303 British / .308 / 30-06 Discovery???
- Thread starter Red Dawg
- Start date
I do have a thing for cast bullets. I have gotten cast bullets to shoot accurately out of some guns that will not shoot a jacketed bullet consistently.
.303 british vs .308 win
I may be wrong but here's my take on this bullet dia. thing:
the .303 caliber is a european caliber (and japanese)
the 0.303 dia. is equal to 7.7 mm exactly ( 7.7mm / 25.4 mm per inch = 0.303 inch exactly or 0.30315 which is close enough for the girls I shoot with)
now a .308 bullet has grooves of 0.300 which gives .004 inch of interference between the groove bottoms and lands. now if you apply the same .004 inch all around the .303 caliber you need a .311 bullet. It's as simple as that!
0.300" lands + 2 x .004" for the groove depth = 0.308" bullet
0.303" lands + 2 x .004 for the groove depth = 0.311" bullet
I hope everyone knows a bullet diameter is equal to the bottom of the grooves so the rifle bullet can be extruded thru the barrel which permits the powder pressure to build up and deliver maximum muzzle velocity as opposed to a muzzle loader bullet which do not have a lot of interference in the rifled bore.
Snippy
PS: the big lines of life are driven by simple principles (excuse my french)
I may be wrong but here's my take on this bullet dia. thing:
the .303 caliber is a european caliber (and japanese)
the 0.303 dia. is equal to 7.7 mm exactly ( 7.7mm / 25.4 mm per inch = 0.303 inch exactly or 0.30315 which is close enough for the girls I shoot with)
now a .308 bullet has grooves of 0.300 which gives .004 inch of interference between the groove bottoms and lands. now if you apply the same .004 inch all around the .303 caliber you need a .311 bullet. It's as simple as that!
0.300" lands + 2 x .004" for the groove depth = 0.308" bullet
0.303" lands + 2 x .004 for the groove depth = 0.311" bullet
I hope everyone knows a bullet diameter is equal to the bottom of the grooves so the rifle bullet can be extruded thru the barrel which permits the powder pressure to build up and deliver maximum muzzle velocity as opposed to a muzzle loader bullet which do not have a lot of interference in the rifled bore.
Snippy
PS: the big lines of life are driven by simple principles (excuse my french)
The problem with your deduction is that the 303 rifles tend to have a slightly greater groove "depth" than do the 308/30-06, etc. The groove depth is usually from .0045" to .005" making the total groove diameter .312" to .313" I have two P14's in 303 [one is rechambered to the Epps] and they are both very close to .313" groove diameter, while having a true .303 bore diameter. If you buy a North American made aftermarket barrel, they usually have a .311" groove diameter, but the offerings from Europe are seldom that small, but are often much larger. Regards, Eagleye
I have some Lee enfields that are incredibly accurate with cast bullets and others that give them a fast tumble so they "buzz" after they leave the muzzle. I have no idea why some guns will shoot jacketed 303 (.312") accurately but tumble 0.314" cast bullets.
"I asked in a post in GNzs once if 308 civilai, 7.62x51 and 7,62x54 was interchange able for relaoding, and got a few answers back saying it was not comparable at all, especiallly nato and soviet, not i read its ok, what ever is a guy to do, i only go by what i am told by those in the know, and when i repeat it, i look like a foll, oh well thats life."
The problem with a fuzzy question is that precise answers may not be for the question you thought you were asking.
308 Wincehster and 7.62x51 are very similar rimmless calibers and funtionally interchangble. That is, the rounds will fit and safely go BANG!
7.62x54 is a Russian rimmed cartridge that looks more like a 303 Brit. It shoots the same .310 - 3.12 bullet as the Brit. Nothing about it is really interchangeble with a 308Win or 7.62x51.
The problem with a fuzzy question is that precise answers may not be for the question you thought you were asking.
308 Wincehster and 7.62x51 are very similar rimmless calibers and funtionally interchangble. That is, the rounds will fit and safely go BANG!
7.62x54 is a Russian rimmed cartridge that looks more like a 303 Brit. It shoots the same .310 - 3.12 bullet as the Brit. Nothing about it is really interchangeble with a 308Win or 7.62x51.
Ooohhh! You have an off square crown or unevenly worn rifling at the muzzle.....
I cured a couple of tumbling Lee enfields by truing up the crown.
I have a couple that tumble cast bullets no matter what I do. They shoot jacketed bullets o.k.
I have a couple 303s that tumble cast bullets but shoot jacketed extremely well. I am still figuring out why the cast tumble and how to make cast shoot well.
After reading this thread, I measured the bullets in a box of 303 Remington core-lokts. They were .307-.308.
Also measured some bullets from winchester .308, they were .308. Measured some 123grain Hornady soft points for sks,they were .310. So in my opinion, some manufacturers definately do put .308 bullets in the .303 Brit cartridges.
Also measured some bullets from winchester .308, they were .308. Measured some 123grain Hornady soft points for sks,they were .310. So in my opinion, some manufacturers definately do put .308 bullets in the .303 Brit cartridges.Eagleye:
I see no problem with my deductions.
The basic principle is correct:
the .303 is a 7.7mm european caliber
the 308 winchester and others are .300 cal from america (308 bullet, 300 groove)
If you have a set of muzzle bore gages for .308 you will see that they are very near .3000 or a little under (.2995 or so ...)
I hope you won't give me trouble for a .001 inch difference on the .303 !
Take care
I see no problem with my deductions.
The basic principle is correct:
the .303 is a 7.7mm european caliber
the 308 winchester and others are .300 cal from america (308 bullet, 300 groove)
If you have a set of muzzle bore gages for .308 you will see that they are very near .3000 or a little under (.2995 or so ...)
I hope you won't give me trouble for a .001 inch difference on the .303 !
Take care
You are confusing bore diameter and groove diameter.
The 308 Winchester and other .300 calibers from America, are 308 bore diameter, not groove diameter as you have stated above.
Ted
No not giving you trouble at all. As Ted just said, I was referring to "groove" diameter, not "bore" diameter. Since the grooves tend to be a bit deeper than .004" on European 303 [or 7.7mm] barrels, the groove diameter is not usually .311", but rather around .312-.313"
To pdpush, the measurer of those Remington Cor-Lokt 303 bullets....were you measuring the part of the bullet that is exposed in loaded ammo? I have some of those Remington Cor-Lokts here as component bullets, and they measure .3112" in diameter just above the base. Regards, Eagleye.
[QUOTETo pdpush, the measurer of those Remington Cor-Lokt 303 bullets....were you measuring the part of the bullet that is exposed in loaded ammo? I have some of those Remington Cor-Lokts here as component bullets, and they measure .3112" in diameter just above the base. Regards, Eagleye.[/QUOTE]
Yes, I did. The .308 bullets I also measured in a loaded cartridge. Did you happen to measure your bullets ahead of where they would be exposed in a cartridge? Just curious,I don't want to pull one of mine.
Yes, I did. The .308 bullets I also measured in a loaded cartridge. Did you happen to measure your bullets ahead of where they would be exposed in a cartridge? Just curious,I don't want to pull one of mine.
Interesting if somewhat confusing thread. Just for grins, I miked an old box of DI Mk.VII2 .303 bullets, and of the 14 I had, 11 miked at .311-.312, and 3 came in at .3085-.309.
My question is, has anyone tried Amax 155gr .308 bullets in a .303 cartridge, and to what effect? I'm looking for the best accuracy I can get for long range target shooting.
Any pet loads for this purpose would be great, too.
My question is, has anyone tried Amax 155gr .308 bullets in a .303 cartridge, and to what effect? I'm looking for the best accuracy I can get for long range target shooting.
Any pet loads for this purpose would be great, too.
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Interesting thread! I just checked 6 different original boxes of ball ammo dating 1943, 44, 45, and 1950. All measured .311 to .311.5 including Canadian Ball. I also checked some FN made AP tracers for the Bren ,still in the box, they all measured .308 and so did quite a number of other mixed manufactured tracers I have here. I also have a box of 1920 and 1922 cupro Nickle jacketed ball with WRA( I assume Winchester manufacture?) and it all is .308 diameter. I've never tried the tracers but have shot hundreds of rounds of the 1920-22 WRA stuff and it shoots VERY accurate out of my rifles. I've also been reloading .303 AND 7.62 X 54R with .308 diameter bullets for almost 20 years now. The farthest I have shot with those reloads is 250 yards and they performed perfectly. I have 2 Polish Mosins and 2 Russians that all shoot just great and 6 Lee Enfields. I haven't slugged any bores but I have used the .308 diameter bullets in all of them with no issues. I like the availability of so many different choices of .308 diameter bullets and once I found they were accurate in my rifles, I switched to strictly .308.
