STEN "Speed Bolt"

[Robert Henley]

Frank mentions in his STEN book (which I enjoyed reading) that some STEN shooters use a "speed bolt," and the following current seller mentions it as follows:

 

https://www.gunbroker.com/item/839415668

 

"In my opinion, the lightened bolt is the best improvement to a Sten that can be done. It increases the rate of fire and smooths out the recoil impulse without affecting reliability. You can really stay on target with it. "

 

My question is does anyone know who can best machine a STEN bolt to create a speed bolt (hopefully someone on this Board), and what would be the ideal rate of fire for a so-modified STEN? I would not want to damage or harm the receiver.

 

Thanks,

 

Robert

[yohuang]

I am lost after reading this ad. Why lightening the bolt was considered as an "improvement"... Ideal rate is 500-600 on SMG, higher rate of firing is terrible in my opinion, especially on those guns which is not very heavy. I test fired Mauser Schnellfeuer, Astra 902, and MAC-11. All of them have fire rate over 1000.... for looking, they are fancy, but not for range use.

[Frank I.]

Hi Robert,

 

That's a book I wrote a long time ago when we did inexpensive "gun show" books, but glad your enjoying it.

 

The original "speed" bolts were lightened for use in suppressed Sten guns so they would cycle. I measured an original and had one cut to those specifications.The machinist who machined the bolt said it was quite hard.

 

I did an article on how it affected the cyclic rate. It raised it 135 RPM.

 

A ten-round average with the original bolt yielded an average cyclic rate of 532 rpm. Installing the speed bolt increased the average rate of fire to 667 rpm, an increase of 135 rpm.

 

https://www.smallarmsreview.com/display.article.cfm?idarticles=2195

[timkel]

I don't remember where i found this pic.

[APEXgunparts]

My STEN MK2 came to me with a second bolt that had been turned down thru the mid section to reduce the mass.
The previous owner ONLY used that "fast" bolt.
We were making a video at the range and so recorded the gun firing with the "fast" bolt and then the "standard" bolt.
I was using normal FMJ 9MM loads (rated as safe for handgun use).
This was a professional video production for YouTube, and I did receive the AK and Galil video, but my STEN video has never been supplied.
Anyways, the ROF difference is noticeable, but not unpleasant or unmanageable, in fact it felt "normal" and the standard bolt felt slow.
Next time out I was shooting the Israeli 9mm "UZI" ammo that is SMG only rated.
You could feel the difference with recoil and the gun seemed to run a bit faster yet.
I had the "fast" bolt in the gun and later in the session the rear sight fell off!
I have since noted that some STEN tubes have the rear sight located in the top of the tube with a pin (on the bottom of the rear sight) and a spot of weld on either side of the sight to afix it to the gun (how mine was built)
I ran across some of our kits where the rear sight had been installed this way and was gone.
Most others have the spot of weld front and rear of the rear sight (more surface area for the weld)

APEX has PLENTY of STEN MK2 bolts if you want to experiment!

Richard
.

[Robert Henley]

Hi Robert,

 

That's a book I wrote a long time ago when we did inexpensive "gun show" books, but glad your enjoying it.

 

The original "speed" bolts were lightened for use in suppressed Sten guns so they would cycle. I measured an original and had one cut to those specifications.The machinist who machined the bolt said it was quite hard.

 

I did an article on how it affected the cyclic rate. It raised it 135 RPM.

 

A ten-round average with the original bolt yielded an average cyclic rate of 532 rpm. Installing the speed bolt increased the average rate of fire to 667 rpm, an increase of 135 rpm.

 

https://www.smallarmsreview.com/display.article.cfm?idarticles=2195

 

Great article. Thanks for the link Frank. I read your book from front to back, and it was great.

[Robert Henley]

I was thinking about this threaded barrel:

 

https://www.gunbroker.com/item/837192742

 

And then attaching an AAC Evolution 9mm Silencer.

 

I wonder how that would work if anyone has any experience with this kind of set-up?

 

Thanks,

 

Robert

[Robert Henley]

I had thought about one of these AWC silencers (which have been for sale a long time on GB):

 

https://www.gunbroker.com/item/830889304

 

However, the price was ridiculous. I contacted AWC, and they told me they originally sold for a MSRP of $895.

 

Robert

[b_san]

 

I was thinking about this threaded barrel:

 

https://www.gunbroker.com/item/837192742

 

And then attaching an AAC Evolution 9mm Silencer.

 

I wonder how that would work if anyone has any experience with this kind of set-up?

 

Thanks,

 

Robert

I bought one of these https://www.tacticalinc.com/catalog/product/id-7057?products_id=7057 for my MKII, fits and runs great with an AAC Ti-Rant 9.

[Frank I.]

I had thought about one of these AWC silencers (which have been for sale a long time on GB):

 

https://www.gunbroker.com/item/830889304

 

However, the price was ridiculous. I contacted AWC, and they told me they originally sold for a MSRP of $895.

 

Robert

If you have my S&W 76 book there is an interesting chapter about those suppressors written by Phil Dater who first made the MK9. I'm not sure if the newer ones have the same features, but originally they were designed to use standard velocity 9mm ammo. They were designed to fit the '76 and the Sten. Classic can that seems to bring big $$

[skoda]

I machined a bolt on my lathe similar to the photo above. It wasn't too hard, I just took a bit off at a time. The rate of fire is higher but in total the gun shoots smoother than with the stock bolt. More like a Sterling. I never use the stock bolt any more. Get a bolt from Apex and give it a try.