I've applied acetone to the exposed threads and let it sit overnight. Then heated up the receiver by the mag tube. Nothing. I've removed several before but this one isn't budging. This is an older Mossberg 20g youth.

Any suggestions?

Thanks.

Picture

Try a mixture of acetone and automatic transmission fluid. Might have to submerge it.

Koril oil or however you spell it. Works awesome.

Walter

this is the one that will do it

was trying to find the article I had read some time back, and this combination beat out a whole lot of other options hands down

found it

BenBeenBanned@VWVortex said: Some of you might appreciate this. Machinist's Workshop magazine tested penetrants for break out torque on rusted nuts. They are below, as forwarded by an ex-student and professional machinist, Bud Baker. They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.
*Penetrating oil ..... Average load*
None ...................... 516 pounds
WD-40 ................... 238 pounds
PB Blaster ............... 214 pounds
Liquid Wrench ......... 127 pounds
Kano Kroil .............. 106 pounds
ATF-Acetone mix.......53 pounds
The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. Our local machinist group mixed up a batch and we all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price.

The material makes a difference too. PB works better on the type of steel GM makes exhaust fasteners from than does WD40 but the tides are turned in other areas. I've always heard of the home brew but have never used it. I have soaked small parts in straight ATF when it alone was readily available.

I can give you advice on what not to do. Don't put the receiver in a vise and use a set of chain vise grips to break it, the chain will put a dent in the tube causing the cap on the spring to hang up and you will have to use your shotgun as a single shot and embarrass you in front of your friends not that I'm speaking from experience

I have used ATF 75% mixed with brake fluid 25%.

PB Blaster works great. I have the same gun and I had to use a cloth and a pair of channel-lock pliers the first time. I gripped the tube at the tip where the barrel screws in and it didn't leave any marks.