Project: making center feed Minimag and RT bodies…

[pneumagger]

So as my two boys get older, I’ve been wanting to build each of them their own minimags like mine, and also fix up my mini and my RT too. The problem is my mag is a centerfire minimag; so I’ve been keeping an eye out for center feed mini bodies for a while now. Well it turns out they’re really hard to come by. I saw that Docs Machine post about converting an RT to vert feed and thought to myself…



Unfortunately, unlike Doc, I’m a shit welder. But I think we can work around that…



So I dug out an old beat up Teflon centerfeed Emag body that some poor guy tried to drill eyes into years ago; had the eye holes welded closed and chopped the feedneck. Tracked down another center feed Automag body and chopped that feedneck. Bought a new No Rise. Fabricated some Minimag tips from .050 tubing and made a crazy RT-Minimag tip with leftover stock… so I chopped up my RT body too.



Here’s everything dry-fit together… I have to do more polishing and blending on the RT. The grades of stainless may be different, mine reflects light more “yellowish” in brighter light. And Minimags I’m just going to sand and scotchbrite them to try and blend a little bit and hope bead blasting takes care of most of the blending and hiding of the eye hole welds - if things don’t blend as nice as I want I’ll just get everything coated in black Teflon. Still not sure if I want to silver solder them all together or just use Loctite 609 or 680.

[alpha_q_up]

That Rt Minimag body is insanely beautiful, bravo......
someone get XMT to make an all aluminum version in his next run

[FredMnkyDad10]

That RT classic looks great. What about doing cerakote or duracoat finish. You would have more choices in colors.

Great job keep it up. Like to see the finish work.

[pneumagger]

That RT classic looks great. What about doing cerakote or duracoat finish. You would have more choices in colors.

Great job keep it up. Like to see the finish work.

Nyet… black and stainless only, comrade.

These 4 mags are getting 1/4” stainless hard-macro lines as well… (do you have any idea how much 16 black CCM macro swivel fittings cost me :/)

[FredMnkyDad10]

16!!!! Yeah I dont even want to know. Seen ridiculous price on a pair or even.single 1.

[alpha_q_up]

That's like 350$ in ccm fittings

[NONOBLITUS]

Awesome, well done.

[The Inflicted]

Is there any issue with the stock RT barrel feeding paint in the vertical orientation?

[pneumagger]

Is there any issue with the stock RT barrel feeding paint in the vertical orientation?

It’s a center feed RT barrel… technically I think an Emag barrel.

its mostly just for aesthetics anyways… they’re not particularly great barrels. If actually playing I’m using a center feed twistlock freak barrel or Doc’s adapter and freak bored A/C barrel.

[pneumagger]

Update…

TL;DR - I had to remove the RT tip after cementing it on. Shitshow ensued and I mangled it a bit.

Unabridged AAR -

so I decided to use Loctite 608 retaining compound instead of soldering because the lap joint still would’ve been stronger than the base tube and the Loctite would allows easier hands on and working time to ensure perfect alignments than … you know… a torch, hydrochloric acid flux and 600°F silver solder.

So before I go to bed, I clean everything with acetone and glue everything together and set them on the workbench to cure overnight. The minimag bodies are easy; they have flat ends and I just stand them on end so that it can cure with their own weight holding it together and no side bending or stress or anything. But the RT body has slant cuts on each end and both ends are getting glued. So I rig up some Rube Goldberg looking stack up of things on the bench to kind of get the body to stand vertically with something holding onto the feed neck, so everything can cure all vertically with no stresses. Lights off and head to bed.

wake up and go to check… the RT body is missing. Where is the RT body? Sitting on the concrete floor. My first thought is “Crap, there’s a ding somewhere on it that I have to polish out”. Well, the fall must’ve happened very early on before much curing because the front slotted section (that I meticulously squarely machined for a nearly seamless gap) now had a 0.5mm gap seam with the body. Well shit. It’s about 50% cured and it’s now or never…

So to recap, we’ve gone from “oh crap” to “aww shit”. The fuckup:

I stick the body section in a vise and grab a torch to get the joint hot. Keep in mind, this joint is machined tight and takes some grunting just to put on even when clean and dry… now it has half-cured Loctite in it. I hit it with the torch for a few moments and stick a 1/4” flat bar through the slots as my leverage/pulling/twisting tool (because a round rod or screwdriver would dent it). It starts twisting off as it gets hot. Awesome. I get it about 1/8” off and progress slows. As I give it more beans it starts to move again… but then I realize it’s not loosening and I’m just twisting and bending the shit out of the Swiss-cheesed slotted section that has basically no rigidity. Fffffuuuuucckkk. (My wife literally ran from the second floor down to the basement at 6AM because I screamed it so loudly, LOL). I was too upset to even throw the wrench across the room.

For a moment I consider slitting it off the body with an dremel and just remaking it. But after rethinking I stuck a piece of barstock in the slotted tip and put that part in the vise and made it stupid-tight. Now I can grab the rigid body to do the pulling/twisting and it eventually comes off. Why didn’t I just do it this way first?!? FML.

Then spent about 45 mins using various sized barstock as mandrels and a rubber mallet to re-round this RT tip thing. No before pics, but just to give you a sense of how far it’s come, the ID is supposed to be like 1.025” and I could only fit a 0.875” barstock down it as a mandrel when I started. And this is where it’s at… I can currently get 1” barstock down the (formerly) 1.025” hole.



Now no way the RT tip is still rigid enough after slotting and torching to try and take any smoothing pass on the lathe. Maybe I can put it between centers and use a hand file knock down the stretched high spots and ripples?? Maybe rig up a dremel tool post holder??

Remaking it is a shit option too; I have no more of this 1.125x.049 seamless 304 tube stock left and it’s $50 a foot delivered. Then machining a new one on my basic Harbor Freight bench top mini mill and small 9x20 lathe would take about 4 hour's (neither has DRO, dial indicators and hand layout only).

Bonus content: if you’re curious how well Loctite 608 bearing retaining compound works, if you look at this picture little chunks of metal either sheared or galled off of the male tenon and stuck to the inside of the tip all around. When I run my finger on the inside surface of the female joint, I can feel a little raised metal bits from the male joint. That’s impressive.

[pneumagger]

Redemption-ish!

it’s not as “perfect” as it was before, but I think it’s serviceable. I mean, my RT is “clean” but still has a couple scuffs and dings. So this kind of flows a little better with the vintage RT. Certainly beats making a new one for $50+ and 5 hours.



I reglued it and we’ll see how it turns out. Dry fit up was decent.

After another hour and maybe a thousand tappey taps with a little hammer on the 1” mandrel and then polishing it with some cratex bits and sandpaper up to 2000 grit… here’s what I got. Oddly enough, right after my second straighten effort it looked 99% perfect - then I polished it and at certain angles you can still see some waviness - but not like before.

The same 8 pics as before:

[pneumagger]

Ok, update… all the bodies are “done”. I’m planning on coarse sand blasting the Minimag bodies for a factory look, but I don’t think I’ll have access to a blaster for another month or two



Here’s how the RT body turned out. I don’t think the fit up was as tight/seamless as before massive screw up, but the front seam still came out pretty minimal. At arms length, unless you’re looking for it, it’s not really noticeable the rear seam is more visible, but luckily completely under the RT sight rail - haha. I stepped up sandpaper from 200-2000 grit then tried polishing with 0000 steel wool and brasso. I might try some polishing compound and a proper wheel if I can get access to one.



The Minimag body made from an Automag body vame
out great. The seam is nearly invisible even up close. I think it will all but disappear after bead blasting.



The Minimag body made from the black Teflon Emag body has probably the noticeable seam of the bunch. But it was a body I found for free in an old junk box with poorly drilled eye holes and bad feedneck cut. So it’s vastly improved. Not sure why there’s such a noticeable seam - I can’t see a visible gap whatsoever and actually installed this tip under pressure in a vise. I’m hoping the sand blasting helps obscure the seam and the weld marks more… if not I can just bondo the imperfections and have this one refinished in black Teflon.

[Cal440]

Those look great 👍

[FredMnkyDad10]

Awesome work.

[RedLeaderSB]

Incredible. Do want

[FredMnkyDad10]

Me too

[LudovicoSoldier]

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