user-1: Can Buddhists make very eccentric vows, and in what sense might these affect their karma? 
I do believe in karma, in some sense, but am struggling to understand something specific -- and a little strange. Suppose person A vows that, as person B is about to be hurt, they will suffer in their place. The event occurs, but person B, in some ill defined sense, does not suffer as much as they otherwise would. Person A then suffers some grave misfortune (perhaps unconnected).
Is person A at fault for their misfortune, karmically speaking? 
But this is a just so story. Specifically: is there any form of vow, in any tradition, which can lead to suffering for you, but good karma for others?

user2282: Not sure if vows alone are sufficient to auto-magically make things happens as one wishes. It's much more likely that intention coupled with concrete actions that will bring about the desired result. So in the case of person A, the event's more likely to happen due to s/he following up with actions that helps person B and maybe at the cost of some suffering to himself. About the concept of collective kamma, it probably is just individual kamma bundled together. An example is the atrocities committed by soldiers during a war campaign. Together they all took part in killing, raping, and plundering their enemies' city. So in some distant future, some catastrophic event happens to a group of people, which on the surface seems like "collective" kamma, but in fact the underlying driving force is still individual kamma manifesting itself.

user254: is there any form of vow, in any tradition, which can lead to suffering for you, but good karma for others?
Well I think that some people, perhaps wrongly, interpret the Bodhisattva vow as leading to suffering to you, because it's a vow to delay your own nibbana which would cause your own rebirth and continued suffering.
As a second possible example, santa100's answer mentioned 'vows making things happen magically' -- the one thing I remember that might be like that is Sacca-kiriyā -- there are several examples in the canon -- that might be like a vow, and like magic which benefits others ... but harmless, though?
The whole idea seems odd to me, as if there's a fixed amount of bad kamma floating around which somebody has to suffer for and it doesn't quite matter who -- like the converse would be killing people as a sacrifice to gain good fortune for yourself, as if kamma were a 'zero sum' situation -- instead I think that virtue and enlightenment are supposed to benefit everyone, not be harmful.
Then again people do make decisions which seem to be altruistic and self-sacrificing.
Anyway -- you might be interested in Sacca-kiriyā.

-1: <p>Can Buddhists make very eccentric vows, and in what sense might these affect their karma? </p>

<p>I do believe in karma, in some sense, but am struggling to understand something specific -- and a little strange. Suppose person A vows that, as person B is about to be hurt, they will suffer in their place. The event occurs, but person B, in some ill defined sense, does not suffer as much as they otherwise would. Person A then suffers some grave misfortune (perhaps unconnected).</p>

<p>Is person A at fault for their misfortune, karmically speaking? </p>

<p>But this is a just so story. Specifically: is there any form of vow, in any tradition, which can lead to suffering for you, but good karma for others?</p>
 2282: <p>Not sure if vows alone are sufficient to auto-magically make things happens as one wishes. It's much more likely that intention coupled with concrete actions that will bring about the desired result. So in the case of person A, the event's more likely to happen due to s/he following up with actions that helps person B and maybe at the cost of some suffering to himself. About the concept of collective kamma, it probably is just individual kamma bundled together. An example is the atrocities committed by soldiers during a war campaign. Together they all took part in killing, raping, and plundering their enemies' city. So in some distant future, some catastrophic event happens to a group of people, which on the surface seems like "collective" kamma, but in fact the underlying driving force is still individual kamma manifesting itself.</p>
 254: <p><strong>is there any form of vow, in any tradition, which can lead to suffering for you, but good karma for others?</strong></p>

<p>Well I think that some people, perhaps wrongly, interpret the Bodhisattva vow as leading to suffering to you, because it's a vow to delay your own nibbana which would cause your own rebirth and continued suffering.</p>

<p>As a second possible example, santa100's answer mentioned 'vows making things happen magically' -- the one thing I remember that might be like that is <a href="https://en.wikipedia.org/wiki/Sacca-kiriya" rel="nofollow noreferrer">Sacca-kiriyā</a> -- there are several examples in the canon -- that might be like a vow, and like magic which benefits others ... but harmless, though?</p>

<p>The whole idea seems odd to me, as if there's a fixed amount of bad kamma floating around which somebody has to suffer for and it doesn't quite matter who -- like the converse would be killing people as a sacrifice to gain good fortune for yourself, as if kamma were a <a href="https://en.wikipedia.org/wiki/Zero-sum_thinking" rel="nofollow noreferrer">'zero sum'</a> situation -- instead I think that virtue and enlightenment are supposed to benefit everyone, not be harmful.</p>

<p>Then again people do make decisions which seem to be altruistic and self-sacrificing.</p>

<p>Anyway -- you might be interested in <em>Sacca-kiriyā</em>.</p>
