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It is currently Fri Apr 19, 2024 8:18 pm
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[ 6 posts ] |
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Checking Scope Elevation Function
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jukk0u
Site Supporter
Location: Lynnwood and at large Joined: Wed May 1, 2013 Posts: 21270
Real Name: Vick Lagina
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Pursuant to another members intent to get some glass for longer range shooting, I thought this might be of use and interest. To see if your scope elevation adjustments are working accurately there is a somewhat simple test one can perform without firing a shot. (It may require some help to do accurately/easily) At an exactly 100 yard range, tape a yard stick to a target stand. Ensure that it is set plumb using a plumb bob or an accurate bubble-level. (It may help to put shoot-n-see dots at one inch increments if your glass or your eyes prevent you from discerning the inch measurements) Set your rifle in a sled or firm sand bag arrangement. Aim at the top of the yard stick. Then have your assistant crank the turret to add 36 mils of adjustment. Make note of the clicks and progress throughout, but at the end of the adjustment, the SCOPE/POA should now be focused on the bottom of the the yardstick for a total of 36" of movement (37.5 if using an MOA scope) -if scope and target were level and the gun held steady during adjustment, the reticle should also be parallel to the yard stick throughout the adjustment. If you know the dope on your rounds, you can also use this process to see if your scope is capable of dialing in enough adjustment to make shots at longer ranges. The above is a paraphrasing of information from this article: http://www.arcanamavens.com/LBSFiles/Sh ... eChecking/
_________________ “Finding ‘common ground’ with the thinking of evil men is a fool’s errand” ~ Herschel Smith
"The said Constitution shall never be construed to authorize Congress to prevent the people of the United States who are peaceable citizens from keeping their own arms." ~ Samuel Adams
“A return to First Principles in a Republic is sometimes caused by simple virtues of a single man. His good example has such an influence that the good men strive to imitate him, and the wicked are ashamed to lead a life so contrary to his example. Before all else, be armed!” ~ Niccolo Machiavelli
Láodòng zhèng zhūwèi zìyóu
FJB
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Mon Dec 10, 2018 8:27 am |
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Brokemillwright
Location: Tacoma Joined: Sat Oct 20, 2018 Posts: 95
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Good luck, I tried a tall target test without firing. Being solo and not having a vise a gave up. Finally just took a 4' level and a roll of paper next time I went out. Shot my 100yd group then dialed in 5 mils, then 10, then back to zero.
Sent from my SM-G900V using Tapatalk
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Mon Dec 10, 2018 9:08 am |
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deadshot2
Site Supporter
Location: Marysville, WA Joined: Fri Jul 22, 2011 Posts: 11581
Real Name: Mike
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Brokemillwright wrote: Good luck, I tried a tall target test without firing. Being solo and not having a vise a gave up. Finally just took a 4' level and a roll of paper next time I went out. Shot my 100yd group then dialed in 5 mils, then 10, then back to zero.
Sent from my SM-G900V using Tapatalk Rather than pack around a 4' level just carry a piece of string and a lug nut. Tie the nut on one end of the string, hold the other end at the top of the target and line up with vertical line down the middle of the target. If you know for sure that you are shooting at 100 yards you can mark off 1.047" hash marks from your aim point at the bottom of the line. (For MOA adjustments, just 1" for hunting scopes that use inches). Zero on bottom aim point, raise one MOA at a time and fire one shot. Should have a nice straight dotted line from bottom to as far up as you want and each shot should be lined up as close as possible to the hash marks. Not only proves accuracy of adjustments but whether or not they are linear. Sometimes, as you increase elevation, intervals can get closer together or farther apart, depending on the error in your scope's mechanism. FWIW, this test is best done from either a "Lead Sled" or with a good bipod and rear bag, well sandbagged on both ends. Also helps if you are using good ammo that is very consistent from shot to shot. Mil-Surp is not necessarily a good choice for this.
_________________ "I've learned from the Dog that an afternoon nap is a good thing"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"For he to-day that sheds his blood with me Shall be my brother" - William Shakespeare
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Mon Dec 10, 2018 10:15 am |
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jukk0u
Site Supporter
Location: Lynnwood and at large Joined: Wed May 1, 2013 Posts: 21270
Real Name: Vick Lagina
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Seems like you're mixing in another variable by firing rounds. Sort of conducting an Audette's ladder test as well as a scope function test at the same time.
The test introduced in the OP is used only to see how the internal mechanisms of the scope is working.
By introducing ammunition, i.e. tacking actual shots, you're mixing in the variables of primer, powder charge, bullet weight/shape/set-back and a whole host of reloading variables.
_________________ “Finding ‘common ground’ with the thinking of evil men is a fool’s errand” ~ Herschel Smith
"The said Constitution shall never be construed to authorize Congress to prevent the people of the United States who are peaceable citizens from keeping their own arms." ~ Samuel Adams
“A return to First Principles in a Republic is sometimes caused by simple virtues of a single man. His good example has such an influence that the good men strive to imitate him, and the wicked are ashamed to lead a life so contrary to his example. Before all else, be armed!” ~ Niccolo Machiavelli
Láodòng zhèng zhūwèi zìyóu
FJB
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Mon Dec 10, 2018 12:30 pm |
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deadshot2
Site Supporter
Location: Marysville, WA Joined: Fri Jul 22, 2011 Posts: 11581
Real Name: Mike
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jukk0u wrote: Seems like you're mixing in another variable by firing rounds. Sort of conducting an Audette's ladder test as well as a scope function test at the same time.
The test introduced in the OP is used only to see how the internal mechanisms of the scope is working.
By introducing ammunition, i.e. tacking actual shots, you're mixing in the variables of primer, powder charge, bullet weight/shape/set-back and a whole host of reloading variables. Agreed but without ammo you really aren't "checking". A weak erector spring can lead to erratic results with recoil that won't be there with a mere static test. I won't say a static test is worthless but for me, if I'm going to go to the trouble I'm going to send rounds downrange to see how the scope performs 'real world'. If I needed a way to do the test in my back yard I might consider this method using a vise and scaling the measurements to fit the distance available. FWIW, I've seen more than just a few scopes at the range that have weak "internals" and behave very strangely. Enough for their owners to tear out their hair.
_________________ "I've learned from the Dog that an afternoon nap is a good thing"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"For he to-day that sheds his blood with me Shall be my brother" - William Shakespeare
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Mon Dec 10, 2018 4:36 pm |
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Brokemillwright
Location: Tacoma Joined: Sat Oct 20, 2018 Posts: 95
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Don't know or care about all the fancy names, just pointing out I tried the no shots fired tall target test and without a vise is was a no go for me. I do everthing solo,so I just find what works with what I have. As for the string and lug nut, sure that'd work but I don't drive a prius and I have no problem throwing stuff in the bed. I typically carry way too much stuff on my outings. I guess you have to start somewhere but if you don't trust your ammo and shooting ability at 100 yds then I see no reason for a person wasting time doing a tall target test. For me it was an experiment after shooting at 900 yards at a 18" target and hitting repadiitly , then moving out to 1104 yds and taking 18 shots to get on target and difficulty after that. Lots of factors, hot barrel, wrong baro pressure from guessing, scope maxed out and holding +2 mil, learning to read wind, lack of skill yada yada. Basically I setup using that big level, shot 3 at zero, 3 at +5 mils(18") and 3 at +10 mils (36") with my reticle following my plumb line. I had just bought and mounted a new scope and cheap rail bubble level that didn't seem to jive with my scope mounting level. So at +10 mills with reticle plumb I was avg say 1/2" right, then moving the rifle so the faulty bubble level was level, I was 2-5/8" left with that one shot. Worked down to +5 mils then zero and groups acted like they should,or close enough for my shooting therapy needs. I do admit I had slightly different +5 mil groups because zero and up I believe I shot in 1 string, them let it cool for my 4th +10 mil shot and worked down letting it cool again before zero. Firing bullets while "testing" works for me since I'm simple minded and need verifiable proof for things to click. I now fully understand how a few degrees of canting (5-10*) the rifle at a high elevation adjustment at 100 yds make such a POI change, that at long distance that's a massive miss like I was experincing, and also I believe I can plug the 1/2" right at +10 mils @ my 100yd zero into my shooter ballistic app and that will be caculated with my correction of bullet twist and scope adjustment. I'm sure I did a crummy job explaining my theory but it works for me Sent from my SM-G900V using Tapatalk
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Mon Dec 10, 2018 5:42 pm |
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