How Useful Are The Caliber Conversion Inserts?

I recently acquired a TC Contender with a 10” .223 barrel. Since .223 is unobtanium without putting the mortgage payment at risk, I bought a .22 LR barrel from another forum. That will help out with inexpensive plinking during the current drought.

As I was looking for other accessories online I came across caliber conversion inserts for use in the .223 barrel that would accept .22 WMR. These look like a .223 cartridge case with a chamber cut in the back to accept the appropriate rimfire cartridge. The inside is similar to a chamber on a revolver cylinder.

I did a bit of research on the twist rates and it seems the OEM Contender .223 barrels had a 1 in 12 twist rate. That seems to be a little fast to stabilize the heavier .22 WMR bullets but might work ok with the lighter 40 grain stuff.

Has anyone played around with any of the caliber conversion adapters? If so was it worth $40?

I know the correct answer is to buy a .22 Mag barrel but, since I see these adapters crop up fairly regularly it piqued my curiosity.

I have no experience with the ones using 22 rimfire in a centerfire chamber, the ones I know of for that use had a small plug deal that fit in the back to transfer the centerfire firing pin blow to the rimfire rim.

The 32 auto in 30-30 have worked fairly well for shorter range plinking and pest and small game shooting, but I load similar loads in 30-30 cases which ends up being even simpler. It is fun to eject the chamber adapter in a top eject Winchester 94, have the adapter come spinning out, self eject the 32 auto case, and catch the adapter in your hand empty.

I used to look for partial boxes of 32 auto ammo at gun shows, they could often be had pretty cheap in years gone by, but thats not likely the case now. If one already had a 32 auto gun it may be practical.

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Originally Posted by Malamute

I have no experience with the ones using 22 rimfire in a centerfire chamber, the ones I know of for that use had a small plug deal that fit in the back to transfer the centerfire firing pin blow to the rimfire rim.

The 32 auto in 30-30 have worked fairly well for shorter range plinking and pest and small game shooting, but I load similar loads in 30-30 cases which ends up being even simpler. It is fun to eject the chamber adapter in a top eject Winchester 94, have the adapter come spinning out, self eject the 32 auto case, and catch the adapter in your hand empty.

I used to look for partial boxes of 32 auto ammo at gun shows, they could often be had pretty cheap in years gone by, but thats not likely the case now. If one already had a 32 auto gun it may be practical.

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I find the .32 ACP in a .30 caliber rifle concept intriguing as well. I've also got the molds to load 100 grain RNL .32 boolits. That might be a fun experiment over the winter.

Ive done 3 grs Unique with a .310" round ball lubed with lee liquid alox, and done 6 1/2 grs Unique with a 100-110 gr cast bullet, it ends up being about like the old 32-20 loads. The round ball loads are about as loud as a standard vel 22 LR. They also will destroy a rattlensnakes head. Shooting cottontails, the bullet makes a WOP sound when it hits and they seem to do a somersault than hit the ground done, dead, over and out. I harvested a record class bull mouse in my yard once with that load also. Utterly devastating load.

Faster twists stabilize heavier bullets. You should be fine with any .22mag ammo. Other than that I unfortunately have anything to add.

Quote:

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Originally Posted by Malamute

I have no experience with the ones using 22 rimfire in a centerfire chamber, the ones I know of for that use had a small plug deal that fit in the back to transfer the centerfire firing pin blow to the rimfire rim.

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No need to that in a Contender. Just flip the switch to the RF firing pin.