View Full Version : How do you properly sight in a gun
December 13, 2004, 04:06 PM
Of course this is considering your rear sight is adjustable.
The reason I ask is that I recently have acquired a few revolvers and are sighting them in to hit the bullseye at 10yards w/ a sandbag. It works out and both my wife and I can put the bullet right in the middle more often than not.
Is it "incorrect" to sight in at such a close range being that it is still taking into account for bullet rise at such short distance yet out at 100yards, it is more accounting for bullet drop.
My dilemma is that sighting in at the indoor range I shoot at is only 25yards long. Should I sight in for bullseye at 25yards and then adjust for everything closer?
I guess what I am asking is what is the standard distance that most guns/pistols are sighted in at to hit the bullseye. All my revolvers are .357mag. but I primarily shoot 38sp. at the range and would like to sight in for the .38sp. I have found that the 138-158gr magnums hit pretty close to the same place as the 138-158gr .38sp at the range. The 110gr .38sp +P+ shoots really low by at least 1.5" :confused:
Last question: Is using a ransom rest the best way to sight in a gun or is it better to sight in your gun over time as you shoot. I cannot seem to get a definitive answer in this area.
Thanks for your help
December 13, 2004, 04:13 PM
I think it's best to set the sights for the way that you shoot. When I shoot my father's handguns (I'm left handed) the impacts are about 6" to the right at 25yds. I wouldn't bother using a rest for that reason.
I generally sight-in at 25 yards. It's mostly a matter of preference.
December 13, 2004, 07:22 PM
Unless the law of gravity has been repealed, bullets do not rise.
There are two lines, line of bore, and line of sight. They are not the same.
The reason the 110 gr shoot lower than the 158 is the 158 has more bore time, thus gun is futher into recoil than the with the faster 110. ie 110 exits bore first.
While Sandbags may be used for accuracy testing, I would rather sight in my guns offhand, at whatever distance I can group well. This is usually 15 to 25 yards depending on the weather, sights, and me.
December 13, 2004, 07:47 PM
I would expect that you could sight in at 25 yds. for a possible long shot, and you would not notice much change at all at 10 yds. I don't think there will be much drop with a high velocity handgun loading. If you are dead in the bullseye at 10 yds, you might even be within the black at 25. But sighting in for target work entails holding at 6 o'clock on the bulleseye. That is because the bullseye and the sights are both usually black so it is easier to set the bullets to strike high in the bullseye center with the visual image of the bullseye resting on top of the front sight-like dotting the i. Sight is then against the light background. But combat shooters look for a point of impact right at the top of the sight. Not the few inches higher with the target bullseye setting. And if you shoot at police combat silhouettes, they are black so you don't get the sight contrast unless you have white dot or colored front sights. So for home defense I would set the sights for a point of impact right where you point. For that kind of sight adjustment I find that a colored bullseye on a white background, like a orange flourescent colored stick on dot from the office supply-get the 1 1/2 inch diameter or larger. Or put one in the center of your bullseye. Ransom rests are used for checking ultimate grouping accuracy of a gun, not for sighting in. It is different than shooting handheld. Could be used to select best ammo, but for sighting onto the bullseye shoot by hand.
December 21, 2004, 02:37 PM
I always sight in a handgun by using a two hand hold and resting my wrists (not the gun) on sandbags. I find that works when I go to an off hand hold. If any part of the gun touches the sand bag or the bench, the point of impact will be affected.
As to the fast bullet shooting low, that is normal. The reason is barrel time. Remember, recoil begins the instant the bullet starts to move, so the gun is actually recoiling while the bullet is moving down the barrel. The faster the bullet moves, the less time it stays in the barrel and the less the gun has recoiled when it exits. The converse is true with slower bullets. (If you doubt this, run a straight edge along your revolver sights and see how far the barrel angles down below the horizontal.)
This is part of the reason why it is difficult to sight in for "pin point" accuracy; you will achieve it only for that one load.
Factory non-adjustable sights are set to zero at 25 yards for the .38 Special 158 grain lead load, and for the .357 158 grain jacketed HP.
December 21, 2004, 09:01 PM
I disagree with KC135 and Jim keenan About why the 110 gr bullet stirikes
lower than the 158 gr bullets. I think it has to do with a factor they call
sectional density. The 158 gr bullet would have a higher sectional density
and woulld retain velocity longer. The 110 gr bullet would start to drop faster. I'am no expert, kind of guessing myself. The only reason I say this is the fact that I have seen two high speed photos of two guns being fired, one was a snub nose 38 special and the other was a winchester 30-30 lever action. In both photos you could clearly see that the bullet was long gone
and neither gun had started to move at all. I don't think recoil affects bullet point of impact. Correct me if i'm wrong. I do agree with the other parts of your comment though.
http://www.firearmsid.com/Galleries/bka/fiocchi.asp This is a link to a
high speed video of a gun being fired to show what i'm talking about.
You might have to register to the site to view it though.
December 22, 2004, 02:56 PM
KC and Jim are, in fact, both correct. Heavier, slower bullets will impact a short range target higher than a lighter, faster bullet. I've seen it happen in my own experience. A 30-30 bullet is traveling at about 2000fps, and there is much less muzzle jump out of a 30-30 rifle than a .38 snubbie, due to bore axis and method of hold...this is an apples/oranges comparison. A .38 Spl bullet out of a snubby is traveling about 700fps. 2" of barrel isn't enough to make much difference, no matter what load you're using, but most snubby shots tend to print high on a target, because they are low velocity, and recoil is sharp.
I shoot a great deal of both 185 and 230 grain JHP's in my .45's. The 185's shoot to point of aim; I must hold at 6:00 to get the 230's in the same area of the target at 25 yards. Same deal with 155 and 180 grains in the .40. I have 2 2" .38's, and I shoot 125JHP's out of those; I must also hold those low at 6:00 at 15 yards...I don't try to shoot them at 25 yards.
Of course, as target range increases, more factors related to bullet weight and trajectory come into play, but at 25 yards and less, that's not much of a factor.
I also had a tough time getting my head around this idea at first...
January 2, 2005, 11:49 AM
Any sight adjustments made after firing a pistol which is held by any other way than Jim describes above will not place your shots where you want them when you do hold it by hand. A ransom rest is good for seeing how well your pistol or load groups but isn't valuable as a tool for zeroing, except in the most general way.
Heavier bullets impact higher at practical pistol ranges, lighter bullets impact lower. That's a fact, period, when dealing with handguns. I personally believe the barrel time/inertia explanation but regardless of the reason, it happens! That fact is used when a pistol is shooting higher or lower than the sights will adjust for. Use heavier bullets, point of impact rises,use lighter bullets and it gets lower.
January 30, 2005, 08:32 PM
You're right about heavier bullets being generally more aerodynamic--but at pistol ranges, sectional density has very little impact on the trajectory.
You're also right that the gun doesn't APPEAR to move in high-speed pictures. However, it is moving--just not much. Which is what you'd expect from the difference in the point of impact difference. The difference in muzzle lift to cause a 1.5" point of impact difference at 25 yards would be measured in hundredths of an inch--not something you'd be likely to see on a photograph.
January 30, 2005, 10:34 PM
Not much impact difference between 15 yds and 25. For a combat gun either of those distances should work out for you. A Fed. LE Instructor of my acquaintence said to sight for 15 yds. For target shooting, adjustable sights can be sighted how ever you wish. Still like 15 yds.
January 31, 2005, 01:14 PM
When I shoot Handgun Silhouette with the .22, I sight in my pistol at 25 yards, and I don't change the sights for the 50 yard shots. I do raise the rear sight for 75 yards and once again for 100 yards.
February 1, 2005, 03:43 AM
Whatever distance you use to zero your sights, always confirm POI from the shortest distance you can shoot (say 3m) out to the furthest distance your range allows (say 75m). That way you have an idea how your gun-ammo-shooter trio behaves at different distances.
As for sandbags and freestyle shooting, try both. Ideally, you start at the sandbags then re-confirm using your freestyle/unsupported stance.
Personally, I only use freestyle sighting-in since I never use sandbags when shooting my guns. YMMV.
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