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Hi, I'm new to the forums and have joined to try and get some experienced advice on holdover and holdunder. I shoot a .22LR at the mo with a variation for a .17HMR and a .22mag (I made both variations at the same time due to being indecisive) and I've since paid the deposit on a .17HMR CZ 455 thumbhole with a 20" barrel.

 

I'm a fairly competent shot, shooting a 15mm group at 60 yards using a wing mirror for a rest.

 

The reason I'm posting is because I've found loads of useful information on holdover using a mildot scope for distances of 100 yards +, but nothing under 100 yards with regards to the size of a mil in inches. I want to be proficient with holdover on my .22 before I collect my HMR.

 

So what I'm really asking is, how do I work out the mil size for ranges under 100 yards? If 100 yards equates to 3.6", then does 50 yards equate to 1.8"? And if so, how do you work out the Mil size for say, 80 yards? Assuming the scope is set to it's maximum magnification and 3.6" does in fact measure 3.6" at 100 yards.

 

My setup is sighted for 60 yards. Occasionally, the odd 15 yard shot presents itself, the 80 yard shots more commonly (I wouldn't like to try anything beyond that, my rifle might be capable, but I'm not), so being able to create my own chart to take out with me that I've made myself would help massively and give me a much higher level of satisfaction than pinching someone else'.

 

I'm not into humidity or elevation, or even cross wind just yet. I just want to be able to calculate the bullet drop for now, and then move forwards from there. I'm as interested in the maths behind the shot, as I am in pulling the trigger and hitting the target.

 

Thanks,

 

Dave

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A ballistic program would be a good start,I believe "chairgun" can be used with rimfire although I favour "Strelock"myself.

worth a look to get general idea.Personally I find the only accurate way is to set targets at different ranges although the programs will get you close.This thread http://forums.pigeonwatch.co.uk/forums/topic/253571-vortex-ballistics-calculator/ may also be of interest.
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Beretta if you could explain how you work out that 1 mil dot over for 100 yards then from there I can work out various distances. Firstly for my .17hmr and from there I would like to move onto a 22/250.

 

 

SIMPLE. I use a target and ammunition. I go down the range and i practice and i work out the various hold overs. I also do this with the ammo i will be hunting with.

 

Be realistic with a .17 HMR you dont need hold over till 170yds plus and for a .22-250 its more like 250/300 yards. What ranges are you planning on shooting at?

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Speaking as an elder geek with more than one geek t'shirt.....

 

You are reading too much and making life too complicated, you will grow out of it soon, this is not USA military.

 

Just spend an enjoyable summers afternoon in the middle of a big flat field and set some targets up at 10 yard intervals and work out your personal "real world" trajectory. There is no substitute for this.

 

A variation on that technique is to make up a long (2 to 3 foot) "banner" comprising a string of "targets" a couple of inches from the top of the paper and leaving that fixed in place just move further and further away from it in 10 yard increments, that way you have all your end results on one long piece of paper.

 

You will now know the precise holdover / holdunder for every distance with that rifle and ammunition combination.

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Speaking as an elder geek with more than one geek t'shirt.....

 

You are reading too much and making life too complicated, you will grow out of it soon, this is not USA military.

 

Just spend an enjoyable summers afternoon in the middle of a big flat field and set some targets up at 10 yard intervals and work out your personal "real world" trajectory. There is no substitute for this.

 

A variation on that technique is to make up a long (2 to 3 foot) "banner" comprising a string of "targets" a couple of inches from the top of the paper and leaving that fixed in place just move further and further away from it in 10 yard increments, that way you have all your end results on one long piece of paper.

 

You will now know the precise holdover / holdunder for every distance with that rifle and ammunition combination.

 

 

Fair enough Dadioles, but nothing wrong with wanting to understand as much as possible. And ain't nothing wrong with aspiring to perfection :)I plan on using the methods you've said tonight :)

 

You could do a lot worse, no chart is going to give you exact answers, by far the best way of doing this is with Your Rifle, Scope, Ammo and YOU shooting.

 

That way you will have EXACT answers and can make a note of specific Mil dot positions as required at whatever mag you chose to use! :yes::good:

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If you have a reasonable quality scope, I find MOA adjustments/clicks far more precise than estimating the gaps between the milldots and its easy to map out a chart using the guys advice above and tape it to the top of the scope. Then you don't have to worry about different mag settings giving variations as you are always on "zero" Just a thought.

Edited by turbo33
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Could be just my luck but my scopes interpretation of mil-dot size varies scope to scope,best way is to set out target with inch or cm graduations at say 30 yds & see just how much a mil-dot measures at the mag you shoot at.You can then calculate size at other ranges.

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All taken onboard. But out of curiosity, how DO you work out the mil size under 100 yards?

That's exactly the point I made in my post 13. You have some scopes that have 1/2 milldot marking, but its still down to picking a point on the vertical line between zero and your first milldot or half milldot and knowing what that range is and all the unmarked increments in between. All a bit of guesswork :yes: Have a look at this, and although its an air rifle shown in the video, the same principles apply. Don't forget as said above, if you change the magnification it will change the calibration of the milldots.

Edited by turbo33
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use the advice above on shooting the banner. 10 dots in a line on a piece of wallpaper. start with left dot as 10 meters and put 3 shots at is. move to 20 meters and do the same. keep going will you get to the 100. you now have you drops for all distances

 

you can, as you go along, mark on paper where your mill dot is by putting + on the group hole and marking where on the mildot.

 

buy your self a flip up eye piece , like a butler creek. get some stick back paper and draw your mildots and the distance next to the corresponding mildot. stick paper to inside of flip up. now, every time you open you scope cover its a quick glance to know the mildot you need.

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use the advice above on shooting the banner. 10 dots in a line on a piece of wallpaper. start with left dot as 10 meters and put 3 shots at is. move to 20 meters and do the same. keep going will you get to the 100. you now have you drops for all distances

 

you can, as you go along, mark on paper where your mill dot is by putting + on the group hole and marking where on the mildot.

 

buy your self a flip up eye piece , like a butler creek. get some stick back paper and draw your mildots and the distance next to the corresponding mildot. stick paper to inside of flip up. now, every time you open you scope cover its a quick glance to know the mildot you need.

Love this one, had a bit of success last night, from a prone position I used a 1 mil dot holdover and got a head shot, It's my first successful hold over shot to date and really impressed with myself. Couldn't have done it without all the helpful suggesttions...thank you!

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