Hey guys! I’m trying to help a friend install a DD Rear Receiver End Plate on his M&P15, and can’t for the life of me get the castle nut off!
I’ve never had a castle nut so difficult to remove! Does S&W use some type of thread locker? I’ve used a RRA stock wrench and a Brownell’s Stock wrench. I even tried a breaker bar with the Brownell’s wrench. I mounted the lower in a Brownell’s/Peace River lower vice block. The Brownell’s wrench is taking peices off the nut!
Any tips or suggeestions those of you who have removed the castle nuts off of S&W’s can provide is very appreciated!
Heat…Is the castle nut stacked? If not put a torch on it until it’s too hot to touch. Use your finger tips to test it. Then crank it. After putting the heat to it it should come off pretty easy. Just make sure to take off any synthetic hardware so it doesn’t melt.
I didn’t have to use any heat to get mine off, just the right tool. If you do get crazy with a torch, (please don’t) make sure you take the buffer and buffer spring out and remove the buttstock. Try not to start anything on fire or give yourself a 2nd degree burn, ok?
Heat will expand metal and consequently it will shrink metal when it cools. Be careful and don’t F yourself up by shrinking the castle nut without getting it off and then you’ll really be up a creek.
The Brownell’s wrench is a nice wrench. Much nicer than the RRA wrench, but I was willing to try anything.
I don’t know for a fact that it has thread locker on it. But it seems a logical conclusion, given the situation. Can anyone confirm wether or not it has locker?
If it does I’ll give it some heat and try again tomorrow.
I’ve never looked that closely on the M&Ps, but I saw one today where the castle nut was indeed staked. If it is, just take a punch and unstake it. Also, use a sharp blow on the wrench instead of a gradual application of pressure.
I can totally relate. I broke the cheap-o wrench in my first attempt to remove the nut. They must have a gorilla that tightens those puppies before they’re staked! FWIW, are you using a lower block in a vise or are you trying to wrestle it off laying on a counter? Just an idea, you could bring it over to your local tactical store and let them slap it in their vise and take it off. No sense breaking more stuff, eh?
I see, I see, said the blind man! You’re doing everything I would be doing and more. I think persistence a little leverage may be the key. I would add a piece of conduit to the end of the 3 tooth wrench and use your free hand to keep the dogs engaged in the slots. Maybe wear a glove so you don’t bust your fingers open when it slips or finally breaks free…
I was using a 24" breaker bar withthe Brownell’s Wrench and wearing one of my old Leather/Kevlar Duty Frisk gloves (I learned after laying my hand open breaking a barrel nut loose once)!
I did finally get it loose though! Using the three tooth RRA wrench and some ridiculous amounts of force.
I don’t remember what the spec for torque is on the castle nut but this one was up there!
The nut is a little boogered up though, so I’m gonna replace it, install the DD end plate, resonably torque it and stake it.
The best castle nut wrench I have that fits only mil-spec tubes only (including S&W) is made by SAW. It works extremely well with no more than a 1/2" drive ratchet.
I had the same issue. Posted a thread on it too. Great advice here. Heat it slightly, I used a damn lighter for 5-10 sec at a time, and just keep at it. I went through 2 stock wrenches before I got it. It’s a bitch.