How important is perfect level your scope to your gun?

[Sawney Bean]

If your scope is canted in relation to the bore, then you can only exactly zero it at one specific distance. Anything farther or closer than that range will drift to one side or the other and will be progressively farther off the farther from the zero distance.

If you calculate how far off from the bore your cant places your point of aim however then you can simply zero it so that your point of impact matches the amount of offset created by your scope cant and then your point of impact will be off by the same amount at any range.

Keep in mind that unless you’re badly out of alignment we’re generally only talking about 2 or 3 millimeters of offset.

You can have seriously offset from the bore and still deliver good accuracy. Just look at where the scope sits on a Dragunov some day. It’s about an inch to the left of the bore and it’s been their sniper rifle for decades.

 

[coastal drifter]

Yes

This is of course only possible if the reference points are true as stated by others.

I'm only giving you all the readers digest version, truing the reticle to the indexing location is another operation preceeding the mounting.

We had a fixture for that.

Nothing is perfect, that's why gravity is better than bubble levels leading back to plum bobs.

 

[Firewalker]

Nothing is perfect, that's why gravity is better than bubble levels leading back to plum bobs.

No, they are not.

No reputable gunsmith will plumb bob it. Nowadays, there are fixtures for this and they beat the pants off the pioneer methods of alignment.

 

[coastal drifter]

I'm certainly not the most knowledgeable person on this site not even close for that matter but... ask any good carpenter how perfect bubble levels are and the shorter the level the less precise

 

[coastal drifter]

No, they are not.

No reputable gunsmith will plumb bob it. Nowadays, there are fixtures for this and they beat the pants off the pioneer methods of alignment.

laughing with you not at you.

 

[Firewalker]

laughing with you not at you.

It's all good, you do you, I'll do me.

Levels are extremely easy to prove, 4 locations and they are proofed.

 

[Sawney Bean]

No, they are not.

No reputable gunsmith will plumb bob it. Nowadays, there are fixtures for this and they beat the pants off the pioneer methods of alignment.

A plumb bob is inherently more accurate than a bubble level. Bubble levels are only as accurate as their manufacturing, while a plumb bob is as accurate as gravity.

 

[Firewalker]

A plumb bob is inherently more accurate than a bubble level. Bubble levels are only as accurate as their manufacturing, while a plumb bob is as accurate as gravity.

The point is not the tool, the point is aligning the right thing.

Align crosshairs that are not true to the tube index and you get can't.

That's all I'm saying.

 

[Vana2]

If your reticle is aligned with the bore and it looks crooked when you mount the rifle you are canting the rifle. The stock does not fit you or your form is bad.

That's all there is to it.

I also level to the bore and, because I do a lot of fast, off hand shooting, I'm fussy about having a proper fit.

I focus on my target and bring the rifle up expecting that the sight picture will be clear, cross hairs level and on target. If not, I'm checking my form and the fit of the stock - I'm not shy to modify the stock (or even make a new one) if needed.

Cheers!

 

[Vana2]

A rifle barrel is round it can be mounted to the action in any of the 360degree and the bullet will still fly straight its the reticle that needs plum/level so the bullet will travel in a vertical flight. Just seems lodgical to me. Some professional shooters cant their rifles...not the reticle.

Theoretically true if the bore has been drilled perfectly to the barrel, in the real world I've had a couple of rifles that benefited from having the bore indexed.

Agree that the projectile (in windless conditions) will fall vertically with gravity if the axis of the bore is properly aligned with gravity. Otherwise, the projectile is "hooked" in the direction of the bias of the bore.

But yeah, sticking to the discussion , the reticle needs to be plum/level. Especially it the scope is high above the bore and you are shooting at longer distances.

Cheers!

 

[coastal drifter]

A picture is worth a thousand words ...

This is @Motorhead, using the "dead man" position for field target.
View attachment 508382

For certain classes of field target, this position is utilized by many of the top contenders. Sure doesn't look like anything resembling rifle shooting "form" as anyone outside of field target would define it. But they practice it and use it to good effect during matches.

To bring it back on topic, if my ear was on my knee during shooting, and my optical sense of up and down was all out of whack because of that crooked neck, I could maybe see the benefit of utilizing a bubble level.

are you sure he is awake?

 

[dgeesaman]

I shoot big scopes raised up kinda high and at a range of distances. Aka field target. Yes it matters.

I use an EXD tool to set the barrel and scope objective on a dead vertical plane, and use a plumb line at distance as a vertical reference. It takes some care to get the scope vertical crosshair on dead vertical but it works.

EXD ENGINEERING VERTICAL RETICLE INSTRUMENT | Brownells

Check out the EXD ENGINEERING available Online at Brownells Today and many more Scope Mounting Tools products are available in our Optics Department.

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You know it’s working when every shot at all ranges has exactly the same windage as your zero.

I suppose there is yet another level of execution where you confirm the entire scope optical line is parallel and vertical to the entire barrel but so far I can’t shoot the difference.

 

[Bedrock Bob]

I mounted a new Sightron S1 on my HW97 while we were discussing this. I used a torpedo level on the rifle and a door jamb of my shop to plumb the crosshair. The mirror shows my vertical passes through the center of my bore and objective. It's mounted square with the rifle, plumb with the bore and plumb with the world.

The weather is changing and it won't be pellet weather tomorrow. As soon as the wind goes away I'm going to shoot the tall target test and see how close it shoots at both ends of the crosshair. We will see how close it's lined up.

I took off a Hawke Airmax and will be mounting it on the Cometa when my scope rings arrive. I might just do the tall target test on both if the timing is right.

 

[Bedrock Bob]

A plumb bob is inherently more accurate than a bubble level. Bubble levels are only as accurate as their manufacturing, while a plumb bob is as accurate as gravity.

Actually a spirit level is perfect even if it's off. It has 2 parallel sides. That's the only important thing.

You draw a plumb line with one side, flip it over and draw a plumb line on the other. Bisect the divergent angles and you have a perfectly plumb line. Thats "level". Then you calibrate your bubble to that line.

Things with bubbles in them aren't "levels" unless they are calibrated. And unless they have 2 parallel sides you can't determine if they are off without calibrating them.

So yeah, "bubble levels" are crap unless they are level. But a spirit level is as perfect as a plumb bob if you use geometry and the 2 parallel sides. On a spirit level the straight parallel side planes make more difference than the accuracy of the bubble.

Old carpenter trick....

 

[nervoustrig]

The only true alignment is the bore and the scope indexing plane.

What is a “scope indexing plane”? This is a term I have never encountered, and seemingly neither is Google aware of it.

 

[Bedrock Bob]

I also level to the bore and, because I do a lot of fast, off hand shooting, I'm fussy about having a proper fit.

I focus on my target and bring the rifle up expecting that the sight picture will be clear, cross hairs level and on target. If not, I'm checking my form and the fit of the stock - I'm not shy to modify the stock (or even make a new one) if needed.

Cheers!

Bingo!

When shooting offhand ergonomics are super important. Especially on long shots. If your feet aren't right and your gun don't fit its going to be a bummer shooting offhand.

Natural shooting position and everything lined up with the world is what you need to focus on trigger timing. You just can't multi task like you can when the rifle is being held in a rest for you. Proper grip, cheek weld, eye relief, forearm position all has to be worked out before you shoot and be automatic. Not during every shot as a process of getting a sight picture.

It's a lot more than getting the gun level and lined up. You must do that but then KEEP IT LINED UP while your wobbling around like a drunk trying to time a shot. If your feet are wrong or your gun does not fit that's going to be impossible.

Offhand shooting with a stock that comes into your shoulder at an angle is like shooting a basketball with a rock in your sneakers.

 

[Bedrock Bob]

What is a “scope indexing plane”? This is a term I have never encountered, and seemingly neither is Google aware of it.

...It's that plane on the scope. That's indexed. It's the one you need a special jig to line up. The kind that all the gunsmiths use nowadays...

I read his instructions a half dozen times and asked for clarification. It's as clear as mud to me now. It must be the way to do it though. He giggled at me. He suggested my methods were outdated. He must know something I don't.

I went into my cave and did it with flint tools and a forked stick. Well see how far off it is shooting off the bottom dot. That's where the mammoth meets the tar pit anyway.

 

[Firewalker]

...It's that plane on the scope. That's indexed. It's the one you need a special jig to line up. The kind that all the gunsmiths use nowadays...

I read his instructions a half dozen times and asked for clarification. It's as clear as mud to me now. It must be the way to do it though. He giggled at me. He suggested my methods were outdated. He must know something I don't.

I went into my cave and did it with flint tools and a stick. Well see how far off it is shooting off the bottom dot. That's where the mammoth meets the tar pit anyway.

"Laugh it up fuzzball!"
-HS

 

[Firewalker]

What is a “scope indexing plane”? This is a term I have never encountered, and seemingly neither is Google aware of it.

Its just descriptive wording, not a term.

 

[Bedrock Bob]

Its just descriptive wording, not a term.

What is this wording a description of? How do you get a level on it?