Got my little 303 back from repair and having the barrels slugged to find a phonecall that the barrels are polygonal. Anyone have experience with these? Do they require special handling, special loading or other treatment?

Thanks,
Frank

Frank, my long range 308 has a polygonal barrel. As long as it is of normal size there should not be any problems.
You should have it slugged to find out its exact demensions.

What do the bbl flats say, ie bullet weight and powder charge?

I've heard this one with a .303 double before. Almost all British built .303s from that era (including doubles) were Metford rifled. Metford went out as smokeless came in, because Cordite eroded it so quickly, so there are quite a few smiths today who've never seen it before. To the uninitiated, yeah, it looks kinda, sorta polygonal, especially if it's worn, but it isn't. A bore slug is measured the same way as one from a conventionally (Enfield) rifled bore, and jacketed bullets should match groove diameter. Stick with conventional bullet designs and avoid hard bullets. It was probably regulated with 215 grain round nose. I think Woodleigh makes one.
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"Serious rifles have two barrels, everything else just burns gunpowder."

Thanks for the info.
I had them slugged to be sure and they measure differently .311 and .312 for the most part. However there is that odd shape- must be the groove and not the barrel flat that measures .315.
I ordered some 215 woodleighs from Midway and should have them Monday.
The info under the barrel was pretty much wiped out when the last re-blue was done.
Frank

Could be Lancaster type oval bore rifling - the grand-daddy of today's high tech polygonal barrels.

The Metford polygonal (seven sided) was indeed used on many small caliber double rifle of the late 1880s, and some into the 1890s, in black powder rifles designed for lead, and paper-patched lead bullets! The polygonal rifleing is easy to measure, by measureing from the center of a flat, to where the two flats opposite join. The bullets should be patched, or moulded to just a couple thousands larger than that measurement! Metford segmental is four sidede and should be measured from corner to corner for bullet size. Both these rifleings are basiclly black powder rifleing, and are common in rifles made in the 1880s! The metford Shallow (Baker 7 groove) was used in many rifle into the late 1890s double, and singleshots for roe deer/ red deer, in England, and Ireland. Most 303 doubles were made for that purpose!The Metford Shallow was used quite a bit by Westley Richards in the last 20 years of the 19th century. This type of rifleing when only slightly worn, looks almost like a smooth bore, but is very accurate if properly bulleted!

Thank you Mac. There is just so much to learn about these old rifles. I will have to take my time to learn more about this one.
Frank