M38A1 CDN3 wheel nut question

[BCA]

Thanks to all for their observations. Interestingly the correct nut 5310-00-391-0687 is described as being "self-locking" and having an "all metal locking feature". I suspect the threads are slightly distorted to make them self-locking. The "all metal" feature means they are not to be "Nylock" or other non-metal locking feature. Look carefully at your original wheel nuts and see if you can see a dimpling or punch marks on the flat hole opening that indicate if the threads were distorted. ……….. Brian