Today is the first day ive had i chance to shoot my m4 long distance , well kinda, 100 yards with iron sights only.
At 25 yards it was 1 inch high but at a hundred it was a foot high.
My buddy told me it should be roughly 3 inches low at 25 becouse of barrel parralax,since the sights are alot higher than the barrel. At 25 yards the groups were touching in a 3 rnd string, i couldnt ask for any better. Iam sure this is my fault every since if had it ive been lowering the sights becouse until recently ive only been able to shoot close,no shooting range,maybe 15 to 25 yards at the farthest.
My question is, is this why its shooting so high at 100 yards? Do i need to reset to mechanical zero and sight in say 3 inches low at 25? The bullets were 55 gr remington .223 they must be climbing still at 100,i also tryed some 50 gr varment tipped american eagle did exactly the same thing, hit in pretty much the same spot at 100.
I sight in my .22 dead on at 25 but it hits 4 inches low at 100,iam guessing here , the .223 is still climbing at 100.
I understand how it flys,as far as bullet drop over a distance and bullet arc to poi., what iam asking about is barrel parralax, as to why it could be 1 inch high at 25 and 1 foot high at 100. Ive cranked the front sight down pretty far, shooting at really close distances. Till now…the left , right is fine.
Yes ive lowered it a ton.lol shootin across creeks and stuff just for fun so do i need to be low at 25 to compensate for the barrel paralax? Or if its on at 25 it should be on at 100? I thought once you had them sighted in at 25 you were g2g to 100. I dont think iam explaining this right.
You will have to excuse my noobness…
If you want your point of impact to go “down” your front sight must come “up.” By turning the front sight down lower into the sight post, you are raising the barrel relative to your point of aim, making your issue worse, not better.
I forgot my sight tool so i couldnt adjust today,thats the thing,i didnt adjust it up or down today. Seems like when i bring it down at 100 yards its gona be low at 25 iam thinking its from the sights being so much higher than the barrel on an m4 what i call barrel paralax or sight paralax. Maybe i just need to sight in at 100 and just exept the fact it will be low at 25,i need it at 100 for what iam useing it for. Iam just wondering if the paralax is the problem becouse ive been shooting so close, and now that the front sight is lowered so much to over come the paralax that its way high at 100…
When i first got it shooting so close it was about 3 inches low so now ive screwed the fron sight down so low. And its low…lol… to compensate that its way high at longer distance.
Each click up or down of the front sight raises the impact how much at 25 yards? Does anyone know is it like a quarter moa ? so 4 clicks equals an inch?
At 25yds, each click will be about 1/4" POI shift. Maybe a little more. I believe that the front sight was designed to be 1/4 MOA adjustment on the 20 inch rifle, so it will be a bit more than 1/4 MOA on an M4 length.
You don’t need a sight tool to adjust the front post, the tip of a cartridge works well (the only tool I ever used for the first 20 years of shooting Stoner rifles).
You need to turn your front sight post counter clockwise to bring your point of impact down at 25 yards… and do more reading… not necessarily in that order.
As others have said, you need to raise you front sight post. Due to bullet trajectories you will never be able to have poa/poi at 25 and 100 using the same zero. With your current zero your bullet will always be high from 25 to beyond 300.
It’s called “offset” and yes, your shooting high because your AR is zeroed at 25 yards. If you zero it at 100, point of impact will be lower than your point of aim at 25 yards. The offset of the AR is more than most rifles because the sights sit up much higher over the bore than normal. In one of the sub-forums, there’s a stickied thread started by user Molon that it explains this well. If you use the SEARCH function above, it should be easy to find. If I weren’t so brain dead from exhaustion, I’d do a quick search and aim you in the right direction
Look at post #182HERE
Maybe that picture will show you why you are shooting high at 100 yrds. Basically you have a 300 yrd zero thus causing your 100 yds shots to be high.
Thanks this is what i was wondering about… Thanks for all your posts its provided very good reading. Also other poster i see about this turning into a 300 m zero becouse of the offset. Very nice thank you.
Looks like a 100 yrd zero seems to be a lot better,ill go do it tomorrow.
Thanks guys… Great info as usual…i feel better about it now,i thought something might be wrong…
As some have indicated you are on the right track now. Otherwise some of the questions and comments on this thread were painful to read. No such thing as “barrel parallax”…but rather sight height over bore, offset, etc…as some have mentioned.
The key thing to know and remember is that you have to find and use the correct zero for YOUR particular use and application. If you don’t expect to shoot much beyond 100 meters, or for someone who is going to be working exclusively in an urban close quarters environment, the 100 meter zero can be very useful. It essentially shifts the trajectory down so much that there is only one range where POA=POI rather than 2 (ie 25/300, 50/200). The 100 meter zero is actually the max ord of the round, which will be low at every range before and after 100 meters.
The other key thing is that your choice of zero also depends on the type of sighting system you are using. Optics with multiple reticle reference points, particularly BDC reticles, should only be zeroed one way, otherwise you are not getting an accurate ballistic representation of that reticle. An example is the Soldier or Marine who mistakenly zeroes the 100 meter reference point on his ACOG at 25/300 meters, which now screws up the entire reticle. He has not been properly educated, and his leaders have failed him. In contrast, a single reference point optic requires the user to determine the proper zero range for his preference and application.
With that said, I know you mentioned only shooting with iron sights…the same logic applies. Most AR-15 style iron sights have an adjustable rear for elevation which is ballistically calibrated. Obviously this depends on the type of ammo you’re using, but it will at least be close. If you have this style iron sight rear, you should zero it on the appropriate setting (300) at the appropriate range (25 meters) and then confirm at other distances such as 100/200 meters. Do this by leaving the front sight alone and only changing the rear…I know this sounds obvious but we still see folks who don’t do it correctly. Then if you plan to only shoot inside 100 meters, leave it on that setting until you push out to something further. Now if you don’t have an adjustable rear iron sight, you fall into the same category as a single reference point optic, decide what you want your zero to be based on your preference and application and stick with that, and ignore everything else I just said.
Thank you very much… That helps alot…the sight in is very confusing. I see that when sighted at 25 its almost a 300 sight in,so setting the rear sight at the 300 setting,sighting in at 25,then using just the rear sight clicking it down to 200 it should be close at 200,then clicking down to 100 should be close to100,and then i guess if the rear sights completely bottomed out its set around the 25 yrd sight in.
Once you get your AR sighted in at 25 using the 300 setting, go to a 300 range and verify. If you can’t verify your sights at 300, at least check your POA at 100.
