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JonWienke

Rim Lock With 3" shells

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I recently purchased 5 of the 8-round Saiga-12 magazines. So far they have worked flawlessly with 2-3/4" shells as long as the action cycles far enough to eject the fired case.

But a couple of them have a problem with 3" shells. The nose of the top round gets pushed down by the feeder foot on the bolt as the bolt is coming back, which causes the rim of the top shell to snap behind the rim of the next shell down. When the bolt comes forward, the top shell in the mag cannot push forward because its rim is caught on the rim of the shell below, and the only way to clear the stoppage is to remove the magazine, and press down on the second shell in the magazine while simultaneously lifting the nose of the top shell to disengage the rims.

 

Is there a fix for this, or do I have defective mags?

Top shell in normal orientation:
post-50825-0-67171700-1452195683_thumb.jpg

 

Top shell rim locked:

post-50825-0-04280300-1452195745_thumb.jpg

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If only a couple of them are doing it then it could be that something is wrong with those magazines. It is always possible to have something not right.

 

One thing I am aware of, is that some shells with softer hulls rim lock more easily when inserted on a closed bolt, the fronts compress making the shells more prone to rim lock.. It was most likely to happen on buckshot shells that don't have a wad because they distort more. The simplest solution is loading on an open bolt to prevent squishing the hulls

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Interesting. I haven't had that issue, but I shoot 2.75" most often. I have shot 3" shells from mine of course, but never with that issue. Your analysis seems reasonable. Are loading them to 8 or 9 shots?

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I've loaded 8 and 9. The problem usually happens midway through the mag. The first 1 or 2 shells go fine, and so do the last 2 or 3. The ones in the middle rim lock intermittently. I've tried 3" Federal, Winchester, and Remington buckshot and slugs, and have had the problem with all of them. Even with the mags freshly loaded (<5 mins from loading to jam).

 

But I have yet to have the problem with any type of 2.75" ammo.

 

The difference seems to be related to the follower. The magazines that don't jam push the whole shell column down in unison when you press down on the nose of a shell when loaded with 8 rounds. The ones that do jam allow just the noses of the shells in the magazine to tip down, while the rims stay stationary. That is how the rims are able to lock.

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One other thing I noticed:

 

Comparing the follower of the CSSPECS magazine to the factory Izhmash follower, I notice that the part of the factory follower that supports the front of the shell extends about 1/4" further forward than the CSSPECS follower. This makes it easier for the shell nose to tilt down in the CSSPECS magazine than the factory magazine.

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Let me look into this a little. We are just about to produce another batch so I'd like to address any issues right now. 

 

Edit:

Contacted Mark who has the design files on these, he pulled up the design notes. Follower was made short to prevent bolt collision. There was a concern that the bolt could be damaged from the metal on metal contact, so it was reduced to prevent this.

 

The opinion is that the magazine bodies spread from heat treatment and are allowing the follower to move outside of its intended path.

 

Contact me at Sales@csspecs.com for a return label for the two trouble makers. We want to measure them and add it to our quality control steps..

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IMO it would be better to extend the follower support shelf back to its original length. It's worth noting that there are many firearms designs, including the G3, SKS, and the AK-47, in which the magazine has a metal follower that is contacted by the bolt/bolt carrier every time the action is cycled on an empty magazine, without damaging the bolt or the magazine follower. In general, there is much less spring tension between the follower and the bolt than there is between the hammer and the bolt carrier, but the hammer does not cause undue wear. Over time you may get a wear mark in the finish of the follower, bolt, or bolt carrier, but it's minimal, especially since it only happens once per magazine rather than every time the gun is fired.

 

The factory follower makes considerable contact with the bolt over nearly half of its length. You can see two distinct wear marks in this photo:

post-50825-0-61801000-1452254392_thumb.jpg

This doesn't damage the follower or the bolt.

 
I just tried pulling the follower from a factory 5-round mag and put it in one of the problem mags. It went from 2-3 jams per mag hand-cycling 3", to zero jams in 4 full mags, using the same rounds (Winchester Super-X #1 buck 24 pellet) that rimlocked with your follower. The factory follower sticks up a little higher because the support shelf extends further forward, which not only eliminates the nose-diving and rimlock problems, it also presses the shells more firmly against the upper barrel extension and straightens them out earlier in the feeding cycle, so they bind less as they are transitioning from being angled upward as they are first coming out of the mag to being horizontal as they enter the chamber. 
 
I'll send you the mags back if you want, but I completely eliminated the problem just by swapping the follower.

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On your suggestion we have been doing some testing. We found that increasing the length of the shell support eliminated 3" rim lock issues completely even with the crappy smashed shells it was perfect. We are going to do a few additional tests with a full steel follower to confirm that bolt contact won't cause any issues with the update.

 

If everything checks out we will have the update available in about 60 days, we will setup a link on our Saiga-12 product page for existing magazine owners to get the updated follower sent to them free of charge. 

 

There is a similar effort going for the Saiga-20. The follower is being updated and will be available for existing owners once complete. The Saiga-20 follower is a complete redesign, so it will take longer.

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We have. Many of our customers want an all steel product, so it would be prohibitively expensive to make them for the ones that wanted the poly.

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Let me look into this a little. We are just about to produce another batch so I'd like to address any issues right now. 

 

Edit:

Contacted Mark who has the design files on these, he pulled up the design notes. Follower was made short to prevent bolt collision. There was a concern that the bolt could be damaged from the metal on metal contact, so it was reduced to prevent this.

 

The opinion is that the magazine bodies spread from heat treatment and are allowing the follower to move outside of its intended path.

 

Contact me at Sales@csspecs.com for a return label for the two trouble makers. We want to measure them and add it to our quality control steps..

 

I am so glad that your first batch is selling well. Also that there are now more firearms on the market which accept this standard.

 

As always, I am impressed with how your business handles things.

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As always, I am impressed with how your business handles things.

 

 

I agree. It's always refreshing to deal with a company that is willing to acknowledge their product is imperfect, and work to fix or improve it just because they want a better experience for their customers. Kudos.

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We have. Many of our customers want an all steel product, so it would be prohibitively expensive to make them for the ones that wanted the poly.

 

I would have probably prefered poly on steel for self lubricating aspect and nois, but I like the fact that steel is easy to tweak. As is, they are remarkably smooth.

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As always, I am impressed with how your business handles things.

 

 

I agree. It's always refreshing to deal with a company that is willing to acknowledge their product is imperfect, and work to fix or improve it just because they want a better experience for their customers. Kudos.

 

 

Thank you.

 

We try to do the right thing. I do regret that it is going to take so long to get the update applied, but the lead times are what they are.

 

I'll try to keep you posted on the progress, do you mind if I post updates in this thread?

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Tooling is done. We came up with a way to make perfectly accurate one off sheet metal samples, we take the sheet stock about the right size and glue it to a block of steel and stick it in the CNC mill and run a 1/32" endmill around it to cut out the part. Costs something like $35-40 each part, which is actually way cheaper than spending 4-5 hours filing the part to correct.

 

I hope to post a little video showing the update tonight.

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Parts are on order with laser cutting and should be here in something like 3-4 weeks. I figured getting the ball rolling was more important than talking about a ball and how it could be rolled.. 

 

Taking a longer look at the follower helped solve the problem we have been having with 10 round magazine testing. So expect those on the market in about 60-90 days.

 

 

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Awesome.

Safe to assume 10rd V12 mags will follow?

 

Yes, same principles involved.. We have the Vepr-54r coming up which will take priority over expanding existing product lines, so it may be delayed a couple months further out.

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Awesome.

Safe to assume 10rd V12 mags will follow?

 

Yes, same principles involved.. We have the Vepr-54r coming up which will take priority over expanding existing product lines, so it may be delayed a couple months further out.

 

 

 

I'm waiting patiently for both 54r an V12.

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Tooling is done and we are waiting on steel parts, I have not received a shipping notice.. The total order was about a ton, so it takes a while to get them cut.

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They are at heat treatment/metal finishing right now. Should be done in a week or so, maybe longer.

 

We dropped off a lot of parts, so it could take them longer to work through it.

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This has been one of the longest waits for metal finishing since 2013.

 

My brother stopped with another batch a couple weeks ago and the place was PACKED, pallets of AR barrel extensions all down the wall probably 250K+, barrels upon barrels of trigger parts.. shipping containers of pistol magazines waiting outside. Apparently every gun maker is loading up for a possible gun run in November...... If trump wins expect some epic sales.

 

Please forgive the delay, this is apparently not going to be a fun summer... Our slot started Friday night, so we could have the parts early this week. I'll keep you updated.

 

Up stream is clearing up, I have been getting billet, bar and sheet goods at record speeds with the sales people saying it just slowed up in the last couple weeks.. So odds are the downstream side of finishing will clear up in the next month.

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