I don't know if they have had any shootings with it yet, but given what I know about the FBI's DSU and that Doc was involved in the testing... I trust the G2. It's been their issued 9mm duty ammo since at least October.
I never cease to be amazed at the eagerness companies stuff their hollow points with material. To include posts, rubber, and plastic, without actually understanding what it is they are doing from a fluid mechanics and dynamics perspective.
So, if you would be willing to be dragged back in for a moment, I seem to recall that there was a test done back in the 90's where the Federal Hydrashok round was tested with post, and with the post removed by manual machining, and that there was found to be a difference in expansion characteristics (the post allegedly did improve expansion performance....)
Wish I had the old test report, but just for the sake of asking, marketing may suck and fail but I was under the impression that this actually was an engineering choice?
As far as polymer inserts for hollowpoints, I was under the impression that this was all an attempt to replicate wallboard and sheet metal performance seen in the EFMJ designs with the bare / clothed gel performance of the conventional / advanced hollowpoint designs.
I have wondered if some of the test failures now that it is leaving the labs may be temperature related changes to polymer characteristics... but I have no insights here, and real test data seems maddeningly difficult to actually come by.
Sort of like we are back to the bad old days...
1. I have had nothing to do with any FBI DSU testing of the Speer G2.
2. Depends on which generation/version of the Hydrashok one is discussing. An FBI test documented a slight improvement in performance with the post in place vs. bullets where the post was deliberately removed prior to testing. Testing at LAIR showed no significant differences whether the post was present or not when shot. In our testing, we discovered that in about a third of shots the post stated upright, about a third of the shots the post bent over, and in about a third of the shots the post broke off; in no cases was terminal performance altered--in short the post was irrelevant.
Facts matter...Feelings Can Lie
I think they know exactly what they're doing from a fluid dynamics perspective.
I think the idea is to fill the cavity with something that will prevent any sort of loose solid from filling the cavity, but has the same compression characteristics as water (meaning it will flow under pressure, but not compress.) If the bullet hits water (or a high water content substance, like living tissue), the pressure exerted on the interface of the cavity filler will be carried though it and exerted on the walls of the cavity, as if the water in the tissue itself had filled the cavity on impact, and was exerting the pressure.