What the actual fluctuation?

[Sweet Shooter]

Okay give me some ideas here. This photo shot this morning shows Hornady Frontier M193 (with the Lake City brass and Hornady bullets). on the left and measures 11/16". Then Federal American Eagle M193 on the right at a bit over 2", and significantly centered left of the POI. Both at 100 yards from the same bench bags etc. Shot literally three gulps of tea apart.

Rifle is a 16" Daniel Defense barrel, LMT AR15 build. I've suspected for weeks that the barrel was picky, but what could be different between two ammo types both claiming to be M193.

Any ideas?

 

[jmr40]

That doesn't look all that unusual to me. It is common for some ammo to shoot better than others and to have a different point of impact. If you fired all 10 shots that quickly a hot barrel could also cause the group on the right to be a little bigger too.

 

[TX Nimrod]

According to Hornady, the bullet is M193, not the load. I can’t find current Federal ammo listed as M193, but suspect what the OP has is loaded with the M193 bullet. Powder and charge will differ, so no surprise that accuracy is different.

As above, this difference isn’t unusual.


.

 

[Aguila Blanca]

American Eagle M193, or XM193?

 

[Sweet Shooter]

This is the actual ammo. The XM-193 claim on the federal American Eagle is very small on the end of the boxes... kinda down-played.

The two groups were shot slow, and it was very cold... about 30 degrees, so the Daniel Defense barrel though admittedly a light profile was not walking, as I shot the test a second time and got very similar results between the two. I guess I'll just have to use the Federal American Eagle for a different rifle. I wouldn't mind so much other than for the fact that it's currently twice the price it should be.

I'm wondering if the Hornady projectile is just way better, or mayby the Lake City brass is more concentric.

Maybe one bullet is a flat base and the other a boat tail? Though neither say FMJBT. It's a 1x7 twist by the way.

Edit: It's American Eagle XM193 so I guess contract over-run?

 

[Aguila Blanca]

Technically, it's military rejects. But that's not as bad as it may sound:

https://www.pewpewtactical.com/federal-m-vs-xm-556-xm193-vs-xm855/

In a nutshell, “M” by itself means that it meets military specification (mil-spec) while “XM” means it does not.
...
Federal must have gotten so many questions that they put up a site that describes XM193. Emphasis is done by me.

XM193 product is first run, first quality product manufactured at the Lake City Army Ammunition Plant for Federal Cartridges and is made to Federal specifications typical for commercial ammunition.

All XM193 product is the same regardless of the sku or part number. (ie. XM193C is the same as XM193F, XM193CBP and etc … ) The only difference is the package configuation.