diff --git a/weapons/space_gun/projectile.gd b/weapons/space_gun/projectile.gd
index ac28361..96dece8 100644
--- a/weapons/space_gun/projectile.gd
+++ b/weapons/space_gun/projectile.gd
@@ -1,9 +1,7 @@
 extends Node3D
 
-const speed : float = 68.0
+const speed : float = 68.0 # m/s
 var velocity : Vector3 = Vector3.ZERO
-
-# @FIXME: with an imaginary box around the map
 const lifespan : float = 5.0 # in seconds
 
 @onready var shape_cast = $ShapeCast3D
@@ -30,8 +28,9 @@ func explode(spawn_location):
 	queue_free()
 
 func _physics_process(delta):
+	var previous_position = global_position
 	global_position += velocity * delta
-	shape_cast.target_position = to_local(global_position - velocity) * delta
+	shape_cast.target_position = to_local(previous_position)
 	if shape_cast.is_colliding():
 		var contact_point = shape_cast.collision_result[0].point
 		explode(contact_point)
diff --git a/weapons/space_gun/projectile.tscn b/weapons/space_gun/projectile.tscn
index 507dc4e..5a115d7 100644
--- a/weapons/space_gun/projectile.tscn
+++ b/weapons/space_gun/projectile.tscn
@@ -8,14 +8,14 @@ emission_enabled = true
 emission = Color(0.482353, 0.65098, 1, 1)
 
 [sub_resource type="SphereShape3D" id="SphereShape3D_umtte"]
-radius = 0.3
+radius = 0.15
 
 [node name="Projectile" type="Node3D"]
 script = ExtResource("1_4j1dp")
 
 [node name="Mesh" type="CSGSphere3D" parent="."]
 transform = Transform3D(1, 0, 0, 0, 0.2, 0, 0, 0, 1, 0, 0, 0)
-radius = 0.3
+radius = 0.15
 radial_segments = 24
 rings = 8
 material = SubResource("StandardMaterial3D_o6j55")