Acceptable weight variances in silver coins?

Hi,

Just received an order I purchased from this Ebay listing:

'Bahamas Silver Two Dollar Coin Uncirculated - lot of 7 (1971, 1974, 1975)
 Each is in uncirculated or proof-like condition and contains 0.886 troy ounce of silver.'

Please help: Two (2) weigh 26.8g, each. This is the weight assigned to the copper-nickel issues, The other (5) weigh 29.1g, 29.0g, 29,4g, 29.6g, and 30.5g...  the weight assigned to the silver issues is 29.8g.

Does anyone know if  there is an acceptable variance of weight on the 'silver issues' within the industry?
Any suggestions?

Thanks..  Dan

I think it's usually +-0.3 grams for modern coins as a rule of thumb.

Thank you...  Dan

What do you mean. 'They killed Kenny.' Kenny from our forum?

No, it's from an US series, follow this link

http://en.wikipedia.org/wiki/South_Park

Kenny was one of the four figures in the series

Ole