Semi-Auto 45-70

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NolanOsborn

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Does anyone here know anything about converting a semi auto/pump gun (Rem 1100/7400/7600) to a 45/70? I realize their could be bolt face issues with the rifles, and pressure issues with the shotguns, but would it be do-able?
Could someone with first hand knowledge tell me about other issues one might face. I think it would make a great gun for open sights, and tons of fun.
 
NolanOsborn said:
Does anyone here know anything about converting a semi auto/pump gun (Rem 1100/7400/7600) to a 45/70? I realize their could be bolt face issues with the rifles, and pressure issues with the shotguns, but would it be do-able?
Could someone with first hand knowledge tell me about other issues one might face. I think it would make a great gun for open sights, and tons of fun.
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I think that the ballistic equivalent of the 45 70 has been done in the .458 socom and or .450 bushmaster?? Cartridges in AR platforms. Please correct me if I'm wrong.
 
I saw a very high end made semi made by a manufacturer out of the US that built a 338 lapua, also I think 450 Marlin, I saw this finely made semi exibited at the 2008 SHOTSHOW, they were around 8-10 thousand a piece! Very refined clipfed with beautiful wood stock. Wish I still had the broshure the fellow gave me, oh well out of the price of the average hunter anyway? I think you would have a hard time finding anyone making a rimmed cartridge semi, but maybe one of the Russian STV-40's, could be the bases for your progect? I like your style, ODD, cheers dale Z!
 
I do not believe shotgun pump and semi actions are designed to handle the pressures of a 45-70. Even though the 45-70 is not a high pressure rifle cartridge, it is extremely high compared to shotguns. The barrel could be made to handle it but the action is the weak link. I doubt you could start this conversion successfully with a shotgun action.
 
In my opinion for what it is worth, any rifle action could handlle the pressures, but it boils down to a management of a rimmed cases out of a mag designed to handle a rimless case. Just buy a Marlin designed to handle the round and have at it.
 
iceman2 said:
In my opinion for what it is worth, any rifle action could handlle the pressures, but it boils down to a management of a rimmed cases out of a mag designed to handle a rimless case. Just buy a Marlin designed to handle the round and have at it.
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This is is basically what I was thinking.

Oh and I do have a 1895 Classic in 45-70 :)
 
zywina said:
I think you would have a hard time finding anyone making a rimmed cartridge semi, but maybe one of the Russian STV-40's, could be the bases for your progect? I like your style, ODD, cheers dale Z!
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Basing from an SVT is probably your best bet. Having it feed correctly from the Magazine would be a whole other ball of wax. Using 450 marlin would give you more options.
 
I know a lot of guys used to fire 45 LC out of 410's wayyyyy back when, and i think the Taurus Judge does handle both, so in terms of physical size it should be doable with a 410. However, pressure would be the issue. Possibly if you used a lighter bullet, say 350 gr., and kept it to original BP velocities/pressures using a powder like trail Boss. I wouldn't use BP or Pyrodex in a semi, because you'd gum up the works. Should be OK in a pump. Now that would be an AWESOME toy.:D

You know, I'm amazed that someone hasn't manufactured a rifled 410 with a 40 cal. sabot slug. It would be a great little deer gun and you could probably get some really nice ballistics out of it.
 
Someone in the USA modifies M1 rifles from 30-06 to .338 & 458 Win Magnum.
A custom gunsmith probably could work out a 450 Marlin or a 458 American out of this action also. But it would cost some big bucks even if you could convince someone to do this for you.
Not many rimmed semi-auto actions to choose from for a custom 45-70.
 
I've been wanting to do this for a long time with a belt fed semi. A shotgun action will be destroyed. It just doesn't lock up strongly enough even for BP pressure loads.

There's no reason you cannot get a rimmed cartridge to feed from a box mag. Think of all the bolt action shotguns and lee enfields. The trick is all in the mag feed lips. The chamfer and angle at the rear needs to allow the rims to stack in the mag when you load it. Getting the bolt to return to the point where the rim will slide under the extractor would be ideal.

I think you could be successful on a box fed action with a long feed ramp.
 
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