Problems Moving from 50 to 100 Yards

S

Swifty Morgan

New member
I shot my AR-15 a while back, with a scope that was mounted wrong, supported on a flimsy Home Depot table. I got something like 1.5 MOA at 50 yards, and then it started to rain, so I had to quit.

I put a better scope on the gun, and I got a shooting mat and learned how to use it. I learned better shooting technique. Today I shot prone at 100 yards, and I was putting 10 shots into 2.5 MOA. This is not good. I should be shooting better, not worse.

I'm wondering if parallax is the problem. I can't think of anything else. The new scope, a Primary Arms 4-14x, has a parallax adjustment knob. The manual says to move around behind the scope and turn the knob until the reticle stops moving relative to the point of aim. Of course, it is impossible to move without moving the point of aim, so I'm not sure how they expect me to pull this off.

How am I supposed to do this?

I'm already itching to buy an Odin barrel, but I don't want to throw money at a problem that may be caused by user error.
 
If you are using bulk ammo 2.5 moa is great. Besides if you were shooting 1.5 at 50y then 2.5 at 100y is an improvement. Pretty good shooting I’d say.
 
Checking parallax doesn't require a very large movement on your part and very doable while maintaining your reticle steady on target.

1. If the parallax knob has the yardage on it, set it to the 100 mark for a reference.
2. Ensure your ocular focus is properly set before setting parallax.
3. set to lowest magnification ( this will alleviate the fine jittering from messing you up)
4. Settle in behind the rifle, good cheek placement etc...just like you were gonna snap off a shot.
5. Once you have yourself properly set up use a shooting bag for the rear to get your reticle on a nice bright backround with a reference to aim at ( most folks use a target but avoid the black backround as you can loose the reticle sometimes.)
6. While on target ever so slight nod or shake your head side to side or up and down without applying pressure with your cheek on the cheek rest.....if the reticle seems to be moving the opposite way your eyes.head are then slightly adjust the parallax higher. While doing so take note if the target is coming into focus or out of focus slightly....this will tell you which way to move the knob next adjustment.
7. Repeat until the movement is non existent or almost non existent.

Make a mark on the knob as a quick reference.....and then if possible do it for all the distances 100 apart out to whatever your comfortable shooting.

Voila.
 
If your spot weld is good,if your eye stays in the same spot behind the scope,the effects of parallax are minimized. If your spot weld is not good,if your eye is not consistently placed,your shooting will open up,anyway.

One way of thinking about parallax (not perfect,but it gives an idea) is think of an aperture rear sight. You can look through the sight without centering everything up.Think of a ghost ring/big arpeture.

But to try to answer your question,try using a rest and sandbags,so the rifle is stable. Set the crosshairs on target. Without moving the rifle,move your head a bit.If the crosshairs displace relative to the target with your head movement,you are seeing the effect of parallax

I won't say its a non-issue,but it is often over pursued. Interestingly, if I do a proper ocular focus on infinity,with p-lax set on infinity, it seems I can get a pretty good p-lax setting at shorter ranges just by focusing the reticle with the p-lax knob.
Is your rifle free floated?

There is a different level of accuracy expectation between a battle rifle setup AR-15 and one built for accuracy.
 
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Thanks for the help. The barrel is supposedly free-floated. I'm not sure how any gun with a gas block can be considered free-floating, but I'm repeating what the manufacturer says.

I did what the Youtube video said to do, on my kitchen table, using a cow and a tree as targets. It looks like my eyepiece was way off, so I fixed that, and then I got the parallax down as low as I could. I can see how it could open groups up by a couple of inches.

Getting a consistent cheek weld is something to work on. When you're happy hitting a 6" gong 100 yards away, it doesn't matter all that much, but it looks like I'm going to have to research it if I want to stay under an inch. There must be tips for consistent positioning. I can't keep my cheek on the rifle all the time. At least I don't think so. I need to be able to go back to the same weld after every shot.

At least I have some things to work on before giving up and buying a barrel that might not have shot any better. If I can get the rifle to work by correcting the setup and technique, maybe this barrel will be just fine.
 
I know what moa is. I just missed it. I was thinking about a 1.5 and 2.5 inch group. My bad. But 2.5 At 100 is still decent.
 
guess getting rid of parallax makes a perfect cheek weld less important.]
Click to expand...

Thats one way of looking at it. I suppose it depends upon your goals.

Up to a point,tuning equiptment is low hanging fruit. And,of course,up to a point,optimizing equiptment is a good idea with a good return.

A Nightforce scope and a Krieger barrel with meticulous ammo and a $275 trigger might make for very impressive rifle performance.

Which means all the alibis are eliminated.

You might have a 0.4 MOA outfit. Another shooter might have a 1.0 MOA outfit He might have a home built rifle with a White Oak barrel and he just runs his Ammo on the Dillon. He's using a Leupold scope.and a Rock River trigger.

From point of aim to point of impact,your advantage is 0.3 MOA . Only hlf group size difference

If the guy with the 1 MOA rifle improved his skill ,maybe by solving his spot weld issue,and it gains him just 1 centimeter closer to the X, he has egded you out.

Equiptment gains are static.They don't grow. Skill and techniue gains tend to build on each other and grow.

Go ahead and optimize your paralax adjustment. Thats good.

Long term,figuring out a consistent place for your face will probably yield better results. Yes,you can do both. Its not "either or"

Usually the greatest gains on target will be found by tuning the shooter,beginning with basics.

Some stocks,such as Magpul,offer versions with some cheekpiece.

Get in position,get general natural point of aim. Now,closeyour eyes. Snuggle up comfortable and solid with your rifle. Open your eyes. If you do not have full scope field of view with your crosshairs pretty much on target,you hve a problem that is either ring height or stock configuration.

A new barrel won't fix it.
 
MOA is distance dependent, not a constant. Say I shoot 1 moa at 100yd, I will have more than 1 moa at 500yd.

Having said that, there should be much difference between short distances of 50yd and 100yd.

When you had the groups, how many rounds did you shoot? Small sample sizes may not give you the true statistics.

-TL

Sent from my SM-N960U using Tapatalk
 
As explained by post #2 and # 3,EZreach inadvertently misinterpreted the use of MOA in post #1.
It created a red herring we are still posting about. The OP correctly used MOA in post #1. Between 50 yds and 100 yds,2.5 MOA is still greater dispersion than 1.5 MOA.

Agreed,sample size matters.

A major variable that has to be considered ,note the initial 50 yd group was shot off a table.
The 100 yd group was fired prone.

So why not consider the OP shoots better off a table than he does prone.

Thats not unusual. Yes,skilled shooters can shoot very nearly as well prone as they can on a bench.

But it might be our OP is a work in progress,and his prone is not as good as his bench.

Too many variables .
 
One thing I was taught that will help your cheek weld and positioning:

Rainy days offer us the chance to work on things we normally would over look or gloss over on a day where pulling the trigger is the goal.

I spend/spent a lot of time with my rifles ( hunting and target/LR) along with my pistols in the basement on rainy days just getting situated. That muscle memory helps me on days I pull the trigger more then I have been able to vocalize. It also helped me discover which rifles I needed to work on in terms of cheek welds, scope adjustments/possible remounting and manipulation.

Case in point, thunderstorms rolled in as I was about to drive out to my back 700 yd spot and I just went into the garage and worked on my rifle manipulation using my rear bag and bipod. I dared even dry fired on my snap caps a little.
 
I think the OP sounds kind of new to shooting his AR . Will help with more trigger time and getting to his AR . Reading up on a good cheek weld , getting comfortable , trigger control , eye relief , parallax and breathing . A tight group at 25 yards will start to open up as it goes further out only stands to reason . Everyone wants to shoot that one ragged hole 10 shot group , there's no short cuts as long as you have a accurate firearm , practice sharpen your skills and group size.
 
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Groups at short ranges won't subtend the same MOA angle at longer ranges because of muzzle velocity and bullet BC spreads. For example, a 308 Win load with a 25 fps velocity spread can have about 1/20th inch/MOA vertical spread at 100 yards. At 1000 yards, the spread will be about 1 MOA; 10 inches
 
Shooting 2.5" ten shot groups at 100 yards with common ammo and typical AR rifles is perfectly acceptable. Your 1.5" groups at 50 yards translates into 3 MOA. The 100 yard group is 2.5 MOA and isn't bad at all and is an improvement.

With quality target grade ammo, in a target grade rifle with a skilled shooter 1" groups for 5 shots at 100 yards is the goal most are looking for. The more shots you take, the greater the odds of something going wrong.
 
I didn't shoot 1.5" at 50 yards. I shot about half of that, or about 1.5 MOA. It may actually be smaller. I didn't get out a caliper and try to figure out where the centers were.
 
swifty,,,for the parallax,,,get on the gun and just kinda nod your head,,,if its out you will see the reticle move up and down,,,dial it until it stops moving,,,most times the numbers on the dial are just reference,,,that primary arms scope has a pretty good rep,,,

next question is ,,,,have you tried any other ammo in you gun,,,what is the twist of the barrel....lol guess thats two in one

how about trigger weight,,,a good crisp 3.5-4 lb. will help too

my sr5.56 has a 1-9 twist and it really shines with a 52gr bullet i reload,,,but i use a 62gr factory load for coyote and other pests around here,,,it does ok with the 62gr maybe about 1-1.5" at 100,,,,my gun isnt a target gun and i know it but it does very well for how i use it,,,,it is minute of raccoon at 200 all day with the 62gr bullets,,,,so for you ,,,maybe try some different weight bullets and or different stuff through your gun

and im sure more trigger time with your rifle will help some too

just some thoughts

ocharry
 
Using bulk ammo and a consumer grade AR--which is probably tuned to work with as wide a variety of ammo as possible--10 shots at 100 that's 2.5 MOA isn't really that bad IMO.
 
Swifty Morgan said:
I shot my AR-15 a while back, with a scope that was mounted wrong, supported on a flimsy Home Depot table. I got something like 1.5 MOA at 50 yards, and then it started to rain, so I had to quit.

I put a better scope on the gun, and I got a shooting mat and learned how to use it. I learned better shooting technique. Today I shot prone at 100 yards, and I was putting 10 shots into 2.5 MOA. This is not good. I should be shooting better, not worse.

I'm wondering if parallax is the problem. I can't think of anything else. The new scope, a Primary Arms 4-14x, has a parallax adjustment knob. The manual says to move around behind the scope and turn the knob until the reticle stops moving relative to the point of aim. Of course, it is impossible to move without moving the point of aim, so I'm not sure how they expect me to pull this off.

How am I supposed to do this?

I'm already itching to buy an Odin barrel, but I don't want to throw money at a problem that may be caused by user error.
Click to expand...

Paralax could well have been your issue.

You are changing a LOT of variables at once. Only change one thing at a time and see what it does.

1.5-2.5MOA is common for AR-15 type rifles.

What ammunition are you shooting. If I remember right you are working on hand loads. If you are, STOP USING YOUR HAND LOADS. You need to take that out of the equation as a variable until you get your rifle sorted out. go buy 2-3 (or pull out of storage) boxes of different factory ammo, Preferable with 1 box being match ammo. SHOOT IT ALL, 4 goups of 5 rounds per box. See what the RIFLE does. Then go back to working on your hand loads once you understand what your rifle will do with basic and good factory ammo.

Also Rate of fire and how warm the barrel is can effect things. A hat barrel can have groups open up. Shoot maybe 5 groups, 2 slow fire at 50yds. shoot 5 rnds per group 10 seconds between rounds then lock the bolt open let it sit 5min. do this the first 2 groups. after the 2nd group heat the gun up, fire 10-20rnds quickly. then, right away shoot 2 groups, 5 shots each, Same pace a before, 10 seconds between rounds, good shots just no 5min coodown between the groups. See if the groups open up with a hot barrel and good technique.

Lastly, if you have a shooting buddy, have him shoot a couple groups, see what they can do with your rifle, could eliminate shooter error.

remember work on 1 thing at a time. if you do several you wont know what worked and what did not.
 
Swifty, most AR's are not moa shooters. Unless you pay big $$$ 1.5 moa to 2.5 is considered normal. A couple of factors that need to be researched by you is the type of twist on the rifle and matching the bullet to the twist. Eventually one type of bullet weight will agree with the harmonics of your barrel where the group will tightened.

Another thing that will help is a smooth trigger and trigger control. One of the best ways we did this was to place a dime at the end of the barrel and gently squeeze the trigger. If the dime fell you were not squeezing as gently as you thought. Ninety percent of accuracy comes from trigger control and the other from the sight picture. Practice the dime drill and when you can achieve 10 trigger pulls without the dime falling you have good trigger control.
 
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