Hornady makes (or merely sells in their red box) all buckshot sizes. Now, all I've seen are hardened, ie: 3 to 5 % antimony. Track says they have pure lead Hornady buckshot - that would be nice. I'd give them a call or e-mail to make sure. I'd ask them if they had hardened buckshot from Hornady and if it says so on the box - if they say yes, "do you have pure lead buckshot and does it say so on the box"? Just an idea.
I have some #2 buck, which is .32 - pretty close and looking good, however they are harder than pure lead. Due to the small size, they'll probably be just fine in the .32 rifle - I'm sure. Same with the .240's even if they are hard, normal buckshot. They are .010" to .015" smaller than the bore already and becasue they are small, they'll swage into the rifling just fine. Merely ensure you have a descent'ly smooth, radiused crown.