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Thank You to Skip For This Useful Post:
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12-14-2012 12:13 PM
# ADS
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Advisory Panel
Originally Posted by
Skip
500 yards to hit at 100 yards
Very unusual for ex-service rifles. The typical problem is to keep the shots down at 100. Check the bullet diameter and slug the bore. There may be a significant mismatch. Or the rifle has been fitted with an extra tall foresight.
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M39 Reloads
It definitely helps to slug the bore. Mine turned out to be .312. I tried a variety of bullets from .308 up to .312 and got the best accuracy from .311 diameter Sierra 174GrHPBT/Match bullets and once-fired, neck-sized Norma Brass loaded with Winchester WLR Primers and 46Grains of Varget--turned in <1inch 5shot groups at 100yd. I'd the diameters of any bullets you shoot as well as they may vary from batch-to-batch. I tried some .312 TMJs (Hornady) and was not impressed with their accuracy. One other point. I had some Sellier-Bellot factory loads in 7.62X54R and tried these on a warm day (20C). I only took two shots because on each occaision the firing pin punctured the primer. I gauged the firing pin, using the Russian Cleaning Kit tool and pin protrusion was not excessive. Maybe the Finns used slightly harder springs to improve ignition in cold weather? I had no such problem with WLR primers.
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Have you tried the light ball in it yet? That may be why you have to raise the rear sight up to the 500 mark as the sights may be regulated for the light ball round.
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I'll try the Czech silver tip on my next outing but I think the front sight is too high. A friend said it might be setup for long range shooting.
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Advisory Panel
Originally Posted by
Skip
A friend said it might be setup for long range shooting.
Nope. Long range shooting requires raising the backsight, not the foresight.
The usual problem with ex-service rifles is getting the POI down at short ranges. Many were "zeroed" for 200-300 meters. and at 100 meters will shoot way above the black, even with the backsight leaf set as low as it will go. Which is why everything "Mauserish" that I have has ended up with an extra tall foresight blade. From M1871 through to the Israeli, they all took the same type of blade. My Swede and Swiss as well (different types of blade, of course).
I think it is more likely that - apart from defects, such as bent barrel, bad crown, bullet/bore mismatch etc - the rifle was rebarreled for target shooting and the previous owner deliberately fitted a tall foresight blade to get the backsight leaf setting well off the floor at 100 meters and have some leeway for adjustment to suit different types of ammunition.
But treat yourself and the rifle to at least one pack of good modern ammo. It is not a fair test of the rifle to use milsurp ammo. If you can find a pack of the Norma Russian Match, you may see spectacularly different results!
Last edited by Patrick Chadwick; 12-17-2012 at 03:28 PM.
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I agree, good reloads helps a lot with the M39. I wish my eyes could shoot as precisely as this gun is capable. In my opinion this gun belong to the category "must own one"
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I am eager to try my new M39. I slugged it the other evening but am still looking for my calipers to measure. This was my first time slugging a bore so I will post the results and perhaps some of you M39 pros can point me in the right direction on ammo selection.
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My bore slugs .310 groves and .299 lands. Anyone have a projectile suggestion?
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Advisory Panel
More precise measurement recommended
.310" is an awkward size!
308" bullets will be too loose, I don't know who makes .310", .311" is tight, and .312" is too tight. I suggest you slug the bore again, at the chamber end, only going in about two inches - i.e. do not drive the slug all the way along the bore, but far enough in to be well past any throat erosion.
The reason is, the bore may be a trifle wider at the breech end than down towards the muzzle end. Maybe just a gnat's whisker, so you need to measure the slug diameter afterwards to better than 0.001". Which means using (borrow, if necessary!) a device more accurate than the usual supermarket or DIY-shop slide gauge, or taking the pieces to be measured to a toolmaker. I use a bench micrometer, with a fiducial indicator, that reads directly to 0.0001". All items involved in the measurement must be at the same, more-or-less room temperature, and spotlessly clean.
(I also have a measuring head that reads to 1 micron, but using this just makes you nervous - wiping over the bullet with your fingers changes the reading!)
If your measurement shows a groove diameter of .310 plus, then you can consider using the following bullets:
Sierra .311" 174gn HPBT
Sierra .311" 180gn Spitzer
Speer .311" 180gn round-nose
Hornady .311" 174gn boat-tail
Hornady .312" 180gn round-nose Interlock
I recently "tuned" a Finnish M39 sniper that was hardly finding the paper at 50 meters. No surprise, considering that the groove diameter was .313" and so .308" bullets were a very loose fit! When I had finished, it was slotting them into one hole with the .312" Hornadys.
And you need to measure some samples of the bullets as well. If you're measuring to 0.0001", then treat the diameter printed on the box as nominal, and check it!
- My batch of .311" Sierra spitzers actually measures .3106". The .312" Hornaday round-noses are dead on. But the .268" bullets for the Carcano measure .2676". Maybe this was a deliberate manufacturing change, as a couple of years ago there was a lot of worried comment about these bullets being too fat and therefore likely to cause overpressure.
According to your measurement, select the bullet with due regard to any overpressure risk. The choice is up to you, and depends on that measurement being really precise!
Last edited by Patrick Chadwick; 01-18-2013 at 05:59 PM.
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Thank You to Patrick Chadwick For This Useful Post: