There are several actions that are strong enough.
But that is not really the issue with the 5MM. All rimfire rifles leave a portion of the rim exposed when the bolt is on battery. The actual rim is not in the chamber, but stands proud of it the thickness of the rim. Most all leave the lower half of the cartridge's rim hanging out in the air. This is a no go for a 5MM rifle.
Examine a 591 and 592 and you will find a dual stage extraction system and a chamber that has no extractor cut, and is cut deep enough the cartridge is flush with the end of the barrel. This coupled with a flat bolt face supports the entire cartridge head and rim. The initial extraction from this sealed chamber is in the chamber wall itself. The mechanism for this is under the plate on the left outside of the receiver. This plate is unique to the 5MM rifles. It contains the magic that lets the 5MM run above the safe and accepted pressure levels of the rimfire case. (33,000 PSI I am told, others are running max at 26,000) This single shot type extractor is in the far side of the receiver and can be seen with the bolt open. Take the tip of a screw driver and catch the grove in the piece you can see, and pull back and discover the extractor the is a spring loaded portion of the left side of the chamber. This on some rifles leaves a tell tale mark on the side of the case as it tries to extrude itself out of the tiny gap this extractor leaves in the chamber wall. As you extract the fired case, a spring on the left side of the bolt engages this primary extractor, and with draws the case about 3/8th of an inch. The outside of the bolt extractor during firing is parked unused on the rear of the barrel shank visible in the ejection port, After the primary extractor has done it's job, this secondary extractor has the rim hooked and finishes removing the fired case.
This unique system it what make the 5MM rifles' special.. The Thompson Contender pistols due to their single shot design already posses a sealed chamber fully supporting the cartridge rim..
A good indication of the pressure levels generated by the Aguila "varmint" loads is clearly seen in the base of the empty case. You can clearly see the center fire firing pin hole in the breech face were the brass is trying to extrude itself in the the firing pin hole, as well as the machining marks from the breech face transferred into the brass case base. This ammo makes a touch over 2,100 fps in a 10" Contender.
The 5MM will leave holes in a forged Tee style fence post at 25 yds. As a farmer I have lots of those lol.. Tonight I shot a piece of 4" heavy wall pipe at 25 yds, and at 15 ft. Deep dent, melted steel, but no hole at 25 yrds. But at 15 ft. different story. Melted a hole right through what I think is a 1/4" steel wall.
I have also used the 5MM to kill a 1,300lb butcher steer the got loose and was standing in a neighbors yard, one head shot, and lights out.... Others have related stories of use on deer, and at 100yrds it will pass all the way through the skull from any angle. This back in the day with the Remington ammuntion.
So long story short there is a lot more to creating a safe 5MM rife than meets the eye. Not saying it can not be done. Just saying careful considerations must be made for it. The brass rim must not be left in the open as in all most all other rimfires. It has to have full support.
The newest batch of Agulia ammunition appears to be casterated. The advertised velocity is 300 fps less that what the earlier run of ammo was loaded to. My guess it is at 22 WMR pressure levels. Maybe their lawyers got a hold of them lol. I will cherish the ammo I currently have.
Some of the early white box has thick rims that can be hard to chamber and extract. This cost me my bolt handle some time ago. I had it repaired and now am back enjoying this light weight rimfire powerhouse. I would l like to try a .17 WSM to see how it compares. Maybe some time I will check one of them out. They use a thicker brass case that has to have a much heavier firing pin spring to detonate the priming charge. This thicker case lets this caliber run at higher pressure than a standard rimfire case with out the fully supported case head, negating the need for any special extraction considerations.
Regards, Kirk