Since you are limited to 10 round and nothing greater than .399 I would suggest at 1911 of some sort in 9x19 and second similar (preferably identical) pistol in 38 Super/ 38 super comp/9x23 or what ever in order to shoot in IPSC major class. 1911 is a great platform as there are lots of different accessories and parts available. Sphinx makes very nice pistol in 9x19 and 9x21.

Revolver in 357 mag I would choose a Manurhin MR73.

Custom 1911 costs more a few pretty dollar and so does a Manurhin, but, they are worth it. Since you can only have a few handgun its better to buy quality.

While you are at it, also, get a quality .22lr for bulk practice, there are 1911 versions in .22lr.

Get a Benelli M2 and a semiautomatic in .556/223 of some sort and you are set up for 3-gun matches.