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.38/.357 prototype


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#1 bruski

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Posted 09 December 2013 - 01:06 AM

This is a six barrel testing platform basically with no fansy or polished stuff involved here. The barrel's are chambered for .357 but I have only been using 38 special cartridges so far with any tests. The bolt carrier and rear barrel plate are T 6 aluminum and the bolts are 1/2 inch cold rolled. I used the gears that I had from a D&E build that I stopped working on years ago. The main shaft is 5/8 cold rolled turned down to 1/2 for the gear with a keyway slot milled into it for headspace adjusting. I drilled a 1/8 hole through it and pressed a dowl pin in it to turn the carrier from the rear. The barrel plate is dowl pinned and is attached to the carrier with 2- 1/4 inch bolts.
Some of the tests are using a pin pressed into each carrier groove that protrudes up into each bolt bottom for a positive ejection of the spent cartridges as the bolts move rearward. The bolts have a slot machined into there bottom areas to allow for this. Another test is moving the cam followers closer to the middle of each bolt to shorten up the housing length. The recoil is absorbed by a piece of 3/8 inch thick flat stock that is welded to the box cam from the under side after milling a 3/8 slot in the box cam exactly even with the bolts backside pathway at BDC with a cartridge chambered. The cam path was releaved some at BDC so the cam followers don't take any recoil at all.
bruski

 

Attached File  post-93-0-66992600-1419801742.jpg   47.42KB   11 downloads



#2 bruski

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Posted 09 December 2013 - 01:08 AM

A couple more pictures.

 

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#3 42rocker

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Posted 09 December 2013 - 04:13 AM

Wow!! I noted in several posts in threads that you were working on something bigger. Way to go getting it done and working and sharing some photos with us.
Thanks.

Might be sending a few questions your way about this and some of the other great work that I've seen you doing on this site.

Later 42rocker

#4 42rocker

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Posted 09 December 2013 - 04:28 AM

Really like how you redid the bolts and the cam follower, nice. The pin and grove to keep things in line is great also.

Is that the same style extractor as in the RG-G plans?

Are you having any problems with the end "cap" of the bolt getting loose as you are using a screw in end cap??

Using the socket head screw as cam followers is nice also.

Very nice

Later 42rocker

#5 42rocker

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Posted 09 December 2013 - 04:34 AM

Forgot to ask two other questions.

1st screw in barrels, right?

2nd one or two piece bolt carrier?

Thanks

Later 42rocker

#6 bruski

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Posted 09 December 2013 - 07:11 PM

The carrier is one piece and the barrel's are threaded 5/8-18 NF. The extractors are off the shelf Marlin 22 rimfire extractors. I used red locktite on the bolt end caps after making sure everything would work ok. I used locktite on the hammer rod pieces also inside the bolts. I haven't had any problems (knock on wood) with these parts coming loose. If they do, I plan to cross drill and pin them in place.
bruski

#7 42rocker

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Posted 09 December 2013 - 10:02 PM

bruski
Thanks for sharing that.

Later 42rocker

#8 Cutter

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Posted 02 April 2015 - 07:37 PM

We are bring this thread back to life.
Three of us talked over two years ago about
building a 357 Gatling gun. Bruski forged ahead
and got his firing. I was too busy with building 4 guns
and Mike decided to go fishing.
Now the 357 group is four, and coping the 1877
5 barrel.
All of us bought our barrels from a guy in Sacramento
18" long .800 diameter and chambered for 357/38S
Probably 2 to 3 year build, we are still gathering information.
We would like as much information as we can get
Thanks
Jerry

#9 4171

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Posted 05 April 2015 - 01:27 AM

Looking good bruski. Cant wait to get started.
Mike

#10 Cutter

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Posted 12 April 2015 - 11:42 PM

Here's an eDrawing of the Cam, for those of you who have
the free Solidworks viewer.
Cam is 4.250 diameter X 3.170 long
Bolt travels 2'

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  • Attached File  CAM.zip   56.96KB   34 downloads


#11 Cutter

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Posted 15 April 2015 - 02:08 PM

A preliminary model of the Carrier.
4" diameter X 5.225 long

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#12 Cutter

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Posted 25 April 2015 - 03:21 PM

Pretty sure we're going with this pin to eject the casings or misfires.
From bruski's prototype.

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#13 bruski

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Posted 19 December 2015 - 05:15 PM

Any more progress on the .357 gats? I was away for a while and some how got side tracked with re-storing a 1961 Swoopster  vintage kart.

bruski



#14 Cutter

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Posted 19 December 2015 - 08:41 PM

The project has been on the back burner.
Going to finish the Rat Gat joint build first.
We'll get back to it in 2016 for sure, but
still collecting information
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#15 bruski

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Posted 27 April 2018 - 01:21 AM

Blew the dust layers off the 357 prototype and got the itch to continue on with it soon.

Bruski


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#16 Sparky_NY

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Posted 27 April 2018 - 11:28 AM

Blew the dust layers off the 357 prototype and got the itch to continue on with it soon.

Bruski

Great news !!      I really like some of the ideas used on the prototype.    I am going to build a .410 gat next, after a break, and will have questions for you.


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#17 Cutter

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Posted 27 April 2018 - 03:21 PM

Blew the dust layers off the 357 prototype and got the itch to continue on with it soon.

Bruski

bruski,
I’ll be following this build close. I still
have 12 barrels from the source you provided.
In fact, I have 6 too many, if anyone is interested
in them.


#18 4171

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Posted 08 May 2018 - 06:12 PM

Hey dont forget me guys :-P . Havent been on in awhile. Anybody working on theirs?



#19 bruski

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Posted 09 May 2018 - 12:07 AM

Blew the dust off of it. I kind of forgot where I left off with the testing. Everything rotates and clicks OK, guess I'll reload some 38's and try it out.

bruski



#20 bruski

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Posted 29 May 2018 - 09:59 PM

Well, I loaded 6 rounds in her and had one fail to fire and another bolt failed to extract. Now I remember where it was that I left off at. Put another ten or so rounds in the stick mag and tried it again. The rounds were hanging up in the magazine even with a brass follower to weight them down some.

 The bolt that failed to extract had a weak spring under the extractor, fixed that. The failure to fire bolt had a broken firing pin in it which is the same type of ejection pin that the others have in them also. These pins are long and are .0625 diameter for the entire length except for the hammer end which is similar to the RGG firing pins but longer. There isn't much room in the bolt for a larger diameter firing pin with the extractor taking up so much depth. It wouldn't be much of a problem except with a center fire type of cartridge the firing pin can't be lowered any. So a larger diameter of bolt is the only other fix that comes to mind. This would allow for a larger diameter of spring also to get a deeper dent in the primers. I realize that the firing pin centered and the extractor depth would still be the same with that cartridge so a different type of extractor would need to be designed to allow for a heavier firing pin. Maybe the firing pins could be necked down where they pass through the extractor area and beefier on the hammer end for a longer distance. The hammer end is where the pin broke in the fail to fire bolt.

 

 Any way, that is where I am at with this.

Bruski


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