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-   -   New DSA SA58 Para 11" and encountered problems (http://www.falfiles.com/forums/showthread.php?t=424288)

FrJH February 18, 2018 08:03

New DSA SA58 Para 11" and encountered problems
 
Hello,

I bought last year a DSA SA58 Para 13". I removed the soldered flash hider and I changed it by a customized one after having cut it of 1" inch to make a new thread. The thread used by DSA is not common in Europe. I added a picatinny handguard and a mount scope on it. For your information a brand new SA58 in France is 4200€ + 700€ for the handguard and the mount scope.

https://image.noelshack.com/fichiers...-03-07-pro.jpg

Since the beginning I have problems, the most common one is I have jams, despite the gas system setting. Impossible to shot a complete magazine.

I shot 200 / 300 rounds for now and the other problem is that the ammos don't chamber properly. First, two out of three when I engage the magazine ( original SA or FN ) the ammo " lift up " :

https://image.noelshack.com/fichiers...-15-13-pro.jpg

( The bolt wasn't present in the rifle )

The other problem is when the ammo doesn't lift up, it doesn't chamber, the head of the ammo is blocked against the beginning of the chamber, you can see the 2 spots here :

https://image.noelshack.com/fichiers...-10-24-pro.jpg

The original magazine is on the left and the two FNs are on the right :

https://image.noelshack.com/fichiers...-55-46-pro.jpg

Last problem is my extracteur " broke " and I had to replace it by an original FN extractor :

https://image.noelshack.com/fichiers...-58-27-pro.jpg

The problem is the following : When the gas system is too permissiv the rifle doesn't work properly, but when I close it, the pression is too high and the extractor is ejected ( the bolt doesn't have any sign of failure ).

My questions are :

- Can I use a dremel to modify the chamber so the heads of ammos don't block against but are righlty directed ?
- How can I solve my problem of " lifted up " ammo ?
- How can I solve my problem of gas system ? Is there any existing bolt spring for SBR Fals ?

Thank you in advance for your help.

4x401 February 18, 2018 11:54

Welcome!

The problems you've encountered have everything to do with the lack of available gas pressure to function the rifle....and the reason DSA doesn't build them shorter than 13".

When you removed that 2" of barrel, you effectively diminished the available gas pressure by about 66%. And adding that Gawd awful blast enhancer up front only compounded the problem. Damn near all your gas pressure is going out the barrel. I'm surprised the carrier even moves at all.

The amount of time a bullet stays in the barrel Past, the gas block/port is referred to as "Dwell time". The bullet being in the barrel After the port has everything to do with the amount of gas pressure to Push back on the gas piston to function the action. Again, when you cut the barrel, and added the muzzle device, you killed the performance.

I don't recall the gas port size DSA uses for that front end, but you can try opening it a bit to see if that helps. Be advised that enlarging the port past .120 is NOT a good idea.

Changing that blast enhancer for something longer to help keep more pressure in the barrel would be where I would start first. I know its not the Look your going for, but at least the rifle may actually function...Good luck.

And for GOD sakes, put down the damn Dremel! :facepalm: Your only compounding the issue.

FrJH February 18, 2018 12:38

Thank you for your reply. My gunsmith was ok with this modification ( ahem ... ).

The best is to get a new barrel.

The following custom is nice :

http://farm4.static.flickr.com/3107/...c78201334f.jpg

Do I need just this :

https://www.dsarms.com/p-15398-dsa-f...-included.aspx

And replace the old one ?

Just for me, how a very short SA58 work ?

https://www.dsarms.com/p-16853-dsa-f...-included.aspx

Edit : Anyway, it doesn't tell me why even a dry loading fails.

Stu February 23, 2018 12:53

Bonjour FrJH! Sorry to hear about your troubles.

Good question. I don't know how that 11 inch bbl (pistol/sbr) one works with the dwell time so low. I do know that I don't want to be beside that beast when a round is fired though.

I suspect that the loss of that 1 inch really changed the dynamic and the brake you picked means the pressure drops immediately (as opposed to some of the other original devices that might keep the pressure up just a bit longer). I'll bet that the few rounds you have fired were a "blast"! My teeth hurt just thinking about it. How much bbl is there after the gas block/port? Is there even 2 inches?

Tell us about the rules in France. You can own a semi with detachable mag (20 rounds), folding stock and 13" bbl? Special permits? Permissions?

lew February 23, 2018 13:19

I wonder of a linear compensator like a Noveske KX-3 (hell, what about a suppressor) would add enough back pressure to provide the additional gas volume required for function.

Stu February 23, 2018 13:59

Quote:

Originally Posted by FrJH (Post 4543079)
Thank you for your reply. My gunsmith was ok with this modification ( ahem ... ).

The best is to get a new barrel.

The following custom is nice :

http://farm4.static.flickr.com/3107/...c78201334f.jpg

Do I need just this :

https://www.dsarms.com/p-15398-dsa-f...-included.aspx

And replace the old one ?

Just for me, how a very short SA58 work ?

https://www.dsarms.com/p-16853-dsa-f...-included.aspx

Edit : Anyway, it doesn't tell me why even a dry loading fails.

Even with a pistol length piston, it amazes me they can get those to cycle.

KoKodog February 23, 2018 14:06

Quote:

Originally Posted by lew (Post 4545899)
I wonder of a linear compensator like a Noveske KX-3 (hell, what about a suppressor) would add enough back pressure to provide the additional gas volume required for function.


thats a tough call, he already chopped the original threads from the muzzle making it even shorter, if he would have gone w/ the Noveske KX-3 Flaming Pig or the PWS CQB right away he might have got it to function, your suggestion of a suppressor may be his only route otherwise he should just have a 16" barrel installed and get back on track

I have both the Noveske KX-3 Flaming Pig on a PWS MK109 (9" barrel) chambered in .300 blackout and also the PWS CQB on a PWS MK107 Diablo (7.5" barrel) chambered in 5.56 Nato both do a good job of keeping enough pressure to ensure full function


and for the OP, welcome, we are always glad to hear from across the pond in Europe, its good to hear that some there are not afraid to own guns

jhend170 February 23, 2018 17:04

If you have access to a silencer give one a try, for several reasons. It will tame the blast the brake is likely providing, does just as good of a job of flash control, but will likely help your dwell issue by holding pressure longer and allowing a better stroke.

tac-40 February 23, 2018 18:39

You might want to PM member PACO and see if he can provide you with a real FN barrel source. He lives up the road from you in Belgium. Definitely closer and faster than anything from the U.S.A. And you may be able to go and look it over before purchase.

Rudolf February 24, 2018 07:26

df
 
I recommend working on the gas port hole. I think.. gunplumber has some exact measurements but I am not entirely sure for something like an 11 inch.

gunplumber February 24, 2018 08:20

I would certainly go with the 13" barrel instead of the 11" Even if that means you have to buy a 16" and shorten it yourself.


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