The .172 25gr Berger that are good for coyote?

[cath8r]

Hi guys. When I bought my rem700 in .17rem i bought it used in a package deal a few years back. It came with about a thousand of the .172 25 varmint match grade bullets. Lot#1504
Are these the ones with the thicker more desirable jacket?
I only killed 1 coyote with them and the 1st bullet splashed (it may have been due to placement) the second that went into neck did the pin prick/no pass through deal.
Just want to be clear if it's the bullets that were discontinued or not.
Thanks
Rob