Actually one of the "Minor points" that helped the Federal gunboats at Arkansas Post was that the Confederate gunners had registered (ranged in) their heavy guns for the first bend in the Arkansas River where the Federal boats would first appear. That was a range of some 1,100 yards. However, the Union gunboats did not stop as expected at that point to shell the fortification, The principal heavier armoured gunboats drove forward to a range of 400 yards where their guns were more effective and where the Confederate weapon (one of which is still on display on the Old State Capital lawn) had difficulty depressing their barrels enough to engage these gunboats effectively.

Interestlngly enough the Fort (Fort Pleasent) which was built to replace Arkansas Post after that forts fall, was built on a higher bluff which the Federals could not use this same tactic against. At Fort Pleasent if the Federals came too close to the fortification their guns would have become ineffective because they could not elevate high enough to engage the Confederates. While at the same time the thinner armoured and wooden roofs of their gunboats would be open to plunging fire from the Confederate Guns above. So at Fort Pleasent the Federals Gunboats would have had to have "stood off" to engage the guns of the Fort, while having to remain at a range where the Confederates guns would have been the most effective.

As for Walker, I still would wonder what would have happened, had he kept his main Infantry intact at Jourdans Plantation and sent his Artillery forward on the Napolean road, in a "Hit and Run" fashion, past Arkansas Post and used it against the thin skinned wooden troop transports anchored there. These were mostly still loaded with troops who had not disembarked? Walker would have risked the loss of his artillery, such as Douglas' Texas Battery for example, but would it have caused enough havoc in the Federal command structure to have caused the Federals to abandoned their assualt?

Clearly Walker could not have committed his whole force for tactical reasons. But could he have committed just this portion of his force to this purpose, even if Arkansas Post had already surrendered?