I'm not exactly sure, I think it was him trying to show off, which backfired of course.

This is from GameFAQs:

Snake: Mmm... Whenever he put a new clip in his gun he'd always load the first round by hand, whether there was a round left in the chamber or not. It's a technique they teach in the Middle East. By making sure there's always a round in the chamber, you eliminate the risk of pulling the trigger with nothing to fire. He must have heard about it from someone, or read it somewhere... in any case, he probably wanted to try it out for himself. And he was obviously motivated by vanity to show off his new technique. That's when you make mistakes. The battlefield is an unforgiving place. The only techniques you can rely on are the ones you've mastered through experience and practice.

Snake's is probably the simplest explanation, concerning the gun jam. Just keep in mind that the Makarov carries eight rounds in each magazine, but Ocelot kept the final bullet from the last magazine chambered in the pistol, before loading another new magazine. Before he arrived at the site with Snake and KGB guards, he had already loaded that new magazine, so he took out the pistol, cocked the slide back, ejecting the first bullet (which was from the previous magazine), and took out the guards. When he loaded a new magazine, he forgot to cock the slide back because he didn't think that there was already a bullet in the chamber. Since there was already a bullet in the chamber, the first bullet from the magazine couldn't be chambered, and was therefore jammed between the loading part of the chamber and the the already chambered bullet, which caught Ocelot completely off guard.

I have no idea how guns actually work, so I don't know if this is accurate or just bullshit.

I'm not exactly sure, I think it was him trying to show off, which backfired of course.

This is from GameFAQs:

Snake: Mmm... Whenever he put a new clip in his gun he'd always load the first round by hand, whether there was a round left in the chamber or not. It's a technique they teach in the Middle East. By making sure there's always a round in the chamber, you eliminate the risk of pulling the trigger with nothing to fire. He must have heard about it from someone, or read it somewhere... in any case, he probably wanted to try it out for himself. And he was obviously motivated by vanity to show off his new technique. That's when you make mistakes. The battlefield is an unforgiving place. The only techniques you can rely on are the ones you've mastered through experience and practice.

Snake's is probably the simplest explanation, concerning the gun jam. Just keep in mind that the Makarov carries eight rounds in each magazine, but Ocelot kept the final bullet from the last magazine chambered in the pistol, before loading another new magazine. Before he arrived at the site with Snake and KGB guards, he had already loaded that new magazine, so he took out the pistol, cocked the slide back, ejecting the first bullet (which was from the previous magazine), and took out the guards. When he loaded a new magazine, he forgot to cock the slide back because he didn't think that there was already a bullet in the chamber. Since there was already a bullet in the chamber, the first bullet from the magazine couldn't be chambered, and was therefore jammed between the loading part of the chamber and the the already chambered bullet, which caught Ocelot completely off guard.

I have no idea how guns actually work, so I don't know if this is accurate or just bullshit.

I'm not exactly sure, I think it was him trying to show off, which backfired of course.

This is from GameFAQs:

Snake: Mmm... Whenever he put a new clip in his gun he'd always load the first round by hand, whether there was a round left in the chamber or not. It's a technique they teach in the Middle East. By making sure there's always a round in the chamber, you eliminate the risk of pulling the trigger with nothing to fire. He must have heard about it from someone, or read it somewhere... in any case, he probably wanted to try it out for himself. And he was obviously motivated by vanity to show off his new technique. That's when you make mistakes. The battlefield is an unforgiving place. The only techniques you can rely on are the ones you've mastered through experience and practice.

Snake's is probably the simplest explanation, concerning the gun jam. Just keep in mind that the Makarov carries eight rounds in each magazine, but Ocelot kept the final bullet from the last magazine chambered in the pistol, before loading another new magazine. Before he arrived at the site with Snake and KGB guards, he had already loaded that new magazine, so he took out the pistol, cocked the slide back, ejecting the first bullet (which was from the previous magazine), and took out the guards. When he loaded a new magazine, he forgot to cock the slide back because he didn't think that there was already a bullet in the chamber. Since there was already a bullet in the chamber, the first bullet from the magazine couldn't be chambered, and was therefore jammed between the loading part of the chamber and the the already chambered bullet, which caught Ocelot completely off guard.

I have no idea how guns actually work, so I don't know if this is accurate or just bullshit.