I've seen a few threads but they're all approaching a decade old from my findings- who out there still modifies Triangle handguards to mid length, or has a set I could purchase? Send me a PM if you have some or can do the work :) Putting together a midlength carbine inspired by the 601

I posted a couple threads with info last year, but I can't access Archives. I found a dude on GunBroker who cut triangular handguards & made a new front end cap.

I wish I could help more than that...

This topic comes up so often I can't believe nobody has started making them. With 3D printers, you'd think it'd be easy. Don't even need heat shield.
I saw an ad in sgn for this company
https://www.smooth-on.com/
Showing how you can reproduce grips and stuff. I thought about getting into it my self, but I'm to busy and not really a good business man to do that. Some one should make the triangular mid length and then pistol length plastic handguards in round, m4 and triangular.

That kind of sounds like forum member jhud.

Seems like it would be simpler to make a rear end cap like the 607's.

It may have been him.  Whoever it was had a midlength flat top that said "We the People" on GunBroker.

The work was great, I posted a couple times and I was asked to post pics, but I am "too retro" to be savvy enough to post pics.

There was another dude who was cropping & epoxying to replace the front of the handguard back to engage a standard end cap-- but the style I bought was different--this is a cut the front hand guard  & make a new front end cap.

ETA better explanation

If you can use basic tools, mix some JB weld or marine tex up. Its a straightforward process.
Its best to do it yourself if you want a drop in set.
The task takes me longer to do than its worth charging for.
That and the selection of surplus h/g is dried. Or its well used.

Which leads me to a point Ive said in nearly every middy h/gs thread.
It is both more durable and economical to produce a front cap that is large enough to fit cut A1 h/g
After looking at countless h/g for inspection. cracks appear in a certain area.
As for durability.. Hold a front cap 607 in midlength or carbine before you say anything about a rear version.
Durable in aesthetically feeling and design. Under the shield are ribs. The cut marks for a front cap fall exactly on the ribs.
I feel it was built in the design.  
Most of you haven't messed with one this style.. rather you have seen or have the rear cap version.
Making cutdowns with rear caps requires a dern near flawless h/g unless you want cracks. This cost more.

From my experience in selling things..  both costing more and cracks are the last thing you want to hear in a h/g ad.
its a puzzle

drop in style DIY  

-cut the first 5/8 or 3/4 or so off the front the the h/g You need enough sticking out past the triangle cap for epoxy to stick.
-trim h/g to midlength. I get close with dermal and grind flat , seems like ever mfg has diff middy specs
-trim back the new front of the liner 1/2 inch or so from the h/g front. You need room to attach the lip.
prep all surface rougly. I cut tiny grooves for the epoxy to fit and fill.
-place lips in cap of upper.  masking tape MT off outer cap.
-mix JB weld.
-with lips in place, apply JB to top of exposed lip cut.
-attach h/gs to upper. wrap with MT
wait 24 hours

remove h/gs. Hopefully it stuck right.

Now use the JB and MT to build the cracks.
You will have to make molds with the MT and make several pours of JB. This will take several days..
Carefully smooth the final shape

You can darken JB weld with lampblack. It makes the material weaker..

I prep the whole finished product for paint. Then I use air dry graphite  cercost.
It needs a heat shield. This is part of the design.

Instead of ruining a bunch of surplus handguards, I really wish somebody who did this would buy a mold kit from smooth-on and make a few dozen copies to sell. IMO, you could do away with the heat shield, or even add a grid pattern on the inside like dpms glacier guards. Glacier guards don't have heat shield and I have a set on a bump fire gun and they aren't hot at all after a 100 drum dump.
You should be able to get $50.

Another consideration when swapping to the traingular handguards is the gas block profile. The handguards with heat shields are pretty tight to the barrel. You may have to modify the existing gas block or swap out to a low profile block.

Actually, that's not entirely correct ...I had to shave the gas block because I put the triangle hand guards on mid-gas 18" with a FSB at the rifle length. "Normally" the gas block is ahead of the handguards. A problem unique to my application.

I bet having some in the market might conjure up some new builds.  
Keep it in that price range   I couldn't.  
It sounds easy but there is an awful lot of time and learning curve.


Maybe promote the prototype.

What we need is some savvy sheet metal expert to stamp out a bunch of new endcaps & Parkerize them so we can cut down our own triangular hand guards.

Based on jhuds description, he didn't do my work--like I said, it was a crop-job & new endcap.

Better to have a stylus made for a carbon fiber set and do a group-funded project like we did with the Prototype FSBs.

That was an amazing thing to pull off together really.

You could even make the vent hole positives as part of the stainless stylus via CNC, have it all polished for ease of release.

I talked to JSE Surplus said they were working on making both Rifle length and Mid length triangle handguards to go with their Carbine length triangle handguards. But they haven't released them yet. So get on the phone and ask them when.

Did you mention this thread to them? I'm probably not going to contact them, but I will state it here, I have 2 midlength pencil barrel builds with early m16 stocks that I will buy triangular handguards for ASAP if they bring them to market. I already have 2 sets of their triangular carbine handguards.

Brownells has new production rifle length handguards now if that makes a difference to anyone as far as a starting point.

That's good news.

I contacted JSE—they’re working on triangular hand guards for mid lengths, but no date fo availability.

I still say the best current available option is for a sheet metal expert to crank out new end caps & Parkerize them, and cut down real M16/AR15 hand guards.

Oh, to be back in the machine shop....

I've bought a few sets of handguards from Tony's Customs.  These worked well for carbine-length gas systems.

https://www.tonyscustomsllc.com/product/xm-177-style-handguard-black/