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What is the diameter of the .308's muzzle


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Guys and gals, I am going to replace the front sight base on my Saiga .308 carbine with a Romanian fsb that will accept an AK-103 Romanian clone 22mm brake. What I need to know is what is the diameter of the barrel under the front sight base?

 

I know that some of you have removed it and I'm hoping you can tell me the diameter. Otherwise, I'll just have to press the fsb off and see for myself and leave it that way until the new fsb and brake arrive.

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It's in the works - I'll post the #'s in a day or so... :up:

 

I had a notion that I'd see a reply from you! :)

 

Thank you!

 

In looking at the fsb on my Saiga, it looks like the nose of the fsb is reduced in diamter so that the fsb is like a "cap" with a hole in the end - is that the way it is? As apposed to a simple "tube" that slips on the end of hte barrel like a standard AKM...?

 

I'm hoping that the diamter of the barrel under the fsb is close to standard size (.550" if memory serves). If it is, that would be cooler than hell - I could get a standard fsb and just press it on without having to bore it out or reduce the diamter of the barrel.

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Me and a buddy just went through this!

 

It is indeed a cap.

it also tapers starting at about 1/4 to 1/3 of an inch from the muzzle, it tapers down to (we didnt exactly measure) 14mm or a bit less at the very tip of the muzzle.

 

When we hammered the one we had off, the barrel inderneath was just over 5/8", at about 15.8-16.0mm, depending on where we measured.

So we used a Romanian AK sized FSb which is 0.591 inches (or 15.01mm) and we spent a loooooong while boring it out to size. We didn't want to do anything permanent to the Saiga barrel- I think a smart move.

 

Next time, we promised ourselves to start with a Bulgarian RPK variety which is 0.611 inches ID, or 15.52mm! that would save us half our hand reaming time.

 

Hope that helps.

C-

Edited by cpileri
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Ah - yeah that's where I get my AK receivers - best available IMHO - they must be busy - I've never had any problem getting them before... thanks again!

 

Edit: to add - I checked that out - is a "standard" type fsb - I'm wanting one with a threaded end - to accept an AK-74 type brake. Apparently, the Romanian fsb's with the threaded ends are too small to bore-out to fit .62" muzzles. They are made for much thinner 5.45x39 barrels, so figures.

 

Perhaps the rpk fsb is shorter and allows the exposed muzzle to be threaded? Maybe that's why you're looking into reducing the diameter?

 

A puzzle to solve to be sure.

 

I'm beginning to think that it would be better to just reduce the diameter of the end of the barrel to fit the fsb of choice... and I now understand why so many just weld the brake on...

Edited by O.S.O.K.
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In general i am big into non-permanent mods to guns- especially ones that work well as-is. Now the S-308 we are fiddling with has been 922-converted, which is kinda permanent, so take it fwiw.

 

Anyway, the Bulgy fsb does leave that maybe 1/3 to .4 inch tapered area exposed, and yes that's the area i am trying to reduce. EWither to a genuine 14-1.0mm-Ak thread, or to ANY diameter which will accept a press-on/set-screw threaded adapter.

 

Once we have some threads on the end of it, we can always make an 'adapter to the adapter' if we have to to utilize say, 24mmx1.5 threaded devices like the krinkov Flash hider. Just as an example.

 

Right now, the thought is to take a 16mm thread die and bore-alignment tool, and thread it to 16mmxwhatever. Then filee down the threads just until they are gone. Then take the next size down thread die, say 15mm- whatever fits, and thread it again. Repeat the process of thread/file smooth/thread/filesmooth until we end up with either 14x1.0 threads, or some diameter that will work as described above.

 

We'll see how it goes.

C-

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  • 4 weeks later...

All the ones that I have done in the past had HK sights installed. So, the front sight is removed completely, the cross slots welded up, and then a flash hider welded in place. I drill through the flash hider skirt first, then TiG through the hole and blend it out. Thanks to WJM, I now have a threading tool, but it's much faster (cheaper) to just weld it on.

 

I already had a customer totally chew my ass for not moving the sight back and threading.......so, that will have to go into my bag of tricks going forward.

 

Tony

Edited by TonyRumore
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All the ones that I have done in the past had HK sights installed. So, the front sight is removed completely, the cross slots welded up, and then a flash hider welded in place. I drill through the flash hider skirt first, then TiG through the hole and blend it out. Thanks to WJM, I now have a threading tool, but it's much faster (cheaper) to just weld it on.

 

I already had a customer totally chew my ass for not moving the sight back and threading.......so, that will have to go into my bag of tricks going forward.

 

Tony

 

how do you get hte rear site to stay?

 

by the way, jsut posted pics of the conversion in a different thread. pure evil. :super:

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