Hello AS Forum Snipers, I purchased a parts-donor L96 that has the upgrade parts that I will use for upgrading my current L96. The parts to be used for the upgrading from the new will be the cylinder, spring and trigger assembly. I have other mods in mind for the hopup/barrel, but for the scope of this thread I'll keep it tight to two questions: 1) What weight bb should I use, and 2) Do bio-bbs ever expire? The specs on the parts-donor L96 .20g bbs - avg 533.22 fps @ 2.634 j <-- D14 in Denton, TX has a 550 fps limit on snipers .32g bbs - avg 430.73 fps @ 2.754 j In testing the rifle with my .36's the sniper jammed on the first round so I can't say what it chrono's with .36's, but we'll get back to this in a second. In looking at @1tonne 's thread on DIY modding an L96, he posts his bb weight joule specs. I found that my donor-parts gun shoots a little hotter than @1tonne 's (given the specs above), and I would like to know if it would be a good idea to buy .4's this time around instead of .36's. I'm not sure about the logic of this, but because .4's were the max joule rating of @1tonne 's build, would mine be slightly higher/more capable because it has slightly high joule-output per bb weight (until the joule-drop at some unknown point). Or was the joule-drop after .4's due to barrel length in which case I should stick with the .36's I bought before? Do me a favor and give me your thoughts on that logic as well... Here's the link to @1tonne 's thread and if you are reading this @1tonne , I'M A HUGE FAN OF YOUR WORK!!! The man's a legend... https://www.airsoftsniperforum.com/57-type96/6465-advanced-l96-sniper-upgrade-guide.html My second main question: Do bio-bbs expire over time even when stored properly? I inspected the bag of bbs after the first .36 jammed and it looks like the bbs are dull/chalky and they don't seem to be shiny/slick as my .25's and .28's I use in my AEGs. I recall when I first bought them that they looked very similar/normal to my standard bio AEG ammo, but now, not so much. I don't remember when I bought them, but I'd guesstimate the purchased date would be about 5-7 years ago for which the bag has been opened and then sealed maybe 100-120 times over the years. The .36's in question are Bio-Shot White bbs as seen at the link below. https://bioshotbb.com/collections/6mm/products/6mm-36g-bio-bbs-3500-rounds-white If bio-bbs do expire, I guess I wouldn't be surprised. But now I'm wondering what I'm supposed to do with a barely used but now possibly expired bag of nearly 2500 useless bbs? Thanks for the help fellas, take care!