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Firstly, this is my first post so I'll take the opportunity to say hello and that the forum is a mine of useful info :-)

I've been using Strelok to push the range out on my Howa 223 and I'm finding the results pretty inconsistent.

Took a rabbit with a 250 yard headshot using the correction but at 315 I'm missing the 3" steel target by miles over the top and have to take off around 18 clicks of elevation from the solution provided by Strelok. At 475 yards I only have to take off 7 clicks to be dead centre.

Shot a 2 1/2" group on the far target last night so I don't think it's my technique.

I'd have expected the error to get bigger with more range rather than smaller?

Any ideas?

I've checked the turret tracking as I have an MTC viper which isn't that great and I've adjusted the click value to match the 1/2 error I got at 100 yards with 2 full turns of elevation. I've rechecked all the values I entered into Strelok and measured my scope height again. No to mention scratched my head a lot.

Cheers

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I've not used that program but have tried a few. A bit more info is required.

 

How did you get your MV do you have a chrono or is it from the box.

If you have a chrono have you checked the BC.

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Shot a 2 1/2" group on the far target last night so I don't think it's my technique.

I'd have expected the error to get bigger with more range rather than smaller?

 

 

My first instinct is always technique.

As you say, the results don't match intuition. Poor modelling should get worse further out.

 

When you group at 100m; do you place your MPI on your POA everytime?

 

Or do you find that you always shoot excellent groups; but they seem to land in slightly different places on each outing?

 

Excellent groups, but their MPIs wander around the POA from occasion to occasion.

 

My first instinct is that you have inconsistent position and hold from occasion to occasion.

 

(ie you hold and place the rifle consistently through a string - and can therefore shoot great groups.

But you change hold between strings - and your great groups therefore land in different places relative to your POA)

 

There are other possible causes. But lets cross 'inconsistent position and hold' off the list before chasing them down :)

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I'd be inclined to check drops for your load data on another ballistics program,but ultimately there is no substitute for actual range/field shooting-that is what the rifle does,and I'd base my adjustments on the actual firing data-but it is disconcerting when the practise is way out from the 'theory'. But the actual shooting results are definitive,if repeated,and unless there is some rather large other variable,and if you use them,you can check,and probably extrapolate-there should be some consistent graph if you plot the actual range/drops.

Gbal

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Crikey! That was quick. Plenty to go at there. One thing I forgot to mention is that at 315 I'm shooting downwards at a steeper angle than at longer range. I've entered the different angle into Strelok so it should calculate accordingly. I'm going from the box on velocity as I don't own a chrono

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Crikey! That was quick. Plenty to go at there. One thing I forgot to mention is that at 315 I'm shooting downwards at a steeper angle than at longer range. I've entered the different angle into Strelok so it should calculate accordingly. I'm going from the box on velocity as I don't own a chrono

That might be crucial-without knowing click values and angle etc,can't check but you can-the 315 has to be off because of the slope-real horizontal distance will be considerably less than 315- and the correct adjustment might bring the otherwise inconsistency back in line- if you don't have accurate velocity (barrel length etc etc?) or BC,then shoot at known (horizontal equivalent) distances and plot- that should remove inconsistency,though you may well be (consistently) out with respect to the ballistic solutions,based on different dat,discrepancy increasing with distance,but you will have what really matters-the drops for your rifle/load.

Gbal

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Without the correct MV in you will struggle to match the output of any ballistic program. You can tune a program without a chrono to some extent but the more accurate the data in the better the output.

 

See if someone local has a chrono if not try the following.

 

get a large target board (lining wall paper is handy) set up at accurate ranges preferably level ground. shoot groups at your target. aiming dead on measure drop to your MPI for each range.

Now the fun part speed up or slow your MV and/or alter BC till the figures match your real time result.

 

Or just test at more ranges and have your own real world drop chart.

 

I have got close with some programs but without a chrono and two speeds at two known ranges or drop from two known ranges you will struggle. Remember as with any other computer program garbage in garbage out.

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I'd be inclined to check drops for your load data on another ballistics program,but ultimately there is no substitute for actual range/field shooting-that is what the rifle does,and I'd base my adjustments on the actual firing data-but it is disconcerting when the practise is way out from the 'theory'. But the actual shooting results are definitive,if repeated,and unless there is some rather large other variable,and if you use them,you can check,and probably extrapolate-there should be some consistent graph if you plot the actual range/drops.

 

Gbal

Sorry -just to add-I was a bit lazy,off the top of my head 315 slope distance is more like 300 yards for 15% slope and 275 yards for a 30% slope.How does the nearest fit to actual slope seem using those distances wrt to clicks-it will certainly reduce the clicks needed(again depends on bullet etc).

Sonic of course is right-there must be a very close match of input data to get useable output-and remember your precision at distance will be a fair bit less than the 'group size' alone-largely due to shot dispersal factors(=/- 15 fps in MV starts to show..)but especially misjudgement of wind speed -out to the target,whatever Kestrel tells you at the muzzle.

That's another very good reason to get real shoot data,by test firing at the distances.The program can't do that-or estimate shooter factors-but it can indicate the very minimum size of paper to put up!!

But it's readily doable,then you know...

Gbal

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Detail's exciting. That's where everyone wants to jump. :rolleyes:

 

But: Horse not Zebras! Look for the simple solution first. :)

 

I'd put money on this being inconsistent position and hold from occasion to occasion.

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Thanks guys, I'm sort of realising that there's a lot more to this than there seems.

I decided already that I need to do a drop chart for my rifle and ammo so that should help. I've realised that any ballistic app will only be as good as the data you put in and that I also need to spend loads of cash I haven't got at the minute on gizmos and reloading gear :-)

I suppose I'm trying to do the best I can with what I've for until I can get the gear to do better.

Thanks so much for all the valuable info. I've just picked up some more ammo so I hope I'll shortly be reporting some better results.

Much appreciated!!!!!

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Just for the record I do think my technique isn't quite there yet and there may well be a bit of variation in my hold etc. I shoot off my Harris bipod without a rear bag or monopod. I usually make a fist under the toe of the stock and either tense or relax to get crosshairs on. An accushot monopod is on my wish list but as there's lots of trees on my shoot I do have to move around a bit to get a shot so the less gear I have to carry the better!

Regarding the angle of the slope- distance to target thing, the slope is 18 deg and to get the corresponding number of clicks that actually hit the target I have to reduce the distance on Strelok to just 230 yards.

I've clearly got some duff data going in there as well so an accurate drop chart should help with that. I'll hopefully get out this evening, check and refine my zero and shoot some reference shots to get some proper values.

Thanks again :-)

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Just for the record I do think my technique isn't quite there yet and there may well be a bit of variation in my hold etc. I shoot off my Harris bipod without a rear bag or monopod. I usually make a fist under the toe of the stock and either tense or relax to get crosshairs on. An accushot monopod is on my wish list but as there's lots of trees on my shoot I do have to move around a bit to get a shot so the less gear I have to carry the better!

Regarding the angle of the slope- distance to target thing, the slope is 18 deg and to get the corresponding number of clicks that actually hit the target I have to reduce the distance on Strelok to just 230 yards.

I've clearly got some duff data going in there as well so an accurate drop chart should help with that. I'll hopefully get out this evening, check and refine my zero and shoot some reference shots to get some proper values.

Thanks again :-)

Maybe you don't need any extra gear-it won't make that much difference in a field shooting situation-though maybe a cheap rear 'bag' -home made works quite well-would be worthwhile-just don't expect bench rest performance in the wild-where there are no

concrete tables etc. For stalking,factory ammo is just fine-bullet jump fine tuning etc is largely a non productive,given the right bullet construction.Nor does a second shot .5 away from the first matter-you should not need it,and if it is .5 away,it will still work.

 

Angle does make a difference-the bullet drop is determined by the horizontal distance,not the distance measured along the slope-though that is all you can measure directly.The 'drop' distance is given by (slope distance)X cosine of angle of slope. ((10% less distance will be an easy improvement on no correction!)) .So your 18 degree slope 315 shot is more like a 285 yard shot for drop purposes.

As sonic says,you need the actual data from your rifle,and then tweak the program to mimic that,NOT the other way round.

imic that,NOT the other way round.

By all means work on consistency of hold etc-given the vagaries of shooting round trees etc etc,but I doubt that such variation will put a shot 'miles high',and give consistent groups.The wrong data might well give the high/low shot point of impact,but won't affect group size.

Being very competitive at the highest level is a quite differennt matter,and that is where the equipment race has to be taken very seriously.but no such will counter a 10% error in judging distant and variable wind speed.Precision can be bought,but not accuracy(aka wind skill),yet.

Gbal

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Angle does make a difference-the bullet drop is determined by the horizontal distance,not the distance measured along the slope-though that is all you can measure directly.The 'drop' distance is given by (slope distance)X cosine of angle of slope. ((10% less distance will be an easy improvement on no correction!)) .So your 18 degree slope 315 shot is more like a 285 yard shot for drop purposes.

 

Noooooooooo!

 

That ballistic distance drop hocum is banned on here.

 

The bullet flies the slant range. It falls for all the time gravity accelerates it whilst it covers that slant range.

 

THERE IS NO SUCH THING AS EQUIVALENT HORIZONTAL DISTANCE!

 

Aaaaaaaaaaaaaagh!

 

:rolleyes::)

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I'm just about to have a snooze to make sure im completely calm then I'm off out with rifle, ammo, large sheet of paper and board, rangefinder, notebook, flask, sandwiches, groundsheet, etc etc. think I need a pack mule :-s

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Noooooooooo!

 

That ballistic distance drop hocum is banned on here.

 

The bullet flies the slant range. It falls for all the time gravity accelerates it whilst it covers that slant range.

 

THERE IS NO SUCH THING AS EQUIVALENT HORIZONTAL DISTANCE!

 

Aaaaaaaaaaaaaagh!

 

:rolleyes::)

Sorry BD,I can't see it as 'hocum' AT THE PRAGMATIC LEVEL,and it helps some understand what is going on-of course I agree with the technicalities of what you say(though gravity 'accelerating' it might confuse,as the bullet is slowing all the time).However,at the practical level of measuring the effect,the cosine formula seems about as simple as it gets,and that uses the 'horizontal' distance on the right angle triangle representation,and the slope(hypotenuse).Uphill too,of course (accelerating if you will).

While I might be forced to bow to authority,I would prefer to acceed to reason,and increase my understanding.

Does not your final sentence mean "the time it would take to traverse the 'equivalent horizontal distance'?"

It may seem to you a heresay,but it is a popular one indeed,and delivers the corect understanding that bullets do NOT shoot high on slopes,(the alternate description you give does not do this either,of course).And as 'equivalent horizontal distance allows a much improved sight allownce,while yours seems to lack how that would in fact be calculated-unless you have a very accurate time of flight etc,at the very least the 'equivalent horizontal distance' is PRAGMATIC when it comes to what to do.

The method (cosine) is in widespread use,I first saw it clearly enunciated on p218/9 of Carmichael's "Book of the Rifle'",where he acknowledges that for rather difficult to explain reasons,the bullet follows a less curved trajectory when we fire up/down a slope-the pragmatic question is "How do we know where to aim to hit our target?",and his 'equivalent horizontal distance hypothesis is close enough and workable in the field-and way bettter than no correction.

Granted this was in the days of the neck top computor,but that is common issue kit.

There is of course a case for the full Monty,as with correolis and so on,but starting with (S=ut +1/2 gX t squared) isn't as handy as "It's 10% closer",though even the cosine formula improves on that.

 

As a psychologist,having something that works well and is easily used by the human brain has advantages.

"rule of thumb,maybe".....is there one that is at least it's pragmatic equal,BEARING IN MIND THE CONTEXT-seeing bullet splash,or an enhanced hit probability,over rather modest distances.

Otherwise,it is rocket science!!

Gbal

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Gravity is an acceleration?! 9.8m/s/s

 

No, if a bullet takes 2 sec to go 1000m it experiences an acceleration (towards the centre of the earth) of 9.8m/s/s for 2 sec.

Whether that 1000m is 'flat' or 'angled' it takes 2 sec to go that far. That's how fast the bullet's going. It can't take less time to cover the distance.

And since it's in the air for 2 sec, it experiences gravitational acceleration for 2 sec. Not some magic lesser amount.

What changes with angled fire is the relationship between you/the trajectory and the direction of gravitational vector - which, in simplest terms, makes it appear to drop less.

Again, in simplest terms, to see how much shorter the drop appears to be, apply your cosine to the drop -Never apply it to the distance; that's 1950's good ol'boy ballistics :)

 

So, whereas Occam's razor almost inevitably applies to people having trouble with long range shooting (horses not zebras!) it almost never applies to the study of external ballistics itself. ;):)

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Much more sorted after 20 rounds, loads of thinking, working out and measuring. I've tweaked the MV and the BC as well as my scope click value to be very close to my actual trajectory which I figured out by shooting and recording a drop chart.

Dialled up and hit a 3" target at 315 yards first shot, then dialled up for a 9" one at 475 yards and hit that.

Shots went a little low but by a more uniform and predictable amount so just tweaked the scope click value and hit dead centre.

Massive thanks to all for your input!

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Much more sorted after 20 rounds, loads of thinking, working out and measuring. I've tweaked the MV and the BC as well as my scope click value to be very close to my actual trajectory which I figured out by shooting and recording a drop chart.

Dialled up and hit a 3" target at 315 yards first shot, then dialled up for a 9" one at 475 yards and hit that.

Shots went a little low but by a more uniform and predictable amount so just tweaked the scope click value and hit dead centre.

Massive thanks to all for your input!

That's great

.

The basic advice is shoot the rifle first,and use the actual data to tweak the program-which can then be used with much more confidence for that rifle and load.

 

((Of course,the generic program is worth an initial look,just to set up your targets etc))

 

It's a slightly 'uphill' walk,but well worth 20 shots.....

 

Gbal

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'An uphill walk'? Ah, you're obviously familiar with my permission then!

Strelok seems to be pretty spot on for my mate's Tikka/ Nikon/Federal combo. I still think it's weird that it was so far off the mark for my set up but I guess some ammo and scope manufacturers are more accurate with their quoted figures.

Thanks again guys, I've definitely saved time and money as a result of your help. :-)

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Luckydan,,,,in addition to all advice given zeroing at 100yds is pretty much a waste of time,,,the trajectory is way too flat here,,,,zero at 200 where plus or minus 10/20 yards starts to show up and get to know actual velocity and strelok when loaded with all the right info will work pretty good for you and any tweaks should be minimal and only further influenced by conditions on the day.

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Yeah, that seems to make a lot of sense. I've only had my 223 for just coming up to a year. It's quite a step up from air rifles and rimfire where effective ranges are so short. I'm really enjoying having the tools to take longer shots and be very humane when shooting live quarry. V maxes certainly seem to be very effective!

I tried my mate's rear bag the other day and it certainly gives an improvement.

The longer the range, the more everything has to be right, anything wrong and you miss! It's seriously addictive. Have a bad day and you want to get out again and get it right, have a good day and you can't wait to do it all over again!

I'm out again this evening so I'll give the 200 yard zero a try :-)

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Yeah, that seems to make a lot of sense. I've only had my 223 for just coming up to a year. It's quite a step up from air rifles and rimfire where effective ranges are so short. I'm really enjoying having the tools to take longer shots and be very humane when shooting live quarry. V maxes certainly seem to be very effective!

I tried my mate's rear bag the other day and it certainly gives an improvement.

The longer the range, the more everything has to be right, anything wrong and you miss! It's seriously addictive. Have a bad day and you want to get out again and get it right, have a good day and you can't wait to do it all over again!

I'm out again this evening so I'll give the 200 yard zero a try :-)

Good,,,,,,You need to hold a good inch sized group if your ammo will allow,,,,good luck

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Yeah, that seems to make a lot of sense. I've only had my 223 for just coming up to a year. It's quite a step up from air rifles and rimfire where effective ranges are so short. I'm really enjoying having the tools to take longer shots and be very humane when shooting live quarry. V maxes certainly seem to be very effective!

I tried my mate's rear bag the other day and it certainly gives an improvement.

The longer the range, the more everything has to be right, anything wrong and you miss! It's seriously addictive. Have a bad day and you want to get out again and get it right, have a good day and you can't wait to do it all over again!

I'm out again this evening so I'll give the 200 yard zero a try :-)

Well said,that is as it should be.

 

There are two issues.What distance to zero at,and how do you get the best data for your ballistic program and drop sheet.

 

As Onehole says, for the ballistics info,100y is workable,but it's more difficult to be sure just how high shots are-the trajectory is pretty flat-so is your half inch group really .75,or 1.5 inches high-or are you confident that i is 1 inch(5 shots in the same hole,centered one inch high-not very likely) and ditto of course for other 'heights'.Now that small potential difference begins to matter out at distance.If you use say 200 yards to 'zero' then the measure will be a little easier-though of course the group will be bigger,but your "half inch possible measure error" will be that bit less critical.So chose carefully and measure as accurately as you can-check at 300 if posible...That data should give you reasonably accurate values of your rifle's actual performance to feed into the ballistics program.

 

OK-now what distance do you actually zero at? With good data as above,it isn't too critical.Whatever it is,you will have two options for a shot-dial in whatever correction is given by the ballistic program (eg to hit the gong)-but remember to dial it out again,before you move on to another target at a different distance (bunnies?)- it's easy to forget.OR "hold over"-program says 2" low,so you hold over two inches( more doable when time is short,don't need to adjust scope back).

It always seems to me sensible to consider what your likely ranges are going to be- if you are expecting most shots to be 125 to 200,say,then a 150/175 zero is optimal(less adjustment/hold over).If they ae more variable-150 t0 250,say,then the 200 zero has merit especially as within the first 150 yards is not where the shot is challenging-compared to 250 yards.

 

Note that a good actual shooting derived program/drop chart should allow quite easy change of zero point,if you need it,for a particular location.

OK play and enjoy-it's even better when you have justified confidence in your equipment.

Gbal

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Glad you got it working for you.

reloading gear needn't break the bank I bought second hand Lee gear even new its not that badly priced. My chronograph was just over a hundred but has paid for its self many times over. Not long since I priced my reloads at 62p each compared to factory ammo you can save some, but you tend to fire more. the best thing is you get ammo tailored for your gun.

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