Where can I buy/find large amounts of these? Gun Runners doesn't seem to have any outside of 25mm HE, and I'm already at level 20+.

gun runners will have 25mm and along route 188 intersection, the person that works for gun runners sells 40mm

Try Lacey at Mojave outpost. Or, the NCR guy at Hoover damn. Or, the quartermaster at McArron field.

I'm with the Legion though, so I can't really purchase from those people, being labeled a terrorist and all.

Anyone with confirmed info?

Most of the time they are random, in fact, I see more missiles (like 30?) the grenades in my current playthough. I am sure Novac, Primm and Mick n' Ralphs would have them, but you want to save and restart to get more.

25mm HE are much better anyway. It's expensive but you won't need that many shots, plus at level 20 you'll probably have a good amount of cash.

Primm has a shop? Ah, where is it?

Inside the Dinosaur.......

And Mango, I am using Mercy.....

The dinosaur is at Novac, Prim's shop is where you get ED-E

And Mercy is cool, I wanted to love it but I think the regular grenade mg with HE grenades and the rate of fire increase mod is more effective.

Anyway, I'm not 100% on where you can get lots of 40mm, Mick and Ralph seem to stock it regularly, and the Boomer supplier has some but I'm not sure his inventory restocks.

I have seen large quantity of them while I didn't plan to use Mercy.

I on the otherhand find incendiary round more effective with the tighter blast radius.

Gah, my Mick and Ralph's never stocks the darn things. Interesting.

You have to ask for the special inventory

That I did, sadly.

Incendiary is often the better choice because the fire effect ignores DT.

Does fire damage over time stack?

There is a thread or two around that states that shops restock every three days, BUT the game resets the day to Sunday every time you restart a saved game. So save on Tuesday when you come back it's Sunday again. Your never see Wednesday or Saturday unless you play for a week straight. Now I can't verify that ... only rumor.

Towards the end of my last playthrough I finally got the grenade machine gun and was frustrated to find very little ammo for it. But the gun runners at I88 had something like 60 rounds of the 25mm high explosive variety so that made me happy. I ended up having way more of that than the regular variety.

Alexander of Route 188, Cliff Brisco, and Sgt. Menendez.

Not sure whether flame damage stacks. Even in the default, a single incendiary 40mm grenade puts a pretty bad hurting on all but the toughest enemies. In the final battle, the 40mm Incendiary was my go-to weapon, used with a single-shot grenade rifle. Run ahead of my allies, pop around the corner and drop one into the pack of newly spawned enemies. Mop-up was a breeze. I just wish I had brought 60 rounds instead of only 24 rounds.

(In the DENV mod, I made sure to add more 25mm and 40mm in tiny quantities to all vendors, with more at the harder-to-reach vendors. If you can get McCarren rep up or Boomers rep up so that they'll sell to you, you'll find larger stocks of explosives. Even a mini-nuke or two from time to time.)

The easy way to gather ammo is stand in front of the merchant that sells it.. Save.. exit game.. restart and reload.. blamo new stock every time.

ahh nice. I hope this works for pc. I'm playing as explosives and grenade machine gun is SO amazing but i can never find 25mm grenades for the rate it eats them.

I love taking out entire packs of cazedores at level 14 within a few seconds. Spamming that gun makes absolute carnage.