about 6 weeks bought a 5 pack of 60 watt incandescent,under a off-brand name,for some strange reason three of the five bulbs had an early death they were suposed to be long life incandescents(1,500 hrs)which is really not that long,but they were not exposed to shock,or anything else that could cause them to fail,any idea what could cause such an early failurw ,besides being chinese made?

You know, vacuum loose can happen also with junk incandescents!, especially if the bulb burns base up. Bad filament can be also a possibility. Globe Electric lamps are good examples of bad filaments: sometimes (1 bulb/50), it burns in the bulb and leave a sort of yellow-white stuff on the glass. Its color varies from sunshine yellow to pure white.

There can be many reasons,

1. poorly made
2. poor quality filiment
3. Loss of vacume

More likely just poorly made!!

That yellow or white powder inside means when powered the filament reacted with oxygen and oxidized. I agree it does happen more with Chinese bulbs. Genuine American and Canadian bulbs have way less of this problem.

when these incandescent lamps went out,they got black all of a sudden,and there was a small muffled pop.

As with any Chinese crap, better don't buy it. My experience is, then weird brand PRC 40W bulb gives the same light output as PHILIPS Poland made 25W...

Are the bulbs that you are talking about made by Sunbeam? Because I have had the same problem that you are talking about with Sunbeam bulbs.