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For a U.S.G.I. M1 carbine, using standard FMJ ammo, what would the trajectory data be if the gun was sighted in for 100 yards....specifically...how high/ low would the POI be at 25 yards and 50 yards.....and what if we went out to 200 yards? Thanks.....:help:
This was done with RSI Shooting Lab software:
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That's nice, but there's no way to zero a carbine at 100 yards, since the sighting is set up for six o'clock hold and will usually be high at 100. you would have to replace the front sight with another one with a taller sight blade, which is not advisable on collectible carbines. I prefer to leave the sighting in it's original context. Take a look at the 100 yd. Sighting Target from one of the manuals. Now, this target leaves open the possibility of a carbine passing with all shots just in the black or cutting the line at the sighting point, but it also passes those 12" higher. This leads me to think that what they expected to see was shots in the center of the black, 6" above the sighting point. This is a very different trajectory than the one pictured, which is why the adjustable sight is marked '1 - 1.5' instead of just '1' at the lowest setting, to provide good hits out to 150 and a little beyond, in keeping with the 'six o'clock' hold philosophy in effect at the time. The reason for that is so the sight post never obscures the point of impact on the target. Military shoulder arms are still set with high trajectories for the same reason.
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I don't think so......:thdown: You can sight the carbine at 100 yds & have excellent POA within 3"...:)Quote:
Originally Posted by INLAND44
"...no way to zero a carbine at 100 yards..." Nonsense. A 6 O'clock hold is just that. That doesn't mean it's shooting high. The shots will still hit in the bull(more likely just the black). 'High' means to be above the sighted-in POI. Hitting consistently above the dotted line with a 6 o'clock hold is shooting high.
"...Military shoulder arms are still set with high trajectories..." Firearms don't have trajectory. Military or otherwise.
.6" high at 50, on at 100, 4.2" low at 150, 12.9" low at 200.
Don't know if you agree with some of the answers but for my Standard Product M1 Carbine with the rear sight set on "1" I get 2 3/4" x 2 1/2" 10 shot groups from the benchrest dead center on the target and 1 1/2"s above my poa using FMJ ammo. This did not come easily for me I had to do a number of things to get my carbine to shoot this way. Recrowned the muzzle, rebedded the stock, added several shims to the end of the stock, flexed the barrel to get a consistant grouping, polished the slide, just to name a few of the things I tried before I got a consistant group from the benchrest. And using the FMJ ammo I get results simular to RSI Shooting Lab software published above. Good luck.
I showed you what's in the manual. There is no discussion possible. If you insist on hitting the POA at 100 yds, you will have to change or adjust the front sight to abandon the original intent.
Timmer; Congratulations! If that was at 100 yds, your carbine is suitable for service.
'You can sight the carbine at 100 yds & have excellent POA within 3"'
Can you say that again? It doesn't make sense. If you aim at the sighting point (POA) and the point of impact (POI) is 3" above the POA, yours would pass too. In fact, 5 out of seven shots within or cutting the dotted line anywhere would pass, which is a huge target area.
My point is it's 'wrong' (in the technical sense - it's your gun, do as you please) to artificially alter the designed sighting of the carbine.
I might be wrong, but I think carbine front sights were manufactured with the blade at the highest end of tolerance.
When the carbines were targeted the rear was set for 100 yds and fired. If the shots went high , but within specs, the gun passed.
If the carbine shot below point of aim, the front sight was filed until it shot within specs. Thats why you see so many carbines with filed front sights.
Some of my carbines shoot 8 inches high at 100 yds, with rear set at 100.
Other carbines have the rear set at 250 just to hit POA.
If your using your carbine for plinking at 25 yds none of this matters, but if your shooting woodchucks or NRA matches its very important.
Jim C
As I see it if your rifle is sighted in at 100 yards as mine is and you aim center mass at 25 or 50 they should pretty much all still be in center mass which is good enough. At 200 or 300 move your rear sight to the appropriate notch if you have the ajustable sight or if you have the flip sight flip it up to the 200 and you should be close enough to be in the fight.