Is it easier to shoot with a smaller gauge

[Znegative]

Really? A certified phlebotomist, or a street level junkie sharp-shooter? I could probably teach a class on phlebotomy lol. But yeah I'm guessing you have pretty thick skin, I had a friend with skin like leather and anything smaller then a 28 would bend on its way in. I think what gauge you use depends on a multitude of factors, like how deep your veins are, how much scar tissue you have built up, how fat/thin you are, and what vein you're trying to access. For most veins, IMO a 28-29g works perfectly. For deep veins I've always used a 27g, either 1/2" but more often the 5/8", but like I said, I used those specifically for my deep femoral. Even for my brachial I'd have an easier time with a 28-29.

The 31g are great for hitting tiny veins on your hands, fingers, feet and toes (especially the toes), but really 31 IME is kind of overkill, a 30g 5/16" will do the trick just as well and have less chance of clogging.