Injecting - Speed of injection related to rush?

[dyingtomorrow]

Just a nuance of heroin injection SWIM wanted to informally poll other SWIMMers about:

Do you think the rate you jam the plunger down, i.e. fast or slow, has any effect on the rush?

SWIM began shooting the small veins in his fingers and palms a long time ago with fine gauge needles (for the regenerative speed and permanence of them). With such veins, if you push the plunger in too hard/fast, you can explode the vein, so one must proceed slowly. SWIM seems to be a heroin rarity in his choice of veins (not that he has a choice since all his arm veins are long gone), but when he shoots up with other people he watches them jam the plunger in as quickly as they can, and always kind of cringes to think of a vein bursting inside from the pressure. Perhaps the larger wrist/arm veins can handle that pressure easily, but SWIM still wonders if the faster shot might give a slightly better rush.

The logic to this, best as SWIM could speculate, is that if you jam it in fast, the heroin will remain in a more coherent and concentrate "blob" in your bloodstream, and will thus hit your brain harder than if you slowly trickle it in.

Does anyone have any speculation or personal experience they could share about this issue?