Receivers from BRP

[roadrunner]

I recall the mg3 rails were wider than the old m53 ones. I ended up milling .010" or so off the back side where it entered my shroud. My shroud was long and it had the rivet dimples to clear. Maybe your shroud is slightly narrower than the rear and pinching in front where it enters the shroud. Rails should be centered in the cam piece. As for the crimp in the mg3 recoup. Hmm. Haven't dealt with mine yet but it is crimped also. I know der alder made it work.

[HKARAK]

New MG3 rails are wider/ extend further leaving less clearance for bolt to travel to and fro. I had to remove some thickness using belt sander. Just be careful not to remove too much.

[rodom]

At this point, my rails are all the way forward and actually touch the camming piece. I think tomorrow I'll pull them out and do as you both have said and thin them a bit in the front by the camming piece. The bolt moves freely every where else. I did pry the crimp out a little bit on the recoup, and the bolt is staying in place now. The MG53 recoup has no crimp in that area, and its bolt has a shoulder on both ends. A better design I think. Thanks for the input, and thanks to the other builders out there who broke the ground.

[rodom]

I just wanted to let you both know you were right about the MG3 rails. They were about .030" thicker than the MG53 rails. I took .020 off the back side and the bolt drops thru like "BUTTER"! Thanks for the tip. So I have the recoup front bolt mounted, and the rails. The next step will be to set up the Lafette and set the gripstick mounting bracket and then the rear recoup bolt. The bolt blocker is going BEFORE the gripstick, see I didn't forget it. Once that's all done. it's down to the bolt. Open question to all of you out there who have used the first gen BRP bolt, how reliable is it? It looks very similar to the Wiselite bolt, and there are quite a few of those out there. Preferences? The BRP kit comes with a recoil spring, so that's a plus. Man it's getting close, it's gonna be my Christmas present to ME!

[rodom]

My Yugo Lafette arrived and I'm in the process of cleaning it up. I'll use it to set the rear grip mounting position, and once I get the MG finished, I'll look at really cleaning it up and refinishing it. Open for all suggestions as to type of finish and color (s?) normally used. I got the MG53 maintenance kit from RTG, and would like to attach it to the Lafette, if it does mount there? The kit is in a canvas bag, and I must thank Robert for the kit, as the bag is in excellent shape. All the internal components are as expected, but I didn't expect to receiver such a nice carry bag. Usually they're "clapped out" pieces of ..... well you know. Not this one, Thanks again Robert!

[rodom]

Nothing new really, just wanted to post a couple of shots of the Lafette. I've been sidetracked with Christmans coming, but I want to get back to the MG ASAP.

I was "eye-balling" the bolt blocker, and it's appears to be directly under the mount for the rear tab of the Lafette. It also looks like it's going to cause problems with the recoup installation. Is this something that I as a noob was unaware of, and you all as skilled builders have already accomplished? Sounds stupid on my part but I didn't realize until now that this was going to be a problem. Or as a noob, am I just over thinking it? I do have a tendency to do such things.

[roadrunner]

Rodom, The prints from brp cover the recup. modifications. and take that into acount. Here is a picture of mine that might clear it up.
P.S. that looks like a great lafette. Also, this really should be installed before your receiver is welded into one piece.

[rodom]

Roadrunner,
Thanks for the response. I guess I just hadn't planned that far ahead, as the exact location of the blocker kinda surprised me. I was thinking further back by the buffer for some reason. But after seeing yours, I can understand the cutting of the recoup to drop into the gap on the blocker. And then the hole for mounting the recoup is drilled thru the open space on the recoup. Pictures really do say a thousand words for me. So I'll get the blocker cut out and welded in before I measure the rear grip mounting point. Still waiting for a bolt from BRP, but I just might go ahead and buy the first gen conversion so I can move forward.
I have so much to learn about on the Lafette, as to what all the knobs and levers do and how they work together. And I started wiping it down with lacquer thinner to get some of the crusty grease off, and using a toothbrush on details. At lease now you can read the numbering and see the chart. I was hoping someone would say it looked good to them, cause it's gonna look good to me! Thanks again Roadrunner.

[rodom]

Well I don't know what I did wrong but this is a duplicate post. I had already posted about getting the bolt blocker slot cut, and the blocker tacked in place. Then I used the Lafette to set the rear gripstick mounting position.

After I got the hole drilled for the rear recoup mounting bolt I set the bracket and snugged things up for testing. I had to trim the recoup to clear the new gripstick but it's ready to have the blocker and the rear bracket welded in place now.

I just ordered the BRP bolt kit, since it's anybody's guess as to when they will have whole complete bolts available. That's the next step, getting a working bolt. Then the charging handle. The slot, and the window are both cut, just need to trim the handle and then fit it.

[roadrunner]

Good progress Rodom. How does the recup. seat in the mg3 buffer tab? Just asking as I will be doing same thing. Oh, the old style bolt mod works fine. You want to pre-heat before welding extension. Carrier is hardened. Seen some with cracked welds but mine has been fine for over 1000 rds. Pre-heated and tig welded it.

[rodom]

Hi Roadrunner,
Here's a shot of how it worked out for me. You can see the end of the recoup tube body is sitting against the back of the buffer plate.

You can also see the bolt blocker down the way. I pulled the rails out to work on the recoup mounting. Like I said earlier, I had it in and out several times trimming for the gripstick.
So you did the BRP bolt already? I was hoping someone would drop by and tell me what I needed to know. I have a fella who can do some TIG welding, and was going to ask him to do the bolt. I know how it needs to be as strong as possible. But thanks for the tip about pre-heating the bolt body, I wouldn't ever have known that.

[roadrunner]

Looks good. Your close. Won't be long now.

[rodom]

Here's a question for the Lafette owners. I used the Lafette to set the rear mounting point for the gripstick, and the MG drops into the rear tabs and locks down on the front clamp. But when I put the gripstick into the MG and try to mount it in the Lafette, the trigger hits the actuator finger and won't allow the MG to lock into place. It looks like about an 1/8 inch needs to be trimmed off the finger to allow it to drop down. I'm reluctant to cut anything without hearing from the others out there who have done this before. There's no way this is going to click into place without something being modified, cut or adjusted somehow.

[roadrunner]

The ar15 trigger is more forward on my original style brp weld-up fcg. I suspect the aluminum grip is the same.

[rodom]

Roadrunner, that's what I had thought, that the modified AR trigger is moved a bit forward. I compared it to the original trigger housing and it's as you said - a bit forward. I can probably bend the actuator forward a bit to allow it to drop into place without cutting anything. I'll do that tomorrow and if it works I'll post something so others will know that it's an issue that will need attention.

[rodom]

Roadrunner, you said to heat the bolt body before welding. How hot? Warm it with a torch or throw it in an oven for? Just some guide lines to follow please, as I'm no welder. Thanks.

[roadrunner]

Hi Rodom. So sorry for the delay. Just discharged from hospital today.
pre-heating is mostly for slowing the cooling of the welded parts. If they are cold they can cool and shrink too fast and crack. There are other reasons and quite a science to it but for this I have just jigged it up and used a torch to bring the whole assembly to about 300 degrees. Don't want to heat too much to change color of the steel.
This also gets the moisture out of the metal.
I'll get to the c/h dimensions soon.

[rodom]

Hey Roadrunner,
Sorry to hear about the hospital visit. Hope things are all good now. Thanks for the advice, but take care of yourself first. I'll just warm the bolt body up with a torch - without getting it so hot so as to change it's temper.

[rodom]

I have another question for the masses. Those of you who have used the BRP first gen bolt kit, how did you drill thru the firing pin holder? It's a hardened piece of tool steel, and my drill bits won't touch it. I wiped out two new bits, and resharpened them by hand, only to wipe then out again. What/ how did you guys do it?

[rodom]

Well after searching the internet, I found a method to drill the pin holder. Using a massonary drill bit I was able to drill thru the tough steel. Lesson learned, something I didn't know and now do.