The Yellow Jacket is Remington's
hyper velocity .22 lr offering in
hollow point.
It uses a 33 grain truncated conical hollow point bullet and has an advertised muzzle velocity of 1,500 feet per second which gives 165 foot pounds of energy at the muzzle.
Because of its light bullet weight it has less momentum and its velocity quickly drops to 1,075 fps (85 foot pounds of energy) by the time it reaches the 100 yard range. While that is a drastic reduction it is still enough to take small game like squirrels and rats.
The yellow "jacketing" on the bullet is some sort of brass or copper wash but don't let the name fool you, it is not a real jacketed round. A true jacketed round has to be swaged into a copper jacket.
They come in boxes of 50 rounds and has an image of a wasp or hornet riding the .22 lr round. This can be confusing to some as there also is a .22 Hornet round which is a centerfire cartridge. The headstamp on the yellow jacket cases can have an image of a wasp or hornet or that distinctive "Rem" stamp.
In my Marlin 60 SB the yellow jackets have performed fine, they are accurate and hard hitting.
I have not yet tested them on live game but from my tests on phonebooks it appears to exhibit very good terminal ballistics in terms of wounding power. One round that I fired at a soda can with a hardbound medical book as a backstop completely fragmented* and only penetrated about an inch and a half indicating quick and instantaneous energy transfer.
In tests on soda cans filled with water, the hydrostatic shock proved to be enough to make the can explode. In empty soda cans it just punched a nice .22" hole through and through.
The bullet I recovered had fragemented leaving one big piece, which probably came from the bulet's base and three smaller fragments which probably what once was its truncated cone hollow point ogive. I imagine it also tumbled as it entered the backstop because of the non circular entry "wound". If this is any indication of how it will behave when it enters a rat then I just imagine the wound channels will be quite impressive and death instantaneous.
This stopping power that depends on hydrostatic shock and plenty of small wound channels is mostly only observed in small game. In bigger animals, humans included, the required terminal ballistic characteristics for "lights out" stops are quite different.
* - Leaving nothing for a ballistician to peruse had one attempted to. No trace of the rifling cuts were left intact.