I have a custom made slug gun based of a .410 shotgun. The barrel reinforced and customer rifled. I have to reload .410 AA shells using 50.5 grains of IMR 3031 and 210 grain .410 Hornady XTP. This load is extremely accurate and powerful out to 200 yards. Excellent for Southern Michigan.

Being extremely intrigued by the Barnes family of bullets, I would like to try .41 180 grain Barnes XPB. My question for you experts is I have heard the Barnes bullets are slightly longer then other manufacturers. Is this true? Is there a powder increase or reductions that should be used with the Barnes as compared to the Hornady? I realize I am looking at some range time to fine tune this load, but I was hoping to learn more about the Barnes bullets and maybe get a starting point.

They ARE longer (assuming the same general bullet shape) because copper is less dense than lead and more volume must be used to get the same weight. Couldn't tell you about the powder charge...... If it was my gun, I'd look at handgun load data to see what happens between the 2 bullets as far as powder charge goes for the same type of powder. And start on the low end, when you find out....

I'm new to reloading so hopefully someone else with more experience can either validate or correct me on my thought here. I'm thinking since you will have to achieve the same over all length, it will compress your powder causing more pressure. With that said I would use less powder to start with. Sounds interesting to do what you are doing with your 410.

Barnes issued a statement to start 8% under max book loads for cup and core bullets.

The point about case capacity is a good one. Are you pushing the bullet with a plastic wad or a fiber column of some type?

Can you post a photo of the gun?....I'd love to see it!