Modular magwell project.

[bigj480]

So I've wanted someone to make a modular magwell/grip system for a while and AFAIK no one is currently working on one. If I'm wrong and someone IS planning on coming out with one, please let me know so I can save my time/effort and not make unnecessary mods to my lower. Other than that, what I'm mainly looking for is input on attachment methods required mods to the lower and magazine/caliber options. The adaptors should work on all M11s, including A1s and RPBs.



Atachment Methods

I've had several ideas concerning attachment methods. At one point I settled on cutting what would basically be partial m-lok slots into the receiver. I now think that's too drastic and just not as good as other options. I thought about using a tab and the unused hammer pin hole, but I was not sure that a tab would be strong enough. Also, the hammer pin hole is small and designing a magwell that was easy to add or remove and locked up solid just didn't seem simple with that setup. I now think that a tab WILL be plenty secure and I'm using one that will lock into the receiver at the rear of the magazine opening. At the front, I'm just using the takedown pin because it's simple, strong and it's just easy to implement and use.



Reciever Mods

Magwells have been swapped on MAC type guns and I don't see removing the magwell as a huge deal. I personally think that the factory trigger guard will not be the most ergonomic option, won't look great with all magells and MAY prevent some options, may not. Basically, I just don't think it's optimal so it's my option that I should just include trigger guards with the magwells so that they can be customized to work well. I could even replicate the stock trigger guard. The larger hole in the receiver for magazines is a given, it has to be done. The size and shape depends on what mag/caliber options I want.



Mag and Caliber Options

This is important to finalize so I can determine what dimensions I need for the magazine opening in the receiver. I only want to cut once, preferably. However, I also don't want to make it unnecessarily large for options that I would never use. I'm going to list only the ones that seem most obvious to me and see what else you guys come up with. I do have others in mind. I will also list common calibers they should work with. Any round using these as parent cases should also work. Obviously any caliber not native to M11s or using double-feed mags will require other custom hardware.



M11/380 Small Mag - 380

M11/9 - 22, 380, 9mm

Glock 17/22 - 22, 380, 9, 40

Glock 20/21 - 45, 10

Uzi (possible?) - 22, 380?, 9, 45

B&T - 9 (I want a pseudo MP9)

AR and AK grip adaptors for rifle uppers, will attach using just the magazine opening, doesn't use front takedown pin.



RULED OUT: M10 Grease Gun, mags are too wide.



So far, I've only started work on the M11/9, Glock 17/22 and Uzi options. I need a G20/21 lower to make that model. I have the stuff I need for all the other models. I think the M11 and Uzi options would work best using commercially available/surplus magwells inside of a plastic grip.

Legality
Magwell changes are legal, there is an ATF letter on this issue. Obviously people change magwells on M11s and M10s.

Next Steps

This will probably take a while to get to the shooting phase, because I don't want to rush into it and because I do this in my spare time. Also, I'm learning the modeling software as I go, largely through trial and error. That said, I am getting better and this seems pretty straight forward. I'm going to be 3d printing a non-functional receiver, installing a real upper on it and the grip modules to test feeding with snap caps. Once I have that working with all of the grip modules we decide on, I will make the mods to my lower and post a shooting video with them. Obviously the double-feed mags and the large caliber stuff I can't test without getting custom parts. I'm not even sure that the M11 bolt can be modified to work with these things. Not a lot of meat on the bolt for the required double-feed mag notches. Those mods are basically a whole separate project. Maybe I will have to just do single-feed stuff for now, 40S&W or less. I think that might be a realistic first goal. Prototypes will be 3d printed and probably cast in polymer once the bugs are worked out.

Here is a pic of the model just to give an indication of what I'm talking about. The adaptor is much larger than it needs to be in this pic, a lot would be cut off of this. It basically should not need to extend past the rear of the grip and doesn't need to be wider than the grip. In that pic, it's as wide a the receiver. The adaptors could probably have a integrated VFG or m-lok slot in the front.

 

[ccosby]

Have you looked at how masterpiece arms did it on their pistol with the glock and 5.7 pistol grips that can be swapped? I've wondered if that setup could be modified to work with a m11. They wouldn't sell the conversion parts by themselves when I asked, almost bought the entire gun to see if that system could be moved.

 

[strobro32]

I have been playing with this idea a long time too. I think the time is right with the W bolts and the rifle caliber uppers.

My most current plan is to keep the trigger guard and use a steel bottom plate welded to a steel grips or grip mounts. The plate will be attached with 2 threaded rods and nylon nuts behind and in front of the grip. The front rod is attached through the safety and safety detent ball holes.

 

[Gaujo]

I think it prudent to rule out .40, 10mm, and .45 options for the A1, M11 models. Perhaps that could work for M11/9 with it's longer stroke length, but if you think about a M10 vs a M11, the stroke length is the same and it'd be near impossible to get enough mass in the bolt to make it work with the reduced width.

Things I think might be feasible that aren't mentioned would be the HK mp7 magwell. That being said, if you are doing this with the idea of doing it for others, I think you'd have to either partner with an 07 or get your 07 to be able to work on other people's lowers.

As to commercial feasibliity, I think your two biggest markets will be new buyers who want to use glock 18 mags, and people with M10/9 who want to change their magwell anyway.

All that being said, I think this is super cool and I will be following eargerly and kudos for going for it!

 

[bigj480]

I don't know exactly how MPA attached their grips, maybe someone here knows. I've thought about picking up their 5.7 model for parts.

I really wanted grips to be easy to swap and make. I don't see the benifit of requiring screws and nuts but that would be a secure system. I think I can better judge how secure my current design isafter I print a sample, I'll do that soon.

I vaguely remember someone making a 40 upper, but support for that caliber is really only a result of it sharing the same magwell of the G17. It just really hurts nothing to make the 45/10mm magwell, it's barely larger than the G17 magwell. I agree that, short of a modified tungsten bolt or something like roller delay, these more powerful calibers aren't a real option for the M11. I'm thinking that I can provide a template for the mag opening and all else is pretty simple. Of course people could get a local machine shop or gunsmith to do the work. I'm not looking to make money at this, but I wouldn't mind funding the next M11 project. I have several other ideas. I don't have an M10 so I can't really do anything with that unless I pick up a semi...and they could accept Uzi mags easily and be capable of handling more powerful calibers. Maybe I'll pick one up...

 

[nklf]

There is probably a market for this and it should be feasible. People have been asking for Glock mags in their M11/Nine for years. It should be possible to modify the bolt for double feed. Lage made a double feed upper for the M11/Nine for a short time. I think he dropped it because it was not cost effective to modify Suomi stick mags to work. In order to get .40 S&W or .45ACP to work in the M11/Nine it would probably require a W bolt. I have no idea if an existing CFW bolt could be modified to work with .40 or if it would require a completely new bolt. Either way it would be expensive. But hey, this ain't a cheap sport anyway. Good luck. and like others, I'll be watching with my check book in hand.

 

[tlrgsxr]

I want a Glock magwell on my M11A1 using a tungsten bolt to shoot 9mm enough that I bought a MPA magwell. It doesn’t seem that great, so I’d prefer something else and haven’t modified anything yet. Email me at hkbeltfed at yahoo dot com and I’ll send you pics of the MPA magwell and how it attaches. Excited to see where this goes.

 

[will4me]

Tagged for more info

 

[attherange]

The only thing I can think of being an issue would be the geometry of the particular mag and feed ramp. If you going to maintain the OEM upper these two things would be critical. My thoughts on a tab.....I think a slot cut in the receiver a few hundred thou. Behind the existing mag well and the tab forward, poss utilizing the trigger hole for indexing.

 

[Swampfoxoutdoors]

If your going with this type of setup on the rimfire you might as well make the whole RR a bullpup design with the grips out front and open up the magwell area for more real-estate to use larger mags with. Example upside down AM180, S&W15-22, BX22

I can think of very few Hicap 22lr mags that can fit in a conventional grip form factor. Keltec CP33, TX22, P17 are the only ones and unsure how they will feed in a FA setup. And CP33 mags are high.

 

[bigj480]

Thanks for the input guys!

Lage made a double feed upper for the M11/Nine for a short time. I think he dropped it because it was not cost effective to modify Suomi stick mags to work.

Yeah, I did vaguely remember that but I wasn't sure about the details. Anyway, if it could work with unmodified Uzi mags, then it would be worth it. If it requires modded mags, I'm not as excited about it. I need to find someone to mod a stock bolt for this and if that works, a CFW bolt.

In order to get .40 S&W or .45ACP to work in the M11/Nine it would probably require a W bolt. I have no idea if an existing CFW bolt could be modified to work with .40 or if it would require a completely new bolt.

I wish someone could modify a W bolt to accept swapable bolt faces. It seems like a rather simple proposition, other than having to machine tungsten.

Email me

Done.

The only thing I can think of being an issue would be the geometry of the particular mag and feed ramp.

You're right, my goal is to match the location/angle of the top round to the stock setup. Notice the Glock grip is at a slightly different angle than normal (look at the bottom). Luckily, I think it will me more ergonomic at that angle. jOf course, as you said, feed lips can be considerably different but I do think that's generally a good idea to maintain reliability. I really won't know until I test. Double-feed mags will require a drop in feed ramp like the one Mr. Lage offered. I would need to look into that if I want to pursue double-feed mags.

My thoughts on a tab.....I think a slot cut in the receiver a few hundred thou. Behind the existing mag well and the tab forward, poss utilizing the trigger hole for indexing.

That rear tab you mention is basically what I have in mind, but it would be more than a few thou and I plan on using polymer. Actually, on the smaller magwells, the table could be considerably larger because there would be plenty of room between mag and receiver mag cut out. I'm not sure there is really enough clearance for using the trigger cut out and I'm not personally sure that it's worth it just to save on not having to run the adaptor to the print of the receiver. It would mean more trouble to change and I just can't see any real pros unless one just hates the look of an adaptor that uses the takedown pin. Let me know what you think.

...make the whole RR a bullpup design with the grips out front and open up the magwell area for more real-estate to use larger mags with. Example upside down AM180, S&W15-22, BX22

I can think of very few Hicap 22lr mags that can fit in a conventional grip form factor. Keltec CP33, TX22, P17 are the only ones and unsure how they will feed in a FA setup. And CP33 mags are high.

I don't know that I'm so into a 22lr bullpup myself, but that seems possible assuming one could get a long enough barrel. I am interested in the CP33 mags. I bought a PMR-30 magazine and grip, I believe the mags have the same external dimensions. The mags are too expensive but they will end up closer to the PMR-30 mags in terms of cost IMHO. All this said, 30 round Uzi 22lr mags are like $10 and seem to have a decent reputation. I bought 10 of them. I don't see the need for the physically larger 22lr mags you mentioned. 22lr mags. A bullpup in 5.7 is something I thought would be cool, I bought a magazine to model that but...that ammo cost. MPA makes a long barrel 5.7 Defender. Maybe at some point someone will submit a lower that has basically been converted to a trigger pack by removing the rear and it will be approved, but I would not hold my breath. I would not want to cut a huge hole in the RR. I think sticking to pistol mags is preferable, but I'm open to suggestions.

 

[attherange]

I don’t think using the take down pin is a bad idea at all, if this is going to be a “one off”..... otherwise your going to run into spec issues fitting other receivers. I almost wonder if drilling and tapping 2 screws (flush) up through the bottom of the front reinforcement tab would save time and cost. There is always the option of using the stock button hole in the rear as well. The mag body is a non bearing part, but needs to be stable for recoil/feeding.

 

[bigj480]

I don’t think using the take down pin is a bad idea at all, if this is going to be a “one off”..... otherwise your going to run into spec issues fitting other receivers.

I almost wonder if drilling and tapping 2 screws (flush) up through the bottom of the front reinforcement tab would save time and cost. There is always the option of using the stock button hole in the rear as well. The mag body is a non bearing part, but needs to be stable for feeding.

I suspect there is some variation but I can't see it being so much as to considerably affect feeding. Maybe I'm mistaken, I wonder how much variation there actually is between takedown pin and feed ramp. The trigger guard/feed ramp fits through a slot pre-made in the receiver flat and the grip butts up against that trigger guard. I can't see there being a huge variation, but I obviously don't know for sure. I could see more potential for variation between models. I'll measure my RPB 380 and compare it to my M11 (only measuring the feed ramp. I would prefer not taking up the rear stock release button and or putting screws in the receiver. I will keep these in mind but if I find out there is enough consistency and that this setup is strong, I think prefer the current design. We'll see.

 

[sparky923]

So I've wanted someone to make a modular magwell/grip system for a while and AFAIK no one is currently working on one. If I'm wrong and someone IS planning on coming out with one, please let me know so I can save my time/effort and not make unnecessary mods to my lower. Other than that, what I'm mainly looking for is input on attachment methods required mods to the lower and magazine/caliber options. The adaptors should work on all M11s, including A1s and RPBs.


Atachment Methods

I've had several ideas concerning attachment methods. At one point I settled on cutting what would basically be partial m-lok slots into the receiver. I now think that's too drastic and just not as good as other options. I thought about using a tab and the unused hammer pin hole, but I was not sure that a tab would be strong enough. Also, the hammer pin hole is small and designing a magwell that was easy to add or remove and locked up solid just didn't seem simple with that setup. I now think that a tab WILL be plenty secure and I'm using one that will lock into the receiver at the rear of the magazine opening. At the front, I'm just using the takedown pin because it's simple, strong and it's just easy to implement and use.



Reciever Mods

Magwells have been swapped on MAC type guns and I don't see removing the magwell as a huge deal. I personally think that the factory trigger guard will not be the most ergonomic option, won't look great with all magells and MAY prevent some options, may not. Basically, I just don't think it's optimal so it's my option that I should just include trigger guards with the magwells so that they can be customized to work well. I could even replicate the stock trigger guard. The larger hole in the receiver for magazines is a given, it has to be done. The size and shape depends on what mag/caliber options I want.



Mag and Caliber Options

This is important to finalize so I can determine what dimensions I need for the magazine opening in the receiver. I only want to cut once, preferably. However, I also don't want to make it unnecessarily large for options that I would never use. I'm going to list only the ones that seem most obvious to me and see what else you guys come up with. I do have others in mind. I will also list common calibers they should work with. Any round using these as parent cases should also work. Obviously any caliber not native to M11s or using double-feed mags will require other custom hardware.



M11/380 Small Mag - 380

M11/9 - 22, 380, 9mm

Glock 17/22 - 22, 380, 9, 40

Glock 20/21 - 45, 10

Uzi (possible?) - 22, 380?, 9, 45

B&T - 9 (I want a pseudo MP9)

AR and AK grip adaptors for rifle uppers, will attach using just the magazine opening, doesn't use front takedown pin.



RULED OUT: M10 Grease Gun, mags are too wide.



So far, I've only started work on the M11/9, Glock 17/22 and Uzi options. I need a G20/21 lower to make that model. I have the stuff I need for all the other models. I think the M11 and Uzi options would work best using commercially available/surplus magwells inside of a plastic grip.

Legality
Magwell changes are legal, there is an ATF letter on this issue. Obviously people change magwells on M11s and M10s.

Next Steps

This will probably take a while to get to the shooting phase, because I don't want to rush into it and because I do this in my spare time. Also, I'm learning the modeling software as I go, largely through trial and error. That said, I am getting better and this seems pretty straight forward. I'm going to be 3d printing a non-functional receiver, installing a real upper on it and the grip modules to test feeding with snap caps. Once I have that working with all of the grip modules we decide on, I will make the mods to my lower and post a shooting video with them. Obviously the double-feed mags and the large caliber stuff I can't test without getting custom parts. I'm not even sure that the M11 bolt can be modified to work with these things. Not a lot of meat on the bolt for the required double-feed mag notches. Those mods are basically a whole separate project. Maybe I will have to just do single-feed stuff for now, 40S&W or less. I think that might be a realistic first goal. Prototypes will be 3d printed and probably cast in polymer once the bugs are worked out.

Here is a pic of the model just to give an indication of what I'm talking about. The adaptor is much larger than it needs to be in this pic, a lot would be cut off of this. It basically should not need to extend past the rear of the grip and doesn't need to be wider than the grip. In that pic, it's as wide a the receiver. The adaptors could probably have a integrated VFG or m-lok slot in the front.

The pic makes me think of a Galil ACE pistol grip. Just plastic enveloping the metal receiver beneath. That would help with rigidity, yes?

 

[bigj480]

Yeah, we'll see if it needs more rigidity once I get an actual physical part. By the way, the MPA grip attaches using a two lugs on the grip and cut outs in the reciever, as well as four screws installed from the top into the grip.

 

[Mackjack]

What if you went and attached the grip well to a U shaped piece of tin or something and it wrapped up around left and right side? Then you could use a pin thru the semi auto hammer pin hole and create a longer trigger axis pin to secure it. Relatively straightforward proposition at that point then. Also aside from removing trigger guard and magwell you don't need to blast any additional holes in the precious reciever and it's more or less undoable.

 

[bigj480]

I guess I'm not seeing what problem we are solving or what that would improve. Now we are talking about custom pins and a new metal piece. A considerably more complicated product to make, which could be worth it if it makes for a better product. I will have to do a quick mock up of the rear tab to give a better understanding of the current design. The lower must have a larger opening for magazines and that's not really reversable short of welding. I appreciate you guys brainstorming with me.

 

[theredneckengineer]

I guess I'll ask a series of dumb questions, since I'm pretty good at it.

1. Is this something you're wanting to remain all sheet metal, 3d printed, or machined aluminum? Or perhaps a combination of those?
2. I'm assuming you're not wanting to modify the receiver at all, except for maybe a little welding (and cutting off the original magwell and trigger guard)?
3. I'd assume you'd want all of the magazine options to work with the original uppers AND aftermarket uppers?
4. Will you be keeping the original mac safety in its original location?

I have given this idea a lot of thought since someone brought it up in the Ultimac thread and I know how I'd do it, but I'm not sure if it would be worth the time and expense. It would definitely require the mac owner to send in their mac to have some welding done to it, but it would be reversible.

 

[Mackjack]

I guess I'm not seeing what problem we are solving or what that would improve. Now we are talking about custom pins and a new metal piece. A considerably more complicated product to make, which could be worth it if it makes for a better product. I will have to do a quick mock up of the rear tab to give a better understanding of the current design. The lower must have a larger opening for magazines and that's not really reversable short of welding. I appreciate you guys brainstorming with me.

It would basically attach similar to an uzi grip assm if it wasn't clear with my sketch.

 

[bigj480]

I guess I'll ask a series of dumb questions, since I'm pretty good at it.

Nah man, great questions.

1. Is this something you're wanting to remain all sheet metal, 3d printed, or machined aluminum? Or perhaps a combination of those?

Cast in polymer.

2. I'm assuming you're not wanting to modify the receiver at all, except for maybe a little welding (and cutting off the original magwell and trigger guard)?

No welding, just removing magwell and enlarging mag opening depending on desired mags. I think trigger guard should be removed, but that's not written in stone.

3. I'd assume you'd want all of the magazine options to work with the original uppers AND aftermarket uppers?

Yes.

4. Will you be keeping the original mac safety in its original location?

Yes, and allowing for the Lage safety. I like the current location.

I have given this idea a lot of thought since someone brought it up in the Ultimac thread and I know how I'd do it, but I'm not sure if it would be worth the time and expense. It would definitely require the mac owner to send in their mac to have some welding done to it, but it would be reversible.

Its reversibility would be hindered by the required larger magazine opening, depending on what magazines are desired. If you are welding something on, then that's something additionally that would have to be reversed. I am curious about your idea, but I get that you might want to keep that to yourself. Plan on making one? I could see a tac welded rail, dovetail or lug of sorts being another method of attachment, but I don't think I prefer that.