Flat base vs hallow base

[AgentAdam]

What are the pros and cons of the flat base vs hallow base bullets?

 

[Steve C]

For wad cutters the hollow base is designed to expand at low pressures and take up the rifling producing an accurate low velocity load. They can't be driven at higher pressures or velocities beyond target level as the "skirt" can tear off leaving an obstruction in the barrel or they can seal so tight in the case that the center blows out.

Solid base wad cutters are the same as any solid base lead bullet and can be driven as hard as you can a lead bullet of similar weight.

 

[Sunray]

"...can be driven as hard as you can a lead bullet of similar weight..." No they can't. The weight of a cast bullet has nothing to do with how fast it can be driven. A soft cast bullet, driven too fast, will cause leading.
WC's are target bullets. Period. Solid WC's are just cast bullets. Poured lead into a mold. Hollow based WC's are swaged.
A swaged bullet is made by pressing pure lead wire into the desired shape with pressure. They tend to be more accurate than a cast bullet.

 

[Steve C]

No they can't. The weight of a cast bullet has nothing to do with how fast it can be driven. A soft cast bullet, driven too fast, will cause leading.

I should have said; "Solid base wad cutters are the same as any solid base lead bullet and can be driven as hard as you can a lead bullet of similar weight, diameter and hardness. Lyman lists data for velocities of 1,382 fps for their 141gr Wad Cutter #358495 out of the .357 magnum, every bit fast as round nose and SWC designed bullets. A soft swaged Speer BBWC would have the same limitations as one of their swaged LRN or SWC bullets.