308 to 30-06 chambering question

I think the 30-06 reamer will not clean all of the 308 chamber out.
 
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I might be wrong about this but here goes...

You'd have to cut the barrel off a bit.

Based on the SAAMI diagram, the .308 is 0.4564 at 1.450" in front of the breech face. Doing the math on the .30-06, at 1.450", it is 0.4504, so you'd have a step there of 0.006" and from that point forward the .30-06 chamber is smaller diameter than the .308 chamber, so the reamer wouldn't cut it until whatever point they intersect again. Somewhere on the .308 shoulder, I'd guess.

So, you'd have to cut a bit off the barrel on the breech end and rechamber.

Besides that, you'd never fit a .30-06 cartridge in a short action or a .308 magazine. You could, of course, swap the shortened barrel to a long action.

Of course, a shorter barrel on a .30-06 versus a .308 is exactly the opposite of what you'd want considering the added powder capacity.

Assuming I'm right about the math, that is.:D;)
 
Brian said it well.
Case tapers are different..308 is straighter.

I have not done the math or looked at drawings,I think you would be doing a dance with the fine edge of individual tolerances,but there is a chance a 30-06 Ackley Improved might work.

In many cases,as Brian said,action and magazine length are a real issue.

In some cases,like an M-70,its the same receiver,but blocked down.

That CAN be reversed..but it will cost some.

Time you pay to have all this done,....there are a lot of 30-06 rifles out there to buy. Cost of doing the work will go a long way to pay for it.

Up through 165 gr bullets,there is very little to be gained by going 30-06.

Bonded bullets,like an Accu-bond,perform pretty well at 165 even on elk.

I'm a 30-06 180 gr guy,but there really is not much to gain.
 
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308 is larger at every point ahead of the head/rim. In order to clean up the 308 chamber, you will end up cutting off about 1.5" at the rear of the barrel.
 
You guys might have looked at drawings, but I have looked at chambers and can confirm that reaming a .308 chamber to .30-'06 will leave a step where the original shoulder was. Will it work? Yes, though resizing the case will work the brass.. Will the longer round work through the magazine? Maybe, depending on the magazine.

So, it is not a very good idea unless there is some overriding need.

Jim
 
How long is the thick tennon portion of your barrel? If it is long enough, you may be able to cut out the .308 chamber and ream it .30-06 so you can make use of your barrel.

I have never tried reaming out a .308 chamber to .30-06 but I trust the advice of the others here.

I can tell you I have seen a blown .30-06 chamber (the shoulder was blown forward really bad for some reason) reamed out to a .300 WM. Wasn't my rifle but I did watch it and it test fired alright.
 
Just a thought. But why? I love 30-06 personally. But, I have to say that a .308 is its match in almost every way. Unless you are looking at very long range where the extra speed of the -06 may keep you super sonic longer to stabilize. Thinking around 1000 to 1200 yds the advantage goes to -06. If you are shooting those kind of distances you may want to consider a fresh high quality barrel.
 
T. O'Heir said:
Different shoulder angle, diameter at the shoulder, OD of the case mouth, length of shoulder angle.
Click to expand...

The hair in the ointment is really that the body taper is different. Sine the -06 is substantially longer, the other angles would just be "erased". IF, that is, IF the point where the .30-06 body diameter equaled the .308 shoulder diameter was at or beyond the length of the .308 from base to shoulder. Sadly, it ain't.

If I did the math correctly, you'd need to cut just a tad more than 0.98" of the barrel, assuming both .308 chamber and .30-06 reamer are exactly SAAMI spec. (Highly unlikely)
 
If you are trying to find a use for a barrel you have laying around, why not pick up an action to fit and make yourself a nice 308?
 
Yeah,I know how that goes.

Seems like having a spare bolt stop laying around can lead to getting a lower receiver to put it in.

We(I include myself!) can pick up a take off barrel(Maybe a Rem 700 factory barrel someone else pulled) we bought for $35 and somehow figure out how to put hours and $500 in it to give us an excuse to buy a $450 scope ,new reloading dies brass,etc.

Oh,my gosh!! There is that 38 Super 1911 slide!!And some GRIP SCREWS!!!
 
I did the AI cross over for a friend of mine. Had to set back the threaded shoulder and recut the extractor slot on his Mauser. For all the headache, start with a new barrel. It will be a better result is my advice
 
Why not? The diameter of the 308 W at the case body/shoulder juncture is larger than the 30/06 at the same distance from the case head by about .014".

For those that measure before and again after the 30 Gibbs is a better choice or the 30/06 Ackely improved can be used to clean up the old chamber.

F. Guffey
 
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