Could Semmes' Brigade have taken heavy casualties, especially the 51st and 53rd GA, on their way to the Rocky Ledge?
I keep a list of identified individuals whose wound is identified by type (gunshot, artillery, etc.) I only have 26 names from Semmes' brigade, which is too small a sample size to draw accurate or firm conclusions, however, half of them are attributed to artillery, which percentage I think well exceeds any other brigade in Lee's army (on my compiled list).
A denotes artillery, GS is gunshot, W is wounded, K is killed:
Cato, Nathaniel C., Pvt, I/10 GA, 2 July, W left thigh by minie ball or grape shot (A or GS)
Davis, James M., C/10 GA, 3? July, W minie ball fractured left humerus two inches below shoulder joint (GS)
Morrow, H. A. “Gus,” E/10 GA, 2 July, K ball passed through his body (GS)
Wilkinson, George, 10 GA, 2 July, W ball struck left knee (GS)
Albritton, J. H., A/50 GA, W, lost hearing from bursting shell (A)
Alderman, James “Jim,” K/50 GA, 2 July, K exploding shell as advance started (A)
Bailey, Thomas R., F/50 GA, W shot two places, ball under left arm and right shoulder (GS)
Bedford, Peter B., Capt.?, B/50, 2-4 July, minie ball struck right ankle joint, amputated (GS)
Centerfeit, Levi, D/50 GA, 3? July, W left arm torn off below elbow, grapeshot (A)
Dixon, James M. “Jim,” K/50 GA, 2 July, K exploding shell as advance started (A)
Griffin, John J., Pvt., I/50 GA, W musket ball above left knee, lower femur shattered, leg amputated (GS)
Hall, Fleming J., G/50 GA, W hip, minie ball (GS)
Jones, William, Sgt., K/50 GA, W right ankle piece of canister shot (A)
Kearse, Francis “Frank,” LtCol, 50 GA, 2 July, K grape shot during advance (A)
Maxwell, Lt., 50 GA, W arm bruised by grapeshot (A)
Merriman, George Henry, K/50 GA, 2/3 July, W left lung as advance started, shell fragment (A)
Stephens, Jesse N., K/50 GA, 2 July, W above left eye by explosion of shell as advance started, bones fractured and lost sight in left eye (A)
Townsend, Lot, 1Lt, H/50 GA, 2 July, W minie ball left forearm about halfway between hand and elbow (GS)
Walker, Henry Clay, D/50, 2 July, W bone shattered and veins severed right foot, shell piece (A)
Adams, James W., B/51 GA, 2 July, W left shoulder broken, shell piece (A)
Armstrong, R. S., I/51 GA, 2 July, W neck and right arm paralyzed, gunshot (GS)
Sauls, Richard R., Pvt, E/51 GA, 3 (2?) July, W minie ball in abdomen, died 27 Aug (GS)
Sellers, David Lott, G/51 GA, W shoulder, shell (A)
Andrews, Thomas C., 1Sgt, A/53 GA, W right elbow by gunshot (GS)
Futral, William J., A/53 GA, W right foot by shell fragment (A)
Heard, Grant D., Capt., E/53 GA, 2 July, W ball never extracted (GS)
According to my research, Semmes' brigade could have been exposed to close artillery fire by: B/1 NJ, 5 MA, 9 MA, and part of the time by C-F/PA and 15 NY, total 26 guns. I also have Semmes passing the Rose buildings at 6:15 p.m., but do not have 5 MA and 9 MA starting to pull back from the Wheatfield road until 6:33 p.m.