smoothbore marked 1864 and US Trenton
Percussion cap musket(?). Muzzle looks to be very roughly 12 gauge size but there is a cutout for a rear sight. The only markings visible are "1864" an eagle and "US Trenton" Length from muzzle to nipple about 30" Any information appreciated.

US Trenton was an arsenal/gun factory in trenton during the Civil war. The gun was probably initally a .577 rifled musket used by the Union forces. As to it being a smooth bore now, below is why it probably is. It probably was a rifled musket at one time but was reamed out to a smooth bore after the war. What happened was this, during the war, all the rifled muskets (most had almost if not straight rifling) were used BUT once the war was over, each man was given a pound of bullets, a 1/2 pound of powdr, and a number of caps to get them home on. They were given littel rations and many were mustered out or let loose from a Yankee or Confederate prison with these few things and were sent home which was probaly a LONG walk. So when they got to a town that had ANY gun smith or black smith who could work on guns, they had the barrel cut outto a smooth bore. Now if you think about this at firt you think WHY, well here is why, a pound of bullets in a .577 rifle was not that many, maybe 30 at best. you can kill a der with that BUT chances are you are going to see LOTS more small game than deer or big game but a .577 bullet would destroy a squirel or rabbit. Once they got the barrel bored out to smooth bore, they could melt the bullets down and make home made shot (which was tear drop by the way) and kill small gane to eat on while on teh long walk home. NOW should they happen upon a deer, the smoothe bore will still shoot a larger projectile so as to kill a deer. In short, chances are your smooth bore began as a .577 rifled musket, was bored out by a gun smith or black smith, and was brought home from the war. Some rifles did not get bored out due to soem being mustered out close to home but eventually many were even if mustered out close to home due to a smooth bore is handier than a rifled musket. It was actualy the smooth bore or scatter gun that won the west over the rifles or hand guns.

Thanks for that speedy reply. Any clues on approximate value in poor condition?

Not really Heny BUt to you poor condition might be good ondition CONCIDERING the age of the gun. I would check with google.com for Civil war forums and ask on one of them (if any but I would think there are some).

Let me add a little to my second reply Henry, I once bought one like yours for $50 about 15 years ago, it wa an Enfield of all things but bored out to smooth bore. I ahd NO CLUE as to the smooth bore BUT a man who did Civil War re-enacting filled me in on teh above info I told you. I gave the Enfiled to a good friend who worked on my cars as my main mechanic plus his wife and he concidered me aa long lost child of theirs. He hung it on the all beside a 38 caliber flinter that had been converted to percussion that he bought off a boy for $100. the boy he bought the 38 cal long rifle from got it in a wooden box full of iron digger, shovel, spade and otehr tools at auction that he paid $100 for teh whole box. He did not know teh 38 long rifle was in teh box till he got home. he sold teh long rifle to my buddy for the $100 he paid for teh box of tools thus the box and tools were basicly free. My buddy got a man we know who is GREAT as restoration to restore the 38 long rifle f0or another $200. I tried everuy way oin world to buy that 38 rifle but he wanted it oon the wall so i gave him the enfield to hang with it. when his wife passed about 3 years ago, he had to have the gun appraised, the one I gave him was appraised at near $1000 and the 38 was well over $5000. He has a will that if when he passes I get he enfield back and the 38 as well. reason I tell youbthis is I thought the Enfiled was JUNK but JUNK is worth $1000 apparently, the enfield was in rough condition IMHO. So check with some one who appraises guns before you say it is in poor condition.