Will a 38-55 clean up a 303 British chamber?
Or specifically, can a SMLE be rechamber/rebored to 38-55?

No.
Have to go with the 375 FL Nitro 2.5 inch. And I have the reamer.

quote:

375 FL Nitro 2.5

Interesting cartridge, has a bit of history to it. I’m playing with ideas to put my second No.1 Mkiii* SMLE back to life. The bore is very dark with some rifling, but worn near the muzzle. One thought was reboring to 35-303, but dies are hard to find. That’s why I thought about the 38-55.

If rebarreled, what would be a good caliber, other than 303 British, that would fit and feed properly.

We get a lot of these original 303s.

Some are so badly worn, I cannot imagine how!

Had one with the bore totally smooth!

A 303 bullets drops straight down the barrel.

Slugged it.

I think it was about .328”???

These normally come from villages in the Omani mountains.

They get worn our from cleaning; poor Armies can't shoot much, but their soldiers can clean the hell out of them. This is why many muzzles are funneled out too.
A good cartridge for an Enfield is the 30-40.
I have also put .444 Marlins on them. And 405s 2.2 inch.
I have also put 45-70s on them and they work better if you turn the rims down. That brass still works on all other 45-70s.

35-303 loads easily on 35Remington dies.
But you won't be able to FL size of course, just neck size, seat and crimp..

Cadanian gunsmiths did a lot with the 303 case, it was easy to come by both for rifles and brass.

I had a bunch of reamers from a Canadian gunsmith, still have the 44-303 I think.

.38-72 or 375-2.5" are good choices, they're nearly identical.

A 375-2.5 on a P14 is on my short list of things to do. Have all the parts, just need to make the time.

Cases for the 375x2.5" FL NE can be made from 405 or 9.3x74R brass.

Roger

I once built a #4 Enfield in 444-35, and used cut off 35 Whelen FL dies; worked great and the owner killed a bear with it in Manitoba.
No special, exotic, or special tooling or parts needed.

quote:

Originally posted by Uncle Grinch:
One thought was reboring to 35-303, but dies are hard to find. That’s why I thought about the 38-55.

CH4D offers them for $116.

375x444 375 JDJones

I would try and stick to cases 303 up to 444...30-30 based rounds, my opinion only, are a bit small for the action....sort of like putting a 223 into a Brevex...again, just my opinion, the actions are long enough for a decent case.

Roger

Your opinion is quite valid in actual fact; the 30-30 is not suitable for the enfield action. Rim is too small; pressure is not the reason.
OP is going with the 303-35.