I did some measuring last night. Realized I had a short action post 99 rifle. Took the bolt apart and compared to the older long action bolt. The firing pin tips and bolt face firing pin hole are the same diameter. The body of the firing pin is narrower on the new one vs the old one. I also inspected the firing pin "tunnel" on the bolt head and the newer heads do have a smaller hole than the older ones. The "tunnel" is slightly larger than the firing pin so that it doesn't drag, but in my opinion, it is close enough to prevent the firing pin from flexing beyond its elastic limit and risk breaking when firing. It is now my opinion if I upgrade to the newer firing pin and bolt head retaining pin, then I should also upgrade the bolt head as someone else on here suggested. That does increase the upgrade cost by $25 or more.

It seems to me the new firing pin is a weaker design than the older one, however, the bolt head retaining pin is stronger. I guess they split the difference with the bolt head retaining pin to reduce failure of both parts.

Thanks for all the help.

Rosewood