Looks like a civil war era confederate button. The eagle on this button matches some used on confederate buttons but I havn't found any with the horizontal bars. When comparing other eagles remember some of the key features such as 'feet together'(not spread apart like most Union Eagles), Thighs of the eagle are not pronounced, wing tips down and slightly spread apart at tips(many wing tips curve inwards at bottom), head looking to left, and very pronounced shield.
http://www.civilwarbuttons.com/cs1025.JPG
Alabama. "AVC" with exra rare "Lambert & Mast/Philada" rmdc. The unusual and desirable mark is easily readable; patina is smooth; device is highlighted with gilt.
http://www.civilwarbuttons.com/cs0807006.JPG
Alabama Volunteer Corps. Dug. Shows some wear and ground action, but is nicer in person, than the picture allows! You will be pleased. "Scovill Mfg Co/ Waterbury" rmdc.
http://www.civilwarbuttons.com/cs0809072.JPG
Alabama Volunteer Corps button. Beautiful, dug example, "Scovill Mf'g Co./Waterbury" rmdc. Found years ago in Dumfries, Va, at Alabama Hill, 1861 winter camp of the 4th Ala. Infantry.
http://www.civilwarbuttons.com/cs0807009.JPG
Mobile Volunteer Corps. Nondug and rare! This is a great button. ".Scovill. Mfg. Co./Waterbury" rmdc. Loaded with gilt.
http://www.civilwarbuttons.com/cs100301130.JPG
Alabama Volunteer Corps with premium backmark of "E. Halfman/Montgomery Ala" rmdc.
These are not matches but just show the similar eagle design used and these are all confederate State buttons.