The Ultimate STI 2011 Magazine Tuning Video from Atlas Gunworks
(smooth club music)

– [Adam] Hey everybody,
Adam from Atlas Gunworks.

We’re going to talk Gen
2 STI mag tuning today.

There’s a couple different parts to this,

but we’ll go through them all,

how we quickly do that tuning here.

This is a how to video
so you can retune mags

you bought from us, or you
can tune them from zero.

There should be enough information
here to do all of that.

This is a 2011 mag that we cut away

so we could see what was going on.

You can see that the
rounds are double-stacked,

right, double-stacked magazine.

At the top of a 2011 mag, the
last three rounds stack up

vertically in a single stack fashion.

So that being said, this
dimension here is critical.

And we need the bullets here to be nearly

on top of each other and not side by side.

When they get side by side,

the spring won’t have enough pressure

when the mag’s fully
loaded to overcome that.

So, a little bit of tuning here

goes a long way in making
these mags super reliable

and work really really well.

What to know about it is over time

as these mags hit the
ground and stay loaded,

they’re gonna give some of that back.

So, a retune probably every
six months is called for.

I retune all my mags
sets, the whole thing,

feed lips, everything,
A-Z, every six months.

So keep that in mind

but what we’re trying to do

is get this dimension square,

the feed lip dimension square,

and then this dimension
square so they fit in the gun.

So these are two mags
that we tuned earlier.

These have the dimensions on them.

So they’ll be there,
hopefully you can read them.

These are the feed lip dimensions,

three, five, five to three.

And I want three..10 minus 10 in the back,

so 345 on the nine millimeters,

380 and 370, these are
all plus or minus five.

So I take 385 or possibly 375,

I like them on the plus side.

360 would be okay, and 350’d be okay.

And then this is the
critical dimension here.

So right here, we take the calipers.

We’re gonna, I like to lock them in

and do all my mags at once,

so I lock them in at one inch.

So just, you got a little lock

usually on your calipers, set them up,

I put a dot right above the one inch mark.

We’re just a tad high but that’s alright.

So that little dot there,

at the bottom of that’s gonna be my point,

I’m gonna measure that
so zero my calipers,

make sure I’m good.

None-zero calipers are often a problem,

so always triple check that
you’re getting good numbers.

At the bottom, I’m gonna measure this.

I’ve got five six nine.

I really want five six
zero in a nine millimeter.

Same thing on a 40 cal,

in fact I lost the mark so
we’ll put a new one in here.

I only have a fat marker so
this might not be the best.

Thinner markers are better.

So we’ll bring the calipers down to one.

And we’re pretty close right here.

This is going to be
tricky with a fat marker.

Let me measure what I got there.

So I’m gonna be just underneath that,

know that I’m a little high.

I’m 611, I want 600.

So, I’m gonna show you
how to squeeze the tubes

on two tubes that haven’t been done,

those were done earlier,

because these tubes are going to be

a little more in depth,

so you’ll actually get a good
idea how to squeeze them.

You want to make your life
simple, do the feed lips first.

So this isn’t a feed lip tuning video,

we have lots of those out there.

This is 350 on a nine
so it’s right in there.

This is 378 which is just a tad under,

so somebody might’ve tuned those for me.


Which is good, that speeds us up,

but use the mag pliers,
there’s plenty of videos

that we’ve got out there
on how to tune the mag.

So I’m at the plus side
there a little bit.

When I squeeze this, those will come in

and then I’ll have to
bring them out and then

I might have to squeeze this again.

There’s a little bit
of give and take there.

And then, more with the
40 cal then the nine,

when we squeeze the bodies,

they’re gonna change the
shape up top a little bit

and they’re not gonna
want to fit in the grips

and we’ll have to adjust there.


We’ll make it, we’ll do
one so that you see that.

And there’s a couple ways to do that,

but let’s do the nine millimeter first.

I’m gonna measure here.

This is 30 thou, 32 thou high.

So the simplest thing that
you might have at home

is just mag pins, magwell pins.

And you’re gonna wreck them,
so don’t use good ones.

Put the center spot of the pin pretty much

in the spot where the mark is at one inch.

And then I’m gonna pinch
with my vice just below that,

so you see my vice lips make
contact just below that.

You’re gonna crank on these pretty good.

It’s gonna take a bunch to bring those,

and they’re gonna wanna
spring back a little.

If you had time, I would do them,

I think, in a perfect world,

if I was doing them at home

and it was my match set or something.

I would do them,

let them sit overnight and
check em in the morning,

they’re probably gonna
give a little bit back.

If they give five or
eight thou, 10 thou back,

it’s not the end of the world.

So, I’m a little, still
a little thick here.

So we’ll go again.

Better to go slow and not wreck a mag.

So, just, again if you’re
doing them at home.

The first couple you do
are going to be slow,

you’ll get much better
at it as time goes on.

That’s just how it works.

We’re still just a little bit,

so I’m gonna get after it this time.

I think the guys here
have a magic turn number,

that it, what it takes to get those to go

and I don’t know what that number is.

And it matters what your
vice is, so I wouldn’t.

So I’m a little under here,

but I’ll tell you that
I’m gonna be narrow here.

Right, that, pinch that way up.

So I’m just gonna come
back, my mag pliers.

I’m still way, I mean, I can
see that that’s not good.

We’re still a little under
here, this should bring it back.

So I went further there then I wanted to,

I would avoid that,

so just go slow if
you’re doing it at home.

Still need another 10 thou.

What you do is

you wanna keep the general
shape of these tubes,

you don’t want the shape
to get way messed up.

There we go, that’s gonna be close, yup.

I love that number, that looks good.

And then we’ll come back
and measure this number.

And then the real test,

we’re still under here so we’re good.

Drops, that mag’s done, good to go.

Again, if you had time,
I’d leave it overnight

and see what happens in the morning.

So just to recap on nine millimeter,

that number we want at .560
and then I want the feed lips

355 minus 10 for the back
and plus or minus five.

On a 40.

We got it queued up here.

I gotta come 50 thou in,

which was what the last
of what we did was,

that’s a fair amount.

That is,

that is a bunch so this is
gonna misshape this body some

and you’ll see how we get those
to come back up in the gun.

I’m close here, 16 thou.

So now I’m going to be
a little more gentle.

Again these things spring in over time,

you’re going to have to
reset them a little bit

but it’s not the end of the world.

You can kinda feel them move too,

so if you feel it move a whole bunch

it probably did move in.

Again this process I’m doing,

of going slow and just working on them,

much better then squeezing
one and racking one.

Getting close, 10 thou away.

Being a little under here would be okay.

It’s bringing my feed lips in,

so I’m going to open my feed lips up

to just over what I need.

And you’ll see that that
bends here at the top

more then it does on the tube part

but it still moves the tube some.

So I’m at 81, I’m gonna take that

to a top number of high 80s, low 90s.

And then I’m gonna squeeze the tube

the last little bit

and it should all just come together.

These don’t want to move
on the last bit here.

Alright, 93.

Squeeze that tube,

squeak that last 10 thou out of the tube

then we’ll bring that,

those feed lips will come
in some part of that.

614, we’re super close.

I’d take 605, somewhere in that zone.

I probably wouldn’t go
much bigger than that.

And then, if you number all your mags,

I would keep a log of where they’re at

just so you have an idea.

That’s helpful over time,

just to know how much they’re moving.

Everybody’s mags are
moving around a little bit.

So 604, I’m okay with that.

Now this probably isn’t fitting in here.

So it’s just barely sticky.

So what happens when you pinch this

is it rounds out here,

you can do it in the
vice or with a hammer.

The guys in the back like
the vice, I like the hammer.

That drops, we’ll come back and check.

Now again, this might be a circle,

you might do a handful of these.

That’s a tad big.

That’s a tad big.

So we’re just gonna come back

and pinch one more time here.

What I like about the hammer is,

you can be a little more specific

about exactly where you’re hitting.

Just over, wanna make this one perfect.

Now we’re back to the 604 number,

I bet it’s gonna be just,

oh and its perfect there, we got lucky.

If I had to hit it with a hammer,

I just use the delrin side,
just some light tapping.

It’s super loud, you might want
hearing protection for that.

Everybody in the shop
hates it when I do that.

But now we’ve got a mag
that’s pretty much there.

So you recheck all your dimensions,

and you kind of work around that

to get them where you want them.

But plus or minus five,

the numbers we’re running are pretty good,

we’ve been running these for a year.

And the 600 and the 560
proved out to be pretty true.

If we get somebody who calls

and says they’re having a mag problem

and they measure that

it’s almost always that the mags

have grown just a little bit.

So an easy fix,

tune them yourself or
retune them yourself.

This is the new Gen 2 bodies

which when tuned right work super well

and they work well with the STI followers

and our overpowered springs

or the gram setups

for extra capacity and no lock back.

(smooth club music)