Saiga 223 SBR Question(s)

[winston]

I'm going to cut it down to 12.5"

What size does the barrel gas port need to be for reliable function..?

[allesennogwat]

It should be the same military ammo if it is the 16 inco barrel.

That should be 0-067".

The 20 inch 223 Saiga barrel likely has a smaller gas port, but maybe not.

Some early Saiga's have a larger gas port for commercial ammo but those aren't common.

Don't make those any larger.

[winston]

Originally Posted by allesennogwat

It should be the same "WITH" military ammo.

Is this what you meant..?

I typically only run the Russian steel cased stuff, Tula, Wolf, etc..

[winston]

It's the 16.25"

Thank you sir

[allesennogwat]

Originally Posted by winston

Is this what you meant..?

I typically only run the Russian steel cases stuff, Tula, Wolf, etc..

Yes, typo.

The military gas port for 12 inch and 16 inch barrels is 0.067".

Some Saiga's have military gas ports. Fewer have military rifling.

Some Saiga's have a commercial ammo gas port that is larger, while some 20 inch barrels have a smaller gas port.

[allesennogwat]

The Barnaul and Wolf by Barnaul ammo is closer to working right than Tulammo 223 ammo.

[allesennogwat]

We used to open the gas port to 0.076" for Russian steel case ammo.

The more recent 62 FMJ ammo is better than the old stuff.

Tula used to make for Wolf and Barnaul didn't offer 62 grain FMJ, only hollow points.

Now Barnaul make 62 grainj FMJ ammo for Wolf and Colt.

Barnaul doesn't list it as a product, but there is some available in Barnaul boxes.

[winston]

Really appreciate the info, thanks again.

[winston]

Does anyone know what the barrel journal diameter is under the gas block of a 223 saiga..?

[winston]

I'm also looking for a handguard retainer with the lever for my .223 Saiga.

Any suggestions..?

I found several for 7.62 AK's and I'm not sure they are compatible.

[Lane_H]

Originally Posted by winston

I'm also looking for a handguard retainer with the lever for my .223 Saiga.

Any suggestions..?

I found several for 7.62 AK's and I'm not sure they are compatible.

same as russian ak74 maybe ?
- akm isn't much larger (0.668 vs 0.670)

https://i.pinimg.com/564x/0e/90/61/0...f38f441006.jpg
^
*some have pointed out that dims on this image isn't 100% correct

ask Rforbus, to see if he has a bbl profile dwg for saiga 223
https://robertforbus.com/wp-content/...k74_545x39.pdf

[winston]

Originally Posted by Lane_H

same as russian ak74 maybe ?
- akm isn't much larger (0.668 vs 0.670)

https://i.pinimg.com/564x/0e/90/61/0...f38f441006.jpg
^
*some have pointed out that dims on this image isn't 100% correct

ask Rforbus, to see if he has a bbl profile dwg for saiga 223
https://robertforbus.com/wp-content/...k74_545x39.pdf

Great info, thank you sir..!

[allesennogwat]

Is the barrel machined for the hand guard retainer?


Some are and some aren't.

[winston]

Originally Posted by allesennogwat

Is the barrel machined for the hand guard retainer?


Some are and some aren't.

It has the channels down each side, but no retainer lever slot.

[allesennogwat]

Originally Posted by winston

It has the channels down each side, but no retainer lever slot.

Then it is machined for one.

Some don't have the slots in them.

[allesennogwat]

If you get an AK-74 rear sight base, you could just use a shortened AK-Builder barrel and keep the Saiga barrel original.

[winston]

You're the genuine wAKipedia

[winston]

Originally Posted by allesennogwat

If you get an AK-74 rear sight base, you could just use a shortened AK-Builder barrel and keep the Saiga barrel original.

I feel ya', but this gun was always meant to be a fast and furious competition gun. It was intended for a chop the day I bought it, just waiting for the stamp to show up.

I have a Romy G kit that I was considering chopping to build a 10.5" gun, but I can't bring myself to mutilate a genuine military collectable.

So I will build an SBR Frankengun in 7.62 from the ground up.

[allesennogwat]

Originally Posted by winston

I feel ya', but this gun was always meant to be a fast and furious competition gun. It was intended for a chop the day I bought it, just waiting for the stamp to show up.

I have a Romy G kit that I was considering chopping to build a 10.5" gun, but I can't bring myself to mutilate a genuine military collectable.

So I will build an SBR Frankengun in 7.62 from the ground up.

It still easy enough to swap the barrel.

No reason to cut up and wear out the original barrel.

There aren't going to be any more Saiga barrels.

[Ak-a-Holic]

Sorry to high jack, I'm building a m72 in 556 in standard m72 config (except m76 RSB), should I do a .067 or smaller port you think?

[allesennogwat]

Originally Posted by Ak-a-Holic

Sorry to high jack, I'm building a m72 in 556 in standard m72 config (except m76 RSB), should I do a .067 or smaller port you think?

A long M72 length barrel?

Maybe slightly smaller.

After a certain point it doesn't make much difference with the small bore or small port cartridges.

7.62x39 has a very different gas port in the RPK, but it starts out larger.

In 308 the difference is 0,058" 16 inch and 0.054" in 20 or 22 inch barrels.

You might try 0.0625" or maybe 0.060" for a 5.56 RPK.

After 18 inches, the gas for 5.56 doesn't change much.

Heavy match bullets in AR15's do, but ammo for an AK isn't likely to make much difference.

Heavy bullets have a bit of difference between 18" and 20" but not a whole lot.

Most all of the 5.56 AK's, short barrel, 16" barrel, Krinkov and 18" inch barrels have pretty much the same gas ports.

The RPK is one that may require something slightly smaller.

An M72 gas block allows drilling larger while installed, so start out small.

Maybe even smaller than 0.060", but I doubt much smaller will work well.

I would guess 0.0625" would be about right, but you can start smaller.

[winston]

Now that I have the original gas block off of it, I've put the calipers to the barrel gas port and it looks to be roughly 0.065'ish.

That is smaller than the 0.067 you were talking about, does that mean this port is a bit undersized or are my calipers off..?

Also, would drilling the new port to a compromise of 0.070 over gas it..?

It looks like a 1/16th inch bit might be perfect for 0.070, what do you think..?

[winston]

Scratch that, I measured a "new" 1/16th inch bit and it is obviously way too small at around 0.061 or so.

My primary question/concern is rather 0.070 barrel port would over gas a 12.5 SBR.

[ruedger455]

Don't drill the gas port. If you do you'll likely be too over gassed

[winston]

Originally Posted by ruedger455

Don't drill the gas port. If you do you'll likely be too over gassed

I have to drill a "new" port for the new GBSB, the location is further back than the GB that came off of it.

[allesennogwat]

Originally Posted by winston

Now that I have the original gas block off of it, I've put the calipers to the barrel gas port and it looks to be roughly 0.065'ish.

That is smaller than the 0.067 you were talking about, does that mean this port is a bit undersized or are my calipers off..?

Also, would drilling the new port to a compromise of 0.070 over gas it..?

It looks like a 1/16th inch bit might be perfect for 0.070, what do you think..?

That's about right, 0.066" to 0.067" I've measured.


0.070" might be alright or might be a bit much depending on ammo.

With military ammo I stick with 0.067".

[allesennogwat]

Originally Posted by winston

Scratch that, I measured a "new" 1/16th inch bit and it is obviously way too small at around 0.061 or so.

My primary question/concern is rather 0.070 barrel port would over gas a 12.5 SBR.

A 1/16" is 0.0625".

What are you saying?

The calibers are measuring small, or the gas port is smaller than you first measured?

[ruedger455]

If you have to drill a new one i would drill it the same dimensions as the original. Or drill it slightly larger and get one of definitive arms new adjustable gas blocks

[winston]

Originally Posted by allesennogwat

A 1/16" is 0.0625".

What are you saying?

The calibers are measuring small, or the gas port is smaller than you first measured?

I think my measurements were a little off on the 1/16 bit. Now I am getting a consistent 0.062

I was saying that when I got the original GB off, I measured the barrel port and was getting 0.065 not 0.067 as you had suggested it should be.

[winston]

Originally Posted by allesennogwat

That's about right, 0.066" to 0.067" I've measured.


0.070" might be alright or might be a bit much depending on ammo.

With military ammo I stick with 0.067".

I will most likely be running Tula and Wolf through it since it looks like the cheap military surplus is drying up.

Will a 0.067 port run Tula and Wolf reliably..?

[winston]

Originally Posted by ruedger455

If you have to drill a new one i would drill it the same dimensions as the original. Or drill it slightly larger and get one of definitive arms new adjustable gas blocks

Right now, I think I will go with 0.067 and see how it runs.

If there are cycling issues, I can always open it up a little until I get it right.

Is there a fractions system drill bit that will get me 0.067, like 3/32's..?

[allesennogwat]

Originally Posted by winston

I will most likely be running Tula and Wolf through it since it looks like the cheap military surplus is drying up.

Will a 0.067 port run Tula and Wolf reliably..?

The Wolf and Barnaul 62 grain FMJ should be more reliable than Tulammo 223.

Barnaul doesn't sell 62 grain FMJ as a regular product but makes it for Wolf and Colt and I have heard of some Barnaul marked boxes of it being for sale, but Barnaul doesn't advertise it.

Tulammo does, but its gas port pressure is way off.

[allesennogwat]

If you have to drill a new gas port, you might consider using a new barrel.

[mancat]

Originally Posted by winston

I think my measurements were a little off on the 1/16 bit. Now I am getting a consistent 0.062

I was saying that when I got the original GB off, I measured the barrel port and was getting 0.065 not 0.067 as you had suggested it should be.

A 1/16" bit is roughly 0.0625" but due to play in quill/bit flex/etc. you may up with a hole slightly larger than that.

I used a 1/16" bit on a 5.56 74 build and initially pressed the GB with a single pin just in case it needed to come off and step up to a larger hole. Sure enough it worked fine with everything: brass, steel case Tula/Wolf/Tiger/etc. Have been running that rifle with the 1/16" port for a couple of years now. No problems. It also recoils very softly while I have always felt that the Saiga .223 was overgassed out of the box in comparison - in fact I typically use a Wolff XP spring with the Saiga.

Unfortunately when I did the full front conversion on that Saiga years ago I forgot to measure the port size. I've always wondered.

0.0625" is the same port size used on carbine-gas 16" AR barrels which was part of my initial decision to try it as a base port size for this build. I figured the AK needed overall less gas to operate than the AR would and that theory seems to have borne out.

[bsdala]

.067 is a #51 bit, but as stated above you may end up with a slightly larger hole. Test first if worried.
http://www.smithbearing.com/images/p...ionalChart.pdf