Some of our builds and the three rail forend

[Jake 98c/11b 0]

Assuming I can add the pictures correctly, what follows will be some of the guns we have built recently.

 

The first is a SBS we built for one of our regular customers. For reasons unknown he wanted the LE Entry AR stock, he pays so he gets what he wants. He also wanted a three rail forend and, since we couldn't find one, we made one for him. Barrel length is 13.5 inches and it runs fine.

 

Next is a 20 for one of our instructors, he is a double distingushed shooter who retired from the Navy years ago, since he is only about 5'3" he asked for the ACE ARFX short stock.

 

The third one is only partially done, it has the ACE SOCOM with their folding mechanism. It will eventually be cropped to 12.75 inches to include the Polychoke. We have had some good results with PolyChoke and this one will eventually wear their non vented choke. The second of our three rail forends will be added whenever I have the time to finish it, I have a few more MG's to do first. I will also have this one refinished with Duracoat, it came with the factory camo and I never did like it all that much. Whenever I get around to finishing it I will post it again (it is a shop gun so there is no reason to hurry).

Edited November 10, 2005 by Jake 98c/11b

[Cobra 76 two 2,677]

Man I think the camo one looks wicked! Of course I'm a little partial toward them because I have one. I may just have to convert it too, that looks sweet. How long is the barrel on the 20?

[Jake 98c/11b 0]

The 20 ga is 18.25 inch (for now).

[Cobra 76 two 2,677]

Are you putting a Poly on that one too? The reason I ask is I have a chance to buy one, a ported Polychoke, with ID of .694" inside the threads. Do you know if this will work on my S-20 barrel and how can I get it threaded to fit the choke? I would rather not have to send it off to Polychoke to get it done.

[Jake 98c/11b 0]

Cobra, I have a few more guns here that we have done (didn't want to post all of them and bore people) and one of them is a 20 that I will add a polychoke to. I think the polychoke you mentioned should work but what I would do is turn down the barrel to ensure the wall thickness is consistent. I THINK this would avoid the misalignment problems I have seen with aftermarket chokes. If the barrel needs to be threaded on the inside you will need to use a carbidecutter to cut through the chrome lined bore before you can thread the bore.

[Cobra 76 two 2,677]

Cool thanks Jake. The one I'm getting has female threads. Since those are American threads shouldn't I be able to get the barrel turning and threading done at a local machine shop rather than having to ship it off to polychoke?

Sweet lookin guns there. Do you have more for sale? We love pics post all the ones you want.

I noticed you have not filled in the old FCG axis pin holes yet. You have a plan for them or do you know about the quick easy fix? Just spend $2.00 for some 3/16" nylon hole plugs from Lowes and they pop right in and look just like rivets.

[Jake 98c/11b 0]

You know Cobra, I never thought of that one. I have welded over a few and ground them down but only rarely does anyone want to pay for that (besides my welding isn't that great). Thanks for the info.

 

And to answer your other question, if the machineshop is comfortable in doing it you should be fine. Specialty shops (like PolyChoke) are usually more comfortable with work like this because they have the specialized tooling and a body of experience that can guide them through the process. Some don't like to deal with guns as it is for fear of violating the complex laws and contradictory perceptions of many in the field.

Edited November 11, 2005 by Jake 98c/11b

[Cobra 76 two 2,677]

You will need to enlarge the holes on the right hand side to the same as the ones on the left. They are slightly smaller and will crush the plugs unless enlarged. I think it's a metric sized hole. 3/16" is the next thing up and though the plugs are made for that I like to do mine a little tighter.

[AegisDei 2]

Does the 20ga cycle well? Cobra and I are both having issues with reliable cycling from ours with light loads, I was curious if you ran into this problem and how you tackled it...btw, hot guns!

[kmoore 3]

Does the 20ga cycle well? Cobra and I are both having issues with reliable cycling from ours with light loads, I was curious if you ran into this problem and how you tackled it...btw, hot guns!

 

I'd doubt that you haven't cleaned the factory gunk out, but want to make sure you cover the "easy fixes".

 

My first was a 20 that would eat ANYTHING. Didn't surprise me a bit, cuz it was an "AK". Then, 3-400 rounds later it started FTF with Federal shells (walmart cheapies) but not winchester or Remy's. Hmmm, finally I figured it needed a cleaning. That factory stuff was like molassas in the wintertime. Never had a problem afterwards. With any type of shell.

[Jake 98c/11b 0]

Aegis Dei, the guns are all running 100% right now. I originally had some issues with my personal 20 ga but have since worked it out. I opened the gas ports to .083 and stilll had issues but I got tired of removing the gas block so I replaced the front half of the recoil spring with a reduced power M1911 recoil spring I had in the parts box, it ran fine after that. Since customers shoot it here at the range I added a recoil buffer. I figured that since we don't bother to change the gas setting based on ammunition when customers use it the buffer was a requirment. No problems since then. One day I will remove the gas block and add a fourth port but unitl then the reduced power spring works fine.

[A|G 0]

Jake,

Thanks for sharing those.

Inspirational.

May I ask, how did you make the forend on the first SBR?

 

A|G

[shooter2 5]

May I ask, how did you make the forend on the first SBR?

 

I have no idea how he got it to mate up with a Saiga, but the forearm itself looks to me like a Yankee Hill lightweight float tube from an AR, with the top rail portion removed.

[TonyRumore 1,332]

Would you mind sharing the gas port(s) size on the 13.5" gun? I am very surprised that would would run on light 1 oz target loads like that. Were there other changes made to recoil spring?

[Jake 98c/11b 0]

Tony, a fourth port was added at .081 and one of the existing ports was opened to the same diameter, the other two are .073". Nothing was done to the spring of this gun. I Have run only three different loads through it since the work was done, 100 rounds of a Remington game load and about 35 rounds of buck and slug. One of the other guys in the shop has done about as much but I am not sure of the mix he used.

 

A little mill work on an existing four rail forend was required. It mounts to the gun at two points and has proven to be solid and runs parallel to the bore on our one and only sample.

[Bvamp 604]

seeing how there are two of you looking at this, I gotta ask something.

 

on the gas block, there is a hole exiting the gas block near the point of the gas holes in the barrel, near the gas piston. Is it possible to regulate the gas pressure with that hole instead of the holes into the bore? the hole in the side of the gas block appears (to me anyway) to regulate the back pressure in the gas system, by allowing excess gas to pass out of the system. I would think that regulating that hole, instead of increasing the amount of gas entering the system, might be a more ideal solution, as I would think it would be less gas in the sysem, and thus lower pressures in the system.

 

the only logic I can see with not trying it is this hole is essentially a gas "bypass" hole, that vents when the new AK-foreign piston passes the hole ans strikes the "gas piston" in the saiga12. I guess it would help with bolt return speed, and keep pressures down in the gas block.

 

if you open up the gas port into the barrel, do you also open this hole as well is my other question?

[Cobra 76 two 2,677]

Bvamp this is from a post I made yesterday in the S-20 forum,

 

I'm a couple of steps ahead of you bro. I already did that, thanks to mikey1 for sending me some springs to try. I have done more testing after replacing the forward spring with a .040 Colt spring. After doing that I did have less FTEs and no FTFs but still had some which is too many IMO. I was gonna post another sheet on that when I got time to scan it. Before trimming coils off the spring I decided to take the whole gun apart, clean the gas system completely, and do some polishing and lubing to see if that helped. After polishing the FCG and putting it all back in as well as polishing the bolt carrier and rails and lubing the piss out of it with CLP I tested it again. After that I did have less FTEs and no FTFs but still had some which is too many IMO. Anyway then I trimmed the spring back from 31 coils to 27 and retested. Still some FTEs with some of the shells but for some strange reason the Remington #6 in the green and white box worked flawlessly for two mags worth so far. Still all the rest had FTEs except the Actrive which I did not try. Then I cut the spring again back to 25 coils this time. Shot some more and still had FTEs. Then I tried the 3" magnums again and they still FTE as well. I switched the gas setting to #2 and the 3" works fine. I would not do this with my S-12 but the recoil is so much less with the 20 i don't think it will do any harm. So now I have one kind of light load that works good and don't really understand why the other 2.5 DR still wont eject. The only thing i can think of is it's the only #6 shot of the bunch. The 3" stuff works great on the light load gas setting. If I cut the spring too much more it's not going to be long enough to hold the dustcover on tight. I even tried another theory that me and Bvamp were hoping was a new breakthrough. Have you ever taken the forearm off and noticed that little hole on the left side of the gas block that you can look in and see the piston through? I tried blocking that off with a piece of tape and holding my thumb over it while firing (with a thick glove of course). Bvamp was thinking if you put a roll pin in there it would reduce the flow. Novel idea. We were hoping that would create more backpressure and solve the ejection problem. No dice. Somehow not that much gas escapes through there anyway. You can hold your bare thumb over it and fire (at least with the 20ga) and not feel much of anything escape. I'm not recomending everyone try this, just stating what I did after I noticed it didn't even blow the elec. tape off.

So there ya go, that's where I am at now on this experimental or maybe just mental journey! I hope I'm not gonna be limited to just one kind of light load I can shoot but that's better than what I had before all the tweaking so far. I wonder how much difference it's going to make after I replace the factory FCG with a G2?

Did any of you guys notice an improvement or was it worse because of the extra drag the G2 hammer causes?

[Jake 98c/11b 0]

I am just a parts changing hack but I have had some success with these things. I will say that in all actuality I am not a big shotgun fan in general, I prefer to shoot rifles (it's an Army thing), but they are fairly easy to work on so we have done some odd shotgun projects in the past. I will give credit to the folks at Ares Defense because it was one of their short (13 inch) 20 ga guns that got me started with these things. The gun belongs to one of my regular customers and he was nice enough to let me take a look inside it. The gun has three ports at .078" and two at .063". The only functioning issues he had with the gun was when he ran several hundred rounds (God knows how many in total, he got it used) through it and it began to have issues cycling. He did not know that there is a seperate, large diameter, piston in the Saiga so he never bothered to clean it. When he learned of the second piston he drove it out with a mallet and cleaned things and now all is well in the world, at least as far as this gun is concerned.

 

Remember, I am not a shotgun fan so I have not done an exhaustive check with 35 different types of ammunition on these guns. We have 2 guns as rentals in our range, one 20 and one 12. We rent these things almost daily and they are cleaned probably once a month. They are well broken in now and that has some benefit for reliability. They are shot, mostly, with cheap game or target loads but about 30% of what goes through them is buck and slugs. For a month or more the 20 was only reliable with buck and slugs and not the cheap target loads. I didn't want to open the ports much more than I did until I learned a few more things (and I was tired of driving the gas block off and on) so I tried the spring as mentioned above and it works fine now. Eventually I will do something with that one, I think I will crop it to the point the vented polychoke will bring it to the legal limit.

 

With the Poly-Choke the 'fingers' inside the adjusting sleeve must be at/over 18", the vented sleeve adds to that.