.32 Rimfire Conversion

I recently purchased a well-used No. 4 Remington Rolling Block because the price was right, I like Rolling Blocks and I thought I could resurrect it. The gun was in reasonable condition but had seen some hard use as witnessed by the 24 notches a previous owner had carved on the forend. I can only assume those notches represented squirrels or rabbits but knowing boys as well as I do, it’s possible they mark tin cans, rocks, or most anything else he hit with the gun.

Bottom: The forend wood came complete with notches from a previous owner. Did some family rely on this rifle to fill the pot at dinner? The only real drawback to putting the gun into shooting condition was that it was chambered in an obsolete .32 rimfire. While .32 rimfire ammunition can occasionally be found, I wanted something that was more readily available and reloadable. The first problem was a loose barrel-to-receiver fit that allowed the barrel to wiggle back and forth in the receiver.

I tightened up the take down lever so it engaged the barrel correctly and held it firmly in place. Upon removing the forend I discovered that the forend extension that goes into the front of the receiver to help stabilize the forearm had been broken off. I was faced with either drilling a 3/4" hole the length of the forearm and gluing a dowel in place or finding an alternative method of attaching an extension.

As the forearm wood is only an inch wide, any error in centering the hole or keeping the hole perfectly straight was going to break out of the wood. I have done plenty of stock repair and published several articles about it, so I used one of my favorite repair tricks to make the extension. I took a 3 1/2" length of 9/32 fully threaded rod and drilled a 3/8 hole in the forend. The size of the threaded rod and hole to seat it in is not critical provided the hole leaves plenty of room for adhesive to hold in place.

I sealed the joint between the receiver and the forend with modeling clay and mixed up some Acraglas from Brownells (#081-003-002AK). After a couple drops of brown dye and a liberal coating of release agent on everything I didn’t want the Acraglas to stick to, I was able to pour a perfectly fitting extension. The original liquid Acraglas filled the oversize hole in the forend, locking the threaded rod to the wood and with the rod extending out of the forend and into the receiver.

I am certain the new extension will be there forever. The tight fit obtained by using the receiver as its own mold eliminated all the forend play. There are many things to consider anytime you want to adapt any gun to a different cartridge. Collectability and how the alteration affects collector value, action length, bolt face dimensions, extractor specs, and action strength are just

This will have to be moved to line up with the center of the chamber to fire a centerfire cartridge. Above center: After coloring the breech face with Dykem, a cleaning rod with a brush was run down the bore from the muzzle to mark where the centerfire pin should be located. a few that will limit your choice of a suitable cartridge without extensive and expensive rework. In this case, choices were limited.

Due to the age of the firearm and the fact that the .32 rimfires were originally black powder cartridges later upgraded to smokeless, any of the hotter .32 centerfire cartridges had to be ruled out. My first thought was that this would be a neat little package in the new .327 Federal Magnum but a bit of research revealed the working pressure is around 45,000 PSI. Even the .32 H&R Magnum has a chamber pressure of 21,000 PSI, far in excess of the 15,000 PSI of the typical black powder cartridge.

Pushing this old gun up to pressures three times what it was designed for was simply not someplace I wanted to go. If the barrel had been bad or the gun in pristine condition I might have put a .22 liner in it for a .22LR conversion even though the once ubiquitous .22 seems to have recently become an out-of-production cartridge in my area. Joking After covering all surfaces except the threaded rod and the end of the forend wood, the barrel and forend are assembled and the Acraglas poured.

Below center: Modeling clay fills the receiver and Acraglas will be poured through the hole to fill the void underneath. If not sealed, the liquid Acraglas will run out of even the smallest gap. aside, since the bore was in nice shape it was less expensive to use the barrel as is. That eliminated the choice to the .32 S&W family.

By converting the rifle to centerfire and reaming the chamber to .32 S&W Long, a cartridge that also started life as a black powder round with a chamber pressure of 15,000 PSI, I’d have a nice, low-recoiling rifle using a more available cartridge in the same chamber pressure range the gun was designed for. The actual conversion process was relatively easy. The first step

Be sure to use plenty of release agent or you will no longer have a take down model. The Acraglas will stick to the metal, permanently attaching the forend to the receiver. after disassembly was plugging the old rimfire firing pin channel in the breechblock. There are a couple of ways of doing this. If you don’t have access to a lathe capable of turning anew firing pin, cut apiece of steel rod the same diameter as the original firing pin.

Solder it in I look to be pretty happy with the group at 9 o’clock to the bullseye. the old channel or use Brownells Steel Bed (#081-040-003AK) to fill any voids and hold the rod in place. It is necessary to use a steel rod to fill the firing pin channel because the conversion requires drilling anew channel for the firing pin. Using a filler like Steel Bed without the steel rod causes the drill to bend and follow the old channel instead of cutting through the side of the old angled channel wall.

To mark the location of the new firing pin hole in the face of the breech block I coated the face with Dykem and reinstalled the breech block. I then ran a cleaning rod with a bore brush down the bore from the muzzle and twisted it when it contacted the breechface. That left a mark on the breechface in line with the center of the bore. I removed the breechblock and used a center punch to mark the spot so the drill wouldn’t wander when drilling the firing pin hole.

Measure the tip diameter of the firing pin and choose a drill bit a few thousandths larger. Drill the firing pin hole in the face of the breech to the same depth as the length of the small section of the firing pin. Now comes the tough part. Select a drill a few thousandths larger than the diameter of the firing pin body (the large diameter) and drill a hole from the rear of the breechblock to a depth that will just intersect with the smaller diameter hole.

Fit the firing pin into the new firing pin channel and adjust the hole depth until the firing pin protrusion is 0.049 to 0.051. The case diameter of the .32 S&W Long is different than the old .32 rimfire originally chambered and a call to Brownells or Dave Manson Precision Reamers (mansonreamers.com, will have a new reamer in your hands in a couple of days.

The results area sweet little .32 S&W Model 4 Rolling Block that is fun to shoot and is capable of putting a serious dent in the local squirrel and rabbit populations. With a muzzle velocity of 718 fps and a bullet energy of 112 foot-pounds, it is not a deer rifle and it really won’t do anything a .22LR won’t do but it has put an old dust collector back to work and it is accurate enough at 50 yards to put a smile on my face when I shoot it.

Of course, you can now reblue, refinish, and/or customize the gun to your taste. In this case I elected not to refinish and allowed the old girl to show her age. I’m not sure why but old guns have a certain dignity and the bumps and bruises give them a personality. Unless they are rusted or broken I like to have guns with personality. Whichever you choose, your last chore is to remark the gun with the cartridge it has been converted to.

After all, the gun has already outlived its previous owner and will also outlive me. The next person that it is passed down to won’t know what you have chambered it for unless you tell them. AG