The reason I stated that 25G are not long enough is because the only come with maximum length of 1", which I suppose is long enough really but for glutes not ideal.
I go by the recommendation of the professionals, simple as that.
Yes that is also true that drug users use slin pins, that is until their veins are shot, then they use flash brown or flash orange packs containing 27G or 25G. The sad shit here in Switzerland is that you can watch everyday the druggies shooting up in compounds just off the main streets as it is legal for them to shoot heroin !
There is also a technical reason why certain pins are used with certain syringes, bottom line being that if you use a 25G with a 3ml or worst a 5ml, you are likely to 'blow' the pin off the end when using low viscosity fluids.
Next time I will cross the 'T's and dot the 'i's.
FYI - I work with documentation electronically stored for each and every pharmaceutical drug produced by the Co. I work for, some of them are mentioned many times in this forum.