Hunters have been taking game for many years using subsonic (under 1100 fps) cartridges. Large bore handgunners are to the fore here, with warm .45 Colt loads being a common approach. Often, a hard cast bullet of about 250 gn is advocated at recommended speeds between 950 to 1200 fps. There seems to be more advocates than detractors.

My thoughts of late have been towards subsonic rifle loads. In playing with the QuickLOAD simulator, it appears 250 gn can be sent 1000 fps from a .32-20 or a .38 Spl. rifle. It would require a relatively fast twist barrel for these chamberings; I'm thinking of a single shot rifle. For expansion, one would probably have to use pure lead at these speeds.

I don't know of anyone who's tried high SD, pure lead bullets at subsonic speeds. Anyone here care to speculate on how effective they might be?

You would need a long for caliber bullet to be effective. The bullet must tumble in the animal to be effective; otherwise, you are just punching a caliber size hole through your target.

Yes, these would be rather long bullets, about 1.25" or more. Military bullets are designed to tumble, but I hadn't thought about that for hunting. I was thinking of pure lead in the hopes of it expanding to at least 40 caliber, but I'm not convinced it would do so.

Do you suppose a tumbling bullet (long spitzer) would penetrate deeply enough at these speeds?

Just build a 45 Colt rifle. I have one for a TC Contender with 27" long barrel. It does not really matter whether it expands or not. It penetrates deer at about 1000 fps and is extremely quiet.

Mike, I agree, but I have in mind an old target rifle, and I don't think the muzzle will be big enough to take a .45 bore.

This question is just a mental tangent, really. I'll most likely just chamber the rifle in a small bore and get a .44 barrel for my Contender Carbine. Where did you get your long barrel? I got my 26" (in another chambering) from SSK.

How about a 300 Whisper or the Rimmed version for a smaller diameter heavy bullet subsonic cartridge? My 45 Colt Contender barrel was built from a Green Mountain tapered octagon barrel blank by OTT. I'm sure someone at SSK would be happy to talk to you about the Whisper cartridges.

The action, a small frame rolling block, won't take the pressure of the Whispers. The gun's maker surely would not chamber it for any cartridge over about 20,000 psi, and I agree with his limit. The QuickLOAD simulator predicts reasonably well the performance of the .44-40 and .38-40 with bullets heavier than normal, so I tried it with similar smaller bore cartridges. I was surprised how much lead you could move to 1000-1100 fps, and I got to wondering if it could be a viable hunting rifle, not just a target gun. My T/C will take care of any deer just fine, so the question isn't terribly important. I figured the handgun hunters have the most experience in this area.

Your earlier comments on the quietness of the big bore pistol cartridges in long rifle barrels was just as I imagined they would be. I'd already planned to get something similar for myself, after I move back to the US this year.

I'm aware of a couple of handgun metallic silhouette shooters who used the .32-20 with subsonic 190 gr. bullets. The load had plenty of momentum to take the rams. Obviously, the twist must be fast enough to stabilize such a long bullet for satisfactory accuracy, and I'm sorry I am unable to tell you what twist they were using.
As Ms. Hitman points out, it, that long bullet must tumble in the animal for best performance in creating a satisfactory wound channel. I understand your thoughts concerning the pure lead bullets regarding expansion. With no evidence in support of my opinion, I nevertheless suspect that a tumbling (jacketed-?) bullet would be superior to one which was pure lead but did not tumble. This would make for an interesting test to attempt to prove either theory.

I haven't done any work with larger calibers shooting subsonic (yet), but I developed a subsonic load in a .22 Hornet to get rid of squirrels. My parents had them eating the bark off pecan trees, and they were everywhere. My own cast lead bullet of 38 grains (Lyman 225107) was left unsized, coated with liquid Alox and seated in the Hornet case, pushed by 0.5 grains of AA #2 and a cotton pellet to hold the powder against the primer. Out of my NEF all it does is "click", and the group is one ragged hole at 25 yards. All head shots with the animals on the ground, so there was no ricochet, and I never aimed up, period. The funny part is, you have to blow down the barrel to dislodge the cotton!

I am seriously considering trying the same thing with the NEF .30-30 barrel and the Lyman 311299, if I can get a load to group. Seems to me you should be able to work on pigs under a feedertty well, without spooking them, if you can make head shots and are quiet enough breaking open the rifle... And if that is the case, maybe there is a way to thin pigs quicker than we have done so in the past. Typically, one rifle shot and they are gone for about two weeks!