Feed Lips giving you lip? (Magazine Feed Lip Guide)
When it comes to magazine problems and feeding issues, the first thought when it comes to blame is the Feed Lips on the magazine. A lot of the time, that blame is justified and usually after some troubleshooting, the exact cause of the problem, be it a sticky trigger or no rounds being loaded in to the hop up chamber can be identified by taking a closer look at the Feed Lips.
Just so we are are the same page here with the terminology, the Feed Lip refers to the part highlighted in red in the image below:
So now that we know what the Feed Lip is, lets consider some commonly accepted issues. The Tokyo Marui MK23 and the ASG (or clones) both feature different feed lip designs. Their differences are subtle at first glance, but they are different enough to have significant affect on daily MK23 operation and whether or not you may end up with a feeding issue.
Lets take a look at the TM and ASG magazines side by side. Both feed lips are brand new, out of the box.
Here we have a top down view of the TM (top) and the ASG (bottom). Some things to pay attention to here for reference to in the following images are: - The rounded outer design of the Lips on the TM.
- The rounded /ramped inner design of the Lips on the TM.
- The width of he gap between the Lips.
The rounded outer design assists in forming the inner curved structure of the lips, the circular ramp design helps align the BB in a central position for more consistent delivery via the nozzle loader.
The increased width of the gap between the TM lip walls allows the nozzle loader to pass through the feed lips to deliver the BB without resistance or snagging, and prevents the nozzle catching on its return travel following successful delivery of the BB. This is most commonly the cause of the "Sticky Trigger" because the nozzle is preventing the reset of the of the trigger arms.
This is the view from the front, with the ASG on the left and TM on the right.
Here we can see some obvious differences in molding. The ASG lips are noticeably rough and almost serated in texture, the curvature of the feed lips is more and almost vertical compared to the TM. The result of this is that BB's can have difficulty passing through the feed lip as the BB is forced through the rough and vertical edges. This increased difficulty can eventually lead to a fracture in the lips. The horizontal cross beam of the ASG feed lip appears to almost be compromised of different levels, with poorly formed structural lines. In the past, community members have seen this cross beam snap off entirely, causing catastrophic failure of the feed lip, and even double feeding in to the Hop Ramp that caused additional damage. Below the cross beam on the ASG, you may also notice an indentation in the channel wall, we'll come back to that in a minute.
Lastly, observe again the width of the gap between the lips, the TM is without doubt wider here, giving it the edge on smooth delivery of the BB and return of the nozzle loader.
Lets take a look at that channel wall now. This time, neither feed lip is particularly pleasant to look at, with both having obvious wall imperfections. But the ASG (top) is clearly worse off in this regard, with a rough horizontal indentation located directly below the cross beam. The importance of having a deformity at this location is that this is exactly where the BB stack separates from a double to a single stack before loading in up in to the lip position. One of the most common issues owed to this imperfection is that the BB stack does not separate and in fact jams due to catching on this indentation. The issue can occur on the TM magazine too, but usually lower down and less often. Users are recommended to do some sanding here regardless of the feed lip being used.
This is the side on view, with the ASG on the left and TM right. Two things are important to note here. The first, on the ASG is the the pinched plastic dimple in the top right of the feed lip. The second is the groove and cut out on the TM.
Starting with the ASG, the area of pinched plastic is not a feature, it's a molding deformity that is pretty consistently present on every clone feed lip. Whether it affects your magazine is a matter of chance, but it can cause jamming problems in the BB stack due to the pinched plastic forming a bump on the inside of the feed lip channel wall. This can be sanded and smoothed out.
The groove and cut out towards the bottom of the lip on the TM is however by design. It functions as a catch for the nub on the TM follower to allow the pistol to lock the slide back when empty. It's a left over design aspect from TM's other pistols, but the MK23 can be modified to allow it to work by engaging the safety when empty.
Here we have a view of the feed lips BB channel, ASG on the left with the TM on the right. From this view, we can discern a few things. Starting with the the cross beam on the ASG.
At this angle, we can see that the ASG cross beam is much thinner than the TM and far less ergonomic to the shape of a BB, with square angled edges facing the inside of the channel, whilst the TM is thick and arched. We also get a great view of how thin the feed lip wall gap actually is on the ASG compared to the TM. Another observation is the poor edging of the ASG channel wall itself, with the TM having almost perfect arches on either side. The ergonomics of the TM feed lips and increased width in the channel definitely owes to its ability to more effectively continue the stacking of BB's from the magazine BB channel and deliver the increased BB capacity over the ASG magazine.
So now that we have taken a comparative look at both the TM and the ASG feed lips? Where does that leave you if you are currently the owner of the ASG magazine, potentially an owner having problems? The most common solution for owners of the ASG magazines is to source a TM feed lip and swap out the ASG feed lip with the TM feed lip to reap the benefits of the improved design of the TM feed lip since they are interchangeable. But this option can be expensive when you consider the additional price of the feed lip and shipping on top of what was paid for the ASG magazine in the first place.
The best option may be to just buy a TM magazine in the first place, but that is entirely a choice the buyer has to make, knowing full well that there are a factors to consider regarding the use of higher pressure propellants and the mods surrounding them. That choice,is left to you, but at least you know now what the differences are between the TM and ASG feed lips and what to look for if you encounter an issue, or wish to avoid one!