How is the recoil of a .45-70 compare to that of a 12 gauge slug? Would it be too much for deer?

Depending on the round, barrel porting, etc...it's pretty close for sure. It can hold groups out to 150 no problem, I think it's a great round for deer.

If you compare a std. remington, federal, winchester 45-70 load to a 2.75" 12ga 1oz load, there is no comparison. The 12ga kicks much harder. If you compare my 405gr 1950fps 45-70 reloads, now you talking. Or my 350gr 2100fps loads, they tap ya pretty good. But its a different recoil in my opinion. Slugguns usually use a fast burning powder and its sharper where my IMR3031 loads are more of a push.

BC hit it right on. It all depends on the loads. It can be a ***** cat or a real stem winder.. Factory loads are not bad at all and are plenty for deer. For bear I like the 350 Grain Hornady round nose at 1900 fps and up. At any velocty over 1600 fps that bullet will go from one end of a black bear to the other. Of course the faster you drive it, the better the trajectory. However penetration will drop off some. Great old caliber Try one, you will love it.

Just curious, how many grains of 3031 are you using?

For the factory loads I have fired in a Marlin lever & the Ruger #1, I would say it is a ***** cat compared to a 12 gauge. Buffalo Bore & Garrett loadings are a different story.

I will have to look, but think its 57gr. I also found a real accurate load of 47gr of IMR4198 and 300gr partitions.

For the most part, the 12 gauge slug would give you the worst punishment. 45-70 is a great timber rifle for deer or larger animals.

My Marlin likes the loading of 51 gr of H4198 behind the Speer 300 gr HP (#8900). I haven't yet used this load for deer because the areas I hunt I can get shots farther than I care to guesstimate the trajectory of the old .45-70 and usually take my .270 or 7mm-08. This load however has accounted for 3 black bear - one shot each and it really cleaned house. It should work fine for deer also and the recoil is less than a 12 ga 2 3/4" slug.

Bronk, I got some serious horsepower out of that load you got but started getting vertical stringing after 47gr. Other than that I get 1.5MOA out to 200 yards. Do you see any vertical stringing? Also is your barrel ballard or microgroove? mine is micro.