What do you recommend for the best thermal scope under $4,000? I'll be putting it on a Bushmaster .450. Most shots will be 200 yards or less.

I recommend any scope that has a 3+ year warranty AND is rated for high recoil.

You’re limited or stand to lose a serious amount of money running a thermal optic on a heavy cal rig.

Pulsar has usually been the answer for rock solid operation on a 338 and up gun.

Thank you. So you think with the .450 I may have too much recoil?

I don’t think , I know via first hand experience - 450 bushmaster is a scope slapping round

If you kill a scope one of the first questions coming your way from the manufacture or dealer is what caliber are you running

Between dead pixels or system shutdowns due to interruption of power you may get some warnings before it totally dies….

Here is a test I run quite often for companies - they’ll give me a unit to run through the ringer from time to time - consider it destructive testing …

A key note is even if the scope survives maybe the mount isn’t up for the punishment ……

Are any electronic scopes rated for anything above a 30/30? At one time a .308 Win would void your warranty?

Yes there are scopes rated for up to 50 BMG the manufacture will list the details on the product page

I don't know of any thermal weapon sights on the market right now that would not readily handle the 30/30, which is fairly light. I started using civilian thermal weapon sights in 2013. I haven't seen a thermal weapon sight that wasn't rated for at least .308 Win.

Then sometimes all the functions work well under recoil but you lose focus in the scope - the higher the recoil the more apt this is to occur.

See this example of a scope losing focus during a string of fire

A good muzzle brake will tame some of the recoil and give your scope a chance of survival.