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Chop, Crown, and Rethread a Saiga 12 barrel.... with no lathe


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#31 mghtymous21

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Posted 09 December 2012 - 08:16 AM

Why remove the threads at the crown? Why can't you just do the half an inch of threads and call it a day? Sorry if this is a stupid question and thank you in advance.
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#32 PapaZorro

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Posted 10 December 2012 - 08:52 AM

Very useful write up! And very good work!
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В ЧЕМ СИЛА, БРАТ? Сила в правде!  ©

 

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#33 Sohei

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Posted 10 January 2013 - 06:33 AM

Could a permanently attached muzzle device on a barrel under 18 inches keep it from needing to become an SBS as can be done with a rifle with a barrel under 16 inches to avoid making an SBR?



#34 midwestbatman

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Posted 13 January 2013 - 12:07 AM

Do I need to alter the gas system in any way if I am cutting the barrel down?



#35 presto_z

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Posted 13 January 2013 - 09:00 PM

Do I need to alter the gas system in any way if I am cutting the barrel down?

Im wondering this as well. Im looking to chop the barrel down about 5 inches and attaching a gk01 brake



#36 evlblkwpnz

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Posted 15 January 2013 - 12:01 AM

I have done a chop and perm at 13.5". A Genuine Russian MOLOT GK-01 was used to achieve non-NFA length. I moved the gas block back 2.25" and used 4 ports at .078". It ran Winchester Universal reliably in SGM 12 round mags. I never tried MD-20s with it because it has a magwell, but I think it would do fine. If leaving the gas system in the factory location, you will likely need to run 5 or 6 ports at .078", or a fewer ports at a larger diameter. The gas block and puck will stay cleaner with small ports angled slightly more that the factory ports, but small ports get clogged easier than large ports. The gas block and puck will foul quicker with larger ports, but larger ports do not clog as easily as small ports. Pick your poison....

 


Attached File  molot perm.JPG   279.02KB   2 downloads


Edited by evlblkwpnz, 15 January 2013 - 12:04 AM.

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#37 evlblkwpnz

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Posted 15 January 2013 - 12:06 AM

Very useful write up! And very good work!

That means a great deal to me. Thank you.


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#38 presto_z

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Posted 15 January 2013 - 12:07 AM

Thanks for the reply, that looks awesome. My brake should be in this week.

#39 Garand1911

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Posted 07 August 2013 - 12:59 AM

"How important is it to have an adjustable tap?"

My tap is not adjustable, so i say, not important.

 

"Why remove the threads at the crown? Why can't you just do the half an inch of threads and call it a day?"

It depends on your muzzle brake. Some you wont need to cut the threads off, the Polychoke you will be required for it to fit properly.

 

I would not recommend using a pipe cutter, just use a new sharp hacksaw blade. The file the muzzle/crown flat, if you use a grinder, i would still file it smooth.

A burr on the inside of the muzzle will make it harder to insert the TAT. To remove it wrap some light grit wet sandpaper around a 12ga barrel mop, then chuck it in a hand drill. It will remove the burr quickly and evenly. DO NOT USE A HAND FILE, it will be slower and not even, and will leave scratches on the inside of the muzzle.

 

Im not sure if i agree with going crazy with cutting oil, lube it and cut it few threads, then do it again. Just keep the threads lubed, you dont need to use a whole bottle of oil. The amount of oil will not make a difference in the quality of the cut, as long as your die is sharp it will cut good.



#40 Hudd

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Posted 06 September 2013 - 03:42 PM

Awsome instructions. Have you happened to post that 8" build as you briefly mentioned.

#41 King of the Hill

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Posted 07 September 2013 - 12:41 PM

Hudd, look up^

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#42 yamadog35

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Posted 28 February 2016 - 06:10 PM

I want to thank Evl for this tutorial.  Last year my state repealed its ban on SBS so I have several projects in process.  One is a 12" S-12.  I've tweaked the gas ports to get it running reliably and am now in the process of dressing up the rest of the gun.  One task was the threading of the now shorter barrel.  Once I got by a bit of an issue (explained below) the process when smoothly and I have a threaded section that will accept my attachments.  So thanks again Evl.

 

S12%20Barrel%20Thread%204_zps4jrwvafx.jp

 

One heads up for anyone attempting this.  Not sure if this has been covered before but I thought I would toss it out.  When I started threading it was not going well.  As soon as the die would start to cut threads it would break off and quit cutting the thread.  I did this multiple times and was starting to get a bit frustrated as I've cut threads on pipe and rods in other situations many times over the years and not had that problem.   Then I discovered the problem.  I was using one of the thread alignment tools with the die to keep it centered with the bore as you started the cutting the process.  The problem was that the bore was not centered relative to the outside diameter of the barrel.   The wall on one side was much thicker than 180 degrees to the other side.  The alignment tool was causing the die to cut deep on the thick side and then let go on the other side because the wall was much thinner.  Luckily I hadn't gotten too far into the barrel when I discovered this.  I ditched the alignment tool and just carefully worked the die on the barrel.  The threading when smoothly from there.  I just did as Evl suggested and made sure I cleaned up the chips and added cutting oil frequently.


Edited by yamadog35, 28 February 2016 - 06:14 PM.


#43 Doogan

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Posted 24 August 2017 - 07:00 PM

so I am sorry but If I don't want to move gas system I can cut to 12 inches For someone who wants to do an SBS without moving the gas block back....
19 3/16" - 12" = 7 3/16" (to be removed)         If I have to I will move gas system but I would rather not I live in Indiana  so SBS is ok with stamp

 






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