Bullpup SKS build, shared experience

[tortirioan]

Hey all, I just got a very pretty SKS today which I want to turn into an "economy" bullpup, something I wouldn't hesitate to pick up and use for self defense or Car work if the need arises. Will be posting pictures of the project as it progresses, Tomorrow am going to get pics taken of the SKS. Then I am going to start the machine work, but this post will outline the mission goals and the materials involved.

Goals:
-Install a Bullpup stock kit for an SKS (I have found two major contenders for this and am not sure which i shall go with just yet)
-Cut the barrel to either 16" or 14.5 (I have not come to a real decision in my mind but will probably go 16)
-Modify the Receiver so that it will accept AK-47 type magazines
-Thread for muzzle Device (Going to use the 14x1 LH)
-Keep the total cost for this project under 1000 dollars.
-kick ass and chew bubble gum until all out of gum, then continue on

That is the plan, not really sure how long this will take with monetary concerns but we shall see what happens.

[00tec]

I'm getting my sks from my brother's house this summer to do the same thing. I will be going with the sgworks stock.

[tortirioan]

I am thinking the same, cheaper and they produce all year around, Maybe one day if i win the lotto I'll go with the other guys but not right now

[00tec]

I would definitely do some double measuring before you cut the barrel, as I don't know what the overall length will be.

[tortirioan]

Already done (at least given the measurements provided by the site), They say that the paratrooper version (which has a 16inch barrel) would have an OAL of 26 and 3/8" which is just over (I usually measure barrels from the receiver face rather than bolt face so I will be double safe)

[Great-Kazoo]

Nice project however for the time and money involved you could build a side or under folder AK, cheaper. Once my paperowrk comes back i'll have a side folding draco SBR for $600.

[cofi]

Nice project however for the time and money involved you could build a side or under folder AK, cheaper. Once my paperowrk comes back i'll have a side folding draco SBR for $600.

i havnt seen a sks thats reliable enough for sd work for me side folding ak would def be the way to go imo(whether nfa or not)

[00tec]

Meh.... All in, I will have about $450 or $500 in mine, and I'll have something that not many people do. It's not going to be sd for me, but rather a neat range toy.

[tortirioan]

i havnt seen a sks thats reliable enough for sd work for me side folding ak would def be the way to go imo(whether nfa or not)

I have never had an issue with my Russian SKS, 100% reliability which while I am a big ar-15 guy I cannot say about that platform. (An ar is my go to end of the world gun btw) And while I agree that the AK is a little better for the job, it is also very hard to find one these days and the bullpup stocks I have found for it do not appeal to me at all,, remember guys i am trying to build a bullpup here.

[tortirioan]

Here are the pics of the base gun before any mods are made to it it's a 1955 Russian with Tula markings, and It's the smoothest sks I have ever worked with (it still needs a little work but it is awesome from the start).
Cost for Rifle: 500 bucks (a little high but the cheapest I could find period).
Percentage of Budget: 50%
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[SAnd]

Just in case you haven't seen this yet-

http://www.bullpupforum.com/index.php

Sounds like a fun project.

Have Fun

[tortirioan]

Thanks a bunch! that it coo!

[tortirioan]

Alright guys! Update on the old SKS project here. I have discovered that unfortunately the SKS mag well on my rifle is just a hair too small for the Metal AK mag I borrowed from my good buddy Mike.So I went to Grainger while I was in town today and picked up a good Carbide End mill to widen the mag well as well as lengthen it a tad. I also am going to take the opportunity to thin the bolt base so it would be able to strip rounds off the AK mag. My only real concern now is feeding from the mag into the chamber. The SKS mag actually sits slightly high of the bottom of the receiver, while the AK mag uses a small feed ramp to guide the bullets into the barrel.

I believe that if the notch is carved high enough in the receiver it will allow the bullets to slip past the face, the other thing which i can do is (using a ball mill) level the mag cutouts in the receiver, this will raise the back end of the mag which will do the same thing.... I think the later is the way to go, but I shall have to contact my machine shop for their help in the matter.

Will take pictures of this stage in the process tomorrow when there is light.

[OneGuy67]

Shotgun news had a series of articles last fall in which the author, a gunsmith named Coffman, showed you how to modify a SKS to accept AK mags. It might be of help to you.

[tortirioan]

Thanks a bunch, this will help out a lot

[tortirioan]

And I have the last 2 articles but not the first which is the one I need to put my mind at rest lol. Does anyone have a copy of Shotgun news Volume 65- Issue 29?

[OneGuy67]

And I have the last 2 articles but not the first which is the one I need to put my mind at rest lol. Does anyone have a copy of Shotgun news Volume 65- Issue 29?

I do somewhere (I kept it specifically for that article mentioned), but I will have to find it. Once I do, I will scan the relevant article and email it to you. If someone has a copy they are willing to give up to you, please don't wait on me!

[tortirioan]

I do somewhere (I kept it specifically for that article mentioned), but I will have to find it. Once I do, I will scan the relevant article and email it to you. If someone has a copy they are willing to give up to you, please don't wait on me!

I found an online copy but they removed the pictures which sucks. I am putting the project on hold until some of the parts that I have on order in, the rifle is still operational even if i don;t have a front sight (that was the first thing to go lol)

[tortirioan]

Update everyone!

As i said i cut the bolt so that it would strip off the AK mag as well cutting out the mag well, Well because i am just so cool I have pulled out my old man's 1952 Tula SKS so you can get a side by side of before and after for all the cuts I have done, This post will have all the pics of the bolt and the next one will be pics of the mag well. Wasn't all that hard really, Just put it into my Smithy mill/Lathe combo and using a carbide end mill I took 107 thousandths total from the lips. Which is actually what it says in the wonderful article in Shotgun news by Reid Coffield, his actually says to take off 100 but I took a little extra off when i was smoothing the faces to my liking.

The Bolt in the box is the modified bolt

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I am going to be getting the Murray's Firing pin as well as several other parts of theirs to help make the gun 922r compliant (as well as eliminating the chance of slam fires), but I am short on cash at the moment so will order those at a later date.

Will post the next set of pictures as soon as I take them in about 10 minutes.

[tortirioan]

This is more of a half way photo than the bolt pics, this is simply because there is a whole lot more that will need to be done to the receiver in order to let it take the ak Mags, one of the big ones is I will need to get a long shaft ball mill to clean up the round area at the bottom of the mag well where the feed lips of both sks and ak mags rest. Then i will have to deepen the cut out I made for the ak's mag catch lump on the front of the receiver, I believe it is long and wide enough but it needs to be deepened at least another 50 thousandths before it will let the mag sit high enough for the bullets to feed right into the chamber. The final stage of course for the receiver will be welding a small plate onto the receiver to act as the bottom of the catch.

In the Shotgun News walkthrough Mr. Coffield uses screws to secure it into place and i think he does this so that if he ever wanted to he could remove the plate and use the original 10 round box mag, However I am not sure I want to go that route.

The bottom receiver is the modified receiver. (I only took one photo of this because as I said it is not yet finished.

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On another note, a part that I was waiting for came in YAY! A Bulgarian Trigger Guard and Mag catch assembly from an AK which i got from Apex Gun parts, came coated in cosmoline and in great shape. The part itself will need some pretty serious mods in order to work on the rifle then it will be welded onto the Trigger guard which will also need to be modified to allow it to work properly. This differs from Mr. Coffield's process because I have always preferred the way that the AK dumps it's mag's over the SKS's, also this is now the SKS-Ms operate and that is what I am using for a template.
Cost of part: 40.00
Percent of Budget: 4%
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[tortirioan]

Just a mini update for you guys today, Have ordered my SG Gunworks Bullpup stock. It cost 244 dollars with the shipping and the tri-rail and enhanced mag release, now i am not using the mag release but the package was cheaper than buying just the tri-rail and the stock. In addition I have ordered some new tooling to finish up the modifications to the receiver to take the AK mags. I will post percentages and all that once i get it in my hands.

[palepainter]

We will probably hear back from you in a year from what I have heard about their shipping practices.

[tortirioan]

If it takes longer than the 5 weeks is says on their site I will be giving them a call, I don;t let things like that stand.

We will probably hear back from you in a year from what I have heard about their shipping practices.

[tortirioan]

So have a little update for you guys, and while i hate to admit it I made a mistake, The standard AK Mag catch assembly isn't going to work and it looks like a couple simple modifications to the existing mag catch will work just fine. I believe that the "extended mag Catch" which SG Gunworks makes will allow me to reload like an AK anyway which is nice to hear but annoying that I didn't realize it sooner.

So moral to this story is that some times you have to screw up before you can do something right, the key is to do that as few times as possible.

[Great-Kazoo]

So have a little update for you guys, and while i hate to admit it I made a mistake, The standard AK Mag catch assembly isn't going to work and it looks like a couple simple modifications to the existing mag catch will work just fine. I believe that the "extended mag Catch" which SG Gunworks makes will allow me to reload like an AK anyway which is nice to hear but annoying that I didn't realize it sooner.

So moral to this story is that some times you have to screw up before you can do something right, the key is to do that as few times as possible.

Someone here acquired an sks AK mag conversion set up from me a few weeks back. It's a simple extended, 2 plate and 1 lever design that fits in front of the sks trigger guard

[tortirioan]

Yay! parts have come in, enough parts that I think I can actually take it to get the barrel cut down and threaded and get the welding done. The parts that came in today are:

A Tapco AK-47 Style Muzzle Break, got this from Cabela's and while it was a little expensive to ship it was pretty close to the regular price. What really surprised me about this part was it's size! Am used to messing around with modern breaks which use as little metal as possible to save on cost, this one weighs almost a pound I am sure of it!

Cost of part: 27.99
Cost of Shipping: 8.95
Total: 37.75
Percent of Budget: 3.8 %
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The other part which came into today was a PRI .650 Railed Gas Block. The funny thing is about the SKS barrel is that it is almost exactly .650 in diameter right infront of the Gas block. So I thought I would give this a try (If it didn't work I would use it on an Ar build down the road), So I ordered it direct from PRI and got a little bit faster shipping because there was like a $5 difference.

Cost of part: 65.00
Cost of Shipping: 19.46
Total: 84.46
Percent of Budget: 8.4 %
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This is a pic of the block on Barrel, and what is awesome is that it is actually a hair too small, this pic shows how far down the barrel i can get the block without hammering or something.
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[zteknik]

I think the rail for the topcover would probably be better then the one on the barrel.There integral to the cover and once the cover is locked in it's solid.
And there not all that expensive.

[tortirioan]

I think the rail for the topcover would probably be better then the one on the barrel.There integral to the cover and once the cover is locked in it's solid.
And there not all that expensive.
The SG Gunworks stock has a top rail, So I will be using that as well, but you can never have a long enough site radius.

[zteknik]

The SG Gunworks stock has a top rail, So I will be using that as well, but you can never have a long enough site radius.

Good point.

[tortirioan]

Hey all, just giving an update because it's been quiet for a while. My welding friend has been very busy over the last couple weeks so I haven't been able to complete the next step in the plan to get this SKS converted to ak mags, and the bullpup stock is still on order and I don;t expect it for another couple of weeks.

it is what it is and just wanted to let you all know that this project is not dead.

[Great-Kazoo]

The SG Gunworks stock has a top rail, So I will be using that as well, but you can never have a long enough site radius.

Lucky you, i happen to have a solid 1pc SKS rail receiver cover.

[tortirioan]

Hey all, just got my sks barrel from sg works and have mixed feelings, will go into details when I post pictures later. Also have some of my 20 end tanker ak mags in, though I will probably hold off on the whole picture when I get all of them in at the end of next week. Looks so far as if I am gonna be under budget, but will have to see

[tortirioan]

Well everyone I got the Rifle finished the other day, I still need to test it and coat, but I suspect it will need a little more work, sorry for not giving you guys any updates in between but here it is:

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[zteknik]

That looks bad ass!![Awesom]
Let us know how she does at the range!!

[Great-Kazoo]

For someone who is not a bull pup fan. I am very impressed. My only concern is the mags. Hope they don't hold more then 15 rds. [panic]

[jreifsch80]

Are those standard 20's? They look like Romanian 20's since how they are stamped with ribs all the way to the bottom!! I need some of those for my Draco hmmmm I wonder if you'd trade me some mag bodies for some of my hungarian 20 rd mag bodies? ;) just speaking rhetorically

[SAnd]

That came out real nice. You did a good job. I hope it handles and shoot as well as it looks.

[tortirioan]

Shot it the other day, having an issue with the followers being different sized inside and not letting me slip the mag in while the bolt is closed.

Took it out to the range, had a couple double feeds/ failure to eject, had one slam fire but I suspected that and went to pick up a Murry's Firing pin (this should fix the issue), Then i had a little sparking off the muzzle device with the Tula steel case ammo Fixed that by boring out the vortex muzzle device, it was made to run on 6.8 SPC stuff so I'm not surprised.

I Am still trying to figure how to fix the double feed issues, it's either caused by lack of gas because of the shortened barrel or from my fitment of the mags into the receiver, not sure which yet. It also might be the aforementioned mag issue as I noticed it only happened on the first or second rounds of the mags.

Does anyone know where I can get some of the 5round tapco followers? they are already made short and would save me a bunch of time (not to mention giving me a couple extra rounds per mag), anf give me another US made part now that I think about it.

[jreifsch80]

Where did you find those mags? Lol

[tortirioan]

Centerfire Systems had them for 25 bucks a shot, are on sale now for like 17 *eyeroll* yea put them on sale after the mag ban

http://centerfiresystems.com/MAGAKA07.aspx

[jreifsch80]

Oh ok are those us made? They look like uncommon Romanian 20's

[tortirioan]

They aren't US made, It doesn't say "made in so and so, but It looks to me like they are imports.

[jreifsch80]

Rechecked pictures of romy 20's and they have normal ribs but are just flat at the bottom instead of having the horizontal ribs, I was mistaken. Those could be Chinese maybe? or most likely are cut down 30's by what ever company sold them to center fire (for a while people couldn't get enough 20's)

[tortirioan]

They aren't cut downs, the "channels" aren't cut off, they stop just before the bottom (at least one the ones I have)

Have been testing them, and all of them but 2 will not go into the rifle with the full 20 in, they cycle just fine once I take 1 round out but I need to mod them a little to make them work right. Cut about 1/8th of an inch off the bottom of all the followers and I think they will work like a treat.

[jreifsch80]

Yeah I remember Jim had to do some follower mods to an sks-d he had a couple years ago (factory Chinese sks that takes ak mags)

[tortirioan]

I think it's because the SKS bolt when modded is deeper into the mag than the standard Ak bolt

[jreifsch80]

Ah it you're daring you could shave a little off the bolt? Maybe try with a spare

[tortirioan]

I could take a little bit off the back side of the bolt, maybe 50 thousandths, come back from the bolt face about a quarter of an inch then just shave off the rest with the mill, that might work... hmm will have to look at an AK bolt shape

[jreifsch80]

That's similar like how an ak bolt inside a carrier is, don't just look at an ak bolt but an ak bolt in a carrier while in the locked position

[lead_magnet]

That thing looks wicked! Keep us posted! If you think it's undergased, have you tried using a booster like the bulgarian 4 piece?

[tortirioan]

That thing looks wicked! Keep us posted! If you think it's undergased, have you tried using a booster like the bulgarian 4 piece?

I got the Vortex flash hider for free because it was the kinda oddball 9/16x24 right hand thread. So now I am kinda limited in my choices of muzzle devices. Stupid of me maybe but worst care i can either take a couple links out of the recoil and op rod springs, or widen the gas hole in the barrel.

[jreifsch80]

It would probably be easiest to enlarge the gas port on the barrel

[tortirioan]

It would probably be easiest to enlarge the gas port on the barrel
Agree, but I'm going to let the rifle break in a little first before i take that step. A pain in the butt to get the gas block off for the first time, so if I can get away with some break in then I'd rather do that.

[tortirioan]

So done a little thinking, and i think i would rather mod the mags in this instance than the Rifle, my reasoning for this is pretty simple. the mags use a standard follower and standard springs (ie. made for use in 30 round mags) and have not been modded much if at all. So a little tweaking here and there will do no harm and will probably improve mag function overall.

I also don;t want to mod the bolt because i just remembered that the back of the bolt is where the rifle locks into battery and messing with the strength of that is probably not a good idea. maybe one day when i'm feeling daring I will be not right now.

[jreifsch80]

Ah good idea I always forget that an sks bolt drops that alone might be giving you problems. By the way how far are empties kicking out?

[tortirioan]

Ah good idea I always forget that an sks bolt drops that alone might be giving you problems. By the way how far are empties kicking out?
When I shot it, I was in a booth so not really sure, I do know that it seemed to be bouncing off the booth wall pretty well, next time I shoot her (probably very soon) I shall have a buddy of mine try to watch so we can get a better Idea. I think the problem i was having was mag related no gas, because as i said the problem went away after the first couple rounds were fired. (also had the mags drop out on me once or twice which was easy to understand why.

[jreifsch80]

The bolt dropping is probably over compressing the mag spring maybe just load your 20's to 18 like how ar guys don't load their mags all the way lol

[tortirioan]

The bolt dropping is probably over compressing the mag spring maybe just load your 20's to 18 like how ar guys don't load their mags all the way lol

What I thought, So am taking one loop out of each mag spring, then am gonna take 1/8th an inch off the bottom of each of the followers that should fix the problem

[jreifsch80]

Does a drum run in that thing?

[tortirioan]

Too long, is a real flaw with the SG gunworks design, it won't take the 30 rounders or drums, it's an issue with the position of the grip. I could mod the grip heavily to take 30s but I'm holding off on that for right now.


I have not tested it with a drum but they are longer then the 30s (at least the ones I have looked at have been) so if a 30 doesn't fit... looking at pics it seems like the romac ones are straighter as well.... hmmm maybe, if i could find one someone I could let test it with *shrug* it may work even if i can't get one till after the ban is repealed.

[jreifsch80]

If the curve is a problem then Romanian/Russian military pattern top load drums might cause problems but back load Chinese pattern drums are a lot straighter, if you go shooting with me I have a couple norinco back load drums and Romanian top loaders so we could test fit both

[tortirioan]

we will have to try it some time, shoot me a message and we'll try to get together.

[tortirioan]

<p>
Ok, modded my first mag to take it out and test. I took 2mm off the bottom of the follower and 2 loops off the bottom of the spring (the mags came with standard 23 loop springs, this is the same as used in the 30s). Have a little bit of issue pushing in the last cartridge, it seems like the mag gets bound up near the bottom, a good sharp tap fixes it no issue but i&#39;m going to look into the mag and make sure nothing is sticking out to catch. (I&#39;m thinking I&#39;ll have to round off the new bottom of the follower)</p>
<p>
The mag seats fine now, so that problem is fixed. I&#39;ll be testing this mag at the range today and I&#39;ll let you guys know what happens, I suspect I might still have some issues with the muzzle device, but we shall see.</p>
<p>
Oh I am thinking of getting stainless steel Mag springs, US made of course, is this worth doing? I noticed some rust on the mag springs when I took them appart. it means i would have to mod a whole set of new springs but is that bad?</p>

[jreifsch80]

Just replace them when they no longer work is my opinion, take the rust off the springs now but I doubt you'll get any more rust on them after you clean them. Just my opinion

[tortirioan]

Ok guys, took it out and shot it again. Their are two issues now, one of which I saw coming. I was having issues with the bolt carrier rusting so i used Alumahide to coat the thing and stop the rust from coming back. This has made the carrier verry tight on the rails and so the rifle cycles slowly. I saw this coming and am not too shocked by it. Going to use my handy dentist pic to remove some of the aluma-hyde from the rails and a couple other parts to fix the resistance issue and that will be all good.
The second is that I am having mag drop out problems, I believe this is because I didn't made the mag catch modification correctly. (it isn't getting enough engagement on the mag) I can whip up a new mag catch and have it in the gun in a couple hours so i'll let ya guys know what happens.

[Great-Kazoo]

Ok guys, took it out and shot it again. Their are two issues now, one of which I saw coming. I was having issues with the bolt carrier rusting so i used Alumahide to coat the thing and stop the rust from coming back. This has made the carrier verry tight on the rails and so the rifle cycles slowly. I saw this coming and am not too shocked by it. Going to use my handy dentist pic to remove some of the aluma-hyde from the rails and a couple other parts to fix the resistance issue and that will be all good.
The second is that I am having mag drop out problems, I believe this is because I didn't made the mag catch modification correctly. (it isn't getting enough engagement on the mag) I can whip up a new mag catch and have it in the gun in a couple hours so i'll let ya guys know what happens.

easiest way to deal with the mag catch / rear lug is to LIGHTLY file the top of the catch. regarding the mag / feeding issue. Use 1 mag as a beta and relieve/ widen the rear section of the mag a little more than the width of the bolt. As for the bolt carrier rusting, that's common with the chi-com sks' i have an unissued [NEW] chi-com bolt carrier, somewhere in my inventory

[tortirioan]

easiest way to deal with the mag catch / rear lug is to LIGHTLY file the top of the catch. regarding the mag / feeding issue. Use 1 mag as a beta and relieve/ widen the rear section of the mag a little more than the width of the bolt. As for the bolt carrier rusting, that's common with the chi-com sks' i have an unissued [NEW] chi-com bolt carrier, somewhere in my inventory

As I said, my issue isn't with my mags, it's the mag catch that I made is too small, I'm getting maybe 1 or 2 mm of engagement on this mag tab. Not nearly enough, I'm going to fabricate a new one with more and then get a new sear spring and not take as many links out of it to make it heavier so that there is more resistance when firing. I am going to look up the specs from the one that Shotgun news made and see how he did his.

As far as the bolt carrier rusting goes, that problem is fixed but mine is a russian (with russian stamps on it), I honestly think it's an issue with the bead blast finish it has, easy enough to fix, will be doing some work on it tomorrow and sunday and get back to you guys asap

thanks for the suggestions though :)

[Great-Kazoo]

As I said, my issue isn't with my mags, it's the mag catch that I made is too small, I'm getting maybe 1 or 2 mm of engagement on this mag tab. Not nearly enough, I'm going to fabricate a new one with more and then get a new sear spring and not take as many links out of it to make it heavier so that there is more resistance when firing. I am going to look up the specs from the one that Shotgun news made and see how he did his.

As far as the bolt carrier rusting goes, that problem is fixed but mine is a russian (with russian stamps on it), I honestly think it's an issue with the bead blast finish it has, easy enough to fix, will be doing some work on it tomorrow and sunday and get back to you guys asap

thanks for the suggestions though :)


I also have one or 2 sks recoil assy's. probably some other misc sks crap floating around too.

[zteknik]

As I said, my issue isn't with my mags, it's the mag catch that I made is too small, I'm getting maybe 1 or 2 mm of engagement on this mag tab. Not nearly enough, I'm going to fabricate a new one with more and then get a new sear spring and not take as many links out of it to make it heavier so that there is more resistance when firing. I am going to look up the specs from the one that Shotgun news made and see how he did his.

As far as the bolt carrier rusting goes, that problem is fixed but mine is a russian (with russian stamps on it), I honestly think it's an issue with the bead blast finish it has, easy enough to fix, will be doing some work on it tomorrow and sunday and get back to you guys asap

thanks for the suggestions though :)
A simple fix for the rusting I would do is polish the bolt carrier using 2500grit sandpaper and mothers aluminum/mag wheel polish,then finish up on a buffing wheel.It also makes the carrier smooth as silk ;)

[tortirioan]

I am planning on Moly-resining the whole firearm once i get my bead blasting cabinet put together. The Aluma-Hyde is a stop gap measure until I get that done in the next week or so and can cart out all my moly-resin stuff. The part that was rusting was the top of the carrier where no wear is supposed to take place *chuckle* so I don't think polishing that face will help with smoothness.

thanks again though, i will be sure to contact you guys if I break something and need a new part *chuckle*