"...failures to extract, sometimes it stovepipes..." That's not necessarily an ammo issue. Failures to extract an be the extractor itself. Stove piping can be a feeding issue or the extractor or its spring.
Start by giving the bolt a really good bath and look closely at the extractor and its spring.
A new extractor and spring runs about $30. These guys are not the only source. Gunparts is sold out though.
http://interarmstx.com/product-categ...ilitary-parts/
There is no gas valve.
http://stevespages.com/ipb-russian-simonov.html
However, is "tried different types" different brands, preferably not steel cased? Not entirely convinced ammo is you issue though. More likely the extractor.