Originally Posted By TGH456E:
So in some of the recent threads I've mentioned my work on getting a M855A1 "clone" to use for practice and getting ready for Military competitions.
In doing so I worked on finding a close-as-could-be trajectory match to M855A1 shot thru M4A1's with M150 ACOG out to 500yds.
In other words- find a clone that shot the same sight settings on the ACOG out to 500yds.
I did- in my guns, my conditions, YMMV.

The Clone is:  Sierra bullet 62gr SBT #9362 going 3150ish thru a 20" barrel.  I use Benchmark, other powders weren't as close in POI's.

Now in this post I did use an SPR type set up, but with my M4A1 it's the same result just larger groups.  YMMV but it's consistent out to 500yds, which was my goal.
And it still mirrors what I found with my M4A1.  

Rifle:  SPR- WOA 18" Wylde chamber, older mk4 scope on top.  1540rd count.
Conditions: 5541ft elevation, 93F, East wind 10-14mph gusts, 29.92" pressure and 53% humidity
Set up:  200yds, benched, bags front rear, shot one-dry fire one.  
Results tabulated by the "On Target" system.

NOTE: I shot 7rds of A1 which are circled with Fruit loops (two overlap) and 10 of the Clone.    

Photo results:
https://imgur.com/a/gg6Bod8

The Clone is 3.560" and LC15A1 is 3.450" (1.7 and 1.65 ish MOA).
The Center to Center (the + marks you see) distance between the two is only 0.694" (0.347MOA) away from another.
The total -17rd- group is +-4.00"  --2 MOA.

The CtC difference is less than a single click on an M150 (which is 1/2 MOA).
The total group (outside edge to outside edge) is 2MOA, inside a 12" at 500.  
The velocities are about the same (3150- 20" barrel) and when I've shot this out to 500, it's maintained its' "closeness."
For me, its about a close match as I can get.
I run the same zero, same hold off etc etc    

@Teller_Ulam:  FWIW I've shot about 10? different groups with A1 and for me it's around 2MOA.
That's why I was surprised at your result.

@ChemTrailZ:  Again YMMV but for me, I feel like I found a good clone.  

@smoothy8500:  Do not look at the photos- it's more fruit loops and lines. :)

 

 


         

Originally Posted By Teller_Ulam:

Understood. I want to try it in that barrel again. The group was so bad I pulled the mag and stopped.
My other barrels were from around 1.4 to a little over 2".

Originally Posted By bpm990d:
That's interesting. The Sierra 60gr TMK is nearly the exact same BC as the 855A1 projectile.

Originally Posted By TGH456E:
Highpower:
You are correct, and I just now verified again the grid spacing is precisely 1.00" line to line.  
PS: FWIW The center diamond was my POA, but I purposely shot off it to avoid destroying the point of aim.      

Aero:
I'm not sure of your comment, that's what was on the weather station there on site (of the range) at the time of shooting .

Originally Posted By AeroE:

The combination of 5541 feet altitude and 93F temperature means the atmospheric pressure at that location is closer to 24.80 inches Hg.  There is no combination of 5541 feet altitude and temperature that will produce 29.92 inched Hg.

If you were at sea level and 29.92 inche Hg at 93F, the density altitude would be 2267 feet.

Check the weather station the next time you're at the range to find out if the pressure displayed ever changes.