As far as my understanding goes, every centerfire semi automatic rifle is limited to 5 rounds regardless of whether it's a shotgun or a rifle.
There is also nothing illegal with owning any magazine that is not a prohibited device and the law states that the magazine is limited to the legal capacity of the firearm it was designed to be used in regardless of what other firearms it may also be compatible with.
You're in a bit of a grey zone on this one, legally you should be fine but
First of all decide if it's worth the trouble if you do get caught using it in your semi auto, you may win eventually but it will be costly and the prosecution is working on tax dollars while you pay your own way. I think that legally you're in the same ballpark as using a pistol magazine in an AR-15 or a 40 cal Glock magazine in a Glock 9mm to get a couple extra rounds.
Second, be prepared, have all relevant documentation with you when shooting, with the important information highlighted so you can hand it to the officer who is arresting you.
Third, be smart about it. As far as I'm concerned we would still have no issues running Beowulf mags if certain people didn't take them out to the local gravel pit and do multiple mag dumps which of course will generate phone calls from concerned lieberal citizens to local law enforcement which forces them to do something about it after there have been enough reports.
Does the company that makes the 10 round mags for the pump action also make a semi auto that they will work in? If so I would say you are going to hit the multi use wall and going to be illegal in your semi because you have to prove the magazine was designed for a pump action and that it coincidentally works in the semi but if it is also designed for their semi then technically it should be pinned to 5 on import.
Remember, they don't want us armed and most police know very little about firearms or the laws around them, many of them have been brainwashed by years of lieberal propaganda and they stop listening to reason until after you're in handcuffs and down at the station.
A lot of people like to tell you it's legal so do it but only you can decide if It's worth the potential headache that might come from it. The police and the judge don't care what any of us think is legal and don't care how we interpret the written law, all that matters to them is how they interpret it.
What's to gain vs what's to lose? A couple extra rounds making your smile a little bigger for a couple minutes or months and months maybe leading to years of court battles and lawyer fees.
On private land or out in the middle of nowhere I say go for it but at the gun range or anywhere there may be unhappy campers listening I would stick to the five round mags.
