FMP G3

animator

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I mentioned this project in my old G3 thread, but that was a few years ago, so I figured I’d start a new one for this. To be honest, I’ve started over on this three times now trying to get a “good” build. I wanted this one to be the best one I’ve done yet, and a few annoying little mistakes on previous attempts bothered me enough to scrap the receivers.

I’ve bought and/or made a handful of tools to help in the areas I’ve had trouble with in the past.

Kit is a matching excellent-grade FMP kit from Apex. FMP is an HK-licensed mfg in Portugal. It’s mostly G3, but these early kits have a few subtle differences, mainly the ****ing tube and hanger.


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Receiver and weldments from HKparts.

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Before bending it up, I drilled a few holes for plug welds for the reinforcement plate. In previous builds, I’ve had this plate deflect while drilling and get deformed in the receiver, and fixing that is not easy. Some people have used a spot welder here, and I would like to, but I don’t have any tongs to fit. The AK builder electrode is a bit too thick, and I may buy another one to shave down and give that a try. Until then, plug welds will have to do.

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Bent

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I made a little jig to locate the stock pin holes for drilling. I’ve used the stock in the past, but don’t like doing that, so this makes it easier.

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I’ve got some pins to keep the bushings in place, but actually didn’t need them this time. They are very handy with the RTG cetme receivers that have the holes already drilled, and are a bit oversized.

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Drilled.

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My good buddy dunno helped me make some copper pins to use as a heat sink to keep from blowing through the bushings.

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Bought this little rear sight jig from someone on gunbroker. It’s a little 3d printed thing that clamps to the receiver and holds everything in place. It’s neat. It’s plastic, so it’ll melt from the heat, so just tack it on, then remove the jig for final welding.

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Welded

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Magazine release parts need drilled. Again I drilled them with metric drills, undersized, then reamed out with metric reamers. Perfect fit.

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My least favorite part—the paddle and denial block. I used the HKParts shelf locating jig to hold it and welded it in place. Drilled the paddle and it actually works. I’ve messed this up several times.

Still need to sand down the extra material at the front of the magwell, and weld the pin in place.
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Dunno again helped me made a heat sink for the ****ing tube. This is a piece of solid copper that’s been turned down to fit the receiver, but also fit the ****ing tube sleeve. The all thread on the other end is to help pull it out once welded.

I also use this as a heatsink for welding the rear sight on. Works perfectly.

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It fits snugly into the receiver and also serves to align the ****ing tube and trunnion.

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Next will be finishing the grip frame modifications and finishing the small details.

Probably here in a week or two I’ll get back on it.
 
Guess I never took pics of pressing the barrel. It’s an RCM barrel. I waited too long and Apex has sold out of FMP barrels before I bought one.

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Grip frame is blocked. Will do a clip/pin eventually.

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I guess I’m at a crossroad now. I’ve always planned on using my apparently rare and in-demand HK wide green hand guard with this kit. Problem is the front sight is slightly different from a standard G3, and the wide handguard will not work without modifications. I wasn’t aware of that in the beginning.

There’s also no front handguard pin hanger like what you see on a typical G3. That much I knew beforehand. So now I’m not sure if I want to modify the FMP front sight, or buy a G3 front sight. They’re not expensive. I may also try to add a pin hanger to the FMP ****ing tube.

Or I keep this as original, and just buy another G3 kit to build for my green furniture. :laughing:

If I were to do it all over, I’d probably buy a G3 ****ing tube and front sight, unless I only planned on using the original slim handguard.

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But it’s otherwise pretty much done. Waiting on some new trigger parts. Got some minor things to clean up, and still need to pin the front sight.

Will paint it when I get around to it.

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I’ve decided to go with a common G3 front sight so that I can use the wide handguard. That means I’m going to make a front pin hanger.

While those parts are on their way, I figured it’s time to drill and pin the barrel. In the past, I’ve used a 5mm end mill in my drill press, but don’t like that since the pins themselves are right at 5mm, with a small variance, so the hole might end up just slightly too big for a press fit, and you really don’t want the pin to walk out.

So I’ve been using a 4.9 drill followed by a 4.98 reamer. That makes for a snug fit that shouldn’t walk out.


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I use this pin jig to hammer it in. It’s also useful to hammer them out.

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Parts arrived, so I went ahead with the modification plan. If I were to do it again, I’d probably just go with a used G3 ****ing tube along with the front sight, but hindsight…

Started with a new G3 hanger from hkparts.

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And give it a slight modification.

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Figure out where it needs to go.

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Clean up the tube and burn it on.

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Weldy weldy.

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Looks like it’ll work just fine.

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Here’s a view of the difference between the sights. The G3 on the left, FMP on the right. That extra protrusion and rim won’t let the wide handguard fit over it. So you either need to modify the FMP sight or replace with a modern G3.

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Question.....
Are the weldment parts that they sell with the flats, just for making it so it can't fire full auto?
 
gt1guy said:
Question.....
Are the weldment parts that they sell with the flats, just for making it so it can't fire full auto?
Click to expand...
Not specifically just that, but they do include the semi-auto shelf for the receiver. The weldments also include the rear sight base plate, the rear stock pin reinforcement piece, and the rear stock pin bushings.

For semi-auto conversion, there is also a block that gets welded into the grip frame, and that block is sold separately.
 
animator said:
Not specifically just that, but they do include the semi-auto shelf for the receiver. The weldments also include the rear sight base plate, the rear stock pin reinforcement piece, and the rear stock pin bushings.

For semi-auto conversion, there is also a block that gets welded into the grip frame, and that block is sold separately.
Click to expand...

So without the block that gets welded into the grip frame and the semi auto shelf for the receiver a standard G3 trigger pack will fit in it. Or would the flats that they sell not not work?

I guess what I'm getting at is could someone make a full auto version and register it? Or would that be considered a new gun and unregisterable?
 
gt1guy said:
So without the block that gets welded into the grip frame and the semi auto shelf for the receiver a standard G3 trigger pack will fit in it. Or would the flats that they sell not not work?

I guess what I'm getting at is could someone make a full auto version and register it? Or would that be considered a new gun and unregisterable?
Click to expand...
Yes, an unmodified select-fire trigger pack will fit and function just fine if you do not install the blocks on the receiver and grip frame. The parts kit comes with the bushing for the grip frame pin.

There’s some nuances here, and I have no doubt that someone will come along to point out any area I’m not fully correct or forthcoming with info with their aaaaaaaccctually comments…. but essentially if the receiver can accept a full-auto trigger pack and bolt carrier, it is considered a machine gun, and if an otherwise unmodified grip frame and trigger pack can fit onto a semi-auto receiver, and you’re in possession of both together, that’s considered a conversion device. Both currently illegal to possess without proper permission from big daddy government.

The only way to make and register a new full-auto is by a licensed mfg with paid SOT. It’ll be papered as a post sample, and is yours as long as the SOT is paid. Once surrendered, you’re either selling to another dealer, sending to the ATF, or cutting up back into a parts kit. A non-FFL cannot currently make and register a new machine gun made after the ‘86 infringement.
 
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My attempt to make the cuts for a claw mount. I don’t see a lot of home builders doing this. I don’t think century ever did, and PTR maybe recently started doing this. I’ve seen it on some, but not all of their builds. Of course I could be wrong, I don’t see everything that gets built.

These cuts give the claw mount a more flat surface to clamp to, keeping it from sliding off. People try to clamp those claw mounts on so tight to keep it on that it compresses the receiver and jams up the bolt carrier.

Quick and obvious solution is to weld a rail to the top for modern scope mounts, but I wanted a somewhat original look for this.

I noticed PTR started welding rails to their rifles coincidentally very shortly after I welded a rail to one of my old builds and posted it over on the old OSR section. I’ll take all the credit for that. :flipoff2:

Simple slot cutter does a fine job for these cuts, and doesn’t take long to do.


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A year later.

It was stripped down and sandblasted. Flash hider and rear stock assembly is parkerized, the rest is paint on top of Parkerizing. Came out pretty good.

Now I’m wishing I’d used an HK tapered ****ing tube. So I’ll cut this one up and rebuild it again some day. But until then, I’m going to take it pig hunting…

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Clipped and pinned.

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Color is VLTOR Black. I love it. Normally I use HK semi-gloss black, but wanted to try something new.

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Took it for a sit to see if any pigs showed up, but no luck. Will take it out again next trip out.

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Took a few rifles out to the range, so I put a box of Frontier .308 through this FMP build. Grouped really well with that, at 3-4” at 100yds with irons, which is what I’d expect from it. Rifle still works, so I guess that’s good.

Had the range all to myself for a bit.

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