Stupid Question of the Day (Year?)

[rraisley]

Okay, I have yet to own a rifle (let alone a scope, etc.), but have my sights set on a 15-22 MOE when it comes in. My birthday was yesterday, so please cut me some slack with my stupid question:

I'm an engineer (i.e. troublemaker), and tend to put everything in spreadsheets or CAD or sketches. I see that any sight, especially a high-mounted scope, has to point way down, in relationship to the barrel, to hit at any distance.

My question is: Do scopes have a built-in downward slope to allow for this? Or are they actually mounted parallel to the barrel, and all the downward scope is accomplished through adjustment?

I've read several articles on adjusting a scope, and they suggest bore-sighting to a location, then pointing the scope to that location. But the mounts I'm looking at (QD double mount) don't appear to have any adjustment. In fact, even separate rings don't seem to have any, do they? If that's the case, isn't the pointing location of the scope completely determined by the mount, and unless something is built in sloped, automatically parallel with the barrel?

Yeah, I know you're all probably rolling on the floor laughing; but I'm really trying to understand how this works.

Please be kind. ;-)

 

[watergun1929]

Scope Adjustments

The only stupid questions are the ones NOT asked. Every scope has a full range of adjustments built in. At longer ranges (1000 yards and up) you can buy 20 moa mounts that will allow more elevation adjustments. If you are shooting at 600 yards or less the built-in scope adjustments will work fine.

 

[OKFC05]

Let's talk engineer (I'm a physicist, but spent my share of time in engineering classes, too).

First, the angle between the line of sight (LOS) and line of departure (LOD) in a .22 LR shot at normal .22 LR distances is small comparted to, say, a Palma rifle. Thus, good quality fixed rings are quite adequate, without getting adjustable rings. The internal scope adjustments take care of zeroing it.
Second, it is to your advantage to get a scope specifically made for a .22LR so the parallax will be set for .22 distances, not for 150yds, which would cause misses at normal .22 LR ranges.
The good news is that there are several such quality .22LR scopes in the $150 to $200 range.
For most normal shooting with the 15-22, .22LR scopes under $100 like the Simmons are quite adequate. The rifle is a fun plinker, not an Olympic bolt .22, and extreme precision optics are not needed.
You know the old engineering saw about "why measure with a micrometer if you're going to mark with a piece of chalk and cut with an ax."

 

[stavman11]

See... no BLOOD was drawn becouse of yer question.....

Actually was a REAL good one.... i learned a bit myself

WELCOME to the addiction buddy....

Start buying mags and AMMO now... youll need it

LOL


Stav

 

[roadkill45]

IMO there are 2 answers to your question, maybe 3. an AR can be mounted as close to the bore as possible on a red dot or holo. my EXPS-1 Eotech has a 7mm riser so that it will co witness the lower third of the buis. it all depends on how much upward or downward adjustment the scope has. a normal hunting scope on a bolt action is mounted low and then the butt of the stock is matched with our face to get a good picture. my McMillon .308 has a 20mm rise on the mount so that i can get more upward elevation for longer distance since it will run out of elevation at a certain point.
so it can go both ways, elevation and incline decline via internal scope adjustment or by the mount.
all my AR's have straight mounts, all LaRue, and the dots have no issue with elevation settings.
sighting in has several schools of thought but the main 2 are to 1. shoot at the center of the target 3-5 shots then leaving rifle in exact same position, move the internal reticule until it is hitting in the middle, so you are adjusting to the middle.
2. the one shot zero is better IMO. take 3-5 shots, leave your rifle in exact same position it was and then adjust scope so that the cross hairs are in the exact middle of the group that you fired. you should then be centered almost in the bull. another 3 round group for micro adjustment, re set zero on dials, lock it down and you are done.
just remember that in either, the rifle needs to be as solid as possible so if you have or can borrow a lead sled of some sort they are invaluable round savers. the less lead sent downrange when zeroing the more to use for practical shooting at known distances as if hunting or dialing in exact as in benchrest zero shooting.
My .02 and how i do it, i'm sure there are others that will chime in with the different ways they do theirs. no one is wrong as long as it works for you.

 

[rraisley]

...Every scope has a full range of adjustments built in.

Right. But they have a limit. According to my calculations, a sight on a 15-22, if mounted 3" above the barrel centerline, and exactly parallel to the barrel, will have to be adjusted down about 16" at 100 yards. If I'm doing it properly, that's 16 MOA or 64 clicks of 1/4 MOA. In only one direction (down). I see a lot of scopes, like the Sweet 22, saying they have a range of + or - 35. Is that +/- 35 MOA, or 35 clicks? If clicks, I'd be in trouble. If MOA, then it would work fine.

 

[roadkill45]

Stav, where you at in the "Desert"? I'm in the "Real Desert" of AZ!!

 

[roadkill45]

Right. But they have a limit. According to my calculations, a sight on a 15-22, if mounted 3" above the barrel centerline, and exactly parallel to the barrel, will have to be adjusted down about 16" at 100 yards. If I'm doing it properly, that's 16 MOA or 64 clicks of 1/4 MOA. In only one direction (down). I see a lot of scopes, like the Sweet 22, saying they have a range of + or - 35. Is that +/- 35 MOA, or 35 clicks? If clicks, I'd be in trouble. If MOA, then it would work fine.

hence the adjustable rings or higher sloped bases to mount on. the variety is endless. i would go to the this or the other forum and look at the picture threads and see what type of scope and mounts they are using and then you will get the idea. practical for my .22 is maxing at about 150y and that is it for using the dot. everything else is kentucky windage, but i would not be taking small game shots at 150, it would be for S&G's at the gongs on the range.

 

[stavman11]

Stav, where you at in the "Desert"? I'm in the "Real Desert" of AZ!!

DITTO....... In Glendale

Heading out to PLAY any minute..... but still on this stupid Computer thingy.....LOL

 

[mathpat]

I'm a mathematician and teacher, if this is a stupid question I don't want to know what a hard question from you would be! Thanks for the interesting query.

 

[rraisley]

I'm a mathematician and teacher, if this is a stupid question I don't want to know what a hard question from you would be! Thanks for the interesting query.

Well, it didn't seem stupid to ME. To me, it sounded fundamental and important. But in all the reading I've done, no one seems to be concerned about the fact that a scope parallel with the barrel will /never/ be pointed correctly in itself. And a mount maker I contacted mentioned I could use another 1/2" spacer, but that I might then run out of scope adjustment to hit the target. So it really got me thinking.

I still don't understand how so many scope mounting tutorials just say to leave the scope loose until it's pointing exactly to where the boresight is pointing, then tighten it down, when it doesn't seem that most of the mounts have any real adjustment; they're just clamps, after all.

 

[OKFC05]

Right. But they have a limit. According to my calculations, a sight on a 15-22, if mounted 3" above the barrel centerline,...

Mounting the scope that far above centerline on the 15-22 is a mistake for practical shooting reasons, i.e., you aren't going to be able to get a "cheek weld" solid position, and are going to be wobbling all over the place. If you mount the scope colinear with the iron sights, you will have a stable shooting stance and backup sights if you have to remove the scope.
Take a look at the multiple sights on 3-gun competition rifle and you'll see the additional sights mounted on the side, not stacked up on top of each other.

My neighbor ignored everyone's advice and stacked all his sights vertically, but later changed them after shooting some friendly club matches.

 

[BillyJack2012]

A post on another forum was a great help. It's specific to the AR15 but concept is the same.

AR-15 Zeros and Trajectories - AR15.COM

 

[rraisley]

Mounting the scope that far above centerline on the 15-22 is a mistake for practical shooting reasons, i.e., you aren't going to be able to get a "cheek weld" solid position, and are going to be wobbling all over the place. If you mount the scope colinear with the iron sights, you will have a stable shooting stance and backup sights if you have to remove the scope.

I'd like the scope colinear with the iron sights, but 1) Near as I can tell, the iron sights are about 2.6" above the barrel centerline (again, I don't yet have the rifle; I'm scaling off pics and looking at Magpul's specs). And using an NCStar cantelever scope mount or equivalent, I calculate the scope's centerline will end up about 2 3/4" above the barrel centerline. I rounded that to 3", but I don't think the average mount, at least if it's going to clear the folded MBUS sights, will be much less than that.

Practically, I'd love to have the scope cowitness with the existing sights, but that would mount it quite a bit higher.

 

[rraisley]

A post on another forum was a great help. It's specific to the AR15 but concept is the same.

AR-15 Zeros and Trajectories - AR15.COM

EXCELLENT post! It will take me some time to read and understand, but it may well answer my questions. And I KNOW it will answer questions I haven't thought of yet. Thanks!

 

[OKFC05]

Suggest you visit one of your clubs having .22 matches and look at the 15-22 setups being used. Most are happy to show off their equipment and answer questions. Take a box of .22 with you and they probably will let you shoot some.

Added:
Here's a ballistic calculator so you can genterate some actual .22LR curves.
http://handloads.com/calc/index.html

 

[rraisley]

Here's a ballistic calculator so you can genterate some actual .22LR curves.
Handloads.Com Ballistic Calculator

Thanks. I've calculated and graphed ballistic curves for my intended rounds, so I have a pretty good idea of that. Actually, I calculate that if my scope is mounted 3.5" above the bore, I'll be able to shoot with the same zero at 25 and 100 yards, but that's probably higher than I really want to put it. And as OKFC05 mentioned, cheek weld will be a problem if I get too high. I can get a cheek pad, but then it will be too high for the iron sights, so IMHO they the two should be as close as possible. Which, in my case, will be having the scope as low as possible and still clear my folded MBUS rear sight.

 

[RolandW]

When I got my 15-22 I knew I would want a scope on it, and never having owned one before, the issue you raise was on my mind.
Here's a path graph I generated for my current setup (Nikon 4x32 zeroed at 25 yards). Bullet-drop is actually my friend, since it counters the effect of the scope not being coaxial with the barrel.
In playing with the Spot On program from Nikon I was surprised at how little difference scope height makes at the distances I shoot at. My scope is 2 5/8" above the barrel, but the most I have to adjust is an inch.
You asked your question in the right place. These guys are always ready to help. Just don't make the mistake of calling your magazine a "clip."

 

[rraisley]

I still wonder if scopes aren't already "optically pointed down." ;-) I mean, NO scope can be mounted less than say 2" above the rifle bore, and even a fast bullet will drop over 1" at 100 yards. So a scope mounted perfectly parallel to the bore will always be AT LEAST 3" high at 100 yards, and would NEVER need to be corrected above zero. Seems it would make sense to "point" them down a bit, so as to give more /usable/ adjustment, up and down.

But maybe I'm over-analyzing.... ;-)

 

[RolandW]

Ah, my internet connection was on the fritz while I was trying to post so now I see that you are way ahead of me.
I've learned that the most important thing is getting the scope so it's comfortable, and of course so it works with any other sights or devices you want to use.