Questions for owners of latest model H&K 416-D 22 rifles

As my boys love to shoot I decided to buy them each a 22 t semiauto 22 rifles. Came across a outstanding deal on H&K 416-D 22 rifles and after reading watching a large number of reviews that were overwhelmingly positive I bought them sach one.
Before I shot them gave both a thorough cleaning but used my 22 bore snake VS my normal 22 caliber Dewey's coated cleaning rod.
Went to the range and shot approximately 400-450 rounds out of each. Absolutely flawless performance using Browning ammo and Winchester

Now for my questions.
Watched a few videos on how to disassemble and clean my 416-D's. Per one video to remove the barrel BCG and charging Handel you screw off the flash guard and pull out the barrel CH and BCG together.
After I removed the FG I discovered there was a second part screwed onto the barrel shroud that the FG attaches to that must be removed to allow the barrel BCG and CH to be removed.

This part has vertical notches in it to allow for its removal. I has no tool nor could I come up with an alternative to allow me to nemove this part without risk of damaging it. So I left it in place and will buy the needed tool for future cleaning.

As I had no other choice if I wanted to use a cleaning rod decided to clean from the muzzle end as much against my policy of never doing so for obvious reasons.

Went to push a 22lr spacific jag with a 22 specific patch and got to about the chamber and it stopped dead. Didn't want to risk getting it stuck so I removed it.
Immediately used the same rod and jag on my Marlin 39 LA 22lr and it worked no problem whatsoever. Then tried it on my other 416-D same result rod wouldn't pass through. I removed the jag and tried just the bare rod and again wouldn't pass once It reached the chamber.
Tried my 22 bore snake and It worked fine.

Now I originally bought this Dewey's rod for cleaning my 556 AR's and it has also worked great on my Marlin LA.
So am I to assume the rod doesn't fit because the chamber on my 416-D's are ever so slightly tighter than ones on other 22lr rifles, or could it have been built up lead fouling, or is it as simple as the brass hardware on the end of the rod is simply to large for this particular 22 rifle.

Thoughts and input from other 416-D owners would be appreciated especially if you encountered the same issue. I am going to try to find a cleaning rod for 17 caliber rifles and use that. But would like to hear from other 416-D owners or anyone with an answer for me to explain why my rod works on a Marlin LA 22 and a Marlin semiautomatic 22lr but not my 416-D's

Thanks,
Art