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leadsled

Jamming on Hood

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Having jamming isses on the hood with everything I've tried except Rio 00Buck. Have the Glassbolt, HD op rod, CSS puck and MD Arms V plug. Have put right at 800 shells through it. Action is smooth as butter.

 

Use mainly Wally World Federal 7.5. Have four SMG 8 rounders/

 

Sometimes it will run no problems, then I'll get a shell to hang. Sometimes every mag, except the Saiga 5 rounder.

 

Has never hung up with Rio 00 Buck.

 

I think it's the ammo. Any other bulk ammo out there that is slightly longer?

 

Was told Estate 1 1/4oz loads are the way to go.

 

Here is a video. Hoping it would jam but didn't. Everything seems fine except the random hangups.

 

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Sometimes the underside of the extractor cutout is a little sharp, an catch on the round as it loads. A small file will lightly round off that area and keep that from happening.

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If you notice the ejection pattern in the video a few of the shells are ejecting lower than the others. I would have to guess here that there is a timing problem and they are hitting something. I would be looking at the shells for tattle tale marks.

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Yeah you can file the inside of the hood and open up the inside part of it (Think funnel) and it'll solve that. At least it did for me. I also had a problem with front of the round jamming while inserting into the chamber so I did the same to the bottom part in front of the chamber, no mo problems.

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Does the feed angle with those shells/ magazines match others with the OEM Izzy 5 rounder? Since you say it has not happened with that magazine, I think you have found what is different. SGM does not excactly match OEM. on mine the shell points a hair lower.

 

If you can reproduce the error by hand cycling with the dust cover off, you may be able to identify where to take off a sharp edge. Or you can go extreme and extend the hood .25" like Evl and others have done. (and as the factory now does) I also wonder if the shell becomes deformed as you load a magazine against a closed bolt, or conversely the bolt pushes down a misaligned shell into the proper place.

Edited by GunFun
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Does the feed angle with those shells/ magazines match others with the OEM Izzy 5 rounder? Since you say it has not happened with that magazine, I think you have found what is different. SGM does not excactly match OEM. on mine the shell points a hair lower.

 

If you can reproduce the error by hand cycling with the dust cover off, you may be able to identify where to take off a sharp edge. Or you can go extreme and extend the hood .25" like Evl and others have done. (and as the factory now does) I also wonder if the shell becomes deformed as you load a magazine against a closed bolt, or conversely the bolt pushes down a misaligned shell into the proper place.

 

2012-05-30225033.jpg

 

 

I staged a jam like I had this afternoon. The edge of the shell is completely over the edge of the hood. It's not a matter of a burr or anything like that.

 

Now that you mention it, I started noticing this happening since I had the ability to load on a closed bolt. Also this mainly happened on the 6th or 7th round. Obviously not in the video where I loaded on a closed bolt. My buddy brought along Federal 1 1/8oz #8 shot and had no issues until he started trying to load on a closed bolt, come to think of it. anger.gif Perhaps the shells are getting shifted where the nose is pointing too high the closer to the end of the magazine.

 

Someone advised to stretch the springs on the 8 rounders. I did that and the problem seemed to dissipate a bit, but not completely.

 

Next range trip, I will try Estate 1 1/4 loads and Federal Bulk and try them both on an open bolt and closed bolt

 

I like the ability to load on closed bolt. I don't want to limit myself to 5 rounders and can't afford Izzy 8's.

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Can you wiggle the magazine around much while it is locked in?

 

adding some material to the hood seems like the best solution, but making the magazine aim 1/8" lower could be another fix. I bet you wouldn't be able to do that with 3" shells, so in the meantime, I suggest 3" #4 Buck for your defense load.

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I had the same problem. It was the 10 round SGM mag. It would high feed the 7th or 8th round almost every time. I cut it down to an 8round mag and it still does it on all 3 of my s12s. Needless to say, I don't use SGM mags anymore. AGPs and MD drums work for my guns. Extending the barell hood may help, but its cheaper to just buy new mags. I think someone here posted a fix for this a year or two ago by using a shim on the back of the follower. You might want to search for that. Good luck.

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The next thing I need to try is loading a 5/8" spark plug socket into the mag and dipping the mouth into boiling water for 10 seconds and letting it air cool.

 

I'll try finding the shim thread if the socket doesn't work.

 

Can you wiggle the magazine around much while it is locked in?

 

Barely any fore and aft movement. Slight side to side.

 

The bottom shells are obviously dragging or getting upset during firing. But it's not all of the time. That's what's pissing me off.

Looks like I need to sample some different magazine makes.

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That is unusual. People don't usually have problems with SGM, and the 8s are usually considered to be extra reliable.

 

I wonder if there are any any burrs or other deformities on your follower or the mag body near the top that can cause the follower to drag as it gets to the top of your magazine?

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http://forum.saiga-12.com/index.php?/topic/54450-the-problems-just-keep-coming/page__p__513795__hl__+magazine%20+follower%20+shim&do=findComment&comment=513795

 

This is a thread I found. Pauly actually PMed me the socket trick and it makes sense to me.

 

2012-06-01002650.jpg

 

Wonder what dremelling down this ridge on the back of the follower would do?

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I would say use a file. Dremmels will gum up and not be as smooth. I think that may help to stop it when it reaches "home", so probably not a great idea.

 

Why not spray the inside with athlete's foot spray and then assemble and push the follower in and out with a pencil? The powder will show where things are tight. Then you can heat and form with the socket or file a bit where needed instead of guessing and taking material that is hard to put back.

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2012-06-01011023.jpg

 

Here is the factory 5 follower. Obviously the follower is longer as there is no tilt.

 

1. The mouth of the SGM is a little tighter. Widening it will help things.

 

2. The back of the inside of the magazine, right before the shell seats in it's top most position is not properly shaped. The factory mag is shaped and finely finished so the rim doesn't scrape the back and drag. The SGMs do drag the shell and are not shaped the same. I will have to deal with that.

 

2012-06-01013034.jpg

 

Here is a shell hung up right before reaching the top of the SGM.

 

Damn. I spent so much time on the gun, the mags were almost an afterthought.

 

The Russians do know how to make a magazine. I can see how people will spend lots of cash on the factory 8's!

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...The Russians do know how to make a magazine. I can see how people will spend lots of cash on the factory 8's!

 

It's a pity that it's necessary to do so.

 

I think US manufacturers could make S-12 mags that are just as durable and reliable, but they'd have to give a shit first. Mike Davidson is the only US mag manufacturer who seems to, hence his MD20 drum's exceptional performance.

 

I expect his double-stack mags will offer similar reliability.. but SGM, AGP, and "Pro"-Mag? They just keep cranking out sub-par crap and seem perfectly happy to continue doing so.

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MD Arms just needs to release a single stack mag built to the same quality of all his other parts and dominate the US made S12 mag market. They could do that easily!

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Before hacking on a polymer mag, try some dry silicone spray. I de-burr and spray every plastic mag before even loading it for the first time.

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I did the spark plug thing and dremelled some material from the back of the magazine right before the shell reaches the top of the magazine. I'll also try some dry silicone spray for good measure.

 

So far everything seems good. Won't be able to go to the range for awhile.

 

Thanks for all the help.

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The magazine tricks discussed here influence the the feed angle anbd are helpful. By reducing the feed angle (or reducing the VARIABILITY in the feed angle), you reduce the probabily of a shell getting hung up on the hood. However, in my experience, that usually isn't the total cure. Do the following test -- it will save you a lot of ammo in testing and troubleshooting:

 

1. Take a screw driver and gently lift a shell and see if it will be captured under the hood, or if it can still slip behind the hood as you have been experiencing. See the attached picture. Notice in the picture that there is no way for the shell to get hung up on the hood. Keep in mind that there is a huge variation on length of the shells so you will want to try a few shells, or measure and pick the shortest one out of the box.. The specification of 2 3/4" length shell is the OPEN length. The closed length varies a lot by manufacturer and even within a box of shells.

 

2, If by doing this test you find that a shell can get hung up, the hood is too short. Sooner or later, a shell will get hung up, it’s just a matter of time and probability. If you want total reliability, you’ll need to TIG weld just a small amount to the rear of the hood. Sometimes this is just 0.100” of material. Then carefully contour the welded area to match the existing hood. DO NOT mess with the angle on the right side (looking from the top) of the hood. Just file the weld material to match the existing angle. This angle is what initiates the rotation of the bolt into battery.

 

The second picture shows a completed hood extension after welding and filing. Notice that the shell is totally captured and there is no way for failure. In my experience, this is the only 100% reliable cure to the problem you are experiencing.

post-31037-0-94689800-1339256045_thumb.jpg

post-31037-0-19649900-1339256072_thumb.jpg

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This was the '09 barrel that went to my SBS (my avatar). I figured I'd add an extension while I had it out. This was before I did the final notch. I think it turned out nice.

 

post-22401-0-42922200-1339448244_thumb.jpg

post-22401-0-18144800-1339448258_thumb.jpg

Edited by evlblkwpnz

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I would love to have that done. If anyone knows who can do this in the greater Austin, TX area, I would appreciate it.

Jack Traver of JT Engineering is about 300 miles east of you in Leesville, LA.

He does them. Fair fee too.

Unsure who else does professionally.

 

Widening the mouth of the SGM will likely help if it's a slow-feed. Slow feeds cause the stovepipe FTF because the feed foot begins to push the shell too high resulting in the nose of the 2 3/4" shell being kicked upward just right to jam on the barrel hood there.

I have found enough SGMs that the shell can contact both sides of the mag at the same time, where now, tuning that part is just something I do to every black SGM S-12 mag.

Once fixed, I've never had issues with them re-shrinking.

Short-stroking can cause the same issue, but when it's short cycling causing it, it's because the carrier is not traveling back all the way as it should, so begins its return early.

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I widened the mouth of the SGM as per your instruction, Pauly. Also removed some material from back of magazine to ensure no part of rim drags right before reaching the top. Hand cycling each magazine several times has not replicated the jams that plagued me at home and the range.

 

Evl, that is nice work.

 

The last thing I will do is get some dry silicone lubricant. That should make the magazines as silky smooth as the rest of the firearm.

 

I just want it to be reliable with all ammo. If need be I'll get some 3" but am not a huge fan of it. The added recoil, at least out of a pump, does not seem worth it.

 

The S12 is my favorite range gun, but not HD at this point. Only when it feeds everything can it stand guard.

 

downloadfile-2.jpg

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There was a thread a few years back where a shim was glued to the front of a surefire mag. I did it to both of my 12 round mags, and all of RRice's surefire mags and neither of us have had a feed failure since. Before the shims we were both experiencing about a 4% failure rate and it seemed the faster you shot, the greater the failure rate.

 

The surefire follower was designed to rock. I believe to make it easier to load. As a result, when pouring out hulls, they rock when feeding and cause issues. Shim the front of the follower and no more issues.

Edited by hobbyshooter

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Could you post a picture and give a little more detail. I thought I read where some put a shim on the back of the follower to keep the nose of the shell from coming up too high.

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I have never had a issue from SGM magazines. Why not contact SGM and see if they would swap the mag out before doing all the crazy stuff to the mag? They have like a year or three year warranty.

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Malcolm spelled it out pretty well. It's not an issue until you get a shell that is too short and drags and hangs on the hood. It's a combo of magazine, shell and hood.

 

I think I've REDUCED the chances of a hangup but not totally eliminated them. My internals are all polished thanks to Pauly. Mags have been widened and smoothed out on the inside. Only factors now are the shells and hood. It will be a couple weeks till I can get to the range.

 

Below are 5 different 2 3/4" shells. L to R : Winchester Super X slug, Winchester Super X 00 Buckshot, Remington HD Ultimate Home Defense BB, Rio Royal Buck 00, and Federal slug.

 

As you can see, they are all different sizes. I've fired about 5 boxes of the Rio and have had no issues. The whole point of this maddening exercise is to make it shoot ALL 2 3/4" ammo. Mainly for the cost. Secondly, I don't want a gun that can't handle all 2 3/4" ammo.

 

I've been told multiple times by a Saiga 'smith in the area (who unfortunately left gunsmithing for other pursuits) to stop shooting crap ammo and shoot what it was designed to shoot. Unfortunately I don't have factory 8's and steel shells.

 

2012-06-12145839.jpg

downloadfile-1.jpg

Edited by leadsled

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Here are a couple of pics. The shim is just a peice of plexi. I sanded the front of the follower and the plexi to prep it and super glued it together. Then I set it in the vice and let it cure over night. Haven't had a single feed issue since regardless of ammo.

 

As you point out some shells are shorter than others. The follower rocking back takes that barely long enough shell and points the nose up too far. Stop that rocking and the surefires feed.

 

 

post-9800-0-01409300-1339538858_thumb.jpg

 

post-9800-0-95421000-1339538876_thumb.jpg

Edited by hobbyshooter
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Mitutoyo says about .060" but it's pretty hard to measure a shim gued to a follower.

 

As I mentioned above I prepped both surfaces to be glued and let it set up in the vice to cure. Then I ran the follower through the mag body with no spring to see where it would hang up under normal gravity. I sanded the follower where it would hang up until the follower would slip through free. Then I polished up the follower with 600 grit.

 

Probably overkill though. Just cut the shim to size, prep, glue, clamp, cure, take it shooting.

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