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seansean1444
October 12, 2012, 09:58 AM
hey guys shooting my bushmaster carbon 15 today, having problem with shooting 3in groups at 100 yards, the 3rd shot of the group is always 6 or 7 inches away from my first 2 shots that are pretty good? any idea what is happening here?

Creeper
October 12, 2012, 10:30 AM
More information would be good. It can be any number of things.

Sights.
Optics.
Loose parts... yes, loose parts.
Ammo... frequently most common.
Shooter... yes, you.
Rests, if any.
Conditions... wind, mirage, karma.
Other, less common and/or obvious stuff.

C

seansean1444
October 12, 2012, 10:35 AM
im using a truglo 3x9 scope
remington umc 55gr
shooting from bench
wind directly in my face

sailskidrive
October 12, 2012, 10:45 AM
Wind will not be a factor at 100 yards.

Do you know the weight of your trigger? Can you put the gun in a sled? While UMC is not the best ammo, it's certainly not horrible. Even Tula or Brown Bear will hold reasonable groups at 100 yards.

Creeper
October 12, 2012, 10:47 AM
im using a truglo 3x9 scope
Mounts tight? Rings snug? Did you use a torque screwdriver when you installed it? Have you tried shooting with the irons?
remington umc 55gr
OK... 3" should be entirely doable in most guns.
shooting from bench
Rested directly on forearm or is your hand in between... what specifically is the rest?
wind directly in my face
How fast... gusting? Your "3rd shot" is away from first two shots... in what direction? Is that consistent, or is that variable as well?

C

seansean1444
October 12, 2012, 10:52 AM
mount and rings all tight and torqued

forend rested directly on sandbag

3rd shot always to the left

wind is maybe 15mph at max

seansean1444
October 12, 2012, 11:05 AM
the trigger is around 5 pounds i belive but i know all the shots were good they felt perfect

MrBorland
October 12, 2012, 11:19 AM
3rd shot always to the left

Are you absolutely sure it's not always the 1st shot? Among the 3, it's unique in that it's manually chambered.

seansean1444
October 12, 2012, 11:21 AM
i never thought about that it very well could be, i will go back 2 the range later and see

seansean1444
October 12, 2012, 11:22 AM
ill give you guys an update around 7

Metal god
October 12, 2012, 11:40 AM
If you have not left yet . Go get some Federal Gold metal match http://palmettostatearmory.com/index.php/ammunition/rifle-ammunition/223-5-56/federal-premium-223-69-grain-gold-medal-match.html .

None of my ARs are fond off UMC but the love this stuff

CDR_Glock
October 12, 2012, 11:44 AM
Trigger pull is critical. I use a bipod. I also use a spotting scope.

Key is finding out the twist rate and ensuring it is appropriate for the ammo.

I have a one stage trigger on a Noveske. It all depends upon the shooter.

Try Hornady Match ammo or black hills.

seansean1444
October 12, 2012, 07:40 PM
i think its my optic, its a cheap 60 dollar truglo probably just cant hold a zero or something

Tangentabacus
October 13, 2012, 05:41 AM
I just want to mention something here... Your optics might be kinda crappy but I REALLY doubt it's going to cause such a dramatic stray. You're only shooting a .223 not a lot of shock to the rifle when you fire, so it should hold zero. Be sure and check your muzzle break and the fit of your barrel if it twists or moves when holding the rest of the gun still. There also could be something loose on the two pins that hold your upper and lower together causing your optics to appear to move on you.

Is your rifle an A3 style? Your optics mounted directly to the upper receiver? Or are you mounted on your carry handle?

Also, if you shoot iron sights does anything change?

hardhat harry
October 13, 2012, 06:53 AM
Also, check these guys out: http://www.accuracysystemsinc.com/index.php

seansean1444
October 13, 2012, 03:49 PM
It's mounted directly 2 the reciver

Metal god
October 13, 2012, 04:39 PM
Hey , I just want to through this out there again . The quality of your ammo matters ALOT . I know this first had with a few of my rifles .

Another thing is . Were you using a front rest ? If so is your barrel free floated ? Is the trigger stock ? Ammo , a barrel that's not free floated , a stock trigger any of these things can make it didifficult to get good accuracy . Put them all togeter and your not likely to get sub 2 MOA ever

This is a thread I posted about me trying to get better accuracy out of one of my ARs . I think the cheeper stuff was shooting more like 2" and 3" groups . http://thefiringline.com/forums/showthread.php?t=500146

seansean1444
October 13, 2012, 04:53 PM
i know i wasnt flinching, ear protection only, i was using a front rest with a free floated barrrel