bore size
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Category: Enfields
Forum Name: Enfield Rifles
Forum Description: Anything that has to do with the great Enfield rifles!
URL: http://www.enfield-rifles.com/forum_posts.asp?TID=3451
Printed Date: March 26 2026 at 4:32pm
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Topic: bore size
Posted By: jorhenderson
Subject: bore size
Date Posted: October 13 2009 at 4:38am
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can anyone tell me why 303 was chosen? why not .300 or .305 even what is so special about 303 ------------- jorhenderson |
Replies:
Posted By: Shamu
Date Posted: October 13 2009 at 8:55am
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"303" is just a name, the actual bore size is (in thoery) .311 inch.
Makes even less sense, right?
 In practice most of it comes from the English system where the bore is measured for diameter. In the case of the Enfield the narrowest part of the bore is .30 inch, so the rifle is a 30 caliber, which is what the MOD wanted. When you add the grooves to the nominal .30 bore diameter you end up with .311 inch (again in thoery).
Of course there is a differeing minimum/maximum bore diameter measurable, depending on the number of lands & grooves, most of them not being directly measurable due to the uneven number of lands.
 The confusion is added to as a lot of Enfield bores are oversized anyway, many being .311, .312, or even .314 in really big ones.
So, in a nutshell the 30 caliber bore+ the depth of the landsX2 (one on each side) is .311.
Clear as mud, isn't it.
 ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: SW28fan
Date Posted: October 13 2009 at 10:17am
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I got curious and this is what I found:
Development The .303 British round is more than just a military cartridge; it is a symbol of a once great empire which for better than seventy years it helped build. This venerable cartridge dates officially from 1888 when it was adopted by a British Royal Ordnance committee along with the Lee-Metford rifle, both the cartridge and the rifle were of foreign origin. The .303 was the result of Major Eduard Rubin, then Superintendent of the Swiss Government Arms Laboratory at Thun (of Schmidt-Rubin fame) and his experiments and development of a straight/tapered walled cartridge in 7.7mm incorporating a crimped on driving band. The driving band system proved inferior for the pressures generated in the cartridge and thus a bottleneck case was developed. The Lee-Metford was the invention of James Paris Lee, a Scot who later became a naturalized American; however, the word "Metford" pertains only to the rifling pattern of the barrel. This rifling form was developed by William Ellis Metford an English civil engineer. ------------- Have a Nice Day If already having a nice day please disregard |
Posted By: Shamu
Date Posted: October 13 2009 at 9:30pm
It's the "BRITISH" bit that makes 'em sound so mean, .303, Vs .303 BRITISH.
.303 Savage sounds nowhere as mean as this round. ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: Tony
Date Posted: October 13 2009 at 9:44pm
Correct!! The stiff upper lip handlebar tash and tiffin time! See we Brits do it in style! 
------------- Rottie (PitBulls dad.) “If electricity comes from electrons, does morality come from morons Born free taxed to death!!! |
Posted By: Shamu
Date Posted: October 14 2009 at 1:40am
They don't like it up em, the Fuzzy Wuzzies, Mr Mainwairing. ------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: jorhenderson
Date Posted: October 14 2009 at 2:37am
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this still dosn`t explain why 303 instead of 30 or 31(my stiff upper lip is quivering) ------------- jorhenderson |
Posted By: Tony
Date Posted: October 14 2009 at 2:49am
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Thank you Corporal Jones! Pikey (aka stupid boy) has just joined the forum! The measurement .303 inches (7.7 mm) measures the nominal size of the bore measured between the lands (Europeans measure bore diameter land to land, Americans measure groove to groove. If you set your calipers to 7.7mm then switch to imperial you will see it comes out at .3035. Hence the 303 lable! ------------- Rottie (PitBulls dad.) “If electricity comes from electrons, does morality come from morons Born free taxed to death!!! |
Posted By: Shamu
Date Posted: October 14 2009 at 4:22am
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Like a lot of calibers it doesn't really make any sense at all when you look at it from the outside.
Why 7.62mm, instead of 7.0mm?
Why 9mm not 10mm?
Why .45, instead of 1/2"?
How about another Brit caliber .455, darn that's almost 1/2" even closer then .45 (which isn't .45.
Or .38, (which is actualy .357) instead of .40?
Or more Imperial oddness like the .577 Snyder, why not a .58 at least.
I think in reality the diameters & sizes were more based on performance of the time developed than some nominal bore diameter, so the effect of the bullet was more in control & the diameter just ended up being whatever worked.
------------- Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force) |
Posted By: Lithgow
Date Posted: October 14 2009 at 6:54am
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Tony is 100% correct.
I dont know why thy didnt make it a bit bigger and round it off to 305 but thats the way it is. Maybe it didnt sound right....305 British doesnt have the same ring thats for sure.
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