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I've always considered full-bore to be anything centre fire and small-bore to be rim fire i.e. .22rf .17hmr etc...

Interesting replies, guys.

Thanks. Feel a bit better now, seems that there isn't a black 'n' white answer, then.

Odd.

Does anyone know what the NRA officially classes the term as? Be interesting to see what they list it as.

I hadn't thought about the rimfire/centre fire exclusions, I mean, afterall, I have a Swiss Vetterli rifle chambered for a .41cal RF cartridge. I wouldn't count that as small-bore.

Interestingly, full-bore seems to be a UK, or maybe a European thing. I was speaking to some yank friends, and I mentioned "fullbore" and they had no idea what I was on about

Most persons on the left of the pond will call full-bore palma or if in the great white north TR.
My 2 cents or pence

For me it has always been .22LR is smallbore and anything above is fullbore, the differentiation between the two was clouded slightly with things like the .17HMR but it is rimfire so smallbore in my eyes...

Strictly speaking* smallbore is small caliber rimfires (.300 or smaller?) while fullbore is just about anything centerfire. But people seem to use fullbore predominantly to refer to shooting at 200 yards or more. Rarely do I hear people describe gallery rifle as fullbore.

It makes more sense I think to drop the terms entirely and just say 'rimfire' and 'centerfire'. Of course you do have some obsolete calibers like .44 Henry rimfire that use the 'rimfire' ignition method but are of a size and power more comparable to centerfire rounds, but generally the terms are cleaner and avoid the more common confusion that arises from powerful centerfire ammunition that uses a 'small bore' like 5.56mm, 5.45mm etc.

*Even more strictly speaking, smallbore would be any round/gun with a small bore but nobody intends to use it in this sense, as above.

I always thought of fullbore as bottleneck-form rifle cartridges, pistol calibres as straight-walled cases and smallbore as .22" rimfire and thereabouts.

Fullbore = anything not rimfire, smallbore = rimfire for me.

I hadn't any idea there were so many variations on this one.

Wow, this is confusing.

What's more interesting I find is that we're all on the same, general page, but there's nothing set in stone to define it.

As none of us really knows what it means, I hereby propose a renaming of the forum to;

Centrefire(UK)

Nah, as we have just proved, the very name of the forum is enough to provoke discussion!

TattooedGun wrote:I've always considered full-bore to be anything centre fire and small-bore to be rim fire i.e. .22rf .17hmr etc...

What about the large calibre rim fires then, like the .44s or the 12.7mm for example or would you call them "small bore"?

Where would pinfire cartridges fit in?