Below is a little bit of 12 gram info,I have been seeing this topic resurface often and thought I would add some numbers. I did the weighing very simply.
I did not have anymore ICO trading 12g's to test so if someone wants to add specs of them or other brands please do,keep in mind alot of brand names are just smacked onto the same 12g's. hopfully we can get info on different mfg's.
First these are the "gold" 12 grams sold by RAP4 they are available in bulk at lower prices c02
we shot these over the weekend and went through about 150 they seemed OK but i was having velocity issues nothing solid if it was 12g related though,it was relativly warm out and one player was seeing 40+ on his buzzard with them.
the neck is similar to a leland but the empty is slightly lighter than both the leland and crossman at 1 ounce even,both the leland and rap4 were a hair longer than the crossmans.
the majority of the RAP4's weighed in at 1.4 full only a few were 1.3 (could've been my velocity issues) none were empty.
Next the old stand by crossmans wich are available all over the place the link is just for reference the price on them is all over the place and i couldnt find them in bulk (over 100) at a discount they by far are the highest priced. Crosman 12 Gram CO2 Cartridge - 100 Pack at ActionVillage.com : Paintball
the empty's weigh in at 1.1 and the fulls anywere from 1.3-1.5 to 1.1 (dud)
my camera battery died so ill be updating pix of the scale
overall not the greatest deal and these seem to be what is giving 12g use a bad name
AVI-action village is now selling bulk 12g's,they apear to be crossmans but i dont have any other info yet. AVI 12 Gram CO2 Cartridge - Single at ActionVillage.com : Paintball
last one (for today)
leland has the cheapest retail bulk 12g's you can buy without a wholesale account. the shipping sucks and kills the deal to a point i have a case of 450 and it was just at 170 total shipped 48 pounds shipping weight LOL,make sure to order them DIRECT Leland Limited
every leland weighed in the same and I have had zero duds or problems with them the empty's are 1.1 and the fulls are 1.5,they are clean and work well
i like them the best so far
they also have a saftey blow off design so if they get to hot the gas will exit slowley instead of rocketing.
ICO trading bulk 12g's im adding this but i dont have the specs. the 12gs we had were good,loads of people have bought them and been happy,i think chuna weighed them and found them to be consistent
ICO info website ICOTrading
ebay eBay Store - CO2 NO2 SUPPLIES ICO: CO2 chargers, whipped cream chargers, NO2 chargers
feel free to add info