Download HaloMapTools
HEREAfter you've installed that, download this file right
HEREWhen you unzip that you'll get an empty folder, a plugins folder, and a readme. Open the plugins folder and move everything from it into the HaloMapTools/plugins directory.
Once you've done that, get a cache file of the map you want to mod.
Run HaloMapTools, go to file, open, then select the cache file you just got.
On the left side scroll down to where it says [proj] Projectile (# items). Click on the little + next to that and go down to where it says weapons\plasma grenade\plasma grenade.
At this point, a tag editor should open up on the right side.
Where it says Life Span, change the 0 to 1000.
Where it says Weight/Arc, change the 1 to a 0.
Change both initial speed and Final speed to 33.33334
If you check weapons\sniper rifle\sniper bullet, you'll note that it has the same settings.
Now, click on weapons\plasma grenade\plasma grenade if you don't still have it selected.
At the top left there's a section titled Tag Information.
Look where it says Meta, there should be a swap button next to it followed by a field with some numbers and letters in it.
Highlight all of the numbers and letters.
Right-click COPY.
Click on weapons\sniper rifle\sniper bullet.
Look up at the Tag Information box again.
Highlight the little field with the numbers and letters in it.
Right-click PASTE.
Click the button to the right of that that says Save. NOT the one that says Save Meta.
Close HaloMapTools.
Transfer the cache file back into the HALO cache on your XBOX.
You will now have a sniper rifle that shoots plasma grenades as if they were sniper bullets.
You'll also throw them in the same way.