Frank

That is interesting as you say they may have been Grape from the gunboat Tyler or the heavy batteries.

I guess the question would be, would round ball ammunition have been effective in a rifled cannon, which clearly the 1st Indiana's guns were? Rifling a cannon was done to improve accuracy, hence usually a bolt or shell was the preferred ammunition to be used in a rifled gun, instead of round shot, which was ballistically inaccurate even in rifled guns.

The federal pattern Ellsworth shell/bolt/bullet was a solid lead bullet shaped projectile 1.5 inches in diameter by 3.3 inches long with a flat base and weight 1.5 pounds. It was wrapped by waxed cord to engage the rifling of the Ellsworth gun barrel. It was highly accurate and used to engage in counterbattery fire against enemy artillery to break up the carriages and wheels of the enemy artillery. Or to enfilade enemy infantry by firing into the flanks of the enemies formation along their ranks.

While these are the desired tactics of any artillery usage it would seem that in several of the action reports of the 1st Indiana battery, this battery was specifically assigned to forward or exposed position, as in Powell Clayton's report at Helena, to do specifically this.