Best Other Marker Trigger Frames for Adapting to Mags

[MrBarraclough]

Looking at rawbutter's pneumag posts, it seems that there are good number of trigger frames from/for other markers that can readily adapt to the Automag rail. Since Tom Kaye wisely and fortuitously chose to build the sear and its pivot point into the rail and make the trigger rod adjustable, the trigger frame doesn't have to do a lot of work internally compared to most other markers. It just has to give the sear enough room to swing and place the trigger within the adjustment range of the rod. Oh, and hold the body-valve-rail-frame sandwich together. That's not too tall of an order, so I would imagine that a fair number of trigger frames from other markers might be adaptable.

Thinking out loud for a moment, I was trying to enumerate what characteristics a trigger frame would need to be a viable candidate for adapting to a mag. So far what I have come up with is

1. Spacing of the holes for the field strip screw and the forward bolt that threads into the body tube. Since neither hole is threaded, I would think that any frame with a rear hole and sufficient space inside the trigger guard to drill a new forward hole at the correct distance from the rear hole would do. I imagine that it would usually be easier to use the rear hole as the fixed point and then drill a new forward hole indexed to that, rather than the other way around.
2. Thickness of the frame at the rear field strip screw hole: would have to either be close to the thickness of the OEM frame or at least shaped in such a way as to allow easy cutting of a space with sufficient clearance for the head of the field strip screw. If thinner than the OEM frame, I would imagine it an easy matter to attach spacers or washers to ensure a tight fit. One could always replace the original field strip screw with any other screw of appropriate length and threading, but I would expect most mag users would prefer to keep the original for toolless field stripping.
3. Width of the frame -- preferably no wider than the flat portion of the underside of the rail. If wider, would need to be able to mill the top surface to conform to the grooves at the edge of the rail.
4. Sufficient hollow space for the sear and trigger rod, or capable of being milled out to create such a space without fatally compromising the structure.
5. Did I miss anything?

Has anyone ever compiled a list of trigger frames from other markers that are particularly suited to adapting for mags? Just curious. While I like my rubber AGD grips on the stock CF frame, sometimes I think it'd be nice to have the hourglass profile of a Dye UL frame on there.

[superman]

Generally across the board I tell people to stick with OEM or something from a well thought out aftermarket company that tries to follow agd spec.
I highly recommend sticking with a stock frame for someone that is not up to speed with tuning a mag especially for sear adjustments.

Issues i normally see are that mounting holes are irregular and frame fitment is not tight and consistent. Sear rods do not have a consistent location to hit on the trigger. damage to the valve from not using a field strip screw and bushing. sears rubbing interior to the frame causing recharge issues among tons of other issues.

I would say most frame are not particularly suited for mags, but im sure someone will jump in and tell me im wrong and they had a friend that did a thing one time.

[lizardking132]

I know I've seen angel frames on mags before, but that's about all I know on the subject

[Hobbes]

Angel frames can work. I feel like I've seen DM Ultralite frames as well. I can't yet speak to the long term effects that Superman mentioned.

I will say on my pump setup the bolt is a little bit tougher to activate with the Angel frame on it.

[Jordan]

I put a heavily modified BKO frame on a (again) heavily modified Classic Mag.

[rawbutter]

Finally...a topic I know everything about.

Let me start by saying that yes, of course it's possible to mod non-AGD frames. We've gone to the moon and split the atom. Surely we can do this. BUT, much like those other endeavors, it's harder than you think, and you maybe shouldn't try it. Not unless you know what you're getting yourself into and you have all the right tools and a lot of time and patience. If you still want to give it a try, then I'll do my best to point out all the problems you should anticipate, but in the end it's still gonna be you doing all the work. Drilling, filing, cutting screws, test firing, running out of air, making your own reverse countersink drill bits, and on and on.

I should also add that (surprise!) besides all the pneumag frames I've done, I have also dabbled extensively in mech conversions. I've done Angel frames, PM5 frames, PMR frames, Rize frames, DM3 frames, DM5 frames, BKO frames, Autococker frames, shocker frames, Ion frames, ETEK frames, ...and probably another half dozen I've forgotten about. There was a long while where I would just go on eBay when I was bored, find a frame (usually tried to keep it under $50, which isn't hard to do), mod it, and then sell it when I was finished. For me, the fun part was figuring out how to make a non-AGD frame work with an AGD marker, and if I could sell the frame afterward for the same amount I bought it for, I was pretty happy. Then I would do it all over again.

But I don't do it anymore, because Jake is right.

...most frames are not particularly suited for mags

See, there's a really good reason why I never made a thread called "rawbutter's mech conversion gallery." And that reason is that most of my conversations failed. Seriously. I think my success rate was somewhere around 25%. For every frame that worked, another two or three frames were scrapped. Sometimes I could salvage those frames and repurpose them as pneumag frames. (I'll circle back to why in a minute.) But most of the time that didn't happen. At first I threw them away, but now I have a box of ruined frames standing vigil over my workshop, a constant reminder to not go down that rabbit hole again.

The challenges of modifying a non-AGD frame are many, but I think I can boil it down to three big problems.

1. Frame geometry.

You might think that you only need the frame to have a flat top, and it should work for a mag. Well, yes, but it's more than that. First of all, the top of the frame needs to be SOLID and flat. Some "flat" top frames (like ETEK1 frames) actually have a bunch of grooves and other features milled into the top to make room for solenoids and whatnot, and that can cause headaches, especially for classic rails. Secondly, if the screw holes don't line up, drilling new ones can be challenging if you don't have a drill press. If you only have a handheld drill, you should know that it's very easy for a drill bit to squirm around when going through metal, and a hole that's even half a millimeter out of place isn't going to work. Finally, you need to think about the field strip screw. Some frames have a flat top, but the back part behind the grip isn't flat underneath. (Again, the ETEK frames have this problem.) So the field strip screw won't be flush against the frame. It will still work, sure, but it will be ugly.

The length of the frame is also worth mentioning. Some frames look fine, but once you try to fit them on your mag, the front of the frame bumps up against the foregrip. This is why most mags with non-AGD frames use the longer RT-length rails.

2. Screws.

Jake mentioned this too, and it's worth repeating. Don't replace your field strip screw with a regular machine screw. Screws have "grades" of strength, and most of the ones at your local hardware store are only grade 2, and so they might snap off in your valve. (Good luck getting it out when that happens.) I don't actually know what grade the field strip screws from AGD are, but I wouldn't replace them with anything less than grade 5. Grade 8 is even better.

Why am I talking about this? Because non-AGD frames are usually thinner or thicker where the screws go, so your old screws won't work. You'll probably have to buy new ones and trim them to length. Maybe you have better stores near you, but I've always had to order grade 8 screws online. And since they're so much tougher than normal, you'll need power tools to cut them to size. I use a Dremel with a cutoff wheel, but I suppose an angle grinder could work too. Then you can clean up the cut end with a file or wire wheel.

3. Trigger geometry.

Hold onto your butts. I could make a whole thread just about this topic.

The trigger geometry of the Automag is deceptively complex. It seems so easy. Just get some piece of metal to push on the sear arm somehow and you're good to go, right? Nope. If you've ever shot a Benchmark frame, you know just how much the trigger pull can be affected by different trigger geometry, and the difference between a Benchmark trigger and an AGD trigger is pretty small.

First there's the problem of how far the trigger can move. You need a good 1/8 inch of movement to make the sear fully engage, and some triggers surprisingly (especially triggers from electronic markers) don't have that kind of range. They might move enough to fire the marker, but not enough to fully disengage the on/off pin so you can remove the valve for maintenance.

Then there's the problem of HOW the trigger moves. The trigger on an Automag pushes the sear rod almost straight back without only a tiny bit of lift. But for lots of other triggers (I'm looking at you, Dye frames), the back of the trigger that's pushing against the sear arm moves UP and back at the same time. This means that the sear pin slides against the back of the trigger when it moves (which causes misfires), and it also means that 1/8 inch of trigger movement doesn't translate to 1/8 inch of sear movement because the back of the trigger is moving diagonally. This might only translate to 7/64 or 3/32 inch of sear movement, which isn't enough.

Then there's the issue of keeping the sear pin in place. Take out one of your Automags and look carefully where the sear arm hits the trigger. Notice how there's a shelf inside the frame for the sear arm to rest on? And the back of the trigger has a rounded bit reaching back and over the sear arm to keep it from moving up? And the frame is narrow on the inside so the sear arm can't move from side to side? All those things are important. Get rid of one of them, and your Automag might not shoot right consistency. Or even worse, it will shoot okay in your garage, but once you're out on the field and holding the gun sideways to shoot around a tree, suddenly the sear arm leans out of place, hits the back of the trigger wrong, and jams.

That was a bad day.

The height of where the sear arm hits the trigger is important too. On most Angel frame mods, for instance, the sear arm hits the trigger lower than it does on an AGD frame. It's not a lot lower...probably only a 1/4 inch or so. But that little difference results in a trigger pull that is significantly heavier. And you can kiss the RT effect goodbye.

So...yeah. It's never a "drop it in and go" kinda situation. Usually when converting a non-AGD frame, I have to put a pin through the frame to give the sear arm a place to rest against so it doesn't fall down too far. And I have to put another pin through the frame to keep the sear arm from going UP too far. And I have to flatten the back of the trigger where the sear arm hits it. And I have to add a nylon bushing around the sear arm to keep it from wiggling around.

Don't even get me started about safeties. If you want one, you'll usually have to add that to the frame too. And they are even trickier.


THIS is the reason why I've made so many pneumag frames. Compared to the AGD trigger, pneumag triggers are easy. You just need a screw sticking out of the back to hit the valve arm. The angles don't really matter. So whenever I screwed up a mech frame conversion, I would pivot and make it into a pneumag frame instead. If I hadn't already completely screwed up the frame, that is.

So, there it is. All the reasons you shouldn't do this at home. Well, I mean, no. That's not really what I mean. I actually do think that you should try this if you want. That's one of the greatest things about Automags, that you can mod your own parts and make your marker really unique and special. BUT, there are lots of challenges to this particular mod. In many ways, making a mech frame is even harder than making a pneumag frame. So, I just want you to be aware of what you're getting yourself into before you start down that road.

[MrBarraclough]

Thanks. That was an awesome read, especially in response to something that for me was more of an idle "I wonder if.." type conjecture. I appreciate your taking the time to lay all that out. After being up way too late last Friday night adjusting and readjusting my trigger rod to work with the two finger trigger cut AGD frame I got from Jake recently, I can certainly understand that the trigger geometry is much more subtle and finely tuned than it might look.