Problem with Charity Mag build

We think the mag is having a Bolt Stick issue.

What this means is that after the gun fires the bolt does not fully reset to the "cocked" position. We first thought it was an on/off problem but it's not leaking down the barrel and it resets if you push the bolt back manually with a dial rod.

I've temporarily fixed the issue by stretching the return spring. This won't last. Eventually the spring will return to shape and the problem will reappear. The root cause can still be a couple of issues.

1) It could be an improper power tube spacer. It currently has a .215 spacer installed. I tried a .225 but that causes it to leak. I didn't have a .220 spacer to try so that could be the fix. I got some spacers from Rob, but the .220 was not included in the lot of parts.

2) It could be that the return spring needs to be stiffer. It currently has a new Gold spring installed. AGD makes a Silver and a Red spring for the lvl 10 which may be strong enough to overcome the bolt stick but I have neither available. So, we might need a stiffer spring????

3) It could be the bolt itself. It currently has an aftermarket Venturi style bolt installed. There is some wear where the bolt engages the sear and it has a point in it's rearward travel that is very stiff just before it resets to the cocked position. I personally believe that the bolt is the troublemaker here. But since the mag came without a bolt, this is the only bolt we have. Moreover, I do not have any replacement stock bolts.

Also, the original sear in the mag was causing a uncontrolled double fire, I swapped out the sear from my smart Mag and the mag is firing properly, but now my mag is without a working sear :( So, we might need a replacement spring?

As of right now the gun is firing properly. I fired about 100 shots through it with no issues before I started running out of CO2.

Smiley

The fourm here is not allowing me to post pics of the mag. Keeps saying that I have too many IMGs. WTH?

The original thread is here - https://automags.org/forums/showthrea...hlight=charity

And the more indepth follow up with pics is here - http://www.mcarterbrown.com/forums/a...ml#post2445789



Smiley

If you have a set of callipers you could grind down a larger carrier to be .220. I actually thought I had an extra, but don't.

I'm not that skilled with grinding. easier to get the insert:)


What I am learning is that mags are tempormental in regards to parts and seals. it most be AGD if you want it to work right everytime.


Smiley

Do you have other mags that u can swap parts with just for troubleshooting? Switching the bolt would be a quick n easy switch to see if u should get a new one

It does sound like standard level 7 bolt stick. You need a shorter spacer than the 0.225 but longer than the 0.215. You can rub one end of the 0.225 spacer on a piece of sandpaper which is laying flat on a smooth surface. That will gently shorten the longer spacer. Once it reaches the desired length, it should work without leaking.

The reason you need the stiffer spring is because it needs to overcome the extra force required to move the oring. That means the oring needs to be held farther back by a spacer. A stiffer spring will only be a stop gap measure and will still cause issues at the most inopportune time.

The aftermarket venturi bolts have been a source of problems throughout the years. They may work fine, but may have different dimensions than AGD bolts. This means that a gun with one of these bolts may need different spacers or a newer sear to work in a gun that was previously working with an AGD bolt.

Quote:

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Originally Posted by infamoussmiley

I'm not that skilled with grinding. easier to get the insert:)


What I am learning is that mags are tempormental in regards to parts and seals. it most be AGD if you want it to work right everytime.


Smiley

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Perhaps grind was a little harsh. Like AThomas said, some fine sand paper on a flat surface will work as well. .005 is not much sanding.