Ozwalt,
I' m gonna help ya out here.

You have the 237grs correct for your Epic400.......but you forgot the nock,insert, and fletching!

Add: 21grs for the insert
13grs for the Nock
and if you have 4" vanes another 25grs for these.

Your total finished shaft weighs approx: 296grs!! Add in your 100gr point weight and your finished arrow now weighs just about 400grs!
THAT' S A BIG DIFFERENCE IN HOW YOUR KE WILL PLAY OUT!

396grs at 240fps = 51 ft lbs of KE

still not a tank killer but way different from your original thoughts........plus shoot thru a REAL chronograph because those ones attached to the video hunt systems stink. The one I use is 13fps SLOWER than the 2 actual chronos I shoot my bow thru.

Your numbers may even be BETTER.
In any event you are still on th low side for mechs........if you do insist on using them try the proven penetrating models with modest cutting diameters like the Rocket " Steelhead" or R.M. " Snyper" , NAP " Scorpion" etc..
Don' t go near the large cutting diameters.
The new style of fixed heads on the market like that Wasp " Boss bullet" sound like they would be up your alley as well. According to 5-Shot they penetrate like heck and are very inherently accurate.

Keep everything tuned well...bow and arrows also. When you get toward the marginal side of the KE levels you can' t afford to lose any because of poorly tuned equipment.