Factory Colt AR 15Carbine issue

[survivalshop]

 The Rail & Front sight Tower & Gas Tube ,are dead nuts aligned , set up with a Laser & measurements & leveling , which took some time to figure out & set up. The rear sight also shows , through measurements , is centered .

   Like has been said , it just doesn't like the Ammo type , really doesn't like 55 gr. Bullets,, we will see shortly . Unfortunately , I'm busy tomorrow , my upstairs A/C Evap fan took a $hit & I have to replace the motor .  

Edited September 22, 2016 by survivalshop

[survivalshop]

  Went to the range today with three Carbines , the Colt , my new Piston build & a POF build . 

-Colt Carbine , 1-7 Twist rate with a DI ,Carbine Gas system . MBUS rear sight & A2 pined from sight second Gen..

-Tactical Machining Receiver set, 1-7 twist rate , 16 " .Brownells barrel, Piston Mid Gas system , MBUS sight set , first Gen. 

- POF Billet Receiver set, 1-8 twist rate , Wilson Combat light wt. Barrel , DI ,Mid Gas System , one of the first MechArmor Defense BUIS

   I shot four different types of ammo , three rounds of each at 25 yards from a sand bag rests . Rear sight was centered in Sight housing on all three rifles .one thing I noticed right off the bat , is the Colt grouped about an inch or so more towards the left or center of the target , so aligning the from sight , did help a little , but it was still grouping to the right , with the rear sight centered in the rear sight housing .

  My other 1-7 Piston build , shot a little to the right of the target center , but not much . The POF 1-8, shot about dead center of the target , as shown in photo's . Ammo used is as follows .

 SS 109 Green Tip

M193 LC BALL

62 gr. FMJ HP , Hand load 

55 gr. Solid Copper , HP , Hand Load

Colt

Piston Build 

POF Build 

  So , thinking that the 62 gr. or the SS 109 would shoot differently than a 55 gr. load ,  it doesn't make a difference at this range , will try 100 yards next & I will have to move the Colts Rear Sight to make sure I don't miss the target .

  

[98Z5V]

Remember, the .mil accuracy standard of the M4 was 3 MOA.  Each of those loads, even at the 25-yard mark, is within a 1in square, so that little carbine is meeting it's acceptance criteria, accuracy-wise.

[survivalshop]

10 hours ago, 98Z5V said:

Remember, the .mil accuracy standard of the M4 was 3 MOA.  Each of those loads, even at the 25-yard mark, is within a 1in square, so that little carbine is meeting it's acceptance criteria, accuracy-wise.

 Thats not the reason for this test , remember this barrel is shooting to the right with the sights aligned ( with a Laser  ) dead in the middle plane of the rifle , as are the other two test samples . This rifle , before I reset the front sight & Barrel Nut , was shooting even farther to the right by at least an inch or more . The Barrel Nut was was not aligned properly for the Gas Tube to be tweaked to one side , no doubt it was rubbing the Gas Key , but that would not make the Barrel shoot to the right , what I think it did was put pressure on the Pinned Front sight tower when assembled to make it torque to one side . I proved , at least that , with the Laser & after adj. the Barrel Nut properly with the Gas Tube passage in the Upper Receiver  & reseting the Sight tower ( A2 ) , the Front Sight was right in line with the Middle of the Upper Receiver , using the Laser .

 My reason for this test was not grouping , it was seeing if the different ammo would shoot differently from this Colt  & using two other rifles , one with same twist rate , to see if this Barrel on this Colt is shooting out of spec's , which I believe it is , maybe not way off , but not normal . I thought the barrel would show it would shoot more to the center of the target with one of the 62 gr. loads , but all three rifles , one with a 1-8 twist rate , all shot about the same with different loadings & bullet weights & types .

 All three Barrels shot very well IMO , with the 1-8 Wilson Combat , match Barrel shooting the best IMO , don't know if it was the Barrel , the twist rate or IMO a better sight picture through the MechArmor BUIS , the Piston Build had the best Trigger of the three , a Rough Justice FCG , the Colt Trigger was not bad at all & the POF has a Spikes Tactical Enhanced FCG , its a little creepy , but has a decent drop .

 Was at first turned off by the 1-7 twist rate , thinking they all shoot like this Colt , because I had just assembled the Piston build with a 1-7 rate Barrel , but after this test , I'm not worried about using them . The twist rate is new to me , I much prefer 1-9 , all the rifles I have built , except for a few of the early ones using 1-14, 1-12 & one I still, have in 1-10 all shot very good & the 1-9 was better IMO . I have now have got two more twist rates that work also , this test was somewhat of an eye opener for me .

 Now at 100 yards , my opinion may change , but I think all these will perform well at the distance .

 One thing that is different with the Colt & the other two rifles , is , its a Carbine Gas system , where as the other two are , Mid Gas systems , but I have a hard time wrapping my head around that that would make the impact of the group , to shoot to the right .

 I was told that , three clicks of the rear sight one way or the other , ( left or right , windage ) is accepted range for military standards . If that is true , the way I was told , this rifle would not pass , because it will take more than three clicks for the group to center this Colts Group on the Target .

[survivalshop]

 the rifles used .