Actually the inserts are now out of the shafts, and glue doesn' t appear to be the problem

If I hold the 75 grain and 100 grain field tips side by side, while they are identical in overall length and the length of the threaded section, the 100 grain doesn' t have as many threads as the 75 grain, by the same amount the tip won' t seat. I thought maybe it was just these tips, but surely the Steel Force would be able to seat in these inserts, as I' ve never seen this problem discussed anywhere else.

Ok, just tried some other heads I have lying around. 100 grain Wasp Jackhammer SSTs fully seat, no problems. So do the 100 Grain Stainless Steel Steelforce...

I' m gonna check all the inserts, maybe it' s just one or two giving me fits. I haven' t checked them all.