Took the Garand to the range on Saturday. The "paper target" stands were occupied, with a queue lasting into Sunday - that's what happens when the temperature finally gets above freezing!
So I had to use one of the "electronic target" stands - and the printer was out. Literally - I could not find it. As a result, I pasted patches onto a couple of old targets to show where the shots landed. In each white circle there is the shot number and the electronic score.
Cineshot
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Hornady Light Magnum
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PRVI
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I now have first results for 3 different types of 150gn ammo. All good, and if you make an overlay of all three groups, it is clear that the Garand could use a 1/2 minute correction to the left - which is not possible with the standard horizontal sight correction, so I shall be looking for a complete NM sight assembly.
I checked the head clearance (NOT gauge headspace) by the usual method, and the result was less than 0.1mm - less than 0.004" - which is about the measurement limit for this method. And the Cineshot ammo places the bullet 0.4mm (0.016") off the lands - excellent. The working of the brass is so small that neck-sized reloads can be chambered with no apparent problems.
Amazingly good for a 70-year old rifle.
My next trial will be to imitate the Cineshot ammo, but reduce the powder charge until the self-loading starts to become erratic, then continue at a level that ensures reliable operation. It's not wanting to save a couple of grains of powder, but rather to save my shoulder!
Watch this space!