I just bought a Hopkins & Allen falling block and a Remington rolling block in 32 rimfire. Both anre substantial robust actions that would hold more powerful cartridges like 32 S&W, 32-20 or maybe 38 S&W or 38 Special Assuming that 32 rimfire ammo, what would you suggest to get them shooting? Rechamber to centerfire, and/or rebore and reline to other calibers come to mind. Suggestions?

I think I would try to rebore to 38 special, and convert to a centerfire breech block. I think 38 special 148 wadcutter target loads would be a lot of fun, and readily available.

If the Hopkins & Allen is a Model 932,

some in .32cal had 2 positions on the link betw the lever and the breech block.
Changing the position by moving the exposed pin when the lever is open/breech block is dropped,,moves the closed and locked position of the breech block up or down a bit.
That positions the firing pin in either the 32RF position,,or the 32CF position.

The 32CF cartridge that those rifles was chambered for was the 32COLT cf.
Kind of hard to find now.
But an easy chamber clean-up with a S&W 32 Long reamer will make the rifle into a usable caliber.

This eliminates changing the FP over from RF to CF in a conversion,,but not all of the Mod 922 H&A 32cal rifles were fitted with this feature.

Having a nice bore to start with is a good thing too.!

The Model 938 was the same rifle but in 38 cal.
The 2 cart were the 38RF and the 38S&W cart (not the 38 Special).

The action is strong but still a cast mallable iron one. IF I were to go to 38Special, the loads would be very low pressure ones for sure.

I would stick to .22rf, 32S&WL Reasonable loads.
They did use the action to build a Model Jr Schuetzen rifle and chambered it in 25-20Single Shot round, (Model 3925) or at least it was cataloged. At BP loadings,,maybe. Not smokeless, not for me anyway.

Which Remington Rolling Block action ?

The # 2 action is a solid frame and large enough to rebuild into a 38 Long Colt/38 Spl

A # 4 action was made in 2 types of take down, and neither of those should be converted into a centerfire
The # 4 action was also made in a solid frame, and yes converting the breech block, and reaming the chamber and you have a really nice 32 Smith & Wesson caliber

J Wisner

Here are photos. The H&R is marked 32 R so I don't believe it's a convertible. The Remington isn't a takedown.

https://postimg.cc/gallery/R3zjvmn

The Hopkins & Allen is not their 900 series rifle.
It is built on their Medium size single shot frame.
That was used for both rifles and some shotgun builds.
Usually found in the shotgun version more than in rifle calibers.

They are a bit stronger than the 900 series mentioned above and some were chambered for 32-40 even at the time (turn of the century) for BP loads.
The breech block does have some rear support shoulders (as does the 900 series) but how good the fit is makes a lot of difference in action strength.

Don't push these any more than any other 100yr old + mallable iron cast action.
Most of these style H&A actions (Large and medium sizes were made before 1900.

The bbl is sometimes threaded into the action with a hand tightened fit and then the 'set screw' on the side sinches it up tightly.
Others are a smooth slip fit like the 900 series and the set screw is just that for holding the bbl in place.

The orig design for these H&A got from BAy STate Arms co who they bought out. The early Bay State rifles are exceptionally nice rifles but still share the weaknesses of the time and materials.

Keep calibers and pressures low and they will hold up just fine. Same as most all of the early mfg stuff.
H&A went belly up in 1914/15 after halting production of all sporting arms and trying their hand at a Military Mauser contract for Belgium, so it can't be any newer than that.
I suspect it was made pre 1898 though before they reorganized and dropped many of the larger single shot designs,,of which they had many.

Nice project rifle..