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I am repairing my existing ratch plate and noticed that many of the pictures show a protrution or nub sticking out from the middle of the plate in the area of the rear demil cut. The cocking handle seems to function with out this feature. Does anyone know what purpose it served? TIA
It can be seen here on the BRP dummy receiver- http://www.brpguns.com/images/semireceiverrear.jpg

i guess you'd call it a bumpstop, limits the normal travel of the cocking handle.

Mine is lost too. The torch took it away. I think it might be for another reason. You guys with the original, uncut receivers can confirm or dispute this - Is there any chance that it is a "Hold Open Bump"??? Will the claw on the charging handle catch behind the bump and keep the bolt open? I would certainly liike to have such a feature. right now my rails are bolted in place and a nut is working to hold the bolt open (it isn't ready to shoot yet). I have even thought about a washer under that rivet to create such a bump.
Somebody fill us in....

I believe that it serves as a stop to catch the operating handle assembly's ratchet-catck before it can be puled too far to the rear ? ......(IE: Limit the amount of reward motion for the assembly). I believe it was made as a "safety" of sorts so that the cocking-assembly would not be broken-off if the assembly were pulled to far to the rear and have the bolt stop against the buffer with the operator still pulling to the rear....this could possible breaf-off the stud that contacts the bolk ? ....or possibly for a set disassembly point ?
I will see if I can drag my MG42 out from under the MG34 and look for you.

Be safe, RichardS.
Blanksguy2001@chartermi.net

All I can add to this conversation is the manual which came with my BRP gun does not mention using the "Bump" as a hold-open. BRP provided a peice of aluminum angle, approx. 2" x 2" painted red. This was to be inserted into the ejection port between the Bolt Face and the Barrel as a hold-open. I eventually got a piece of 3/8" thick UHMW and cut to fit.

With the SA gun, the bolt always goes forward, so I feel if the Bump does hold the Bolt back, it could come loose at most anytime from an accidental hit to the the gun and MIGHT cause a slamfire. Be safe and use a mechanical hold-open for the SA guns!

The "claw" on the protrusion at the rear of the "ratchet-plate" (sharp-edge) faces towards the front of the weapons which dictates that it is some type of "stop" when pulling to the rear.

Be safe, RichardS.
Blanksguy2001@chartermi.net

The receiver drawing in the faqs show the bump in two different spots and neither view has it dimensioned. Could someone please measure the dimension from the rear edge of the reciever to the front edge of the catch. Thanks.

The bump is there to limit rearward travel of the cocking handle when charging the gun, there is not a hold open device on the mg42.

FTB1-SS wrote:The bump is there to limit rearward travel of the cocking handle when charging the gun, there is not a hold open device on the mg42.

That's pretty much it. The most rearward the bolt can go is when it bottoms out on the buffer, and the ejector bar is pushed forward, and we know the F/A had to be able to do that (troubleshooting, eject a dud, etc.). Just beyond this threshold is that tab, and in some pictures I see that it sticks out facing forward. I'd venture to say it was a clever way to let the gunner know "by feel alone" that he's ejected the round, and could proceed shooting.

On the semi, I welded that tab back in place, yet ramped the front smooth, and filed the back off into a hook. It is my bolt catch.
The F/A did have a bolt catch too......but it was the sear.

The "bump" is not really necessary. The cocking handle will stop when it hits the buffer-butstock mount.

I agree with JS412- why have the bump at all if the buttstock/buffer assembly is there?

Question #2 Aside from the block of wood or metal that Abwher mentioned does anybody have a hold open device that works? I would certainly like to have something like what is found on the M-16 or the FAL

What about reversing the design of this "claw" that we're talking about and adding a lip on the bolt retracting hook, so the hook can be fully caught by the claw? Pulling back on the charging handle would lift the hook, letting go would let it chamber a round?

Wouldn't loading a belt be a whole lot easier if the bolt was back to begin with?

88comm wrote:I agree with JS412- why have the bump at all if the buttstock/buffer assembly is there?

Question #2 Aside from the block of wood or metal that Abwher mentioned does anybody have a hold open device that works? I would certainly like to have something like what is found on the M-16 or the FAL

What about reversing the design of this "claw" that we're talking about and adding a lip on the bolt retracting hook, so the hook can be fully caught by the claw? Pulling back on the charging handle would lift the hook, letting go would let it chamber a round?

Wouldn't loading a belt be a whole lot easier if the bolt was back to begin with?

I'm thinking you posted w/out reading my post. also...
One cannot load a belt, and drop the cover down when the bolt is in the forward position.

Karbinator - you are correct, I read your post but did not think it through. What you have done is what I seek to do. Use that bump, in a modified fashion, as a bolt hold open device. Your other note -

"One cannot load a belt, and drop the cover down when the bolt is in the forward position."

Was also on my mind, as I thought this to be the case. Even your point about the sear being the bolt catch finally sunk in and made sense. It took a minute as my auto sear has long been lost to the file and beltsander. Thanks

When I was Kosovo we crosstrained with the Spanish and they had MG3s. The bump stop prevented you from accidentally pulling the charging handle off when field stripping the weapon.

icarus wrote:When I was Kosovo we crosstrained with the Spanish and they had MG3s. The bump stop prevented you from accidentally pulling the charging handle off when field stripping the weapon.

yup thats it

So, theoretically, that bump can do both jobs, if it is reconstructed as a bolt catch as well -

On the subject of ratch plates, here is my repaired plate without the handle catch protrusion. I filed out the missing plate from the weld. It had a 1/2" gap with the 2nd bump on the edge missing completely.

Very nice work I hope mine looks as good when I'm done. Any Tricks on rebuilding the bump?

88com, I used a dremel tool to shape it and hand files for the final work. I find it is hard to screw it up with a hand file. Whenever I try to grind it down that extra bit, I end up with a wavy surface from over cutting. None of the receiver rebuild is hard, it is just alot of work.