What gram airsoft bb should I use?

I recently bought a UHC super 9 pro airsoft gun.  The problem is that .2 gram bbs curve dramatically (a very steep curve) up after about 75 feet or so.  The hopup is off, and if the hopup is on, the problem is worse. Will .25 gram bbs make much of a difference, or should I use .30 grams or higher?  Note: the fps with .2 gram bbs is about 410.  I am hoping the airsoft community at Instructables is willing to help me. Thanks.

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rickharris5 years ago
In general with any air powered gun the lighter the ammo the flatter the trajectory will be.

At the lightest limits then air drag has a significant effect on range.

SO You need to try a range of weights under the same circumstances and see what suits your purpose best.

For small bird and mammal hunting I tend to go for a lighter smaller load as this flies more directly and over 60 feet or so will deliver a killing blow.
hunter1125 (author)  rickharris5 years ago
.12 grams are the lightest and they fly straight up as soon as they leave the barrel. I know I need a heavier bb, but I don't know how heavy I need to go or if by adding .05 grams makes much of a difference compared to .10 grams.
As you increase weight you will see the trajectory curve down ultimately the range will shorten.

hunter1125 (author)  rickharris5 years ago
I understand your point and thank you. I probably failed to mention that the airsoft bb at .12 grams-the lightest ammunition-will curve upwards about 15 to 20 feet higher than the height it was when shot. This will occur almost right out of the barrel, hence no accuracy. .20 grams will do the same, but at about 75 feet instead of 5 (with .12 gram). You probably are thinking about airguns, not airsoft guns, which shoot a plastic projectile.
I use .25s in all my guns when I go skirmishing. I only use .2s for waste BBs (shooting at pop cans outside, destroying stuff, etc).

.25s will actually carry farther in a high fps gun AND be more accurate then .2s. The joules that a .25 holds is quite the bit more then what a .2 holds, and therefor the BB will hold its FPS over a larger distance.

The terrible thing about .2s is if you can get them to stop curving up so you don't have to barrel down, they are still effected by every atmospheric difference around you. A random sudden gust of wind will send all your BBs off to the left or right, and that's not good.

My friends use .4 gram BBs in their sniper rifles, not because it makes the gun VERY accurate, but also because nothing will affect the bbs. They can cut through leaves, rain, and even wind with plenty enough power to hit the target in the end.


P.S. - DON'T use .12s in your 410 fps gun. Your gun is probably running a M110 powered spring, springs of that strength can completely shatter .12g BBs, lodging hunks of plastic into your gears that will strip and break your gearbox. Also, by using them, you have completely voided any warranty you may have had.
hunter1125 (author)  mastermaker5 years ago
Thanks. I appreciate an airsoft player informing me on these things. I know .12 grams are bad to put in my gun and I only put about 2 or 3 through. I just bought .25 gram bb's today and I'm going to test them tomarrow. Hopefully I can snipe somebody in a skirmish, because last time I got owned. The person was about 50 feet away and all five of my shots missed him when he was running at me, and then he unloaded on me. Well, thanks and I'll hope for the best.