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Sagerider
March 24, 2016, 05:27
So I checked my M1 out with my go/no go Gage's and found out the no/go chambers just fine. I do not have a field gage so I can only assume I have a problem that needs to be corrected. I did a little research on how to head space a Garand and it looks like excessive head space can only be corrected by installing a new barrel and finish the chamber to spec with a reamer.

My rifle is chambered in .308 and I was thinking what if I rechambered it to .06?
Is this possible and safe? Is there anything else I need to do to rechamber it?
The rifle,is nothing special, typical M1, chambered in .308 with the spacer in the mag well.

Would changing the bolt out with another one help, I know it would be a long shot.

bubbagump
March 24, 2016, 05:39
So I checked my M1 out with my go/no go Gage's and found out the no/go chambers just fine. I do not have a field gage so I can only assume I have a problem that needs to be corrected. I did a little research on how to head space a Garand and it looks like excessive head space can only be corrected by installing a new barrel and finish the chamber to spec with a reamer.

My rifle is chambered in .308 and I was thinking what if I rechambered it to .06?
Is this possible and safe? Is there anything else I need to do to rechamber it?
The rifle,is nothing special, typical M1, chambered in .308 with the spacer in the mag well.

Would changing the bolt out with another one help, I know it would be a long shot.

Swapping bolts can work provided you have one that fits and gives you the correct head space.

As to reaming for .30-06, I've never tried it but the .308 chamber is a bit wider at the shoulder (.454") than the .30-06 round is at that distance from the case web (about .445"), due to the lesser taper of the .308 round. So no, you can't ream it out to .30-06. If you can find an old Garand guy with a bucket of bolts he can probably find one that fits, other than that swapping barrels is what you'd be left with.

Then again you could always just make brass for it, fireform it with a light load and neck size. I had an M14 I had to do that for it was a full 20 thousandths long but shot like a house on fire so I went to the trouble. Worked fine.

b.

ArtBanks
March 24, 2016, 06:42
Before getting too excited, if you were using .308 guages, you might think of getting a set of 7.62 and check. I think you will find that your rifle is within NATO spec.

gunplumber
March 24, 2016, 07:24
Before getting too excited, if you were using .308 guages, you might think of getting a set of 7.62 and check. I think you will find that your rifle is within NATO spec.

This. My .308 gauges are tighter than my 7.62.

Adding a .004" shim between the bolt face and the nogo will duplicate a field.

Sagerider
March 24, 2016, 10:33
Thanks guys :)
I will try the .004 shim and see how that looks.
I have not had any issues with this rifle and case head separation.

AliYahu
March 24, 2016, 10:53
So I checked my M1 out with my go/no go Gage's and found out the no/go chambers just fine. I do not have a field gage so I can only assume I have a problem that needs to be corrected. I did a little research on how to head space a Garand and it looks like excessive head space can only be corrected by installing a new barrel and finish the chamber to spec with a reamer.

My rifle is chambered in .308 and I was thinking what if I rechambered it to .06?
Is this possible and safe? Is there anything else I need to do to rechamber it?
The rifle,is nothing special, typical M1, chambered in .308 with the spacer in the mag well.

Would changing the bolt out with another one help, I know it would be a long shot.

Yeah, uh:

Before getting too excited, if you were using .308 guages, you might think of getting a set of 7.62 and check. I think you will find that your rifle is within NATO spec.

As I recall, a 7.62 'GO' is the same spec as a .308 'NO-GO'. Do the old FAL trick of wrapping some tape and checking, or better yet get a set of 7.62 gauges - or at least a 'FIELD' gauge.
On semi-autos, I'm not really sure what purpose a 'NO-GO' gauge is. The 'GO' will show minimum headspace, and the 'FIELD' will show excessive headspace - anywhere in between is generally acceptable for a Battle Rifle.
Just an FYI, you cannot re-chamber a .308 barrel to .30-'06. The chambers are different enough that a ridge will be left in the chamber.

Eli

ArtBanks
March 24, 2016, 11:19
OP stated that his rifle closed on a .308 no/go = 1.634 and he thought it might be long on the headspace. My suggestion for NATO guage is to try the 1.640 no/go and see how that works. NATO field is 1.645, so I am going to guess he does not need to worry about long headspace until trying a new guage. Then again I wonder about the calibration on the guage being used. We have had some come into the shop that bubba allowed a bolt under op rod spring tension slam on a .308 guage and ruined the guage as far as taking any meaningful measurements. Needs to be done with bolt stripped and no op rod or spring in the rifle. Under "light" finger pressure only.

Impala_Guy
March 24, 2016, 19:08
The Clymer and Forster gauges are typically slightly different and that goes for most calibers. I had a Garand that would almost close on one field gauge and no where near close on the other. GO and NO GO gauges only useful for building a rifle or looking for a tight action for a match rifle. Never apply excess force to see if a bolt will close on a gauge........I was surprised to hear several people (not here) say they do this.

gunplumber
March 25, 2016, 09:01
Never apply excess force to see if a bolt will close on a gauge........I was surprised to hear several people (not here) say they do this.

The question is defining "excess." It is defined in specifications for a variety of guns and and several countries as GO / NOGO at < or >X pounds. FAL is the undefined "double thumb."

Bolt actions I let gravity close or not close the handle. Garands and M14s I typically tap it with my forefinger.

RG Coburn
March 25, 2016, 10:28
Is all 30-06 the same dimension? Military vs. commercial? Or is there a slight difference like with .308/7.62x51?

Douglas Wozny
March 25, 2016, 10:30
Is all 30-06 the same dimension? Military vs. commercial? Or is there a slight difference like with .308/7.62x51?

Yes, all .30-06 is the same!

tdb59
March 25, 2016, 10:31
Is all 30-06 the same dimension? Military vs. commercial? Or is there a slight difference like with .308/7.62x51?

.30-06 was the last commercial cartridge to begin as a United States military round, and have common dimensions in both types.





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SteelonSteel
April 04, 2016, 08:28
Swapping bolts can work provided you have one that fits and gives you the correct head space.

As to reaming for .30-06, I've never tried it but the .308 chamber is a bit wider at the shoulder (.454") than the .30-06 round is at that distance from the case web (about .445"), due to the lesser taper of the .308 round. So no, you can't ream it out to .30-06. If you can find an old Garand guy with a bucket of bolts he can probably find one that fits, other than that swapping barrels is what you'd be left with.

Then again you could always just make brass for it, fireform it with a light load and neck size. I had an M14 I had to do that for it was a full 20 thousandths long but shot like a house on fire so I went to the trouble. Worked fine.

b.


I bet you're probably fine. Put a piece of scotch tape on the base of your no go and measure the change on the gage with dial micrometer so you know how much length you picked up. Then use the taped gage.

if you really had to swap the bolt some of the longest are Winchester bolts and -19 bolts. The -19 generally being the longest. The 65 series bolts are pretty long too.

V guy
April 04, 2016, 11:03
HS gages.........

I have a set of Forster .308 match HS gages.

I also have a RCBS 308 precision micrometer......not a precision tool really, but it is like a standard of sorts...compares similar objects like the .308 HS gages and .308 ammo in relationship to each other.....

I was astounded to find that what was marked on the HS gages, was not seemingly correct, at least in comparison to each other, or the ammo, with the RCBS mike........

I found the 1.630 gages (2) to both measure 1.628 on the RCBS...might mean the RCBS is just .002 short reading...

Ammo--NATO and factory .308 measured 1.628-31 on same RCBS gage.
Not so good........too close for comfort.

A .308 case gage was also used to also check the ammo & gages........... and it agreed with the RCBS readings on what was acceptable ammo, and it back checked on the comparable sized 1.630 marked HS gages.

GAGES:
1.630 reads 1.628
#2 1.630....... reads 1.628
1.631 hs gage reads 1.629
1.632 reads 1.630
1.633 reads 1.632

1.634 READS 1.632 ****
1.634 #2 READS 1.631*****

1.635 reads-1.633
1.636 READS 1.633 *****
1.637 reads 1.635
1.638 reads 1.635.5 ******
1.639 reads 1.637
1.640 reads 1.638

Mostly .002 off and measured many times.

To repeat, NATO and .308 factory ammo was checked, was measured in the RCBS, and all fell between 1.628-1.631.

If the RCBS mike is .002 off short, it would be 1.630-1.633 sized ammo, but factory .308 does not run that big..........just the NATO.

This is a pretty good range and probably pretty close to reality. I find ,308 factory ammo to mostly measure under 1.630 and that makes the RCBS mike likely very close.

So the RCBS mike was reading maybe.001- .002 short of reality, or it was close to spot on..............

The concern comes when loading ammo that reads 1.630 on the RCBS mike into the gun that has close to 1.628-30 hs using the Forster gages............

Using MY set of gages, and ending up with a 1.634 no-go reading--(actually 1.632) would be 1.632 actual HS in relation to the RCBS gage AND the ammo.....................apples to apples, but .002 safe.

So.........what brand are your gages? It may be that they are not as marked, and the no-go, may be about the same size as the go.........explaining everything.

If you have a magnetic base, a dial indicator mounted on it........ and a .308 cartridge headspace gage........put the go gage into it and zero the dial indicator to zero... with the go gage in the cartridge gage....carefully take the go out and put the no go in and see if there is a difference..........cheapest way to check hs gages against each other.