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SAIGA 12 BOLT 'TIMING' OF THE ROTATIONAL LOCKUP


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I have posted this before, a couple two/three years ago, but there seems to be a lot of disinformation and lack of understanding on how this exactly works, so here it is again. If you have any questions that are not meant for everyone, then PM me.

 

For the sake of anyone who is interested, I am going to explain exactly how the Bolt "Timing" works and why it is so important that the angles of the barrel hood and the top lug of the bolt body not be improperly modified, filed, ground, profiled, etc.

 

I have put the picture of the bolt and the receiver in this post so you can see the relationship of the two angles I am referring to. The angle of the Barrel Hood and the Angle of the lug on the top of the bolt body. This is the same lug that you fit the bolt into the carrier/slot when you are reassembling the two components.

 

Imagine taking the barrel completely out of the receiver, now there is just a hole through the front trunnion. Now set the carrier/bolt assembly onto the rails in the proper position and push it forward like it was stripping a shell from the magazine and then going into battery.

 

This is what it would do: The bolt will keep going straight with NO rotation until it stops against the front trunnion of the receiver. Why? Because it take the angle of the barrel hood and the top lug of the bolt body to come into contact with each other, STOP the bolt from going any further forward and to START the clockwise rotation of the bolt body. THEN the carrier will continue to move forward (bolt is stopped) and complete the roll over of the lugs into complete lock up/battery.

 

The angle of the barrel hood is so critical because it indexes the bolt exactly where it needs to engage the male lugs with the female lugs. Move the angle a few thousands forward the the front edges of the bolt lugs will beat themselves trying to go into the female lugs because they will try to engage a few thousands too far forward.

 

This is the "TIMING" that I refer to. I like to have it within +/- .002 not to beat the lugs.

 

NEVER take advice from someone who does not even know the name of the components of the weapon system and then that person talks in 1/64s instead of decimals as in thousands, ie: .002

 

There is too much bullshit being put out on this forum and no one is calling the people on it.

 

Jack

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It also needs to be made very well known that a few "how to" like threads that are posted (some even "stickied") on this forum are leading new S-12 tinkerers every day to hack up and ruin their Saigas by doing things to them with drills, files, stones, and dremels that are completely unnecessary and very damaging to their weapons. Sure you may go read some "DIY" thread with a gazillion different 'opinions' posted by different people about "how to" modify your own Saiga and save money.... but at what real cost? Oh sure why not? Someone else took and posted lots of pictures saying it worked great for them and fixed their gun. For how long though??? That is the question. "Rounding off corners" on certain critical parts, such as the lug on top of the bolt body Jack is referring to above.... I see people posting about it so much these days it's obvious why I keep unwrapping sets sent to me to work on and they are ruined beyond reasonable repair. Take off those sharp angles and corners and the bolt and carrier, in conjunction with the barrel hood, all start working together (or against each other...) to eat away at and destroy each other. All this DIY this and that on this forum got way out of hand a long time ago when folks started putting up threads about re-profiling and polishing bolts, then took it further with overly extreme mods to the S-12 gas system. It's bad info from the beginning most of the time, then it gets made even worse when misinterpreted. Butchered Saigas and parts are the result so far. How long before someone actually takes a bolt through the face?

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Well said. Thanks for contributing good, quality information. Favorite line:

 

NEVER take advice from someone who does not even know the name of the components of the weapon system and then that person talks in 1/64s instead of decimals as in thousands, ie: .002

 

Truer words were never spoken.

 

These guns are imported in sporter configuration leaving the owner to perform his own conversion/restoration. I believe that, for many owners, this is the first bit of actual "work" they have ever done on a gun. Once they have successfully completed the relatively simple restoration, I think theres a tendency to go a bit "gunsmith happy". After all, they've seen how easy the restoration was, and they've watched that Youtube AK animation a few times so they get a bit overconfident in their understanding of the platform. Pretty soon they're modifying crucial geometry with no understanding of function or consequences. This forum has always been "DIY-heavy" and that's one of the things I like about it, but people should really understand what they are doing before breaking out the dremel.

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More importantly, people should not take what they think is a good idea and go putting up "DIY tutorials" all over the place for unsuspecting new members to stumble upon and start trying with no idea how good or bad that info actually is.

 

Maybe that's it. Maybe a new forum rule should be put into place that requires anyone wanting to start a "DIY" thread, or even post detailed DIY comments in threads, to first get permission through moderator preview.

 

What this forum needs is a Technical Moderator. Hello??

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