group drastically spreads from 200-300 yards

[fjbiker86]

Rifle: ar-15 RockRiver pursuit upper 1:8 twist 16” barrel
Ammunition: 55 grain Remington UMC (need brass so I can start reloading .223)
Sight: Eotech No magnification

Hi, im pretty new to this so please bear with me. I just built my rifle So I went to sight it in. Was shooting about an inch high at 100 yards, Dead on at 200 yards ( well for me), it was about a 5-6” group, and at 300 yards the “groups” went to garbage. My question is How can my group spread so dramatically from 200-300. The red dot is a little tricky at distance but I don’t think that was the issue. Is the 55 grain bullet to light for my twist rate? I just ordered some 77grain Nosler HPBT to try out.

 

[Trigger Monkey]

Re: group drastically spreads from 200-300 yards

How big is "went to garbage" at 300 yards? That Remington ammo isn't made for accuracy, its accuracy standard is probably right around 2-3 MOA which was proven by your results at 200 yards. However, a lot of things may have come into play at your 300 target such as any wind that may have been down range, your trigger control, breathing, steady position, and what did you mean by the reticle was a little tricky?

I don't think you have a bullet/twist rate compatibility problem, I'm using 55 gr bullets in a 1:7 twist without any issues. The accuracy will probably improve with the 77 gr bullet but by how much I can't say.

 

[fjbiker86]

Re: group drastically spreads from 200-300 yards

Ive never shot with a red dot sight before. Red dot on a black background was a little hard to tell if I was centered or not. These are 200 yard military type targets.

 

[Trigger Monkey]

Re: group drastically spreads from 200-300 yards

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fjbiker86</div><div class="ubbcode-body">Ive never shot with a red dot sight before. Red dot on a black background was a little hard to tell if I was centered or not. These are 200 yard military type targets.

</div></div>

That probably has a lot to do with why everything opened up at 300 yards, its hard to diagnose issues without being in person but that says a lot. Combine the accuracy limitations of the ammunition with probably some growing frustration over consistent sight picture issues and the fundamentals start to get left by the wayside. I've seen guys start to fall apart because they missed a couple targets during qualification and before they knew it they were slapping the trigger, breaking their cheek weld, and all sorts of stupid shit. I saw one guy empty all of the rounds he had left in his magazine at the 50 meter berm because he missed a 150 meter target. He qualified expert the next go around but still...sticking to the fundamentals (i.e. proper sight picture, trigger control, follow through,etc...) is vital but doing it consistently is key. There's a great sticky about the fundamentals of marksmanship in the Advanced Marksmanship sub-forum.


Also if you're going to be shooting at 300 yards or so and using heavier bullets such as the 77gr SMK I'd upgrade optics to a low power variable optic.

 

[fjbiker86]

Re: group drastically spreads from 200-300 yards

thanks for the info!.... I built this rifle for 3 gun but it just frustrates me if I cant shoot it far as well. The 77 grains are probably overkill for what im doing with it but I wanted to give this pellet gun some sting!

 

[ChadTRG42]

Re: group drastically spreads from 200-300 yards

Get all the same brass you can, and then work up a load with the bullet you want.
Next, use a scope with some magnification for load testing and not the red dot. It is very difficult to shoot a precise group at anything more than 50 yards with a red dot. Once you find a good load, put the red dot back on.

 

[samnev]

Re: group drastically spreads from 200-300 yards

IMO using a red dot at 300 yards is streching it. That with the ammo you are using is part of the problem.

 

[fjbiker86]

Re: group drastically spreads from 200-300 yards

Chad, thats what im probably going to do. Very good idea with the scope.

Santo, no arguments there! Will be working on reloads shortly.

Speaking of reloads, I bought some PMC ammunition and the brass looks really nice. It also looks like its annealed?. Do any of you have any experience with reloading this brass? Is it decent?

 

[MALLARD]

Re: group drastically spreads from 200-300 yards

why did it spread change so dramatically ? my guess , some of it might have been your fault , trigger control , sight alignment, ,weapon to shoulder/recoil management/npa , wind calls. The rest is the result of your short barrel and 55gr factory ammo and scope.

16in barrel and 55gr at 300y ? my 24in Match AR its hard to hold 6in groups at 300y using crappy 55gr ammo in windy conditions, now the 69smk , thats another story.

i would immeditaly , if i was you , get some 69 smk and try them out , or 75gr

all brass unless you buy once fired should be annealed. I dont think a factory would sell ammo/brass that wasn't annealed

PMC brass is ok , its capable of producing better results then what your getting right now.

i never really shot 55gr well at 300y or beyond.

 

[jbailey]

Re: group drastically spreads from 200-300 yards

biker-
nothing is wrong with the rifle or bullets. In fact, I thought your groups were pretty darn good, given the kit. As others have said, your spread at 300 is due to difficult sight conditions at that range (non-mag) plus a bit of crappy loads (heavy 60's or 70's will do better job at that range).
Keep practicing and you shouldn't be frustrated at all. Good shooting.

 

[Greg Langelius *]

Re: group drastically spreads from 200-300 yards

When I first started using dot scopes, I was impressed with them as a means of combatting aiming problems related to parallax issues.

Then I heard a few references to them not being parallax-free. Honestly, I don't know if they are or aren't; and would be grateful if somebody with precise information could clear this up for me.

Greg

 

[mattmc40]

Re: group drastically spreads from 200-300 yards

it's hard to hold an exact point of aim at that range. good shooting though

 

[gunsnjeeps]

Re: group drastically spreads from 200-300 yards

Depending on the load PMC and Winchester don't tumble after anealing their brass. Premium boxed brass gets tumbled so it look better.

Looking at your targets I'm assuming the bottom is 300 yards. You had what looks like a typical drop from 2 to 300, your group opened up with range. I'd say you had some wind from the left and maybe a little vertical stringing but not much. I'd also say you have pushed the ammo and sight to it's limit. 55 grain ball isn't the best. For the targets shown the groups look pretty good.

 

[fjbiker86]

Re: group drastically spreads from 200-300 yards

thanks for all the help guys! I really appreciate it. I will get back with the results from my 77 grain bullets. They should be here Monday and hopefully I can get to the range this Friday.