100m and 300m groups

toad

Well-Known Member
hi guys, if my rifle gives me a nice group at 100m should the group be the same at 300m . taking out human error and weather conditions. i have just been out putting a few ronds through my 308 .100 bob on 150 bob on 200 still ok 250 starting to wonder , this is in field conditions sticks sitting with long bipod. my eyes are not great and this is definatly my limit. but if a better shot than myself was to do the same should my rifle be as accurate through these distances. hope this makes sence.
 
the rule of thumb so to speak is 1 MOA at 100 will be a 1 inch group so at 300 yards you should get a 3 inch group so for ever 100 yards you go your group grows by 1 inch,but this dosent always work out some rifles will shoot shocking at distance and others will shoot small groups.you have to put it on paper to see,but not off sticks as you wont really get a true reading of what you and your rifle is capable of,just as an example one of my rifles will shoot given the right conditions sub 2 inch groups at 500 yards so that blows the theory of 1 inch for evert 100 yards.
 
My rifle, with me firing it, does 1MOA out to 150yds and then the group begins to open up pretty quickly. Never worked out exactly why. I guess as the bullet loses velocity it becomes more affected by any cross winds etc. Also my rifle doesn't shoot as flat as ballistics tables suggest.
 
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What sort of rounds are you using? You ought not to loose a lot beyond the group opening up directly in proportion to range under nice, benign, conditions. Was there a breeze when you tried the test? Even a little bit is quite a lot at 300 yards plus and when it varies it'll may your nice group turn into nice doubled.
I'd expect top of the line bullets to be close to match quality but you never know with some of the others. A lot of the stock soft point seems to be loaded with right rubbish but at 100 -200 yards it'll do the job well enough.
 
Only 1 way to find out really...

Couple of things will affect this, bullet profile, velocity, scope magnification, size of target, wind... All begin to play a role.
So it's likely the rifle will do it's bit but the influence of variables becomes greater in relation to the distances...

Unlikely a .308 will even be close to running out of legs at 300yds with any conventional bullet.
 
i am loading 150gn hornady sst verry accurate at 100m in a tunnel. but i have to get out into the fields for more distance. but thats ok i want realistic conditionds i do take onboard what you all have to say lads . i would love for someone who really know there onions to show me what my rifle is capable of . back out tomorrow less wind forcast might even take a bench and a rest . cheers ken
 
Hi. It helps to visualise a sequence of shots as a cone within a cone. The smaller cone is what your rifle can do when clamped in a vise under perfect conditions, say 1" at 100m, 2" at 200m, 3" at 300m. The larger cone is what you can do when holding it, with wind, visiblity, humidity, etc. all having their input. The effect of all these external factors increases exponentially with distance. You may still get your 1" at 100m but it becomes increasingly difficult to hold to that tolerance as range increases. You have to practice to be good at distance in all conditions; well done for knowing your limit.
 
I guess that would be Vaenol tunnel? I have always found my 'tunnel' zero to be off for windage by a minute or so when checked outdoors. I'm not sure what causes this but suspect the unusual light conditions or the fact that the bullet travels closer to the wall on one side.
 
Having groups open up in a strictly linear fashion is pretty rare, actually. Physics is against it.~Muir

Exactly !

However, using good solid rest, duplicate your shooting position and technique every shot, let your barrel cool between shots, relax and choose a calm day.

Andy.
 
I guess that would be Vaenol tunnel? I have always found my 'tunnel' zero to be off for windage by a minute or so when checked outdoors. I'm not sure what causes this but suspect the unusual light conditions or the fact that the bullet travels closer to the wall on one side.
yes it is vaenol tunnel. where is your tunnel do you have more than 100m.
 
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