If you have fully upgraded pulserifle, it holds 200 rounds, which will be 8 rounds of grenade without reloading, but you really don't need to upgrade, since I am sure our members here are competent shooter players that will utilize stasis, and if necessary another weapon for quick kill then go back to pulserifle.
Alternative can be Force Gun and Detonator, but I do not advise them as much as pulserifle. Force Gun needs to be upgraded to do one shot kill (unless you use alternate fire which will slow you down considerably). Detonator draws an arc, and travels slower than the grenade from pulserifle so if the tripod decides to do a little dancing wiggle to stretch out to you in an attempt for a swipe, you probably would miss.