SKS to FAL conversion, MK1 (56k warning)

[H Wally]

I'm not saying that I would shoot it, but I'm damn proud of the guys like you who are willing to put the work in and make the attempt. I'd say that all things considered, you've really got something to be proud of there. Congrats!

P.S. Are you/Are you allowed, to change the charging handle from right to left?

I'm not sure what you mean by that. I am using the sks cocking handle that is attached to the bolt carrier. In this situation, it is not necessary to move it, especially when I still have not solved the more important issue of getting it to fire consistantly.

Maple Leaf Eh: I think you're right - there is likely enough force in the spring (I have two, both are quite strong).

Instead I believe curtton may have solved my FTF problem. What it may be is misdirected energy; it is striking the firing pin, but the force is not being applied only along the same axis as the firing pin moves, and the bolt and bolt carrier are absorbing too much of the hammer's force.

Depending on how much time I have tomorrow I may be able to update the problem (or post the solution)

 

[Corpus]

Asthetics my-man, strictly for FAL-style aesthetics. The more I look at this thing, the more impressed I am with your work.

Vs.

I know you can't get it in the actual position that a real FAL would have, but having on the proper side would add points I think. It might require too much machining however. Just a thought.

 

[marshall]

Corpus, what model is that you have?

H-W , you said you had to modify your F.M. hammer?
I so, post a picture of it, may be of help???
I would think that the hammer spring would be O.K as they always
seem to work fine on 7.62 nato , s was stated , Check that the hammer
is coming up flush and square with the rear of bolt/ firing pin.
does your hammer spring (s) seem smooth- not rust or crap in them?
I have never tried to take one a part, ( impossible)???????
Should be a great project.

 

[Corpus]

http://www.canadiangunnutz.com/forum/showthread.php?t=262450

All here; don't want to derail this thread.

 

[banskopivo]

That looks quite cool actually...

Good job and waiting for the updates...


Hmmm...just remembered my "spare" SKS...hmmm....all the wife said was "no buying anymore guns" but she didn't say anything about building one ...

 

[H Wally]

I'mmmmmmm baaaaaaccckkkkk!

Not much new, but got another pic and some more questions for the masses.

First off - used the sheisty sks stock to make a knock off AK style lower hand guard so I can actually hold the darn thing. Obviously FAL hand guards will be used, but I've got to wait until I can find some suitable plastic ones, so that could take a while.

(And I actually made sure to include my big toe in this pic)

Anyways - back to the important stuff - the gun still won't fire consistantly!!!

Here's what I've worked out

1) There is no play in upper/lower bonding, so power loss isn't a factor there.
2) The hammer only contacts the firing pin, so no rubbing during firing.
3) The new firing pin exactly copies the sks pin in profile, with the exception being it is slightly longer. It is still very loose, is made of hard steel, does not deform from use, and actually has slightly more than average pin projection on the bolt face.
4) Both of my hammer main springs are the same strength. Both are ishapore springs (could they be cheap, worn out, etc?)
5) Hammer had to be shortened slightly. Lost about 1 cm in height. Have tried with full size hammer, still doesn't work.
6) Have heavily cupped the hammer to avoid slipping when firing. This was done to test if force was lost by the hammer striking and sliding. If done in S/A it will jam. Still no success.

Can anyone make any suggestions or give any advice???? I'm completely at my wits end!!!!!

EDIT: I knew this was an issue, but just putting it out there for everyone elses info:

The FAL hammer axis pin is about 3/4cm -1cm forward of where the SKS hammer axis pin would be. This is because the SKS hammer has a large knob on it that reaches forwards and contacts the firing pin. I can't add this to the FAL hammer because the FAL hammer's axis pin is higher than the sks, which means that it does not have enough room to clear the bottom of the bolt with any extra metal on the face being involved.

The SKS also has a heavier spring and hammer. Go figure.

All internals removed but the hammer - note the cup for the firing pin:

Bolt assembly with firing pin, in firing position, with hammer cocked:

Trigger pulled, hammer firmly seated against the firing pin.

This was meant to show how it mates to the pin, but it's blurry:

Bolt showing new firing pin profile:

New pin projection on the bolt face:

Somebody has to have a solution for this!!!

 

[suprathepeg]

Maybe the hammer is too light. I wonder if you used winchester ammo with the softer primers if this setup would work?

I don't know how you could test this but it could be useful to compair a stock SKS hammer's striking force to the one you have. I'll bet with the loss in length on your hammer combined with the loss of material at the end of the hammer you age getting significantly less force then you think.

 

[cantom]

Maybe the hammer is too light. I wonder if you used winchester ammo with the softer primers if this setup would work?

I don't know how you could test this but it could be useful to compair a stock SKS hammer's striking force to the one you have. I'll bet with the loss in length on your hammer combined with the loss of material at the end of the hammer you age getting significantly less force then you think.

SKS's are known for slamfires if the firing pin chanel is greasy or dirty, and presumably if soft primers are used.
Perhaps normal SKS Commie ammo uses rock hard primers? Try different brands of ammo including American, as suprathpeg said the hard primers may be defeating you.

 

[mmaguy29]

I Like it!

 

[Kasat]

Word of caution !!!! Any build up on the chamber's walls could result in an out of battery kaboom. and you most likely know that , I presume.

 

[Dimitri]

Seems to me you only made the SKS attachable to a new stock should be good to go

Wonder if I could do the same to my FN49 hummm.

Dimitri

 

[Kasat]

Unlike the original SKS trigger group the Fal one will not be disabled when the bolt is not securely locked so be very careful. Altering original designs may be very dangerous.
Sorry for repeating myself but I don't want to see someone hurt.

 

[cantom]

Unlike the original SKS trigger group the Fal one will not be disabled when the bolt is not securely locked so be very careful. Altering original designs may be very dangerous.
Sorry for repeating myself but I don't want to see someone hurt.

He has a good point H Wally. The original design of either rifle used a disconnector designed to not allow the hammer to be released till the bolt is fully forward in battery. If you ease the bolt half way into battery and can at that point pull the trigger and have the hammer fall...which I suspect it will...
The original FN design used a safety sear which accomplished this...the bolt carrier hit it and released the hammer, which in semiautomic fire let the trigger sears then control the hammer.

 

[H Wally]

Word of caution !!!! Any build up on the chamber's walls could result in an out of battery kaboom. and you most likely know that , I presume.

You mean by causing it to not fully seat in the chamber before the firing pin struck?

SKS's are known for slamfires if the firing pin chanel is greasy or dirty, and presumably if soft primers are used.
Perhaps normal SKS Commie ammo uses rock hard primers? Try different brands of ammo including American, as suprathpeg said the hard primers may be defeating you.

I was thinking I might have to... I did however stockpile a rediculous number of crates of czech surplus, so I had been hoping that would work.

Seems to me you only made the SKS attachable to a new stock should be good to go

Wonder if I could do the same to my FN49 hummm.

Dimitri

I thought about that too. That was the original plan acutally. Thing was I found the FN 49 much longer than the FALs, much more expensive, and had historical value, unlike the sks. Something tells me the FN 49 project would be a money loser unless you did a beautiful job.

Unlike the original SKS trigger group the Fal one will not be disabled when the bolt is not securely locked so be very careful. Altering original designs may be very dangerous.
Sorry for repeating myself but I don't want to see someone hurt.

No worries - it's a very valid comment. I realised I removed the disconnects from both weapons (sks trigger, and FAL bolt carrier and disconnector). There is still the gap for the sks trigger arm, and adequate space elsewhere for one to be added. Another idea I had was to make a thick guard that mounts to the bottom back of the bolt carrier that would shield the firing pin until it drops down and into battery. Since the bolt carrier doesn't need the clearance there, and the hammer can't go that high, it would block the firing pin until the bolt was completely locked into place. It wouldn't prevent the trigger from being pulled, but it would prevent the hammer from striking the primer, and if pulled before in battery, the hammer would just slide onto the firing pin as it entered battery.

He has a good point H Wally. The original design of either rifle used a disconnector designed to not allow the hammer to be released till the bolt is fully forward in battery. If you ease the bolt half way into battery and can at that point pull the trigger and have the hammer fall...which I suspect it will...
The original FN design used a safety sear which accomplished this...the bolt carrier hit it and released the hammer, which in semiautomic fire let the trigger sears then control the hammer.

This was the main reason I wanted to see an active FAL in the flesh before I started the project - it allows me to understand how everything works and compensate for what I've done. I'm thinking a balanced spring loaded arm could take the place of the FAL disconnector on this one. I would have to slightly alter my design, but there is space for it. It's possible the old disconnector could even work..........

 

[Dimitri]

I thought about that too. That was the original plan acutally. Thing was I found the FN 49 much longer than the FALs, much more expensive, and had historical value, unlike the sks. Something tells me the FN 49 project would be a money loser unless you did a beautiful job.

Like using a loaded machine shop to do your work in/pay to have bits of it done in.

Personally was thinking of a new dust cover, a FAL lower piece to accept a FN49 as a drop it to accept the grip and buttstock and new foregrip wood with a tube to protect the piston/spring assembly and attach the foregrip at the front. And possibly going to 308 with M14 magazines.

Wouldn't be accurate like yours but will mean its just a cosmetic stock change so no RCMP/CFC approval is needed.

Edit other then to change OAL/chambering registration papers I mean there wouldnt be a need as no real FAL parts execpt for stock parts would be used really.

Dimitri

 

[Dimitri]

Wonder though if I was to make a conversion look alike stock, I should probably get the RCMP's approval before slapping a K98 Trench gun magazine thats 20 rounds on the gun huh ??

Dimitri

 

[H Wally]

Unless it's over 5 rds the mag doesn't make much of a difference. A mag is a mag to them as long as it isn't prohibited from what i understand.

P.S. - Because of that comment about the machine shop, I'm going to be staying with you next time I'm in ontario. It's just going to happen, don't fight it

 

[Dimitri]

That trench gun magazine is a 15 round extension to the normal 5 round internal magazine.

So a built into the "stock" Mauser 98 5 round magazine + K98 Trench magazine = 20 rounds of 8mm Mauser in a Semi-automatic. Eventhough both are meant for a bolt action.

Dimitri

 

[H Wally]

That trench gun magazine is a 15 round extension to the normal 5 round internal magazine.

So a built into the "stock" Mauser 98 5 round magazine + K98 Trench magazine = 20 rounds of 8mm Mauser in a Semi-automatic. Eventhough both are meant for a bolt action.

Dimitri

Unless I read you wrong, I think any rifle that's semi auto cannot hold over 5 rds, so be it FN 49 or sks, they can't run more than 5 consecutive rds before reloading...

 

[Dimitri]

Unless I read you wrong, I think any rifle that's semi auto cannot hold over 5 rds, so be it FN 49 or sks, they can't run more than 5 consecutive rds before reloading...

Magazine restrictions are based on what the magazine was designed te be used for not used in. Hence why 10 round AR Pistol mags are ok in rifles. So if bolt action magazine then should be unlimited how I see it.

Dimitri