M39 front sights.....redux
Posted: Wed Jul 06, 2005 6:27 pm
I had posted a question about M39 front sight heights awhile ago, which was apparently lost in the great ez fire.
The gist was that I had read that the armorer stamped the proper height of the front blade behind the front sight base when the rifle was zeroed. On my M39 the barrel is stamped 82 (8.2mm or .325) while the front blade bore 78 (7.8mm or .307") which is what is measures. I have read posts about other M39's with blades shorter than the number on their barrels too. With this combination my rifle shoots high, like 5" at 100 yards, and with the rear sight at 150m it should be around 1.5" high at 100. Well it seemed to me that with a 8.2mm front blade the rifle ought to shoot to where the rear sight says it should, since the .018" discrepancy represents about 3 MOA.
Well, I got a tall front blade from Tenn. Gun Parts and I got some of the Lapua D166 bullets which are the bullet the rifle was designed to fire. I finally got around to working on this over the weekend. I surmise that the Finn Military Ball must have run around 2350 FPS. After working up a load near that velocity I started working down the tall sight blade. The upshot of this evenings shooting is that with a blade matching the number on the barrel, and with a close (hopefully)approximation of the Finn ammunition, my M39 shoots about where should. That is +1.5" at 100 meters.
Just my not too scientific experiment with 1 rifle.
MM
The gist was that I had read that the armorer stamped the proper height of the front blade behind the front sight base when the rifle was zeroed. On my M39 the barrel is stamped 82 (8.2mm or .325) while the front blade bore 78 (7.8mm or .307") which is what is measures. I have read posts about other M39's with blades shorter than the number on their barrels too. With this combination my rifle shoots high, like 5" at 100 yards, and with the rear sight at 150m it should be around 1.5" high at 100. Well it seemed to me that with a 8.2mm front blade the rifle ought to shoot to where the rear sight says it should, since the .018" discrepancy represents about 3 MOA.
Well, I got a tall front blade from Tenn. Gun Parts and I got some of the Lapua D166 bullets which are the bullet the rifle was designed to fire. I finally got around to working on this over the weekend. I surmise that the Finn Military Ball must have run around 2350 FPS. After working up a load near that velocity I started working down the tall sight blade. The upshot of this evenings shooting is that with a blade matching the number on the barrel, and with a close (hopefully)approximation of the Finn ammunition, my M39 shoots about where should. That is +1.5" at 100 meters.
Just my not too scientific experiment with 1 rifle.
MM