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Posted: 3/21/2005 10:53:07 PM EDT
| I know that the M3 turret cams are interchangable for different calibers. But, If have a Leupold scope with M1 turrets and another with M3 turrets can I switch them? |
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No. You cannot switch M3 and M1 knobs on the LR scopes, and you cannot switch M3 LR with Mk4 M3 (fixed) knobs either. M3 Windage--1/2 MOA clicks M3 Elevation/BDC--1 MOA clicks. M1 Windage--1/4 MOA clicks M1 Elevation--1/4 MOA clicks Premier Reticles will take your Leupold scope with a 30mm tube and put M1 knobs on it for a fee. They cannot put M3 knobs on any scope. |
no, one scope has 1/4 moa clicks and the other has 1 moa clicks, preimer reticals will make you a BDC cam or point you in the right direction. |
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Call these fellas and they'll fix ya up: www.premierreticles.com/, no matter how confused ya are...... Mike ps - no offense but looks like the blind leading the blind around here.......  FWIW, anything that can be done with the M3 camed turrets are at your fingertips w/ the M1 turrets, all you need is a come-up chart for your rifle's caliber and load. |
Agreed. However, even us M3 users need a come-up chart. I just didn't want the finer adjustments. 
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Most long range shooters prefer the "finer-adjustments" mentioned above by Zmeja. With the 1 MOA adjustments of the M3, at 1000 yards that one "click" (1 MOA) moves your POI (that's Point of Impact, btw) 10". With the 1/4 MOA adjustment of the M1 turret, one click (1/4 MOA) moves your POI only 2.5". See the difference? Finer adjustments means the ability to make more precise adjustments to your POI at long range. Mike |
I don't think anyone has ever produced a turret like that. Great Idea... if it would work. If Leupold produced a turret like that, then the M1 would not exist. |
That make a lot more sense. LOL |
The M3 doesn't work any different than any other scope turret. You turn the dial and it changes your point of impact (POI). What makes the M3 different is that one click of the elevation dial equals 1MOA shift in POI. The same is true for windage except it changes in 1/2MOA increments. Most scopes have 1/4MOA adjustments and very few exceed 1/2MOA per click increments. But the M3 turret is purpose built for military personnel. It was designed to let the shooter go from a zero range out to 1000 yards in one revolution of the dial or less. This takes some of the guess work away from finer graduated turrets when you are trying to remember how many revolutions that you've already made to go from one range to another. For example, I shoot .308win out to 1000yards on a regular basis. I have a 180gr SMK load that takes an adjustment of roughly 42MOA up from my 100 yard zero to get me on target. I have a Leupold 6.5x20 LR M1. Since the M1 is only 1/4MOA per click, I can only get 60 clicks (15MOA) of adjustment per revolution. So, its roughly 2-3/4 revolutions. Which is great if you remember where you were last zero'd at. But, what if you've forgotten that you were adjusted for 1000. To you, the dial just reads 12 (15+15+12=42MOA). I normally keep good records on my guns, but on a shoot a couple of months ago, I did just that. As recreational shooters, we can afford to take a round in the dirt just to get back on target. Most military personnel can't afford that luxury. Assuming that the M3 has the same 60 clicks per revolution that the M1 has, then it's only 3/4 of the way around to get to 42MOA and getting back to a different range is one step easier. I hope that makes sense. I kind of get the feeling that you are not clear as to the reason for changing out the M3 dials. Are you familiar with the Bullet Drop Compensation (BDC) principal? |
This is why "most" long range shooters always crank their scope back to "zero" before cleaning or placing their rifle away. (and the horizontal lines below the M1 turrets are graduated vertically so you'll know at a glance you forgot the crank the turret back down,  )"Safety first always", one should NEVER squeeze off a round without first making certain where the POI is supposed to end up. Mike |
I have hestitated to comment on this issue because I don't own any Leupold scopes w/ the M3 turrets on them, but here goes..... M3 turrets I equate w/ BDC type knobs, in that the "cams" (whether keyed for 308 or 223) are specifically attuned to both barrel length and the rounds being fired. You zero the rifle @100 yards, with the round the cam is set for, then use the "marks" on the BDC/turret to go directly to 200, 300 400 & 500 yards, simply by lining up the desired yardage marks with the range your shooting. I have an old ATN 5X33 scope which is graduated this way out to 500 yards/meters for the M855 round. (never worked worth spit, which ATN said was because my barrel length was wrong, personally I think the cam was a lousy fit for 223 rounds in general) I'd never expect a problem like that using a Leupold, in that I'd be willin to bet money that Leupold has cams that closely fit the calibers and rounds their designed for, that said this is my understanding of how the M3 turrets work. Given the comments above I suspect the M3 also has 1 MOA clicks/notches in between the 200-500 yard marks allowing for intermediate shots between the even 100 yard increments. Having different cams allows for the customization of the actual come-ups for each 100 yard increment tailored to fit varying rounds, both in bullet weight and caliber. I'm certain someone will correct me if I've mis-spoken. Mike |
Unfortunately, the horizontal graduations on the elevation turret are not a precise as they should be. That is the nature of having such a fine thread. If you change the angle at which you look at the turret even a small amount, you could be looking at a completely different graduation. As it turned out, I was only one revolution off and my example was just that... an example. As for safety, I knew that I would either be on target or short. Either would result in a safe and controlled shot. I took all of the options into consideration prior to pulling the trigger. |
Unfortunately, I don't own an M3 either. But I've handled several. If you reference the information on the Leupold website they make reference to different "dials" for the BDC. I don't believe that they offer different clicks, just different markings. Personally, I wouldn't want a dial that is only set to a specific load. No two guns are alike and unless the same round leaves your muzzle at the same speed as tested, it won't be accurate. You will probably find that you will be +/- 1MOA from the marks on the dial depending on the range. In which case, you will still want to have full adjustability. That is the reason I choose the M1 turrets and carry range cards. |
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Correct. The M3 (I have both, the M3 LR variable and the M3 fixed 10x) cams are designed to be zeroed at 100 yards, and the dials set with the index mark on the scope's tube. Each click is 1 MOA, but with the 168gr cam, I have to click twice to get to the number 2, which denotes 200 yards. 3 more clicks past the 2 is the 3. As you turn the cam, the numbers are a little farther apart. The placement of those numbers is determined by: 1) bullet weight in grains 2) barrel length 3) bullet velocity 4) temperature 5) elevation above sea level What fools many people about the stock M3 cams is that they think that if they have the rifle zeroed at 100, and set the cam to 1, that they can simply dial it to 10 and hit center mass at 1000 yards. That may or may not be the case, and many times, it isn't. Environmental conditions will play a great effect, along with the velocity of the round. The cams that come with a M3 are supposed to be matched to 55gr FMJ for .223 Remington, 168gr Federal Gold Metal Match, and the other two are for 30.06 and 300 Win Mag, but I don't use those, so don't remember the weights (although I think the 300 is supposed to be for a 190gr Sierra Matchking). Just because you have a M3 cam doesn't forgo knowing your come-ups in different conditions. Well, you may ask, what is the advantage to the M3 if 1) it doesn't always put the rounds exactly where you want them and 2) 1 MOA clicks for elevation are rather coarse for precision shooting? Well, speed, is the primary answer. Scenario: You are given a rifle zeroed for 100 yards, and the cam is set to one. You have to engage multiple targets at preranged distances (either at a known distance style range, or you've prepared an accurate range card for your sector) in a short time. First target is at 100 yards, and you hit your mark. Next, a target at 800 pops up, so you should be able to turn the dial to 8, and then take the shot. Next a target pops up at 300, so you turn the dial back to 3 and make the shot. In about the same amount of time I've taken to type this, you've acquired, identified, fired, cycled, and run through two more targets. M1 turrets, or ones with 1/4 MOA elevation would require you to have turned the dial back and forth several more times, and you may have only fired on 1 target. Also remember, the M3 is a military sniper scope in the context that military snipers are shooting man sized targets in the torso. Precision isn't necessarily required because a hit will still incapacitate the enemy to varying degrees. A military sniper may never need to make a central nervous system (CNS) shot at range. As illustrated earlier, 1 MOA at 1000 yards is 10", so 1 click too high, and you may have missed completely. Back to the cams. You can, through Kenton Industries, get them to make different cams for you. If you shoot a factory ammo, then you let them know your barrel length, cailber, bullet weight and manufacturer, general weather and elevation, and they'll send you a cam. I got one for 175gr Federal Gold Metal Match in .308 Winchester, with a elevation of 500' MSL, 70* F, and a 26" barrel. What was nice, and is different from the M3 cams from Leupold that came with the 10x scope, is that it has graduations for each click on the dial. Therefore, I can use it for 175gr, but also 168gr, as long as I know the come-ups for that ammunition. The numbers will not match up to the 168gr dial, but that's ok. Kenton will also make a M3 cam with just graduations at each click, without range numbers, so you can just turn to what you want and shoot. Or, if you shoot enough and handload, you can send them your data from your logbook and they'll make one for your specific load. The M3 LRs (formerly the VariX III M3 variable 3.5x-10x 40mm) do have graduations for each click on the cam, so it really doesn't matter if you have a tailor-made cam for your scope or not. Just know your come-ups. I have my M3 LR on my precision AR rifle, and regularly shoot 75 and 77gr Black Hills Match out of it, and the scope came with a 55gr FMJ cam. The cam is pretty much on with those match rounds out to 300 yards. Beyond, well, it just depends on the environmental conditions. Wow. That was a lot to type. Hopefully it was clear. (edited for spelling) |
Yes, I have 4 precision rifles with Glass, and I also have always used M1 turrets with range cards, but wanted to explore what M3 turrets could do for me.
This is part of the reason I was asking my original question, about the interchangabilty of the turrets. |
2 clicks from 100 to 200, that makes sense. I shoot 168gr .308win and there is about a 4" drop (rounded) from 100 to 200, which is 2 MOA at that distance. So, I guess that M3 turrets can be compared to the rear A2 elevation knob on a AR15. |
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