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Old April 12, 2019, 10:44 AM   #26
Pahoo
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Sorry bout that !!!

Quote:
how do you know if the level is level?
Verify with a Plumb-Line. !!!!

Be Safe !!!
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Old April 13, 2019, 02:40 PM   #27
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There are different methods. Hdbiker offers a reality check approach that is good. I set guns up with the sights mechanically straight first, then try snap shooting at some dryfire targets to double-check that the particular gun doesn't mount funny for me, but mechanically straight usually works for me.

The way I set mechanical straightness is with a nifty little tool that NECO sells. It is a V on the end of a plate with a vertically adjustable V with a bubble level vial on it. The lower V centers on the barrel under the scope bell. The upper V is then adjusted until it is centering on the scope bell simultaneously. The vial is then indicating level when the scope is straight up over the barrel with respect to gravity. It would not work on an offset scope, but for most rifles, it is just dandy.

The way I use it is I clamp the gun in a vice with leveling feet. I put that gadget on and adjust the feet until the bubble is centered. At that point, the gun is mechanically upright. This works regardless of whether the gun has a convenient flat spot on the receiver or not. I remove the level and loosen the scope screws and use a self-leveling laser line (indoors) or a plump line (outdoors; this is what fluorescent orange plumb line is for) to adjust the reticule position. I then alternate tightening front and back on one diagonal with doing it on the other diagonal and checking the reticule position until the rings are tight and the reticule is still aligned with the plumb line. At this point, if I'm going to put a cant level on the scope, I recheck that the gun is still level and put it on and make sure it both levels agree as to where level is.
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Old April 13, 2019, 02:47 PM   #28
pete2
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I eyeball it.
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Old April 13, 2019, 04:40 PM   #29
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A little different than some of the above but I'm doing this on a
1) Get the rifle boresighted at 200 yards with a known plumb in a mount.
2) Level left / right using a ... level (no surprise) in the mount.
2) Mount the (lapped) scope rings.
3) Mount the scope in the rings.
4) Zero the scope on the laser dot
5) Rotate the scope until the reticle is zeroed.
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Old April 14, 2019, 01:02 AM   #30
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How do you know if the level is level?

Well, it's not called an unlevel.
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Old April 14, 2019, 04:32 AM   #31
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All this begs the question. Why do we need to level the scope? A unleveled scope leads to a canted rifle. Then what's wrong with a canted rifle?

Furthermore, all that level and plumb line only ensures the proper setting of the rifle BEFORE the shot is fired. How do we know it is still proper after the trigger is pulled?

Perhaps the ultimate check is what's on the target paper?

-TL

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Old April 14, 2019, 05:22 AM   #32
Spats McGee
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Quote:
Originally Posted by tangolima View Post
All this begs the question. Why do we need to level the scope? . . . .
This is exactly what I was wondering. Why level the scope? As long as it's been properly sighted in, does it matter if it was leveled? I've heard of leveling the scope before but do not understand the reason.
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Old April 14, 2019, 08:40 AM   #33
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A level scope allows you to adjust POI vertically using the elv knobs and lets the bullet track along the vert line of the reticle.

If the scope is out of level, as you put elevation into the knobs the bullet also get windage adj
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Old April 14, 2019, 12:11 PM   #34
Pahoo
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Bingo !!!

Quote:
A level scope allows you to adjust POI vertically using the elv knobs and lets the bullet track along the vert line of the reticle.
Sharkbite
Great reply and right on the money. Gravity is always at work !!! ….

Thanks and;
Be Safe !!!
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Old April 14, 2019, 12:28 PM   #35
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That's correct. If the vertical line of the scope is canted, you then have to dial in some windage as well as elevation to maintain zero as you shift sight settings for longer ranges. If you have a mil-dot scope or another scope with range lines on them, they will be off to the side if there is any cant, and not directly usable.

In general, because most rifles have their bore lines above the center of support for the stock on the shooter's shoulder, the main vertical recoil moment, which affects POI, will be straight up and needs to be co-linear with the vertical reticule hair as well as aligned with the direction of gravitational pull to keep vertical sight adjustments strictly vertical and not contribute to the windage setting. This is why long range shooters put cant levels on their guns. It tells them when they have all those elements aligned at once.

You could also choose to intentionally put a slight cant in the direction of your rifling twist to compensate for wind drift. The old Springfield '03 ladder sights have that cant built in and a scope can make use of it too.

As with much to do with precision shooting at longer ranges, this isn't an issue for someone hunting medium and larger game in places where the shots are never over 200 yards. Where it bites you hard is shooting at ranges long enough for the bullet to be falling faster than flat shooting helps to overcome and where range correction has to be made. Beyond 300-350 yards would be typical numbers for most medium to high power rifles.
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Old April 14, 2019, 11:18 PM   #36
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My thought exactly. We always assume the barrel flips up always the stock's center line. But it is not necessarily always so. It depends on how the rifle is held, the shape of the shooter's shoulder, and some other things. The level / plumb line rituals just get it close. But live fire is the only final check.

I would crank the elevation up and down, firing groups at different settings, while trying hard to hold the gun consistently. If the windage significantly changes with elevation, I would rotate the scope slightly to compensate.

Another rhetorical question. If the group drifts to the left with increased elevation, should I rotate the scope clockwise or counter-clockwise?

-TL

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Old April 15, 2019, 05:31 AM   #37
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Thank you all for the explanation. Long-range shooting is pretty much PFM (Pretty Freakin' Magical) for me. I do notunderstand its intricacies. It seems to me that having the scope "out of rotation" (for lack of a better term, where the vertical crosshair is not quite vertical) might require adding in some windage adjustment to let the bullet track the vertical, but when I hear "level," I'm thinking front-to-back. It may well be that my understanding is deficient, but I don't quite get how having the front higher than the back, or vice versa, would affect the bullet's ability to track that vertical crosshair. Or am I misunderstanding how you're leveling? Are we talking about leveling front-to-back, or left-to-right? I get that "both" is probably the answer, but I'm trying to pin down which one is a problem.
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Old April 15, 2019, 10:10 AM   #38
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Spats, leveling as we are talking about refers to the rifle tilted to the right or left or the scope is "out of rotation" to use your words. Basically you need the crosshairs to point perfectly up and down and perfectly level to the right or left in order to keep the bullet from going to the right or left when you start dialing in elevation.

For your other comment about the scope being level front to back, this isn't really a thing. You can buy scope mounts that purposefully puts the objective lens (closest to the muzzle) lower. Most common example is a 20 MOA base. Basically what happens with a normal scope mount is that the scope runs out of adjustment to account for the extreme drop of the bullet at longer distance. The 20 MOA base right off the bat means you can get your crosshairs to aim 20 MOA lower. Or looked at another way, the 20 MOA base allows you to zero your rifle at 100 yards about 80 clicks closer to the top of it's adjustment range (assuming 1/4" per click @100 yards). As you get out to the really long distances, you have 80 more clicks of elevation you can dial in. Hope that makes sense.

I remember when long range shooting seemed almost magical to me. The crazy part is it's no where near as hard as I thought it would be. The exact same principles that helped me shoot small groups at 100 yards is the majority of shooting long distance (I'll caveat within 1000 yards). The hardware you're shooting likely has to be upgraded, but other than that it's mainly some math, learning to read ballistic tables and the wind. My uncle is responsible for this expensive past time of mine, and I really didn't believe him when he told me the problem was more my equipment than me. He was right! Of course this was in the days before The surprising level of accuracy you can get from guns like the Ruger American for cheap (I wasn't familiar with Savage back then.. I wish I had learned about them sooner). Now, even more so, reasonable accuracy at distance is very attainable with most budgets. And I say "reasonable" on purpose. Chasing smaller and smaller groups such as is required for competition shooting is a never-ending black hole of tweaking, testing and buying new reloading equipment. I can tell my desire for small groups is only so strong! Haha

There's something addictive about hearing that "gong" at 600+ yards. And imagine the confidence you have with a 300 yard shot on an animal when you can hit 600 yards 4 out of 5 times. I love long range shooting and hate that the closest 600 yard range is about 3 hours away from me. I've got 100 yards 30 minutes away and 200 yards an hour away. When I can find time to shoot, I normally go to the 200 yard range.

Last edited by ndking1126; April 15, 2019 at 10:27 AM.
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