If you enjoy the forum please consider supporting it by signing up for a NES Membership The benefits pay for the membership many times over.
#4 buck is not the same a #4.
Here's a chart:
Lead shot - Wikipedia, the free encyclopedia
Why would you want #4 buck? That's a custom load for a 12ga, IMO.
You might find some sub-gauge loads with it.....
I found #4 Turkey.
Is that different from # 4 Buck ?
My Mossberg is loaded with Winchester PDX1 a 1oz and three oo buck it should get the job done