For a few reasons, the only bow I have to shoot presently is the first bow I bought years ago. (An old Stemmler "semi recurve")
It has a noticeable twist in the lower limb, seemingly mostly towards the tip.
Tried many times to straighten it, but it seems to be permanent.

My shooting isn't it's best right now, limited by the harsh winter here, but I'm wondering what the twist may, or may not be contributing to the performance of the bow.

A bow with a twisted limb can and a lot of the times will shoot very good if the arrows are tuned to the bow. Sometimes the twist will throw the limb timing and alignment off enough to cause some hand shock but if this is the case the string could also come off during the shot. If it shoots good for you just shoot it.

James

I've owned a number of bows with twists, but I have found a couple things shooting them.

1.  If the string stays on, it seems to shoot just fine.

2.  If the string stays on during shooting, I have not had a bow I could not straighen.

With that said, I bet you could straighten out that twist with the right technique.

That's encouraging so far, guys.

Blackhawk, the method I have been using is to twist the limb, unstrung, in the opposite direction of the twist. No change, despite several attempts. Anything I'm missing?

I leave the bow strung and warm up the limbs with hair dryer (but do not heat too much.)  

Some use hot water, but I am afraid of moisture getting in where I don't want it.

Twist limb in opposite direction and hold for 10-20 seconds.  Repeat until string stays in groove.  

Leave the bow strung. I usually hang the bow on pegs horizontally by the string.

Repeat process daily until you can pull back the string and it stays in groove when you let down.

Hold the limb under warm water out of the faucet in your tub. Once warmed up, straighten  it and turn the cold water on it. I have cold "bumped" a couple but the warm water works better. Not hot but warm water.

Heat gun and a crescent wrench . Slowly heat the limb and he it past the twist til it cools. String the bow and check correction.

If it needs more apply heat again. Slowly!! After it cools completely string it and draw it a few times.  If it is lined up true leave it strung and draw it every couple of hours and check it.

Worst thing is you might have to do it a couple of times. Be patient it will correct and stay corrected eventually.

Bretto

Very helpful suggestions. I'll have another go at straightening.