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I have a 1943 SA Garand that I am rebarreling. I need to know where Top Dead center should be when the barrel is hand tightened. The barrel that I have indexes to 11:00. This seems a bit much considering the type of threads on the barrel.
As a side note, when hand tightened, the head space is .003 short. When the barrel is properly indexed, how much shorter will the head space be?
i use a level bubble accross the sight ears, and slide the gas cyl, over the barrel, and level the front sight base, when the bubbles match up, your indexed,
remember, check it 2 times before you assemble, sight picture should be straight when you look down the rifle, if its not, you have some adjusting to do.
Did you actually read my original post?Quote:
Originally Posted by chuckindenver
guess not...good luck
That's not bad for intitial draw by hand. Since one full turn = .100 of an inch,Quote:
Originally Posted by Maddogkiller
then 100 divided by 12 (11 o'clock draw or 1/12th shy) = .0083" so you would be about .011 - .012 short headspace, including what you have now, at top dead center.
According to Jerry Kuhnhausen and john C. correct index is 20 minutes before top dead center. I use a 360 degree electrician's protractor. Vise the barrel, slide on the Gas-Cylinder, check it with the protractor on the sightbase of the Gas-Cylinder and mark it with the dog. Start my final draw and when I get close I rest the protractor(They have a magnetic base) on the flat behind the rear sightbase and do the final draw, stopping jusy shy of the dog mark. For example; if the dog is sitting on the second mark from zero, I stop when two thirds of the space is behind the pointer. Each mark equals one degree. Done, perfectly indexed. I've done this with eight of my rifles and a few dozen other Garands. Centered both the rear and front sights and never had to move them, just elevation adjustments.
Gus Fisher taught me this method.
If the barrel sits at 11 o'clock hand tight,that translates into 30 degrees. The military stipulated that the hand tight position for a new barrel was to be from 9-15 degrees off. Ditto for Kunhausen. In an exchange on the old board,Gus Fisher quoted at least 15 deg on a new barrel with no upper limit given. The Kulek book talks about a 30-60 degree initial position-yikes!!
I installed one new barrel that was 15 deg off and had to use an extension on the wrench to grunt it on. the last new one I did was from an 18 deg position and it turned on with less resistance than the other.
If there is too much offset it might be necessary to face the barrel shoulder off on a lathe. Conversely,one that under-indexes would need to be roll swaged to increase the draw.
All new barrels are short chambered and all must have headspace set up with a pull thru reamer after installation.