Any Laylax part that has "PSS96" after it.
If it's PDI your after, just got to AirsoftAtlanta and the PDI upgrades will have "Type 96" in their name.
Here's a ton of upgrades from AirsoftAtlanta:
http://www.airsoftatlanta.com/Airsoft_Type_96_APS2_L96_s/279.htm?searching=Y&sort=11&cat=279&show=15&page=1
They seem to be the store in the US that carries most of these bolt action upgrades. AirsoftExtreme also has a good bit. Some of their stuff just went out of stock though.
Also, I'm sure there's a plethora of "MK96 Upgrade Guides" in the Others Section, or even the Maruzen Section. I also know that there are a ton online. You'll have to do some re-searching on your own to find out what you truly want.
I'd recommend looking through fuzzy's upgrade guide on here. Here it is:
http://www.airsoftsniperforum.com/phpBB/phpBB3/viewtopic.php?t=1156
Zulu also has a great one:
http://www.airsoftsniperforum.com/phpBB/phpBB3/viewtopic.php?t=681
Before you go posting upgrade guides, you should really do some searching.
Edit: I see that this is your first post. You should probably go make an intro post, since that's a rule here.
If it's PDI your after, just got to AirsoftAtlanta and the PDI upgrades will have "Type 96" in their name.
Here's a ton of upgrades from AirsoftAtlanta:
http://www.airsoftatlanta.com/Airsoft_Type_96_APS2_L96_s/279.htm?searching=Y&sort=11&cat=279&show=15&page=1
They seem to be the store in the US that carries most of these bolt action upgrades. AirsoftExtreme also has a good bit. Some of their stuff just went out of stock though.
Also, I'm sure there's a plethora of "MK96 Upgrade Guides" in the Others Section, or even the Maruzen Section. I also know that there are a ton online. You'll have to do some re-searching on your own to find out what you truly want.
I'd recommend looking through fuzzy's upgrade guide on here. Here it is:
http://www.airsoftsniperforum.com/phpBB/phpBB3/viewtopic.php?t=1156
Zulu also has a great one:
http://www.airsoftsniperforum.com/phpBB/phpBB3/viewtopic.php?t=681
Before you go posting upgrade guides, you should really do some searching.
Edit: I see that this is your first post. You should probably go make an intro post, since that's a rule here.