Need help interperting Target Shooting Results

[Henry455]

I have a early model Colt AR-15 SP1 with a 2-7 scope mounted on the carry handle. Today I went to the range with 5 different brands of popular inexpensive .223 55 gr. FMJ ammo. Shooting at 100 yards, I shot 5 shot groups then let the barrel cool to ambient temp before shooting another 5 shot group. The gun was previously sighted in and there were no attempts to change the scope adjustments while shooting the 5, 5 shot groups. here 9is the target:



Top left target is Remington UMC, first 2 shots hit in the red, the last 3 way left

Top Right Target is Winchester USA223R1 , First shot 9:00 in the red, last 4 high or left

Lower left target is Federal AE, First shot almost a bullseye, other 4 either left or high.

Lower right is Federal XM193, First shot high to the left, other 4 low

Middle target Black Hills "blue box", First 3 in 10 rings, last 2 way left.

It appears that my rifle liks a cold barrel temp. I do not think its the ammo because all seem to exhibit the same pattern. Could this be a scope problem or is this normal for thr first shot to be different from the following shots with a cool barrel. Any input would be appreciated.

 

[ny32182]

Well... it looks like you are impacting to the left. First thing I would do is move the windage so that your mean POI is centered.

After that, check that your scope is tightened as well as possible with whatever mount you are using. Also keep in mind that if it is a relatively cheap scope and mount, that might grow the group size. The carry handle generally doesn't make a great mount for optics.

After that, check out your rest, and make sure you are resting it as well as possible.

Depending on your rate of fire of course, I don't think that heat is affecting your groups here, within 5 shots.

Also, keep in mind that while you can expect some fairly decent groups, the rifle isn't really intended to be a sub-moa tack driver.

This is what my Bushy 20" HBAR does. Relatively cheap Simmons AETEC 2.8-10 scope and 1-piece RRA mount on the flat top, 100 yards, Georgia Arms canned heat, ~20 rounds, one round every 3-5 seconds, fired with me sitting on a bench with the stock shouldered and the forearm resting on a White Flyer box:



As you can see, the "group" isn't super impressive. Cheap ammo, optics setup, and rest are probably the main factors contributing to the group size. You are probably experiencing the same sort of thing.

 

[Brian Williams]

Typically you will experience a bit of group walking with a cold barrel. First how are you going to shoot this gun. Are you going to shoot it rapid fire alot or just target plinking. shooting alot of rapid fire find the ammo that groups the best with a warm barrel. Then fire a few warming shots and it will fall in place, then zero your scope for a warm barrel. If you are just doing some plinking, zero it where you see it hit.

 

[ocabj]

I'd recommend cleaning between groups if you are shooting different manufacturer/types of ammo in each group, or at least shoot 2 rounds of the next ammo you plan to shoot to foul the bore.

As far as the horizontal spread in some of your groups, I would be a little suspicious of the scope or scope mounting system.

 

[Henry455]

Guys, thanks for your input, I do not think its the mount, Its an ARMS extended carry handle mount that is a press fit in the handle. I had tried some other "less expensive" mounts that just fell into the handle channel ( and had to "locktite" the mount screw) but I feel the ARMS mount is top notch. I am using Leupold QRW steel rings that have not budge in over 1000 rounds so I think I am OK there. I have had this combination on the gun for a while now and have found in other outings that I seem to get tighter groups the more I shoot. It may sound crazy but I get tighter groups, with a hot barrel, I am talking 2 MOA.. I think I will take your advice and adjust the scope for a warm/hot barrel rather than a cool barrel because 98% of my shooting with this gun is at the range. It just seemed strange that my first shots with a cool barrel from all but one group were close to the "10" ring, and that group was with XM193 that probably has a little higher MV than the other ammo.

 

[Henry455]

OCABJ,

I hear what you are saying but why is the first shot of each group very close to the 10 ring except for the XM193, if its the scope or mount.

 

[ocabj]

I hear what you are saying but why is the first shot of each group very close to the 10 ring except for the XM193, if its the scope or mount.

Yeah, I reread your post. It sounds like more of a barrel temp problem rather than a scope issue. The amount of shift in the POI is very disconcerting, though. It's not uncommon for a 1 MOA shift in POI from the clean cold bore shot to the next shot, but the amount of shift you're experiencing is a bit on the excessive side.

Are those handguards free floating? I was under the assumption that all AR-15 variant handguards are free floated, but I was told that some are not.

 

[ny32182]

Unless he has a free floating rail system/tube, they are not FF. The stock handguards are not ff.