diff --git a/src/engrave.c b/src/engrave.c
index 7e8915377..104f5922a 100644
--- a/src/engrave.c
+++ b/src/engrave.c
@@ -613,7 +613,7 @@ doengrave()
 	    case WAND_CLASS:
 		if (zappable(otmp)) {
 		    check_unpaid(otmp);
-		    if (otmp->cursed && !rn2(100)) { /* same as when zapping */
+		    if (otmp->cursed && !rn2(WAND_BACKFIRE_CHANCE)) {
 			wand_explode(otmp, 0);
 			return 1;
 		    }