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10MM MAGS SWELL


gunfrog

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I just got a Witness Stock II in 10 MM, and some additional mags, all the mags are the K-10 type. I shot 50 rounds so far and the gun runs great. The only issue is, the mags "swell" when loaded with more than 12 to 13 rounds. As in they will not drop free with more than 12 rounds and are difficult to insert with this number of rounds. They 'Shrink" back to size when you remove rounds, such that the total number is 10 or 11 and will than drop free and insert smooth.

Is this normal? Is there a fix?

I did load one up and observed where it was rubbing, than squished it in a padded vice ever so slightly, and it would than insert smooth and drop free fully loaded. But once I removed the rounds and reloaded it went back to expanding.

I suppose I could bring a vice with me to matches and simply squish my magazines before each stage, but I do not want to be "that guy" who is not helping to reset because he has alot of gear issues.

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I just got a Witness Stock II in 10 MM, and some additional mags, all the mags are the K-10 type. I shot 50 rounds so far and the gun runs great. The only issue is, the mags "swell" when loaded with more than 12 to 13 rounds. As in they will not drop free with more than 12 rounds and are difficult to insert with this number of rounds. They 'Shrink" back to size when you remove rounds, such that the total number is 10 or 11 and will than drop free and insert smooth.

Is this normal? Is there a fix?

I did load one up and observed where it was rubbing, than squished it in a padded vice ever so slightly, and it would than insert smooth and drop free fully loaded. But once I removed the rounds and reloaded it went back to expanding.

I suppose I could bring a vice with me to matches and simply squish my magazines before each stage, but I do not want to be "that guy" who is not helping to reset because he has alot of gear issues.

If I recall correctly, CHA-LEE reported this issue early on when the new MecGar mags started coming out.

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I've got a new Witness Match (w/ acc rail) in .40 S&W and I load 12 rounds in each of my four new K10 magazines without any problems. I haven't checked for "swelling", but with 12 cartridges the mags load into the magazine very well and drop free very nicely. My only complaint and it is a very very minor complaint, is that if the slide is forward the mags don't want to seat in the magazine well. But if the slide is locked back there's no problem seating the mags. Since I shoot to slide lock, the "complaint" doesn't matter to me.

Sorry I can't help with your problem.

Edited by jmbaccolyte
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Hey, mbaccolyte, will your mags hold more than 12 rounds? Mine work ok with just 12, but have a witness hole marked 14. The gun was advertised as holding 15.

Just got back from the range have about 200 rounds threw it at this point, feeds everything, hollow points, truncated cone, handles everything from mild 10, to buffalo big bore heavy loads.

Its obvious the mag has a strong/long spring. And the follower has a long skirt on it, that keeps it from tilting. I think these combine to make for reliable feeding, along with properly dimensioned mag lips, and smooth surface inside of the tube, to include the inner edge of the mag lips.

The options for a fix that are on my short list.

1. Disassemble and re-size the body, (may lose capacity)

2. Get a base pad that gives a little more volume

3. Shorten Spring

4. Get a smaller follower.

5. Open up the inside bottom of magwell, the area that it is rubbing on when swelled.

First step will be to take some measurements and get the actual size difference along the length of the tube.

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The new 10mm mags swell because they have lines down the sides. When you cram a lot of rounds in the mag they push into the sides and cause the magazine to bow out causing the sticking issue. There is no fix to this that I know of.

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Gunfrog, mine hold thirteen, if you're "high speed-low drag" enough to make it so (and they fit into the gun fine like that too). Alas, I am not, and I cut my finger putting that extra round in here. Fortunately, I was raised on seven round 1911 magazines, so having trouble free twelve round magazines is like remembering my anniversary- life is excellent.

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  • 2 weeks later...

On my magazine that came with my Match I can put 14 in, I do notice the magazines sliding into the frame with a little more drag then empty but nothing that stops it from dropping free. Also my follower has never gotten stuck. Guess I'm lucky...

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It's Sunday, i couldn't remember. I got the Hunter 10mm out and reloaded the K10 mags. All hold 14+1 and drop free. I've got one K10 mag with a short Henning H500 pad on it. That one just loaded 15+1.(PPU 180gr-JHP) 20 lb spring also helps, just can't find the brass!

Maybe before beating and banging on those mags, try loading back to twelve rds and letting them set for a week. Use loader and go for 13 nexk week. These K series mags are funny sometimes and you have to sneak up on them.

They were mis-advertized at first as being a 15+1 mag but they are a cold stone 14+1 mag.

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Thanks, David S. With 14 loaded in the magazine, do they drag when you insert them into the pistol? I know some of the guys here want to know.

No drag, runs great. Keep in mind this is Factory ammo (OAL). K series mags won't run long loaded ammo. I measured the three brands of 10mm factory ammo and both brands of the 180gr ammo came in at 1.25", the 200gr was 1.258". So the K series will end having a max. OAL for each caliber.

10mm 1.26" CHA-LEE

9x23 1.255" Bret k-38 mag

The 1.18" is the OAL for HiCap long tube race mags? Where did that # come from?

This post rebuilt Monday morning

Edited by david s
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David S.,

I've got a .40 S&W with one new K40 magazine (came with the pistol) and four new K10 magazines (with black followers ordered from the EAA website). The K40 won't let me load much longer than SAMMI specs. The K10 mags wouldn't feed properly at 1.18" cartridge overall length but feeds perfectly at 1.26" OAL (tried the extra length on CHA-LEE's advice).

Sounds like the short Henning H500 pad that allows 15 is what Gunfrog was looking for.

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  • 7 years later...

So. With my 10mm witness mag. If you load it to 10-13, slam it onto your hand to essentially use Newton's law. (Object in motion stays in motion) to relevel the rounds. They end up sitting perfectly so you can finish off with 14.  I also noticed by reverse loading. Taking out spring and dropping rounds in from the bottom. The guide literally sits at the very bottom with 14 rounds.  So an extended bottom cover is probably needed since I'm not sure how close the follower should be to the bottom plate when fully loaded

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