And from the top

Jomini is much more important in teaching ACW generals than in explaining the Napoleonic wars. Added to that the Mexican war practice.

Napoleonic armies did engage in trench warfare but were more mobile operationally ? ACW armies tend to be more tied to rail or river/sea supply lines (cos they had them). An entrenched army is a thing to send a couple of Corps to outflank then you can then fight a maneuver battle (as in the great entrenched camp the Russians got maneuvered out of in 1812), or besiege rather than assault, but at for example Borodino, Leipzig, Dresden and I think Vitoria there were fieldworks. There are also a lot of fortresses in most of the European theatres. The big entrenchment is of course the lines of Torres Vedras but also Cadiz and Walcheren.

I also think that there may be a geographic one ? the US was much more wooded that most the  Napoleonic battlefields so a shallow trench and big breastwork is feasible whereas in more settled areas in Europe a trench is a 5 foot deep ditch which takes a while to build. And a technological one ? ACW troops had more spades and picks  available to the infantry. No idea why but they did.

Don?t overate the rifled musket in the ACW ? see Griffith and Nostworthy, - most were not used much above 200m and then by snipers. Tactical practice generally seems to be very similar to Napoleonic wars, or less given the terrain. Effective range for canister is ~600m (spherical case/shrapnel is I think closer to 1200m and round 1500m with ricochet so infantry in trenches unless below ground would get blown away. A good battery could burst fire 3 rounds per minute.

Start doing the maths on the comparable effect of artillery and muskets on the battlefield and you see why Napoleon liked lots of cannon in masses and why both a thin line and advanced skirmishers (preferably with rifles) become very important.

If you are in trenches you don?t need mortars ? one howitzer per battery will do the job.

The chief metric for a Napoleonic army absolutely NOT rate of fire. It is fire discipline. Oman was wrong.

From Frederick the Great?s experiments at 50 paces 50% of a battalion volley will hit a battalion sized target. At 75 paces 25% and at a hundred you miss. It takes about 20 seconds to reload a musket in a hurry and they have horrible misfire rates that become truly madly horrible if you mess up a step.  Like Herald says a running (or quick marching) man can cover more than 50 paces in 20 secs. If you fire at range the other guy will close with loaded muskets to a range that they will become devastating before you can reload and you know it (and normally ran away from the French column that is attacking you). If on the other hand the fire is held as you approach 50 paces  the 50/50 chance of getting shot tends to cause panic and then when it comes the disruption caused often means that the firer can reload and deliver a volley before you then charge with bayonet ? about 10 paces before the attacker ran off.

At least that?s what Bugeaud?s description of being in a French column attacking a British line says happens.

Where you get two standing lines that take the first volley, you get a slugfest that goes on for a long while. That?s quite common when the brits are not involved with both sides flinching just beyond the 50 pace mark.

My reading of Bugeaud is that the thickness of the brit skirmish line, and the smoke, as well as hiding the main line tended to draw  the French into the close zone before they had realized it.Takes a good colonel in the line though.

French cavalry Vs Brits ? very limited exposure. The French in Spain had arguably second rate cavalry and not the best battlefield cav. and in Spain not a massive superiority on the battlefield. I think apart from Fuentes they were tactically insignificant, and at Waterloo badly misused, but Waterloo is in many ways an exception. Off the battlefield the Brit cavalry did quite well and not just the KGL ? who were magnificent.

Brit Artillery ? probably were more significant than most histories tell certainly they get more of mention from the French than the Brit diarists..

Best general officer of the ACW ? Lee, Grant, Farragut or Foote ? Jackson in the Valley is a gem but after than he is one of Lee?s Corps commanders and would need to be judged alongside other subordinates with limited missions so compare with Longstreet, McPherson, Sherman, Stuart, Thomas (and when someone gets back at me about his brilliance at 2^nd Bull Run please explain the Seven days.) Forrest I would discount ? brilliant raider and division commander but not an army commander, never got promoted.

For two contentious ones to compare with Jackson in the Valley? Kirby Smith in the invasion of Kentucky and Rosecrans 63 campaign up to but not including Ch