I got a Springfield 840 [Sav340] 30-30 for $75 on 5/14/2005.
I got a Savage 340B 30-30 for $119 on 12/29/2016.
I wondered how to get the barrel nut off, for rebarreling to 25/35.
In Jan 2017 I contacted LeeRoy Wisner who seemed interested in Sav 340s.
I was shocked how smart the old guy was.
He said to use pin gauges in a crescent wrench.