RDSWriter 5 Posted March 17, 2008 Report Share Posted March 17, 2008 (edited) First, thanks to Dinzag for offering the S12 threading die. I've used it on all my S12s. As for my SBS gas ports, I added the fourth and overdrilled them to 3/32 (0.0937) while slghtly tapering them to a 45 degree angle. No problems taking it nice and slow. It should be ready to go with heavy bird loads. For those of you who are concerned about mucking up your barrel, (1) use a vice and barrel blocks if you own them (2) use quality cobalt bits, (3) follow the instructions on this board, and (4) go sloooowwwwww. Edited March 18, 2008 by RDSWriter Quote Link to post Share on other sites
22_Shooter 1,560 Posted March 17, 2008 Report Share Posted March 17, 2008 Damn, that came out nice. Quote Link to post Share on other sites
Vultite 57 Posted March 17, 2008 Report Share Posted March 17, 2008 nice job, when can we expect a range report? Quote Link to post Share on other sites
6500rpm 670 Posted March 17, 2008 Report Share Posted March 17, 2008 Did you use a lathe, or something different to dress down the step at the front of the barrel? Quote Link to post Share on other sites
RDSWriter 5 Posted March 18, 2008 Author Report Share Posted March 18, 2008 (edited) Did you use a lathe, or something different to dress down the step at the front of the barrel? Nope... I wish I had access to a lathe for some of my projects. I just use an set of aluminum barrel blocks, 1/4 inch triangle file and a set of calipers. I use the depth of the threads as a guage of how far to file. Basically, just file the threads slowly until they disappear. Then rotate the barrel and file again until the threads disappear, and so on until the barrel has rotated 360 degrees. If you go slo slow you can 'follow a thread' all the way around. The exposed smooth surface should be (if I remember correctly) about .350 inches from the muzzle. However, after doing two S12s to factory spec... this one I just took off about 1/4" as I like the idea of having more threads. Then, I just light file another 360 degree rotation using the calipers to ensure a consistent edge and to blend in any low/high spots . Finally, I hit it by hand with 600 grit paper to polish. FYI, I tested this smaller 'unthreaded area' with a Tromix shark brake and the following Russian chokes/brakes - paradox, (0,0), short flash hider, long flash hider, muzzle nut. All of them work. I made the mistake on my first S12 of just checking with one brake... and even the Russian factory ones have some variance. So my recommendation is to double check with as many chokes/breaks as you own. Edited March 18, 2008 by RDSWriter Quote Link to post Share on other sites
6500rpm 670 Posted March 18, 2008 Report Share Posted March 18, 2008 I was just curious, I did mine a few years ago on a cut back 22" and that step was the biggest p.i.t.a.. I did it more or less the same way using a cut back thread protector as a guide and a way to protect the threads. I think I used automotive valve grinding compound for the final fit. Just wondering if someone came up with a better way other than pressing the barrel out and chucking it in a vice. Dinzag's got a lot of stuff on his site to take advantage of, back in the day it cost a lot more up front, and results were always a risk. Between the tools and items he has available, if you have basic hand skills, even a caveman can get professional results. Looking back a few years, I think it was Brian and Shannon's builds that really got me hooked. It's amazing what you can do if you try, your conversions moving along well-good luck. Quote Link to post Share on other sites
RDSWriter 5 Posted March 18, 2008 Author Report Share Posted March 18, 2008 Actually, I didn't press the barrel out. I just used some AR15 aluminum barrel blocks in a vice with a piece of rubberized drawer liner to preven marring and give some extra grip.I then put the entire barreled receiver in the barrel vice with only the barrel clamped. Then I'd just file, loosen up the vice, rotate, retighten, file, loosen up the vice, rotate, retighten, file.......... ad nauseum. Quote Link to post Share on other sites
dinzag 31 Posted March 18, 2008 Report Share Posted March 18, 2008 Nice & clean job! Quote Link to post Share on other sites
eodinert 1 Posted March 28, 2008 Report Share Posted March 28, 2008 How long is the barrel? Does it run? Have you shot it yet? Keep us updated! Quote Link to post Share on other sites
eodinert 1 Posted April 14, 2008 Report Share Posted April 14, 2008 Any updates for this? Quote Link to post Share on other sites
eodinert 1 Posted May 8, 2008 Report Share Posted May 8, 2008 ?? Quote Link to post Share on other sites
RDSWriter 5 Posted May 22, 2008 Author Report Share Posted May 22, 2008 (edited) UPDATED May 23 Well, I finally got out to test the modifications and it looks like I'll need to do some more tweaking. The following images show the outome of shooting 10 rounds of each type of ammo, 5 rounds with an original Russian flash hider (no choke), and 5 rounds of the Russian choke (0,0) that is equavalent to a cylinder choke. The cylinder choke basically made the barrel 14 inches. Rather than wait to post the final modification 'solution,' I figured that many of you might want a step-by-step of the modifications so that you can understand what won't work and what is the eventual solution. On a #2 gas setting with buck shot and the heaviest loads (3 3/4 drams and 1 1/8 oz shot), the gun ran. With the #1 setting or anything lighter, my SBS was inconsistent. I don't consider this too much of a surprise, but I was hoping that by leaving the SBS barrel a bit longer may minimize the REQUIRED work to get it to run. I was plannig on doing a couple more modifications to the gun... so I'll do them and then re-test. Also next time I will bring a a modified choke to test out... I had meant to take it to the range rather then the cylinder, but accidentally took the wrong one. So, my next steps are to re-contour and polish both the bolt and the feed ramps. I'll test and if that doesn't work, I'll open up one or two of the gas ports a litttle bit more. Edited May 24, 2008 by RDSWriter Quote Link to post Share on other sites
eodinert 1 Posted May 23, 2008 Report Share Posted May 23, 2008 Most awesome update. Keep us posted! Quote Link to post Share on other sites
RDSWriter 5 Posted May 24, 2008 Author Report Share Posted May 24, 2008 In going back through my range bag, I just realized that I grabbed the wrong choke in my initial test. Instead of taking a modified choke (0,5), I took my cylinder choke (0,0). The chart above has been updated to reflect this change in information. Hopefully, I can get out this weekend or next week to test with the next round of modifications to the bolt and feed ramps as well as with a modified choke. Quote Link to post Share on other sites
loner42 6 Posted May 27, 2008 Report Share Posted May 27, 2008 RDSWriter, was wondering if you could tell me how you made the chart : I posted a list of ref. dim. for AK Barrels and components above in this forum and would really like to have been able to make it like your chart is done. Thanks Quote Link to post Share on other sites
RDSWriter 5 Posted June 5, 2008 Author Report Share Posted June 5, 2008 (edited) UPDATE JUNE 4 Got out the range with a Polychoke with a modified/polished bolt and feed ramp area. I basically tried out most of the same ammo as well as some other varieties. I'm not planning on posting another chart until I get it to work a little better. Loner - to answer your question, I used MS Visio to create the table and saved it as a JPG file. In short, the Saiga12 ran a little better but would still not reliably function with high brass or heavy field loads - EVEN WITH A FULL CHOKE on the 2 gas setting. 00 Buckshot and slug had no issues on the 2 gas setting and ran 80% on the 1 setting. So the issue appears to be the amount of gas. I am very close to getting it to run... I just need a bit more gas or a bit less recoil spring pressure. My next step is to replace the front recoil spring with a 14lb 1911 recoild spring. I highly doubt this will solve the issue... but I'm actually enjoying getting out the range more often and this step-by-step testing is definitely forceing me to make more trips to the range. I just take a couple other toys each time I go to make it more interesting (as if it needs to be more interesting than firing an SBS S12 on an indoor range ) If the spring replacement doesn't work, then I'll open up the hole(s) a bit more. On another note, I appreciate C&S Metall Werkes posting in a different thread about their experience making the ejector a 1/4" longer. Most of my failures can be tied to a weak-ass ejection that does not THROW the brass. Even with 00 buckshot on a 2 gas setting the empty cases are only being thrown about 3 feet. Once again... indicating a gas issue. Stay tuned.......... Edited June 5, 2008 by RDSWriter Quote Link to post Share on other sites
anatak23 0 Posted October 6, 2008 Report Share Posted October 6, 2008 RDSWriter, You ever get this nailed down? Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.