BP 16710 inserts are not gen spec size.
Gen-spec: 30.6mm / 37.65mm +/- 0.05
BP 16710: 30.6mm / 37.45mm +/- 0.05
You cannot fit a gen-spec insert in a BP bezel without shaving the OD of the insert, opening up the bezel well diameter, or a combination of both. The case will not take a gen-spec bezel either without being modded. The BP bezel is held in place by the octagonal wire clip. There is no crystal retaining ring to hold a gen-spec bezel. It is possible to mod the case to take a gen-spec bezel but it requires some exacting lathe work.
Many aftermarket insert vendors make untrue claims about which models their inserts will fit into - for example 1675 and 16753 etc (plexi crystal models) have a completely different size insert from 16700 / 16710 yet some vendors claim universal compatibility. Worse, some vendors like WSO don't provide measurements so it's a crap shoot until you know.
There are a decent number of vendors who make aftermarket GMT inserts with near Rolex fonts in the size that BP accepts. You just have to hunt for them. Sometimes you can shave a little off the OD of a gen-spec one and not eat into the numbers. It's hit or miss whether any insert will press fit into any given BP bezel. Many of them will if they are close to the BP insert OD listed above.
Vostok inserts are a good fit for BP 16710 bezels. I got several of those from Ebay vendor am-diver but it appears he has nothing listed now (Russian part origin).
You didn't say which insert you wanted - this vendor has some pretty nice ones but are too expensive. But just so you know what to look for. These are gen-spec but take note that the two's are not hanging. That means the top curve doesn't hang over the left edge of the base like many do. Even this one doesn't have the bases of the twos following the arc of the curved inner perimeter. Look at a gen to see what a really good insert should have.
https://www.ebay.com/itm/2750488486...n2lcq9Q0bQ6NJriTJkeV|ampid:PL_CLK|clp:2047675
Post back which one you are wanting and I'll see if I have any good links.
