slowly cut until the bolt closes? I know the 308 chamber is a bit (.0004) wider at the .200 reference point than the /06, will this cause any issue-it is less than 1/1000 after all.

Thanks in advance

A std 30-06 will not clean up the shoulder area of the 308. A 30-06 Ackley will.

Paul,
Not sure I follow- the 30/06 will move past the shoulder/neck/throat of the 308, no? I did not notice any diameter issues once past the .200 reference diameter, what am I missing?

Andrew

At the point where the shoulder starts on the 308 case 1.56" the body dia of the 308 is larger than the body dia of the 06 as the same point. For sure the 06 reamer would leave a shoulder at that point. Normally setting back far enough is not an option either. If you don't want the 308 and want to keep the same barrel you will need something like the 06 AI to clean up the old 308 shoulder area.

I'm sorry I don't have a loaded drawing of the difference. Don't hold me to this but I "believe the 308 is .454" the 06 at that point is around .44". Could you rechamber and fire probably. The 06 case would expand to fill the void. Would it be dangerous I wouldn't think so you blow a case out more for the AI. Would it look like $hit you bet. It would look like bubba gunsmithing 101.

Okay, I see the numbers on my prints. I don't know if I can find a pull through 30/06 AI finish reamer.

I'm sure that people have simply ran a reamer through the rear of the action to do this rechamber. Issue is the pilot has nothing to engage when it starts to cut. Can you cut it that way probably and it would probably be fine for a hunting rifle.

Even with a pull through you really need to rent gauges as well. 06 brass from one batch much less manufacturer to manufacturer is not perfectly the same. SAAMI gives a range. So you are looking at $50-60 for rental. Otherwise yo might be able to chamber Hornady but not Remington ammo.

Getting a smith to pull the barrel and do it right probably wouldn't be that much more. There are several that post on here than can help you out.

If it were mine I would spend a few $$ more and get it done right.

Forget about pull though reamers; they are only for finishing jobs. You need to pull the barrel and do it right, which is actually easier. As stated, a standard 06 chamber won't clean up the 308 shoulder, so you will have a double shoulder on fired cases; no real problem unless you want to reload the brass, in which case you will work the brass more than required. An Ack Improved chamber will work fine.

You could just have the barrel pulled and set back a thread and chamber again to .308 Win. That should refresh the throat and you can continue as usual. Way less than a new barrel and install with no other changes. Probably around $150.

Do you loose any performance firing a std. 30-06 round in an Ackley Imp. chamber?

Yes, of course you do; your expansion ratio suddenly becomes a lot greater once the case expands. You do that whilst fire forming so it doesn't matter. How much do you lose? I don't know. It isn't done for serious work.

quote:

4427 September 2014 21:44Hide PostDo you loose any performance firing a std. 30-06 round in an Ackley Imp. chamber?

You loose a little velocity (not enough to be noticeable) and often the accuracy is just as good as with a formed case.

+1 and you can fireform on critters instead of paper, a lot more fun.

Stepchild