10mm chrono numbers

I got bored today and ran some hand loads and factory ammo through the chronograph. I ran the ammo through 2 different guns, both Glock 20s, both with the same upgraded guide rod and recoil spring. The only difference is one has about 500-600 rounds through it, and the other has about 100. The one thing that stood out to me, is the gold dot 180 grain hollow points were a lot faster than the HSM 180 grain FMJs. I cant remember what the HPs were loaded to, but I do know it was between 14.6-14.9 grains of aa#9, and the FMJs were loaded at 14.6 of the same powder. The only thing I could come up with is the HPs were a solid core, and the FMJs are not, hence expanding and distorting in the chamber/barrel. Here is my numbers, and for you statisticians out there, yes I know the sample sizes aren't big enough, but with a setting sun, the chronograph numbers I got I'll take.


180 gr HP old gun
1) 1361
2) 1354
3) 1312
4) 1437
5) 1327

180 gr FMJ New gun
1) 1211
2) 1209
3) 1191
4) 1203
5) 1207

180 gr FMJ old gun
1) 1235
2) 1242

Remington 180 gr FMJ New gun
1) 1015
2) 1039
3) 1037

Remington 180 gr FMJ old gun
1) 1027
2) 1084
3) 1039

(PS I also took out the 460 Rowland, and the hollow points had higher velocity than the FMJ which are both hornady 230 grain, with a solid core, both types of bullets were loaded at the same time with the same pull from the powder measure.)