Purely biased for the Handi and the .45-70 - I have one myself. Will take care of anything in North America, even the stuff that wants to eat you. I don't recommend a scope (as I have a scar on my head which agrees with me) but a good set of peep or ghost rings suit the 'handy' aspect of the gun.
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I take my coffee how I take my women: bitter and overbearing.
Currently I have 3 handirifles. If you get a good one, one that shoots good groups and doesn't have a 10 lb. trigger pull, they are good "handi" rifles. If you are wanting something comparible in price, look at the savage/stevens model 200. This rifle can be upgraded with triggers, barrels, etc. What you buy is what you get with a handirifle. And yes you can get other barrels for it, but you can't get better quality barrels for it.
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One hole groups are as easy as pulling the trigger, until you pull it the second time.
Well, I can't say they are great, kinda blocky and flat black, but sufficient for minute-of-critter at hunting ranges (I can consistently hit milk jugs @ 100 meter berm). I have wanted to add a Lyman peep or an AO type setup like on the Marlin Guide Guns.
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I take my coffee how I take my women: bitter and overbearing.
I personally like bolt actions, so that would be my vote. I also like the 30-06 for most situations. If 45-70 were available in a pump action similar to a typical pump shotgun, I think that would be excellent.
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Trust is earned, not... GIVEN away. - Worf
Here's my NEF Handi rifle in 30-06 with aimpoint scope. I can get the 45-70 barrel for under $100.00 for it but it would only be for giggles since I feel quite confident with my own handloads. I don't know anything about the Marlin but suspect the Handi price could get you the rifle and a spare varmint barrel.
I have a handi in 30-06 and its just OK....i haven't really had a chance to shoot it too much though. my dad bought it off a friend for 100 dollars and we just haven't had a need for it at all so have only shot it about 10 times to see if it was sighted in, and it wasn't so i quit because the ejector was sticking alot and pissing me off. once the ejector is fixed i would imagine i will like it much better.
If you can't tell from that I voted XL7, i have heard nothing but good about them.