I would like to get something like this for a rifle.
https://modlite.com/products/modlite-okw-light-head
Is there anything better? Mount will be on a rem 700
Looking for max throw in like a 1.5” head with an 18650 body with a tape switch
Are you looking for an integral light like the Surefire or Streamlight forends? Those companies also make industry leading weapons mounted lights- just pick you specs and price point and there is likely a model that will work.
I prefer more versatility than an exclusively weapon mounted light for HD and the like. I have se myself up to use standard 1in mounting rings and your choice of flashlight. Solarforce L2M, Surefire G2/G2L/6P/etc are good choices. I like P60 modules for this before they are module as well as, typically, well sprung. I avoid the newer Surefire G2X/6PX series as they are a solid circuit board contact on the positive side. Many makers such as Malkoff, Lumens Factory, Sportac and customlite make P60 modules rated for weapons use. A good budget light for this that is readily available is the Streamlight Polytac. Probably not the best for heavy recoil, but its lasted almost 1000 rounds on a 5.56 for me so far. It is notable that the Protac line from Streamlight seems to be unsprung on the positive contact- at least my HL3 is.
There are a plethora of picatinny mounts available. I can PM you some links if you’re curious. So far I really like the Aim Sport and GG&G. Of course, if you run magpul furniture (not sure if its available for your 700) then you could potentially get an m-lok direct mount. Interestingly, the Magpul v-blck flashlight mount seems to hold a AA sized body just fine. I can even get my Lumens Factory Seraph in them if I remove the rubber grip rings.
Again, not sure about mounting on your 700 but if you wanted max throw without spending a fortune, the Streamlight Polytac HP may offer a good solution.
THOSE PRICES ARE INSANE! (IMO) 
Grab a Convoy C8 momentary tailcap here:
Convoy C8 Tail Cap Remote Contrl Switch Pressure Swicth Flashlight Accessories
Buy the newest Convoy C8+ here:
Convoy C8+ SST40 2000 Lumens 6500K 5000K 18650 Flashlight - 4 modes driver 6500K
The hardest thing is finding a weapon mount that will work. Most flashlight mounts I have seen are 1in diameter, and most 18650 flashlight bodies are less than that. In which case, this other light would work, but without the momentary switch:
Convoy M21A SST40 2300lm 6500K 21700 18650 Flashlight White Tint LED Torch
Either way, it will be twice as bright as the alternative. Is it as solidly constructed? Possibly not, but are you deploying for war with it?
I agree the Convoys are great lights but I would strongly caution about using them as a weapon mounted light. Maybe fine for recreational shooting or even varmitting but the electronics on those lights are completely exposed to battery contact under recoil. I would not, and have not, utilized them as defensive (or offensive for that matter) weapons lights. In those applications you are paying for more than just a flashlight.
Buck91, youreid thanks much for the help! I have some researching to do and your direction is very much appreciated! I’ll keep you posted
OP never said anything about a defensive or offensive weapon. He also never said anything about caliber or usage. The Remington 700 comes in many configs and calibers ranging from .223 to .338 Lapua mag. Hard to recommend with no info.