I have shot 4198 and 50gr bullets with 3 different ar's and two of them cycled fine. The one that I had issues with would cycle 50gr soft points loaded to OAL of 2.210" just fine. It would not cycle the same powder charge with 50gr V Max loaded to 2.250". With the 50gr bullets, I was loading 21.2 gr in mixed brass and had good results. I went all the way up to the max of 22gr without any pressure problems. If you already have the components, it is worth a shot to see if it will work in your gun.