My department has been issuing Federal LE223T1, the 55gr bonded bullet, for some time. I've never had issues with it, and my rifle is zeroed with it.
We recently switched to the LE223T3, the 62 gr bullet. (I don't know why, it's just what was delivered.)
I was also just issued an AAC Mini supressor, and just mounted the adaptor on my M4 rifle, replacing the A2 FH. I wanted to check my zero to see if the new adaptor and supressor would change my POA/POI, and test the new ammo.
I went to the range and fired 3 rounds of the 55gr stuff first, to confirm my zero. At 50 yards, I wound up with a nice group of about 0.5", dead center. (I love my Aimpoint.)
Next I shot 3 rounds of the 62gr bullet. I was shocked to see my group open up to about 3". (The group was a little low, but I expected that.)
At first, I thought it was me, so I went back to the 55gr. bullet. My 3 round group was a little more than 0.5", but still pretty tight.
I had some ASYM 75gr ammo with me too, and thought I'd try that as well. It printed low, with about a 1" group.
Rifle: DPMS LE lower with BCM upper, 14.5" H barrel, about 600 rounds through it, Aimpoint T1 4MOA. All rounds fired from a solid prone position at the 50yd line, using the same PMAG as a monopod, no supressor.
Frankly, I was shocked at the difference between the 55gr and the 62gr. I know some rifles like some ammo better than others, but this was ridiculous.
Has anyone else had this experience? Or am I missing something?