AR Sponsor
Posted: 3/22/2007 4:17:53 PM EDT
| I'm a nood so bare with me. I have a rock river lower. I'm trying to get the castle nut off so I can replace the rear plate with one that has a loop for an HK style sling hook. For the life of me I can't get it off. I tried heating with a hair dryer and no dice. Now here is where I'm nervous. I put the castle nut wrench on it and had the lower laying down flat on a pad and tried hitting the wrench with a hammer. I had my hand on the other side on the lower so it wouldn't go anywhere. I hit it a couple times with no luck. I gave up and decided to try something different at work. After putting the rifle back together I noticed that the car. buff tube looked like it was not perfectly inline with the rest of the rifle. This has me concerned. It still works fineand it dosen't look as if the lower is twisted but I never noticed this before. Am I just parenoid? |
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Yes you may have twisted it with your antics, most likely the dammage isn't permanent other than the to the groove on the bottom of the receiver extension. For some reason Rock River Arms loctite's their castle nuts to the receiver extension. A hair dryer just isn't going to cut it. Either get a propate torch, or try the freezer method where you put the lower in the freezer (the steel of the castle nut and the aluminum of the receiver extension contract at different rates). Then try to unscrew it after the lower has been in the freezer for several hours. |
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(In before the loctite crowd) Assuming it's just on their tight, you're probably going to need a vise and a longer wrench to gain some decent leverage. My bushy had that nut on their tight as well. I had to use my FOOT to hold the rifle down, and with a steady hand and some balls, I got that thing off. My wrench has TWO teeth to engage the nut, I wouldn't trust the 1 tooth CAR wrench but that's just me. So either put some elbow grease into it, *OR* get a vise, a heavy duty wrench, and get to work. If there is loctite on there. 
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for my RRA I put the lower down on a carpeted floor and put everything I had into that wrench and it finally gave way. took a good 20 minutes of fighting. by the way, be careful of the takedown detent spring... I shot one off into oblivion and was without a rifle for 2 days 
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Thre is a nub on the receiver end plate (the part you are looking to replace) that fits into this groove. It's job is to prevent the receiver entension from spinning. I've seen this before with commercial receiver extensions (like yours) where the nub doesn't have enough to grab and with sufficient force you CAN rotate the reciever exension (doing minor damage to a few threads in the process). |
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Ok. Had the same problem with my DPMS when I first got it. 1. Take the upper off the lower. 2. Remove the grip screw, grip, selector detent and spring and selector. 3. open up vice and lay a thick towel or cloth across it. 4. Drop the lower into the corner of the vice. Put the part of the lower where the grip would cover in the vice. The vice only contacts the recessed grip area. Snug the vice up... SNUG, not tighten. Just enough to bring the cloth in contact with the lower. Dont really need to clamp it in, just want to keep it from twisting. 5. Put a hair dryer on low and move it around the nut for about 5 minutes... until you get a sweet smell. Thats the loc-tite getting warm. Dont hold it in 1 place, move it around quite a bit that way it heats up evenly and doesnt overheat the finish. 6. Set your wrench in place and lean in it just a bit. if the barrel would be pointing left, then pull the wrench. Righty tighty, lefty lucy. If needed, put a short piece of pipe on the wrench to give a little more leverage. Nut should spin off with just a little effort now. Let me know how it works. Also, if you dont have one, I suggest getting a good 3 point M4 buttstock wrench. I have 1, 2 and 3 point wrenches. While they all work, you have a better bite with the 3 point and less chance of slippage. |
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