Mapping out build plan bolt, trigger, and FA blocker

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Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Sat Mar 16, 2013 2:31 pm

Just purhased a MG3 parts kit. I am trying to decide on a few directions for my first SA build. I will weld up the reciever. Weld in a 3/8 drill bit where the last rivet of the trigger bracket for a FA blocker. Whitch leaves the bolt and trigger. I want to build the bolt. I have all the equipment but not the time. I will use an AR trigger.
Would the gun be worth more if i converted all the original parts or does it not matter? (Bolt and/or Trigger)
What is he point of the bolt extension?
On the single firing pin design is there anything other than the spring that would prevent a slam fire or prevent gun from going off if dropped?
Does any of he current trigger designs have a functional saftey?
When I get the parts kit in a post some pics.

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby roadrunner » Sat Mar 16, 2013 7:06 pm

Congrats. on getting an mg3 kit. You might consider getting yugo bolt carrier to mod if you don't build one. It would be a shame to mod. An mg3 heavy carrier. Extension is there to move spring back and provide clearance for semi hammer. I just finished installing roller feed stud on mine and there is no other firing pin safety provision other than the spring. Brpguns trigger group has an insert to allow original safety to block ar15 trigger. As far as value goes. My opinion is the value is in the original parts. Once Semi modded they cant hold the same collector value. Good luck on your project. RR

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Sat Mar 16, 2013 8:09 pm

Ok now the bolt extension makes sense. I guess for modding will depend on what I get.
If the gun runs a way is there anything to stop it safely? (can't remove a magazine :shock: )
I read a few forms on out of battery ignition. I talk to BRP and from his opinion it was from bad ammo (turkish, WW2). Is there any other part that can cause this that I really need to pay attention to. (like how far the firing pin is recessed)

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby drooling idiot » Wed Mar 20, 2013 3:32 pm

Schwartzer wrote: Weld in a 3/8 drill bit where the last rivet of the trigger bracket for a FA blocker.

Weld the bracket to the receiver as well.

Schwartzer wrote: If the gun runs a way is there anything to stop it safely? (can't remove a magazine ).

Twist the belt and it can't feed.

Schwartzer wrote: I read a few forms on out of battery ignition. I talk to BRP and from his opinion it was from bad ammo


Bad firing pin designs, the pin should not be able to hit the primer unless the gun is in battery. search my posts on firing pin design all the dimensions are there to make your own better than store bought. If your running an SA thats the design you want.
"good , bad, .....I'm the man with the gun."

Its amazing anything works right around here with a bunch of
over-age juvenile delinquents running the place.

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Fri Mar 22, 2013 10:16 am

Thanks DI
The only FP design i found with a workin picture is this.
viewtopic.php?nomobile=1&f=9&t=10175&p=77452&hilit=+Design#p77452
Two piece design. I read a few people switching to one piece design do to something jamming. Have you had any jamming issues wih your design. What prevents slam firing. Is there a spring not shown in the picture to preven slam fire.
I like the idea of using the original FP. I also like the idea of a hard stop to prevent FP from OOB ignition.

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby drooling idiot » Sun Mar 24, 2013 1:32 pm

Thats the one.

most jambing is traced back to too long of rear pin after rear collar & hammer not hitting square. Thats why most bolt extensions will have a window cut so the user can see the alignment

haven't had any slam fire issues. whole firing pin is very light weight, rear pin is held back by the front collar riding the striker until bolt is in battery, front original pin is way too light to slam fire. No springs used.

Never seen any dents on unfired primers but would like to test the design on the "special" super soft primers ATF is reported to use when "testing" if a gun is a MG , if i ever find out what they are.
"good , bad, .....I'm the man with the gun."

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over-age juvenile delinquents running the place.

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Tue Mar 26, 2013 10:52 pm

Just got my kit. It seems to be a MG42 converted to a MG1. On the reciever, feed cover, and bolt have the bird standing on the nazi ring. The trigger housing and bibod has a bird but no ring. The bolt and receiver have the same marking. The trigger and the feed cover i think have the same stamp numbers. Last digit, one looks like a nine the other maybe an 8 or 9. So i plan turning this to a SA gun. Should I spare the bolt and trigger housing or use all original parts? Still on the fence for the firing pin, 1 or 2 piece.
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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby roadrunner » Wed Mar 27, 2013 1:03 am

Great looking kit there Schwartzer, Glad you held out for the real deal. :D RR

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Sat Mar 30, 2013 7:04 pm

Thanks for thr comps!
Drooling idiot. I have been really thinking about your design and jamming if the trigger is not aligned perfect. What if the tube was not floating but supported. This would allow more slop in alignment. Or has this already been tested? Poor Drawing is only depicting the idea...not to scale.
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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby 42rocker » Sat Mar 30, 2013 7:12 pm

On the """Should I spare the bolt and trigger housing or use all original parts?""" my thoughts are save the German parts and get a yugo set to convert. Also some say that the yugo bolt is made from a better material? They say it holds up better than the wartime steel German used. Myself son't know about that part. But I think convert yugo first save the German.

Later 42rocker

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Not just a bolt blocker

Postby Schwartzer » Thu Apr 04, 2013 5:50 pm

Found this interesting thread. It seems that BRPs bolt blocker does more than block the bolt it also blocks the sear.
viewtopic.php?nomobile=1&f=10&t=4187&p=31824&hilit=Prevent+gripstick+housing#p31824
Can anyone confirm this? If this is true there is more that would have to be done than just a stud and lengthening the gripstick hole by 1/4" to be legal. I did notice BRPs drawing is different then the other drawing on the site by .02". Its actually in his manual.

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby 42rocker » Thu Apr 04, 2013 7:00 pm

Schwartzer
Brian is a super nice guy and I'm sure that if you were to call him he would be happy to talk with you about everything. That said next week he might be at Knob Creek. Hope so.

Later 42rocker

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Sat Apr 06, 2013 8:04 pm

Well I called BRP and it was not Brian, the gentlemen said he did not know much about the FA parts to compare, but he did say the grip stick cutout is different. After thinking about it I decided to install BRPs blocker... when I get it I will decide how. I will add some metal to block the sear but still allow the SA gripstick so a FA gripstick could not be installed front or back. Does anyone know if the placement of the bolt blocker further toward the nose will effect any other parts? Does anyone have any measurements comparing BRPs to Original? Particularly from the back to the gripstick pin and then to the gripstick cutout? On BRPs hand drawing its 5.700" from the rear to the Gripsitck pin and from the rear to the begining of the gripstick opening its 6.500" (three other places in the manual show these measurements 6.519", 6.520", and 6.521") I guess its 6.520 +/-.001 and not 6.500".
Also picked up BRPs ar15 weld in trigger housings. Now I need a M53 gripstick to convert.

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Sun Apr 07, 2013 1:10 am

Is it easier to leave the original rails in for tacking the receiver in alignment or screw the new ones in?
If a piece of the receiver is slightly bent out of alignment should I try to fix before I jig it up or use the jig to pull it into place?

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Sun Apr 07, 2013 1:10 am

Is it easier to leave the original rails in for tacking the receiver in alignment or screw the new ones in?
If a piece of the receiver is slightly bent out of alignment should I try to fix before I jig it up or use the jig to pull it into place?

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Gripstick

Postby Schwartzer » Tue Apr 16, 2013 10:00 am

For the ar15 trigger assembly is there an advantage/disadvantage of having it hook into the ejection port instead of the gripstick port?

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby 42rocker » Tue Apr 16, 2013 6:48 pm

From your photo I can't tell. Were the rails still in the receiver when cut?

Any rate using used rails to find out where to weld things up is a bad idea unless they were uncut rails that came with the weapon. Use the posted measurements from this site for welding up. Then install new or weld up the holes and re-drill them in place.

Later 42rocker

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Re: Mapping out build plan bolt, trigger, and FA blocker

Postby Schwartzer » Wed Apr 17, 2013 10:04 pm

Yes I noticed that when trying to fit parts to test the bolt blocker. It seems they have moved a little and jams some parts. There is a bend at one weld joint not horible. Looks like the cut was not complete when they pulled the part off the other. Its the area where he gripstick goes. I wounder if i should stress releave the area and get it straight or just jig it up and let the weld do the stress releif.


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