first shot 1.5 inches low 2nd shot high

dan158

New member
Some help here please.. AR 223, 95 percent of my first shots out of the magazine are 1.5 low then the 2nd shot about 1 inch high then the 3rd shot hits about where the crosshairs are.. And this is very consistent...
I just load my mag to 3 rnds..

It took 75lbs to get gas tube to line up with barrel nut.. The barrel extension is bedded in the upper..

Any help what this might be from???

Thank you.. Dan
 
My first thought is that you are not getting consistent neck tension on your brass when sizing...

The second thought is that you need to adjust your crimp factor, as the recoil may be jarring the rounds enough that the bullet is slipping in the case, to different degrees, but consistently, which would cause a pressure difference when the rounds are ignited....
 
I don't crimp my ar rounds...Atleast not on 20 practical or the 204.. Would the 223 need crimped? These are once fired rem umc reloads.. Dan
 
Originally Posted By: dan158I don't crimp my ar rounds...Atleast not on 20 practical or the 204.. Would the 223 need crimped? These are once fired rem umc reloads.. Dan

NO....
 
Originally Posted By: dan158Some help here please.. AR 223, 95 percent of my first shots out of the magazine are 1.5 low then the 2nd shot about 1 inch high then the 3rd shot hits about where the crosshairs are.. And this is very consistent...
I just load my mag to 3 rnds..

It took 75lbs to get gas tube to line up with barrel nut.. The barrel extension is bedded in the upper..

Any help what this might be from???

Thank you.. Dan

I had a barrel that would always shoot the first shot an inch or so high and left. I had to torque it to about 80lbs to get the gas tube to line up. I ended up using shims to re-torque the barrel nut to 45lbs. It did help but the very first shot was always a bit high and left. Very frustrating, good luck.
 
Make sure you have .002 to .003 neck tension. Dryfire the gun from the bench while watching crosshairs. Make sure they are not jumping around. I quit using hanguards with barrel nuts that the gas tub has to pass through.
 
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Got the .002 tension.... I am going to put the lower on that has the geissel trigger and see what effect it has if any... Dan
 
Quote:Some help here please.. AR 223, 95 percent of my first shots out of the magazine are 1.5 low then the 2nd shot about 1 inch high then the 3rd shot hits about where the crosshairs are.. And this is very consistent...
I just load my mag to 3 rnds..

I'd look at the rifle as opposed to ammo. Ammo would not be "95% consistent" but would be random fliers.

I have a Savage scout that first round from clean/dry bore is 1" left @ 100 every time. Next shot and all following shift to correct POA.

What happens when you load more than 3 rounds in the magazine?

It's been a while, but I had an AR that always threw the last round out of the magazine out of the group every time. Figured it had to be something to do with how that round fed into chamber due to less drag on bolt carrier, but not sure???

Regards,
hm
 
Originally Posted By: hm1996 Quote:Some help here please.. AR 223, 95 percent of my first shots out of the magazine are 1.5 low then the 2nd shot about 1 inch high then the 3rd shot hits about where the crosshairs are.. And this is very consistent...
I just load my mag to 3 rnds..

I'd look at the rifle as opposed to ammo. Ammo would not be "95% consistent" but would be random fliers.

I have a Savage scout that first round from clean/dry bore is 1" left @ 100 every time. Next shot and all following shift to correct POA.

What happens when you load more than 3 rounds in the magazine?

It's been a while, but I had an AR that always threw the last round out of the magazine out of the group every time. Figured it had to be something to do with how that round fed into chamber due to less drag on bolt carrier, but not sure???

Regards,
hm


I stripped it down again today...
Had to use a wooden dowel to get barrel out from being glued in with Loctite..
I again lapped the receiver to get less torque on barrel nut and to line up the gas tube..
It lined up at 35lbs this time..
I noticed when I tightened the nut that draws the hand guard in that I actually turned the barrel nut also.. Anyone who has an mmr hunter and took apart knows what I mean.. This put some force on my gas tube... Was this the problem from the first time??? I will let the Loctite sit up tonight and see how it goes tomorrow..
I am not sure if it was from the brass pushing up against the BCG and applying extra pressure to the gas tube that altered my rounds?? It could be a possibility??? Dan
 
I will never us a handguard with a barrel nut with a hole or notch for a gas tube ever again. The Matrix with the small nut is the cat's meow in my opinion. The ID is just a little small to clear the .936 gas blocks except for a Troy.
 
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Originally Posted By: varminter .223I will never us a handguard with a barrel nut with a hole or notch for a gas tube ever again. The Matrix with the small nut is the cat's meow in my opinion. The ID is just a little small to clear the .936 gas blocks except for a Troy.

I can understand that sentiment but it will sure eliminate some great gear.

Greg
 
Originally Posted By: varminter .223I will never us a handguard with a barrel nut with a hole or notch for a gas tube ever again. The Matrix with the small nut is the cat's meow in my opinion. The ID is just a little small to clear the .936 gas blocks except for a Troy.

I agree... the Matrix is a great deal! some of the Seekins handguards are the same way just cost a little more...
 
What I might do from now on is torque the nut and align the gas tube then remove the nut and drill out that hole a lot larger or file the notch larger and reinstall the nut.. I am also thinking that a lot of accuracy issues on ARs are caused by the gas tube touching the barrel nut... A plus to use a nut without holes or notches is you get your 35lb torque every time.. Dan
 
I just looked up the matrix and joebobs came up.. 15 inch key mod for 63$ I ordered 2 of them.. I like plain jane ones without holes but for 63$... I will like them... Dan
 
Originally Posted By: varminter .223As long as you use low pro style set screw gas blocks you will be good.

Will Joebobs work under those handguards?? I got out and shot the rifle today.. At 100 yards I did 3 ,3 shot triangle group about an inch.. No flier that time.. I am uncertain though what caused the pattern before... I torqued barrel nut to 35 lbs. instead of 75.. Also bedded the gas block that I didn't before.. Made sure the gas tube had some play in it through the barrel nut hole.. Something made it start to group fine.. Now to start to seat bullet to tighten group up.. Thanks all for replies.. Dan
 
Originally Posted By: dan158Originally Posted By: varminter .223As long as you use low pro style set screw gas blocks you will be good.

Will Joebobs work under those handguards?? I got out and shot the rifle today.. At 100 yards I did 3 ,3 shot triangle group about an inch.. No flier that time.. I am uncertain though what caused the pattern before... I torqued barrel nut to 35 lbs. instead of 75.. Also bedded the gas block that I didn't before.. Made sure the gas tube had some play in it through the barrel nut hole.. Something made it start to group fine.. Now to start to seat bullet to tighten group up.. Thanks all for replies.. Dan

Joebobs adjustable GB work just fine with the Matrix handguards..
 
Went and shot the AR today with new seat depths.. I got 3 inch vertical with 1 inch between each shot.. 4 3 shot groups all of them are vertical string.. Started high and went low.. Perfect line almost though.. Quite frustrated again now.. Maybe take scope and rings off tomorrow and re do it... Or any other suggestions?? Thanks you all.. Dan

Its 1-9 twist and I am using 53gr sierra FB.. Should I bump up to 60+gr bullets??
 
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