rolling block caliber conversion?

[Bow View Haymaker]

I am interested in getting a rolling block but in a more available caliber than .43 or 7x57.My first thought is could a 7x57 be rechambered or rebarreled to .30-06 ( a common caliber easy to find ammo and reload for) or would a .43 to .45-70 conversion be easier?

[Bugscuffle]

The way that most rolling blocks are converted is to re-barrel them. It is usually a little less expensive and gives you a more accurate job. Sure you can have a .43 Egyptian bored out to .45 and rechamber it to 45/70 or 45/90 or 45/whatever, but you'll still have to cut new lands and grooves in it. With re-barreling, you can either fish around and find the right barrel for your rolling block or buy a blank in the right bore diameter and have it chambered to your caliber and threaded to your action. Either way though it aint cheap. You are going to end up with a $300-$400 rolling block action with a $600-$800 barrel.

Oh yeah, I for got to say you can get the ammo for that .43 whether it's Egyptian, Spanish or Mauser at this URL: http://gadcustomcartridges.com/#military . But like I said it aint cheap. I suggest you get about 40 rounds and reload them yourself.

[Pettifogger]

.45-70 is your best bet.  Easy to get ammo and a round the RB was designed for.  The antique RBs are simply not suited to the .30-06.  The pressures are to high.  The 7 x 57 is on the edge of what the old ones can handle and are loaded to lower pressures than the .30-06.  Another nice conversion is the .30-40 Krag.  One other thing to consider.  The 7 x 57 was designed for a rimless round and the extractor also acts as an ejector.  It won't work properly with the .45-70 or other rimmed rounds.  Better to start with a standard BR than has an extractor only and is designed for rimmed cartridges.  These are the BEST RBs made and are made of modern steel.  Check the calibers available and you will see none are high pressure rounds.  The old ones are certainly not candidates for high pressure conversions.  http://www.lonestarrifle.com/Calibers.html

[Bow View Haymaker]

Thanks for the input everyone.  I knew the .30-06 was a long shot.  Its just that I already have the components to load those cartridges.  maybe a 7mm to .30-30 would be possible.  what is the bore dia. of the 7x57?  or maybe I could comvert a .32 rimfire to something more avaialable?