180.3% Accuracy

Every 1 in 20 swings.

When fighting enemies with 25% defence or more.

(Assuming no +tohit, 25% defence yields a 50% chance to hit - 50*1.8 = 90, which is less than maximum to-hit chance.)

Doesn't he mean plus 180% accuracy? In which case it would be base number for the attack (1.05 for most weapon attacks, for example) plus 1.8, for a total of 50*2.85?

I think he meant 180% total accuracy but in any case that isn't actually quite correct. Accuracy bonuses (both set bonuses and accuracy enhancements) are applied as a multiplier to the base accuracy of the power. So for a weapon power with a 1.05 base accuracy if you had +180% accuracy the final accuracy would be 1.05*(1 + 1.8) giving 2.94 as the final accuracy multiplier.

Assuming 180% total accuracy, no to-hit buffs, and that the attack itself has the standard base accuracy (not a weapon with redraw or an AoE control power, for instance), you have a 48% base chance to hit a +3 enemy. 180% x 48% = 86.5% chance to hit after accuracy is factored in... that's good, but not capped. On +4s you will end up with about a 70% chance to hit, which isn't that good. You really need to-hit buffs to hunt +4s... just adding a Kismet 6% Accuracy IO (which is mis-named, it's actually a to-hit bonus) would cap your to-hit against +3s and boost you to around 81% against +4s.

If you mean plus 180% accuracy (280% total accuracy), you'll be capped against +4s or less but will only hit +5s about 84% of the time. Of course +5s are rare, so no big deal there. More importantly, a +3 with more than 15% defense or a +4 with more than 6% defense will result in less than capped to-hit chance, as will being to-hit debuffed by those amounts. Unless you get hit by a significant to-hit debuff like Chill of the Night or Hurricane or hunt +6 mobs you'll be fine at this level.

Gah, I knew that.

If you're running at +4 difficulty, somewhere between a quarter and a third of all opponents you face will be +5s.

Ecsuse me, but doesn't Defense subtract from Accuracy and not To hit? (and your base chance of hitting is To Hit not Accuracy, if I'm not mistaken) So, 25% defense would yield a 95% chance of hitting ( (180%-25%)*(75) ).

Now, if you ran up against something that debuffed your To-Hit smething fierce and dropped your To-Hit (base chance of hitting) to 5%, then that 180% wouldn't do much. You'd have a measly 9% of hitting.

Of course, I'm not the math wizardess that Arcanaville is, nor have I spent all that much time investigating the whole Chance of hitting formula. But, I do believe that I recalled Defense subtracting from Accuracy and not the base to-hit.

I could be wrong however.

In any case, carry on.