Jump to content

What's your combined port size????


Recommended Posts

This is directed toward the 19" barrel Saiga S-12's.

 

I recently did alot of Mods.

Bolt Polish, Extractor slot fix, reshape hammer,opened up ports, opened up G/B, etc.

 

I opened up my ports from the factory 3 ports about .075" each to a 4 port config 3 at .097" and 1 at .075".

My goal was to cycle the walmart universal 2 3/4 1200 fps 3 dr. eq. 1 1/8 8 shot loads and I could not.

 

I would be interested to see who would give up their combined port size (mine is .366") and what their able to cycle.

 

I believe this is probably a very Taboo subject and that all S-12 problems stem from this very issue this is probably the most critical.

 

I am very curious to see who chimes in and what they say.

 

Please reply with combined port size and load cycling ability.

 

No need for other mods, just the port size.

 

 

This should be interesting.....

 

TYBOY

Edited by TYBOY
Link to post
Share on other sites

My gun now has 3 x 7/64 ports whatever that works out to and it cycles everything. Then again, I'm using a Medium Twister puck that is low on efficiency and requires a good amount of gas to run low brass.

 

 

>>I believe this is probably a very Taboo subject and that all S-12 problems stem from this very issue.

 

 

I can't say I totally agree with that. The performance of the gun is related to all aspects of it's parts. It may be true that the gas ports have a large impact on cycling, but so does the drag on the action. Not a taboo subject at all, it's been covered plenty.

 

The S-12 was designed for high brass loads. If you modify it to favor low brass loads, it's going to take a pounding when you go back to high brass loads. Ideally there should be a balance in between. Take heed of the warnings of CGW and beware of broken parts (carrier, rod, etc.) on over-gassed guns.

Link to post
Share on other sites

Gas port size is less than half the battle IMHO. I have one S12 with 3 holes all .093 (which is supposed to be the factory port size) that will cycle Federal Bulk on -1. Mind you it barely gets out of the gun and occasionaly FTEs but it will shoot it about 95% of the time. I would work on the gun until it hand cycles very smoothly, once you have done that then address the gas ports if you are still having problems. I just got finished building a side folder and I spent a week trying to get it to hand cycle well, I have yet to put a single round through it but once I get it right I have no doubt it will eat anything I throw at it even with the 3 .070 gas ports it came with.

Link to post
Share on other sites

As I understand it, 4 port guns have .073 ports. Since mine is a 4 porter, that would put it at .292 total. Breaking in the action, as well as polishing things up will make a large difference. IMO if you open the ports up on a non broken in gun, you'll eventually have an over gassed setup.

 

Corbin

Link to post
Share on other sites

I appreciate the replies..

 

My goal in this thread was to just more or less hear what people with guns cycling the low to high brass had for total total port size. I figured we had alot of people on this forum that met this criteria.

 

I have almost whipped my own issue's with the way I want my S-12 to perform.

 

This was really to help the new guys on this form (like myself). It kind of seemed to me that you could buy every aftermarket part on this forum and might get it to work, but all of these parts seemed to be compensating for the real issue GAS PORTS. I have been on this forum for awhile now and just thought that you could save some money and frustration if you had a standard port size to open these up to and work from there. I have read plenty of post's indicating what is supposed to be on a stock Saiga with regards to port size, but is that really what all the people with flawless running Saiga's are using. I really don't think so.

 

I do realize there are other contributing factors besides port size but I wanted to focus on that specifically.

 

I may be way off in my thinking, but i was just trying to help.

 

I must admit though, I am suprised at the lack of responses.

 

Disregard and this thread will eventually go away also, LOL

 

Thanks

 

TYBOY See below for examples I was hoping for...

 

 

Joe Blow

 

3 ports for a total of .350" Runs Low to high brass.

 

Noname

 

4 ports for a total of .390" Cycles everything.

Edited by TYBOY
Link to post
Share on other sites

I appreciate the replies..

 

My goal in this thread was to just more or less hear what people with guns cycling the low to high brass had for total total port size. I figured we had alot of people on this forum that met this criteria.

 

I have almost whipped my own issue's with the way I want my S-12 to perform.

 

This was really to help the new guys on this form (like myself). It kind of seemed to me that you could buy every aftermarket part on this forum and might get it to work, but all of these parts seemed to be compensating for the real issue GAS PORTS. I have been on this forum for awhile now and just thought that you could save some money and frustration if you had a standard port size to open these up to and work from there. I have read plenty of post's indicating what is supposed to be on a stock Saiga with regards to port size, but is that really what all the people with flawless running Saiga's are using. I really don't think so.

 

I do realize there are other contributing factors besides port size but I wanted to focus on that specifically.

 

I may be way off in my thinking, but i was just trying to help.

 

I must admit though, I am suprised at the lack of responses.

 

Disregard and this thread will eventually go away also, LOL

 

Thanks

 

TYBOY See below for examples I was hoping for...

 

 

Joe Blow

 

3 ports for a total of .350" Runs Low to high brass.

 

Noname

 

4 ports for a total of .390" Cycles everything.

 

 

Be careful, a lot of the aftermarket pieces will cause the gun to cycle worse than stock. I have a friend who had a very fancy and popular quad-rail that caused the gun to FTE about 10% of the time. Pulled it off and the gun runs like a champ. I myself had a similar problem with a side mounted optic rail, gun would stovepipe 10-15% of the time, pulled off the rail and the gun will eat anything on any setting.

Edited by NinerRider
Link to post
Share on other sites

I appreciate the replies..

 

My goal in this thread was to just more or less hear what people with guns cycling the low to high brass had for total total port size. I figured we had alot of people on this forum that met this criteria.

 

I have almost whipped my own issue's with the way I want my S-12 to perform.

 

This was really to help the new guys on this form (like myself). It kind of seemed to me that you could buy every aftermarket part on this forum and might get it to work, but all of these parts seemed to be compensating for the real issue GAS PORTS. I have been on this forum for awhile now and just thought that you could save some money and frustration if you had a standard port size to open these up to and work from there. I have read plenty of post's indicating what is supposed to be on a stock Saiga with regards to port size, but is that really what all the people with flawless running Saiga's are using. I really don't think so.

 

I do realize there are other contributing factors besides port size but I wanted to focus on that specifically.

 

I may be way off in my thinking, but i was just trying to help.

 

I must admit though, I am suprised at the lack of responses.

 

Disregard and this thread will eventually go away also, LOL

 

Thanks

 

TYBOY See below for examples I was hoping for...

 

 

Joe Blow

 

3 ports for a total of .350" Runs Low to high brass.

 

Noname

 

4 ports for a total of .390" Cycles everything.

 

Sorry reread your thread and wanted to comment further. As I stated if port size is half the battle then what good is a survey of various members port sizes? If you drill enough holes in your barrel I am sure you will probably overcome the lack of proper tuning in other parts of the gun. Like I said my new gun has 3 ports all .070, if I can get it to hand cycles as smooth as my first S12 I have no doubt it will perform as well. But if you just want half the equation here you go.

 

3-ports all .093" total .279" eats everything and never FTEs! Highly tuned internals!

 

3-ports all .070 total .210" never shot it who knows what will happen! Internals are close but may need more work after a trip to the range.

Link to post
Share on other sites

NINERIDER,

 

Thanks

 

I'm not meaning to come off bad.

 

I guess what I'm trying to do is best described like this:

 

If I was to build a Dragster, I would rather start with a V8 than a 4 Banger. I could get the 4 banger to run fast but it would take alot of add-ons. I will still have to add-on to the V8 and tune it, but it sure does make an easier starting point for the build.

 

Thanks NineRider

 

TYBOY

Link to post
Share on other sites

Gotcha no offense taken! ;) Just trying to pass on what I have learned, I drilled my first S12 from .070 to .093 and while that helped it probably wasn't necessary and may limit what I can shoot since the gun is operating so efficiently now. That is why I am approaching my latest build completely different, opening the gas ports or making any kind of gas port modification will be my last resort. Once you feel how well a tuned gun cycles it is obvious that this is where most problems need to be addressed. Again IMHO and since I have worked on just three of these guns I am by no means an expert.

Link to post
Share on other sites

I just matched the angle that was already there, the drill bit wants to follow that path anyway. On my friends gun the holes were drilled almost perpendicular to the barrel so we re-drilled them about 45 degrees to the barrel.

Link to post
Share on other sites

NineRider,

 

I guess I will settle for how the Gun functions now. It will run High and Low brass (Just not Walmart Universal Low) LOL.

I will not open up the ports any more than I already have and will just replace the Hammer I screwed up. I do want to do a little more work on the feed ramp I saw mentioned before.

 

Thanks Again

 

 

TYBOY

Link to post
Share on other sites
  • 6 months later...

NineRider,

 

I guess I will settle for how the Gun functions now. It will run High and Low brass (Just not Walmart Universal Low) LOL.

I will not open up the ports any more than I already have and will just replace the Hammer I screwed up. I do want to do a little more work on the feed ramp I saw mentioned before.

 

Thanks Again

 

 

TYBOY

open the ports. :lolol:

  • Like 1
Link to post
Share on other sites

You can't just add the diameters of the ports together to get a total port area. You have to halve the diameters, square them, multiply by pi then add them together.

 

port.jpg

 

You can see the difference between one blue circle with a 400px diameter v. four yellow circles with 100px diameters. Four circles have a total area of 4(50px^2*pi)=31,416px whereas the single circle has 1(200px^2*pi)=125,664px, or roughly quadruple the area.

 

This can obviously be a problem when drilling ports to spec.

Edited by Axman
Link to post
Share on other sites

Good explanation by Axman.

 

The "area" of the openings have to be calculated in square inches, or square mm or whatever units you are using.

 

So if you are using a 3/32" (.093") drill bit which is what many guys have said that is a good size for a 3 hole gun, including Tony, then the area of that opening is .0069 square inches.

 

So 3 of those holes would give you a total opening area of .020 square inches.

 

To match that opening with 4 holes, you would need a #59 drill bit (.041" diameter) which is a little smaller than a 3/64"

Link to post
Share on other sites

^^ 4 eyed cookie monster! :lolol:

:lolol: :lolol:

 

On topic, I have a three-hole, I believe it's an '08 but I'm not too sure. Aside from adding a V-plug and polishing the bolt and carrier with my dremel (just enough to shine a little, all I wanted to do was take the paint off) it hasn't been touched.

 

With the stock plug, it would cycle just about everything just fine, as long as I backed the stock plug out one full turn from bottom and adjusted from there.

 

With the V-plug, it runs everything. I sometimes have a failure to feed but that's not the gas system, every time when that happens, it's on a hot day and the plastic shell digs into the feed ramps.

 

I DO believe that my gun is a bit undergassed, but I've never been able to check port size, all three are there though, and unobstructed...

Link to post
Share on other sites

Area of a circle is calculated by....

pi x radius x radius

 

I have 4 @ .093", so....

 

(1) port is.... 3.14 x 0.0465 x 0.0465 = 0.006789465

 

(4) ports are.... 0.006789465 x 4 = 0.02715786 sq in

 

This is not exact, but close.

Edited by evlblkwpnz
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Chatbox

    Load More
    You don't have permission to chat.
×
×
  • Create New...