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Posted: 2/3/2010 4:41:05 PM EDT
| Okay, I finally broke down and am building a 630 replica because of all the beautiful ones I've seen lately. I have one of 45Bravo's grenade rings and modified BM flash hiders. So, my questions is, do you put a lock washer inside the grenade ring? If so, wide or narrow? |
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When I sent this pic to 45bravo and asked about it,his reply was what I posted up top. I'll just add this,if the washer is inside the grenade ring,there is no room for the lip of the grenade launcher mounting bracket to fit inside the ring,,picture even kinda confirms that,no??
ETA Remember we are talking about the XM148 for this time period,,there is no "barrel clamp" that holds it on.The 148 front mounting bracket slips into the grenade ring,and is held in the back by the slip ring. |
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Quoted:
When I sent this pic to 45bravo and asked about it,his reply was what I posted up top. I'll just add this,if the washer is inside the grenade ring,there is no room for the lip of the grenade launcher mounting bracket to fit inside the ring,,picture even kinda confirms that,no?? ETA Remember we are talking about the XM148 for this time period,,there is no "barrel clamp" that holds it on.The 148 front mounting bracket slips into the grenade ring,and is held in the back by the slip ring. I disagree - the XM 148 attached to the barrel at the front. The grenade ring is a point of reference that prevents the GL from sliding forward under recoil forces. 
Notice the flange at the top front of the XM148 facing forward - note below the flange is ON TOP of the moderator, facing forward. The 148 clamps to the barrel, it does not fit inside the grenade ring. 
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NO! NO NO! 
You DO NOT use a split ring washer with the grenade ring! The XM177 moderator has wrench flats so that it could be torqued to spec to keep the XM148 grenade launcher in place. If you use a split ring washer you will do two things, you will create a space so that the ring will not seat properly on the barrel shoulder and you will fill the shelf for your XM148 grenade launcher retaining lip! You guys DO want to be able to mount your XM148 grenade launchers, don't you?!? See photos, I know this comes up from time to time but I hope this clears things up. 
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Quoted:
Here is a later type of XM148 that does show a lip to go in the grenade ring - not like the earlier version. http://www.autoweapons.com/photosv/xm148a.jpg I stand corrected. UXB,I also stand corrected.I was not aware of the early / late difference.I thought there was only the one. |
| I was under the impression the washer goes over the threaded area,then the grenade ring and then the moderator was torqued.The washer and grenade ring was THE pressure against the moderator.The washer is 1/8" thick and only fits into the first slot(closest to muzzle),not the larger slot |
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POMM 9-1005-294-14/1 dated July 1967
Operation, maintenance, repair, and replacement parts SUBMACHINEGUN, 5.56-MM, XM177E2 Illustration C-4 shows an exploded diagram of the 177E2 with listing for each part. It shows a barrel, then a grenade ring, and then a moderator. As I stated above - I stand corrected. |
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You beat me to it uxb!
Yep, you are correct 45Bravo, I remember thinking it odd that in the XM177E2 draft manual that it only shows the grenade washer and not a lock washer, learn something new every day! I bet someone will be pissed after reading this, the fact that they pinned and welded their moderator with a lock washer behind the grenade ring
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Quoted:
POMM 9-1005-294-14/1 dated July 1967 Operation, maintenance, repair, and replacement parts SUBMACHINEGUN, 5.56-MM, XM177E2 Illustration C-4 shows an exploded diagram of the 177E2 with listing for each part. It shows a barrel, then a grenade ring, and then a moderator. As I stated above - I stand corrected. can you scan that illustration and post it...I'd like to add it to my xm177e2 file ...so I remember to do mine correctly 
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Quoted:
You guys got me squared away. I just sent Pat an e-mail to see if he could do my barrel. M1: The die-hard retro buff would get a real NFA grenade launcher... Way out of my price range,someone listed a site within the last 3 months,there was one NOS in the box,IIRC price was $8,000 or $8500. I also don't think NY would trust me with one anyway... 
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That explains why the lock washer wanted to ride over the barrel. I ended up using a crush washer.
I have now removed the crush washer and the steps make more sense. Who's going to be the one who changes Eike's post about the lock-washer? EDIT: My clone without washers. 
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