I just checked your loads against my (mfr) sources--AA, Hodgdon
1. 10.8 gr. for a 110-gr. Speer is the start load in AA 2004 manual.
2. Hodgdon currently rates the
Hornady 110-gr. XTP from 8.0 to 9.0, so your 8.5 gr. of 231 start is, their standards, "midrange"--with a different bullet--and with that bullet the LOA is 1.590.
If I were pursuing these two powders with this bullet, I would back up both loads 10% and try again--but, essentially, I'm with Jim Watson. I'd reserve 231 for lowball-light loads, and I'd explore more with #5--i.e., try a reduced load.
Did you double check your scale? Have you got a second scale, or a set of checkweights for calibrating?
FYI, here's
a link to what my primers looked like after that overpressure incident.
I would describe these primers as flattened and cratered--but not excessively so, and there is no 'flow.' If your primers look flatter--or like they actually "flowed" in the primer cup, then your pressures are awfully high.
It might be a gunsmithing problem--but I gotta wonder about scale accuracy (at least for this batch). If you have any rounds left, disassemble a couple and re-weigh them.
Was there sticky extraction on ALL the rounds? if extraction seemed to get progressively worse, you might have been dealing with bullet jump (which is an indicator of a weak crimp).
If you can post a picture of the primers, that would give us some more information--but
I would NOT shoot any more of those rounds IF I had not found the error. In my incident, after shooting the one cylinderfull, I took the remainder home, disassembled them, and looked for the source of the problem. (In my situation, it a was piece of paper holding the scale tray--and I had missed seeing that--so my 38 special cases had about 17-18 gr of #7 in them, and it was NOT a 'double-charge' error.) At the time I built the rounds, I was not experienced enough with #7 loads to recognize the awfully-full case....which is a situation not too dissimilar to your situation.
The point is, find the problem before you shoot any more.
Jim H.