Breaking in the new M4, shooting slugs at 15 yards to check red dot and it's all over the place. Laying prone with a bag under the barrel. I shoot a lot of handguns/rifles so I'm fairly certain it's not me. If it was all low/left I could see the argument but it's spraying all around and I was in a very stable platform.
I'm shooting this cheap Sterling ammo, I really hope it's just the ammo. Bought cheap stuff just to break in the gun.
https://cltammo.com/product/12-gauge-2-3-4-1oz-slug-10-round-box/
Any advice would be appreciated, thank you.