45/70 shooters

[378]

Just rec'd a nice 23" 45/70 barrel from a member.  I was wondering what grain ammo are the 45/70 shooters using out of the original Contender frame. 

[Blackhawker]

Just rec'd a nice 23" 45/70 barrel from a member.  I was wondering what grain ammo are the 45/70 shooters using out of the original Contender frame. 

I have a pistol barrel in 45-70 for my T/C and according to the load manuals and the manufacturer, only trapdoor loads should be used in the pistols.  I don't understand why because the pressure of trapdoor loads is VERY low as compared to other calibers used on the T/C frame.  I believe it's the recoil that is produced via the short barreled pistol that is the reason.  If in doubt, however, you could always call Thompson Center and ask what is suggested by them.  They're a very friendly and helpful bunch of people to work with.

[378]

Was thinking of purchasing these to start: HORNADY AMMUNITION AND RELOADING 45-70 GOVERNMENT 325GR LEVEREVOLUTION BALLISTIC FLEX TIP 20CT. 
Do you think they will be safe on the frame?

[Blackhawker]

To be honest, I've never fired a factory load of 45-70 ammo, it's all be reloaded ammo for me.  I suppose that if you buy standard factory ammo (not Buffalo Bore) that you'll be OK.  I don't think ammo manufacturers would sell ammo that might damage a firearm or injure a shooter.  Imagine the liability!!  The only ammo that I know of that is over the top and more than likely for much stronger firearms than trapdoor 45-70's would be Buffalo Bore ammo. 

To be on the safe side, however, I'd look up the ammo specs and maybe call T/C and ask.  The T/C people may tell you other than what I have.  They're the ones with the liability on the line.....they'll give it to you straight.

[Hopalong7]

     What's OK in a Contender is not just a function of pressure.  It's pressure and the internal cross-sectional area of the case head that determines the load on the standing breech.  i.e.  45-70....very low pressure and very large case head......223REM high pressure and small case head.....30-30 Win medium pressure and medium size case head....All are OK.  Change either variable on any one of the rounds and they may not be OK.

[Blackhawker]

Thanks for clearing that up Hopalong.  I never really knew why they call for the lower pressures in the 45-70 but that seems to explain it.  What's odd though is that one can really jack up the pressure on a 45 Colt load (40,000cup) and it nearly has the same cross sectional area on the case head.