The Katyusha BM-13 on Zis truck or Guards Mortar as it was officially designated was as unpopular with Axis infantry as it was popular with Soviet troops. I am very fond of the two metal models that YesThatPhil gave me some time ago.
Even though they are showing their age, and the newer Zvezda models are more accurate in almost every respect*, I am loathe to retire them. Consequently, when Phil also gifted me a couple of spare Zvezda launch rails, it was time to do an upgrade.
Off came the original metal rails and on went the plastic ones. I’m happy!
* The Zvezda kit only comes with enough M-13 rockets for one side of the rails.