I was wondering if anyone knows if the Pedersoli double rifle in 45/70 can shoot hotter loads like the Garrett 415 grain hard cast loads.Or could it be rechambered to one of the 45 caliber Nitro Express cartridges.Any thoughts or ideas.I'd dearly love to have a double but I think thats the only one I could possibly afford.Thanks.

I gave this some thought years ago, especially rechambering for 45-120, but it occurred to me that you might experience trouble with regulating the barrels. I don't know that they are regulated as it is, but if so a change of that sort will probably be detrimental. I decided it was too much money to risk on that big a question. If there is enough latitude in the sights you might be able to compensate.

I asked Pedersoli time ago and result is:

The double express is proof tested acccording to CIP rules and we recommend=the use of commercial cartridges with a pressure of 28.000 PSI.

9,3x74R, the gun is proof tested following CIP rules at higher pressures t=an .45-70 cal. of course, but we always recommend the use of commercial ca=tridges.

Jiri

Maybe: Be patient and we may be able to smoke out one of the posters here who has a couple of the Pedersolis and punched one of them out to .458 RCBS, giving close to NE performance at low pressures, with very good results. Dugaboy, was that you?

Mac37D has done it and posted on the subject within the last couple of days on the Big Game or African Hunting section.

There are gunsmiths that will rechamber these rifles and regulate if necessary. The charges are not all that bad (compared to purchasing a big bore double). Obviously, as Jiri stated you will be limited to about 28,000 psi or better yet limit yourself to 25,000 CUP. Another issue with rechambering to the 450 NE is that the rim is considerably larger in diameter that the
45-70. I would suggest that you rechamber to the 45-120. You should be able to push 500 grain pills out the muzzle around 2100 fps and stay under 25,000 CUP.

Todd E

What is different between 45-120 and 450 nitro express ? (except rim diameter and brass thickness is the same I think . . . )

Jiri,

The 450 NE as I recall is a bottlenecked case. The 45-120 Sharps is a 3.25" long straight walled case (essentially a nonbelted lengthened & rimmed 458 Win Mag). Therefore to rechamber to 450 NE you will need to do a considerable amount of extractor work also while the 45-120 Sharps has the exact same rim as the 45-70 Government.

Todd E

You are true, rim of 45-70 or 120 is .608" but rim of 450 nitro is .620, I confused 45-120 with 450 black powder express . . .

With pressures at about 25000 PSI it could be comfortable to shoot and 2100 fps is enought for everything . . .

What is your opinion about penetration lost at higher speeds ? I have been reading about hydrodynamic effect, which is registerable at speeds over about 600 m/s - 1970 fps, so I think this is reason for it. Penetration could be growing to maybe 2400 and then decrease, because higher hydrodynamic repulsion and faster energy - momentum loss, Of course, bullet construction is the key but . . .