There are only 3 "BAPP'S" listed from VT in the Roster of Union Soldiers, 1861-1865:
Bapp, Paul E. VT 1st Hvy.Arty. Co.D,C
Bapp, Paul E. VT 7th Inf. Co.K
Bapp, Paul S. VT 1st Hvy.Arty. Co.D
Dyer's, Compendium of the War of the Rebellion, Vol II, page 1648
1st VT Reg Hvy Arty organized at Brattleboro & mustered in as 11th VT Inf Reg 9/1/62 - left state for Washington, DC 9/7/62 - designation of Regiment changed to 1st VT Reg Hvy Arty 12/10/62 -old members mustered out 6/24/65 - veterans and recruits consolidated to a Bn of 4 Co's with duty at Fort Foote, Defences of Washington, DC to Aug 1865 - mustered out 8/25/65
Reg lost during service 10 officers and 154 men killed and mortally wounded and 2 officers and 410 enlisted men by disease. Total 576.