Comments

1. On February 16, 2023 at 6:00 am, Ratus said:

   This video from C_Does was very helpful.

   https://youtu.be/B475m1skueQ

2. On February 16, 2023 at 6:16 am, Ratus said:

   The Vortex Nation Podcast has a lot of good information and presents it in a way that is easily understandable.

   Their “10 minute talks” are great short-ish explanations of a subject.

   #10MinuteTalk – “Over-Torqued Rings”
   https://youtu.be/l4gty8I6j6k

3. On February 16, 2023 at 10:20 am, Paul B said:

   Pretty good. Loose is #1 in my book. Another is attempting to reset the zeroing dials. You can really mess up your zero doing that.

4. On February 16, 2023 at 11:14 am, Wyotana said:

   Loose. Bases. Bad.

5. On February 16, 2023 at 1:39 pm, =TW= said:

   Tube style red dot in factory rings on my Mini 30- no problems.
   4X compact scope in medium height rings on my AR- no problems.

   CZ 527M (rustic), 1-4X Leupold shotgun scope in 1″ Burris med height rings.
   Scope and mounts were selected after considering eye relief, bolt handle clearance, height over bore, cost and availability of mounts.
   The low comb on this stock is suitable for using the irons but is not high enough for proper cheek weld for scope use. Oops.
   Those who have a 527 American should not have any similar issues.

6. On February 16, 2023 at 4:21 pm, Georgiaboy61 said:

   Follow the torque specs specified by the manufacturer of the scope or optic; if you deviate from them it can void the warranty. You’ll need a gunsmith-type torque wrench graduated in inch-pounds, such as a “Fat Wrench” (Brownells and Midway have them).

   If you plan to do any longer range shooting, consider investing in a scope leveling device. Even a small amount of cant in the reticle can throw off your aim (POA vs. POI) significantly at longer ranges.

   A do-it-yourself method of getting your scope mounted precisely is as follows: Once you have mounted the base and rings, secure your rifle or carbine into a gun vise or steady mount, and then – with the scope mounted in its rings but with the ring screws not yet tightened – sight through the scope at a known vertical reference of some kind.

   Index the vertical axis of the reticle to this plumb line or other vertical reference. You can then check the orientation with a scope leveling-kit or similar tool, if desired. Once you have the reticle squared-up and the eye relief set properly, the ring screws can then be stage-torqued to spec. Do this in a star or criss-cross pattern, just as you would when tightening down a head gasket on an engine.

   Once everything is tightened to spec and secure, and you have verified yet again that your firearm is not loaded and is safe to manipulate, get behind the rifle and manipulate the optic as you would in the field, in order to verify that it is set up as you wish.

   If the scope isn’t precisely as you want it, make needed adjustments. If it is mounted as desired, loosen the scope ring screws one at a time or in pairs on opposite sides, in order to apply a small amount of thread-locker to the threads. Once this is done, reinstall the screws and tighten to spec. Do not over-tighten! Repeat this process until all of the fasteners in the rings and base have been coated with thread-locker and tightened properly and to spec.

   The whole point is to install, mount and center the optic securely-enough to test it, but not so securely that you can’t repeat the process, this time using thread-locker if desired.

   Don’t forget to test the operation of any controls on the rifle that may impinge upon the scope and the area around it, such as operation of a bolt for a bolt-action rifle.

   Before finalizing things is also when you check the height of the scope, and make any adjustments needed.

   A handy tip is to record the specifics of the operation on an index card or in a small notebook kept in your gun-case so that you can recreate the mounting of the optic when needed, such as reinstalling the scope after the rifle or the optic has been serviced. If your scope and mount are true “zero-hold,” recreating the same conditions as prior to removing the optic may allow you to maintain your previous zero or very close to it. Which will save you time at the range re-zeroing your optic.

   Bore-sighting or the use of laser bore-sighting devices will help you minimize the use of ammo at the range sighting in your rifle. In a conventional bolt-action one can remove the bolt and actually sight down the bore at a target. Then, while holding the rifle stationary in a vise or mount, the optic is then brought into zero with the same target. Typically, this is used to get on paper at short range, before lengthening the range to whatever actual zero is desired. This is done not only to conserve ammunition, but for reasons of safety.

   Laser bore-sighting devices are an ingenious refinement of this method, which use a visible red or green laser designed to fit inside a cartridge of a specific kind and caliber to fit a given chamber. For example, a laser bore-sight in .308 Winchester is a .308 Win. case with the laser installed in it instead of a projectile. One simply installs the battery to turn on the laser, then chambers it in the rifle to be zeroed. The rifle is then held steady with the laser aimed at the desired POI (point of impact), and the scope or optic adjusted to correspond to it. In a later step, a 3-5 shot group of rounds can be live-fired to verify the correctness of the desired zero.

7. On February 16, 2023 at 4:51 pm, Georgiaboy61 said:

   One more method which may be of use…

   Ballistic computer software programs are a useful tool for the sportsman, hobbyist, hunter or professional who wishes to zero an optic or sight but who does not have access to the required distance range for zeroing. You’ll need a reputable ballistic software program such as those offered by Applied Ballistics, Hornady, Sierra, JBM or Strelok, among others, as well as a straight edge ruler or set of calipers. You’ll also need the data for your particular load, particularly its muzzle velocity, preferably from your rifle or carbine or one like it with the same barrel length and twist rate.

   Veterans of the U.S. Army and Marine Corps will recognize the methodology used here. The Army has zeroed its M-4s and M-16s at 25 meters for years, since AR15/M16 carry-handle sights are designed to be used with a battle-sight zero of 25m/300m 0-300 meters, and elevation adjustments thereafter.

   Step one is to measure the height of your optic or scope over the bore. Measure from the center of the bore to the center of the optic. Record this value, 2-inches, 2.5 inches, whatever it happens to be.

   Next, enter the data for your chosen load into the ballistic software program. If you do not have access to environmental data, many programs will let you default to standard temperature, pressure and conditions. Unless you are crunching data for long-range work, these parameters do not impact the outcome all that much at close to near-medium range, say inside 100 yards.

   For example: If you are shooting an AR15 with a 20-inch 1:9 twist barrel, using 55-grain M193 Ball/FMJ @ 3240 fps, enter that into the program. Enter the sight height over bore also, the value you measured earlier. If you do not have the precise MV of your load from your firearm, the next-best alternative is to use the published values from the manufacturer. These appear on the website or often on the ammo box. The bad news is that barrel length isn’t often specified in such information, but that’s OK for the moment.

   Enter the range increment into the software. You’re going to start off at 25 yards, so make the increment small-enough to matter. Five yards or even one yard intervals. Set the maximum range a bit beyond the actual zero you ultimately want on the scope or optic. If you want a 100-yard zero, then set your maximum range for something like 200 yards.

   Next, and this is important: Even though you are going to fire your first group at 25 yards, set the rifle zero in the software program for whatever value your desired zero happens to be. If you want a 100-yard zero eventually, then that’s what you enter. Hit start to crunch the data in the program. What should result is a range card or printout showing the trajectory of your load at various ranges out to the maximum range inputted. Print this information off for use at the range, if possible.

   At the range, safely fire a 3-5 shot group at 25 yards. Start closer yet if needed to get on paper safely. Once you are on-paper at 25-yards, fire a group to see where your point of impact is versus your point of aim.

   Using your ruler or caliper, measure the horizontal and vertical distance of your group from the point of aim. Record these values.

   Next, compare your data printout (range card) to your group location. If the software printout says that for a 100-yard zero, your group should be at 0.75″ low POA versus POI at 25 yards, then that’s your new zero at 25 yards. Adjust your elevation and windage dials until you can center your group on that spot, 3/4th of an inch below your point of aim.

   Remember that angular measures, whether in minutes of angle (moa) or milliradians (mils), change in value according to range or distance. At 100 yards, 1 moa is equal to 1.047 inches of angular dispersion. At the same distance, 1 MIL is equivalent to 3.6 inches dispersion. However, at 25 yards, the respective values for each of these is reduced. Since 25 yards is 1/4th of 100 yards, 1 moa at 25 yards = 0.26 inches, and 1 mil is 0.9 inch at 25 yards.

   In other words, you’ll need more clicks to move one inch on the target paper than you would at 100 yards….

   Once you are center/center point of aim versus point of impact at 25 yards, according to the data on your range card, you are also zeroed or close to being zeroed at 100 yards, if you have done things properly.

   This method allows getting a decent zero at short range, if that is all which is available, which can then be checked at longer range when possible. It is almost always prudent and desirable to check your desired zero at the longest range possible. In other words, if you plan to hunt with your deer rifle zeroed for a 200-yard far-zero, then if at all possible, before your hunt, verify at 200 yards that POI corresponds to POA.

   Ballistic software can get you close, but you still need to perform your due diligence in the field when you can, for reasons both of accuracy and safety.

8. On February 17, 2023 at 1:28 pm, =TW= said:

   The US military battle zero is an application of ‘maximum point-blank range’, taking into account the arc of the bullet in flight. A slower, heavier projectile will have a higher arc and therefor a shorter MPBR.
   A useful consideration when adjusting the scope.

   I don’t expect to engage targets at much over 100 yds, more likely well under that. My carbines are set up accordingly.

9. On February 17, 2023 at 2:16 pm, Georgiaboy61 said:

   @ =TW=

   Yes, that’s my understanding as well. Maximum point blank range is the same general idea as battle sight zero, just a different name and a different application – hunting instead of military use.

   Getting back to the zeroing of an M4/M16/AR15, the U.S. Army and Marine Corps part company somewhat over zeroing procedures and best practices. The Army relies on meters, the Corps on yards. Whereas the Army has stuck with the 25m/300m near/far-zero method, the Corps has gone to a 36-yard zero, if my sources are accurate. Maybe our host can chime in on that one, since his son is a former Marine.

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