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308 garand zeroing issues
I have a Springfield Armory 1980's Garand
in .308 with national match rear sight assembly.
Took it to the range today to zero at 50 yards. the POI was at least 15 inches to the left of point of aim and about 4 inches high with the rear sight centered and at its lowest elevation.
I moved the front sight left as FAR as I could without it falling out of the dovetail. and still had to move windage about 50% of the way to get it shooting straight.
Still POI was about 4 inches high with nowhere to go on the elevation control. Both of these seem so far out of whack I am wondering if the rear sight could have been fitted incorrectly? or is this a common occurrence?
Also had a couple of failures to fire with lightly dented primers, what should I look at first for the remedy for this?
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08-14-2016 03:11 PM
# ADS
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Advisory Panel
Hard to say without it in my hands, sounds like the front sight may be not at top dead center. That's a problem that sometimes surfaces with M1s... Or, your barrel is bent. I had a Danish
return that was like new and it hadn't been shot. The barrel had a bend in the thickest part at the chamber that had to have come from the factory, it took a hydraulic press to straighten it.
The light strike could be a hammer spring, but the op rod could have been just out of battery too...
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The front sight had to be highly off center (to the left) to get anything like a straight grouping. The rifle actually does group very tightly, just in the wrong place. Rear sight does appear to be in the correct place.
Would a bent barrel not be cancelled out by the presence of the foresight on the end of the barrel????
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Contributing Member
newcastle--
As per what BAR said, sounds like your barrel is on too tight thus throwing your gas cylinder and front sight off. Check to see if the top gas cylinder spline perfectly top dead center on the barrel aligned with the receiver. If its perfectly top dead center than there other issues with the gun. I use two yard sticks to check the barrel alignment with the receiver. Its easy to check. Strip the gun down to the barrel action, you can leave the rear sight on. Take the front sight off, you will using the flat area on the gas cylinder as a reference point. Place the gas cylinder on the barrel action. Place the barrel action in a vise that is straight. Place one yard (meter) stick on the flat of the front sight balancing it equally than place the second yard (meter) stick on the flat area immediately behind the rear sight. Step back above two yards (meters) looking down the barreled action from the rear sight. Both yard (meter) sticks should be perfectly aligned with each other. If they are not, the barrel is on too tight or loose depending on the direction the front yard stick is leaning or the barrel splines are not properly cut. I hope this is helpful.
--fjruple
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Advisory Panel

Originally Posted by
newcastle
Would a bent barrel not be cancelled out by the presence of the foresight on the end of the barrel
A bend in the barrel is damning. A tiny bend is so bad you can't zero properly. Your front sight should be centered and so should the rear. Yes, they are designed to be adjusted but yours is out to lunch. It's easy to find out how bad...shoot at 25 and zero, them move to 100 and shoot. If you aren't on the center vertical line and you're back where the original error was at 25 then you have a TDC or bent barrel issue. If you correct again then at 200 the error is back. If you correct again, at 25 you'll be that far the other side of correct zero.
I suspect it's the age old and simple barrel not TDC. A close friend of mine has one of those M1s and when I examined it, there was no end of surplus parts on it that were less than stellar. I didn't find it their best effort...just needs a tweak.
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Appreciate the advice - what is TDC please?
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Thanks - I will check out the alignment as instructed above and report back in a couple of days. Appreciate the advice!
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Contributing Member
TDC
Or as Mona Lisa Vito said in My Cousin Vinnie, "Top dead centuh"
Best sequence in the whole movie.
Real men measure once and cut.
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