Hammer and Strut modification

[Kilibreaux]

Hammer and strut before and after modification.

[Kilibreaux]

A point to add is that the hammer now rests fully against the bolt which is slightly better than I managed with the GSG strut mod...but I've figured out why!

With the strut re-contoured to allow it to swing deeper into the hammer, the lower tang becomes the limiter, however this cannot be determined without comparing how the parts interact while in place.  So it becomes necessary to shorten the lower tang to allow the strut to move even farther than manually comparing the parts would indicate.  The result is the hammer fully down with zero play.  This equals a safer action, less chance of case rupture, and less fouling blown back into the receiver.

[Microgunner]

That's what I like about you. You ain't afraid to dig right in and figure stuff out.

You're a wealth of information when it comes to re-engineering.

Thanks and keep it coming.  :thumb:

[Kilibreaux]

Well thank you!  I think.

Hey the rifle only cost $600...

Seriously though, ATI provides a complete list of replacement parts, so it's easy to replace a part if needed and bring the gun back to OEM condition, though I would NEVER reverse the hammer/strut mod on a gun I intended to use.

I think I've bought about four barrels for my GSG just for experimenting purposes...I would proffer that the GSG and STG are equal to the "Gold standard" 10/22 for modular construction, and variety of configurations, only at present the ATI series require custom mods to sub components while the Ruger benefits from decades of aftermarket interest.

[Microgunner]

Well thank you!  I think.

It was a compliment.

[Kilibreaux]

I know...thank you!

[ccw1911]

I haven't taken mine apart yet but I'm wondering why not just remove the lower tang?

[Kilibreaux]

The lower tang?

[Firecaptain]

So Kilibreaux, is all still going well with this modification?

In the "after" picture it appears that there is some brazing(?) (gold color) that has been done, or is that some kind of reflection?

I'm arriving late to this party....one good thing being late in the game is I got a pretty good price, and good folks like yourself have already figured out the bugs and mods to make the firearm better!

Surprised though that there are so few STG owners in these forums.....

[Shadowtengu]

Howdy Everyone I am new to the Forum!

Howdy Kilibreaux! I have been reading and following your GSG work all over the internet! I had a few questions I was hoping you'd answer! I just purchased a new STG 44 and I love it, I have just completed your Hammer strut and Hammer Mod and took it out shooting with 200 rounds of HV stinger Ammo. It cycled cleaning with 3-4 jams which I'm hoping are Mag Related. I wanted to know roughly how well has yours held up. Has there been damage to the plastic buffer? And have you experienced signs of cracking in the extractor groove?

Thank you for your time! PS This forum is very informative and cool!

[Kilibreaux]

So Kilibreaux, is all still going well with this modification?

In the "after" picture it appears that there is some brazing(?) (gold color) that has been done, or is that some kind of reflection?

I'm arriving late to this party....one good thing being late in the game is I got a pretty good price, and good folks like yourself have already figured out the bugs and mods to make the firearm better!

Surprised though that there are so few STG owners in these forums.....

Sorry for the lateness of reply.  No brazing was done on the hammer strut.  Only careful grinding to deepen the slot that bears against the hammer pin which allows the strut to push far enough forward to press the hammer face firmly against the back of the bolt.

[Kilibreaux]

Howdy Everyone I am new to the Forum!

Howdy Kilibreaux! I have been reading and following your GSG work all over the internet! I had a few questions I was hoping you'd answer! I just purchased a new STG 44 and I love it, I have just completed your Hammer strut and Hammer Mod and took it out shooting with 200 rounds of HV stinger Ammo. It cycled cleaning with 3-4 jams which I'm hoping are Mag Related. I wanted to know roughly how well has yours held up. Has there been damage to the plastic buffer? And have you experienced signs of cracking in the extractor groove?

Thank you for your time! PS This forum is very informative and cool!

Hello, the STG simply doesn't need the "work" the GSG required.  With the STG all that is needed is the hammer strut mod to eliminate that goofy rebounding hammer feature.  The trigger's travel is adjustable via a tiny set screw and I've not found any reason to get more into the trigger system.  However the STG is highly "modular" and in that regard offers serious potential (beyond the GSG) for front end modifications such as a complete, dedicated suppressed barrel, or heavy barrel modification.

My STG has been humming along smoothly after about 3,000 rounds fired.  The hammer strut mod IMPROVES durability by drawing off bolt thrust energy that would otherwise carry to the rear of the receiver.

I've read plenty of low opinions about "Zamak" firearms but my current experience with the GSG, the STG, the P22, S&W M&P22 is validating that such construction is plenty durable.  I"m not sure exactly how one might go about "breaking" the GSG or STG without resorting to deliberately smashing them with a hammer.

[eness76]

Thanks Kilibreaux for posting this mod, was very simple to do and now that weak 1/4" of bolt travel from battery is gone! 

I didn't do any experimentation to support this thought, as I just replicated the work you've already proven to work, but I was thinking the stock hammer strut profile allows the hammer to strike the firing pin while the bolt is in full battery, I wonder if the strut remained the stock profile but the rebound spring and hammer notch were removed only if the mod would still work?  My wondering stems from the thought that the hammer is getting far enough forward momentarily to do the job in stock form, if it were allowed to stay up there instead of rebounding would it still apply it's spring pressure to keep the bolt in battery like after the hammer strut fix?  Any thoughts?  Thanks again,

Eric