Recently I purchased a Springfield M1a Loaded 22 (Full length) rifle. I've got a ARMS-18 steel scope mount for the rifle; and I'm going to get the Leupold Mark 4 steel scope mount. Reason I'm making this thread is I want some input/advice or just any thoughts on the Leupold Mark 3HD 6.5-18X50mm scope.

I plan on shooting from anywhere between 100 yards out to the 750 yard range (roughly). I'm looking for something quality and durable for a rifle like the M1a. I'm not looking to spend more than a grand on the optic and ideally use a leupold scope. Although I'm open to suggestions

Link: https://www.leupold.com/mark-3...50-p5-side-focus-tmr

The first question I have is what type/discipline shooting you plan and whether you would ever anticipate using the scope to hold off for targets at different ranges rather than always dialing the elevation and/or windage.

That scope has a second focal plane reticle and the specifications state that it’s properly calibrated only at the highest magnification. If you might want to hold for elevation or windage and the magnification isn’t set to the highest, then the reticle won’t help you. If you adjust the magnification, forget to set it back up to the max, and then hold for windage or elevation, a miss is very likely. I still recall the misses I had years ago when I relied on range estimation and point of aim adjustment with a second focal plane scope, and I was again reminded just recently that I dislike such scopes. In fact I’m in the process right now of switching from a second plane scope on a rifle I plan to use more frequently in the future to one with a first focal plane.

If, however, you never anticipate estimating ranges, and especially if you don’t plan to use the reticle to adjust your point of aim, then there’s nothing wrong with a second focal plane scope, and it can actually be better for some purposes by keeping the reticle the same size at all magnifications.

Added: I assume you are referring to the Mark 3HD 6-18×50mm scope. I don’t see a Mark 3HD 6.5-18×50. If I am wrong, disregard.

Honestly I plan to do a variety of shooting styles including hunting and medium to longer range shooting. I really do appreciate you explaining secondary focal plane to me. I'm not very experienced with optics and that's something I honestly looked over.

So let me ask you this; So if I were to zero the optic to lets say 200 yards with the optic intending to use it on the lowest magnification (6.5X), The Mil-dots won't reflect the true windage and elevation of that said range? But it will work on the full power of the optic (18X)? Also if I do run it on 6.5X could I learn where to hold to adjust for windage and elevation as long as I'm on the same power as I zeroed for?

Front focal plane, and second focal plane

quote:

The reticle and its location.
When it comes to reticle, the choices are endless; from the simple yet effective crosshair to the fancy-shmansy Horus-type reticle, for the target dot to the bullet drop compensating circles, there are endless gimmicks and tricks out there.
Also, there are two locations for the reticle in a riflescopes and their position is rather important when it comes to their use. So let’s talk first about the position of the reticle and then we can start a discussion on the type of reticle
Everyone here has heard about the misnamed FFP and SFP reticles. FFP is incorrectly called the First Focal Plane reticle, when it is actually in the second focal plane, behind the erector cell, but in front of the zoom assembly. The “FFP” reticle is placed in that plane so that it merges with the image focused by the erector cell to present a parallax-free image at that distance. Because it is in front of the zoom lens assembly, when you twist that zoom lens the image, including the reticle, will grow. The upside is that the reticle adjustments and markings are always in proportion to the objective regardless of the magnification, which is great for ranging and hold-offs on unmarked targets, but can be a bear to surgically place said reticle on target at higher magnifications.
The equally misnamed SFP reticle is place behind the zoom lens assembly at the third focal plane, right in front of the ocular lens. The SFP reticle will remain the same apparent size, regardless of the zoom setting which makes it very usable in high zoom range scopes but useless for ranging and hold-off on unmarked target unless set at the proper magnification, usually the highest one.
The choice of SFP or FFP is very important and is very much dependent on the use of the riflescope. As a rule, FFP are more expensive because I believe the skill level required to set the FFP perfectly is even higher than what is required for the SFP, and is thus an added complication, but what do I know?
Another feature of reticles is illumination and there are various types of those. Quality illumination can easily add another $100 or more to a riflescope. If you know you will never need it, don’t waste the money. I love illumination for specific reasons, age is one of them.
Whatever reticle you get, make sure your knobs match the unit of measure. If you get a Mildot reticle, look at getting a Mildot master to go with it, unless of course, you have extensive training.
The BDC things are neat but are made for a specific bullet launched at a specific velocity. Some manufacturers will have methods to customize this for your own load. I have virtually no experience with that so I won’t talk about it.

Found in this thread
https://sigforum.com/eve/forum...0601935/m/4890078914

quote:

Originally posted by CrewDog77:
So let me ask you this; So if I were to zero the optic to lets say 200 yards with the optic intending to use it on the lowest magnification (6.5X), The Mil-dots won't reflect the true windage and elevation of that said range? But it will work on the full power of the optic (18X)? Also if I do run it on 6.5X could I learn where to hold to adjust for windage and elevation as long as I'm on the same power as I zeroed for?

My first scope on a precision rifle had a SFP reticle. It worked well for single targets at known distances, but the SFP challenges arose immediately once I started playing the steel-target-game.

Your mil dots will be accurate at the 18x.

At 6x the mil markings will triple in value -- what was .5 mils at full power will now be 1.5 mils.

If you can accurately set the scope at 9x magnification, the mil markings will double in value -- what was .5 mils at full power will now be 1.0 mils.

Magnification has no effect on your zero. If you're zeroed at 18x, your zeroed at 6x, and any magnification level in between.

If you have plenty of time to make the mental calculations, you can use the SFP reticle for holds at lower power. But it is a challenge, and eventually you will make mistakes.

I think the scope would be a good starter scope for you to learn on. It's got plenty of power, but I wouldn't count on the reticle values. I'd just use clicks to adjust for elevation.

More importantly, I want to point out that the loaded model, depending on the stock and bedding, if it has it, is likely to be a 2 to 4 MOA gun. It doesn't make sense to put a $1,500 piece of glass on a 2 to 4 MOA gun when your SFP glass is more than enough for now. I'd take that extra $900 and invest in accuracy mods like a McMillan or SAGE stock, a unitized gas cylinder, a proper cheek rest, and a bedding job. I'm giddy when my M14's shoot MOA or better but I'll take 1.5 MOA if that's the best I can get.

The M1A can be made to shoot very well, but it can take some money and a good M14 gunsmith to get you there.

Tony.

Thank fritz for giving me a little more info on SFP. Now knowing that and what benny6 told me I feel a lot better about what I'm getting this optic at the skill/experience level I'm currently at. I think this optic will allow me learn about "longer" distance shooting and like y'all said really be a good starter scope.

I appreciate all y'alls input, information, experience and suggestions.

quote:

Originally posted by CrewDog77:
So let me ask you this; So if I were to zero the optic to lets say 200 yards with the optic intending to use it on the lowest magnification (6.5X), The Mil-dots won't reflect the true windage and elevation of that said range? But it will work on the full power of the optic (18X)? Also if I do run it on 6.5X could I learn where to hold to adjust for windage and elevation as long as I'm on the same power as I zeroed for?

Yes, you are correct that at any power other than 18×, the milling marks won’t be accurate reflections of the angles you expect. As fritz explained, if the magnification setting is exactly one-half of the maximum, then a 1 milliradian mark would actually cover 2 mils of arc rather than one. If you’re not familiar with what milliradians (“mils”) refer to in conjunction with all this, there are any number of YouTube videos and other sources that explain. In short, though, dialing a 1 mil change with your scope will change the point of bullet impact by about 3.6 inches at 100 yards; 2 mils will change it by 7.2 inches, and so on. But that’s true of reticle marks only if they are accurate. If a 1 mil hold difference using the reticle actually moves the point of aim by 1.3 mils, then the point of impact will change by ~4.7 inches, not 3.6.

It is possible to learn how to adjust mentally for the differences in arc values with variations in magnification settings, but as I know from personal experience, it’s very easy to lose track of what the magnification setting is. If you’ve set it at 15× rather than 12 or 18 that you’re familiar with, the visual difference may not be noticed, but the discrepancy will affect where you aim and where the bullet hits.

You could develop a trajectory (“dope”) table for any particular magnification setting that used the reticle for aiming adjustments. For example, if you wanted to use 12 power, your table might indicate that you should aim up two mil marks for a 200 yard target, up four mil marks for 300 yards, seven mil marks for 400 yards, etc. You would still have to be careful to ensure that the table you use was for the proper magnification setting, and you’d need separate trajectory tables for each magnification setting you might want to use.

On the other hand, if you make all your windage and elevation adjustments by dialing, then none of that matters. The question is: Can you?

I am usually hesitant to make recommendations, but I will in this case. For the type of shooting that I understand you plan to do, I would try to get a scope with a first focal plane reticle. They are not without their drawbacks, but they would make things much less complicated for you.

sigfreund thanks for the information and recommendation and I'll definitely consider looking at the first focal point optics and or making a DOPE card.

You’re welcome and you will of course get a lot of good information here. There are different experiences speaking and therefore different factors being considered.

Not to beat any dead horses, but a final comment about dialing all point of aim adjustments: I and many other long range shooters will usually try to dial elevation adjustments whenever possible, and it usually is possible unless there simply isn’t time. There are a couple/three advantages to dialing rather than trying to hold using the reticle.

Compensating for the wind, though, is another matter. If the wind is completely steady, then dialing works, but in many locations absolutely constant winds are the exception rather than the rule. Where I shoot, for example, when the wind blows (often) it varies literally every few seconds. If I’m not going to just dial an adjustment and wait (and hope) for the wind to match my setting, that means I must judge the wind, hold off left or right the proper amount, and take the shot at that moment. One of my rifle drills requires me to fire a shot within five seconds of a start signal, so waiting until things are Goldilocks just right isn’t an option.

There are two common ways of holding for the wind. One is to hold by absolute distances such as X number of inches for Y wind at Z distance. That method works with any sight, but is somewhat difficult in practice if we’re not shooting at the same distance all the time and using the same targets. For example, bull’s-eye shooters will know things like that they need to hold at the left edge of the black if the wind is 10 mph from 9:00 o’clock and the target is at 600 yards.

The other common method these days is use the calibrated reticle to hold for windage. There is a method I developed and which I refer to as the “standard wind unit” that works well for me. For many loads at sea level elevation a wind of 4 mph from 3:00 or 9:00 o’clock will drift the bullet about 0.1 mil every 100 yards of target distance. I can therefore use the reticle to adjust my point of aim by that amount. For example, assume it’s an 8 (2 × 4) mph wind at 9:00 o’clock and the target is at 300 (3 × 100) yards:
2 × 3 × 0.1 = 0.6 mil aiming adjustment left.

With a calibrated reticle, I just adjust my point of aim 0.6 mil left of the target without trying to determine how many inches that is at 300 yards. That method works for several hundred yards, but only if my scope reticle mil marks are accurate as I discussed above. Again, one could prepare a dope chart that would compensate for a second focal plane reticle’s calibration at different magnifications, but then that’s another complication.

I hope all that’s clear. If not, let me know or just ignore this post.

Yeah, most of that made since. Like I said I'll probably make DOPE card. I'll probably set it up to something along the lines of minimum power (6.5x) and 9x. Again thanks sigfreund for the information regarding optics and SFP and FFP optics.

quote:

Originally posted by CrewDog77:
Like I said I'll probably make DOPE card. I'll probably set it up to something along the lines of minimum power (6.5x) and 9x.

If you will be shooting from your proposed 200 yard zero out to 750 yards, you will need a dope card. Not probably, not maybe -- you will need one to reliably hit targets.

Your dope card can be based on actual data from trial and error. Or you can start with a ballistics program and accomplish the same results much faster, with less ammo cost. JBM ballistics is one of the free programs, which I am using below. Assuming 2600 fps muzzle velocity, a Sierra Matchking 175 bullet, 3000' air density altitude, 200 yard zero, 2" scope over bore height. These assumptions may be in the ballpark, or maybe not.

The following data is distance to target in yards ___ elevation in mils ___ wind drift in mils for 10 mph crosswind.
200 __ 0 mils __ .8 mils
300 __ .8 mils __ 1.2 mils
400 __ 1.7 mils __ 1.7 mils
500 __ 2.8 mils __ 2.1 mils
600 __ 4.0 mils __ 2.7 mils
700 __ 5.3 mils __ 3.2 mils
800 __ 6.8 mils __ 3.9 mils

I just pulled data for targets at 100 yard intervals. My own dope charts are built on 10 yard intervals. It all depends on your target situations.

I absolutely do not recommend separate dope charts for different scope magnifications. I've tried it before, and it doesn't work in competition. Dial your elevation for various targets, as you will almost certainly have time.

Now if you want to make a quick transition between say a 500 and 600 yard target, the above data shows a 1.2 mil difference. Hold this exact number at 18x magnification. Or cut it in half for 9x. Windage is as much a feel thing as hard numbers. Few people can accurately predict crosswinds early in their long distance shooting career.

Dial your elevations, using 18x data. I'll be right up front -- I don't like the reticle on your proposed scope. IMO it's one of the weaker mil reticles on the market, and probably even worse than the TMR that I had in my long-gone Leupold Mark IV 4.5-14x scope. The .5 mil subtensions (i.e. hash marks) are OK. But it's hard to determine on a quick glance what is a 1/2 mil versus a full mil subtension. There are no markings that state 2 or 3 or 4 mils off reticle center -- just a bolder line at 5 mils. Trying to do accurate hold overs/unders with such a setup, while adjusting the values for a different magnification levels, will produce ongoing error in elevations. Try it, and you'll find out soon enough.

Where you need to start for long-distance shooting:
- Get an accurate measurement of scope over bore height. This is center of scope to center of bore.
- Get an accurate muzzle velocity for the load(s) you will use. If you don't have a chronograph, borrow one from another shooter.
- Develop a really solid zero. Determine if 100 yards or 200 yards or whatever yards is your preference. With all this data, build some preliminary dope cards. Don't futz with data for less-than-full magnification levels.
- Get out and shoot. Experiment with different ways to work elevation for targets at various distances. Shoot on windy days.

Thanks man, I will refer back to this thread when making my dope card.

quote:

Originally posted by CrewDog77:
Thanks man, I will refer back to this thread when making my dope card.

I told ya sigforum was the place to come and ask these questions. The folks here are unlike any other place on the internet.