Firstly, to answer some questions:
Modern military ammunition (and guns chambered in it) is perfectly legal, the law makes no distinction between, say, .30-30, and 5.56mm Nato. Anqique rifles are always considered firearms even if they're obsolete, unlike shotguns and muzzle loaders.
Pistol ammunition is legal. It can be used in pistol caliber carbines like leverguns and the Armalon PC (pistol caliber) Enfields (and even if it couldn't, there is no law banning it).
I don't have a specific budget, name anything you like really.
A straight-pull AR is an AR with the gas system removed so you pull the bolt handle before each shot.
A rifle must have a barrel at least 30cm in length, and must be at least 60cm in overall length.
Silencers are un-restricted if they are integral (like on the De Lisle carbine). If they are readily detachable, you need 'good reason' to have one. However, my local police force (who handle the lisencing of firearms in my area) are very lax compared to some so it's not at all hard to get silencers.
A crank trigger would be illegal because of the wording of the law regarding full autos. A semi-auto American 180 or Calico would be legal, however.
Theoretically, you can own an AR upper with the gas system (from a special UK legal single-shot, auto-ejecting AR), and the AR lower from a straight pull rifle. You could put the two together when the SHTF. But I want a finished rifle which is UK legal, not something I have to break the law to complete.
The most common pistol calibers would be .38 special and .357 magnum.
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Ok, with that out of the way:
I already have a Marlin 1894C in .357 magnum (with an Eotech and Surefire
).
I was wanting something with more range really, something in a proper rifle caliber.
Enfield would be good, but I'm suprised nobody is thinking something more modern, like an Armalon PR. Not really looked at the Steyr Scourt. Is it a removable magazine? What capacity? How comfortable is it to shoot (looks a bit short and light)?
Yes, KC&97TA, my perfect rifle would be a 5.56mm levergun that took M16 mags but I don't believe one exists