303 British / .308 / 30-06 Discovery???

Red Dawg

Red Dawg

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Hey guys.

I have baffling information to discuss with you guys. I've been reloading 30-06 for a little while and 303 british longer. However, I added .308 to this thread because it also takes a .30 cal bullet.

I purchased a lot of tracer bullets (projectile only), some boat tails, and AP bullets as well during a gunshow I attended in Ontario recently. I went to measure a few of each with a digital caliper to see what the actual diameters were and they all came to either .308 or .309.

However, I had some pulled .303 bullets from 1944 that were duds (yes I am sure), both copper jacket and nickle, and decided to measure them and they came to .308 as well.

So, from previous understanding .303 bullets should be slightly larger and decided to measure some bullets in factory cartridges from modern and past. Modern came to .308 and past came to .304.

My question is: Am I losing my mind or is it true I can use .30 cal bullets in all 3 calibers????

Thanks!
 
Red Dawg said:
Hey guys.

I have baffling information to discuss with you guys. I've been reloading 30-06 for a little while and 303 british longer. However, I added .308 to this thread because it also takes a .30 cal bullet.

I purchased a lot of tracer bullets (projectile only), some boat tails, and AP bullets as well during a gunshow I attended in Ontario recently. I went to measure a few of each with a digital caliper to see what the actual diameters were and they all came to either .308 or .309.

However, I had some pulled .303 bullets from 1944 that were duds (yes I am sure), both copper jacket and nickle, and decided to measure them and they came to .308 as well.

So, from previous understanding .303 bullets should be slightly larger and decided to measure some bullets in factory cartridges from modern and past. Modern came to .308 and past came to .304.

My question is: Am I losing my mind or is it true I can use .30 cal bullets in all 3 calibers????

Thanks!
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Now that is real information! Can't wait to get measuring. Some one said maybe US made accounts for it. I have lots of different cartridges, both commercial and military, including some Winchester made military from WW2.
 
Gibbs505 said:
It is because that is what the british picked as they were impressed by the swiss 7.5.
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The 7.5 Swiss uses standard .308" bullets and is the only European rifle cartridge I know of that does so. .311" calibre seems to be much more common among European cartridge designs:

-7.65x53mm Mauser
-7.62x54Rmm
-.303 British
-7.62x39mm M43
-7.62x45mm Czech
 
The origional 7.5 swiss used .304 bullets. If I remember correctly they didn't change to the .308 until the 1911 model.
Kimzter
 
Not to question your reloading methods or experience, but could your calipers be goofed? Had a set of digital calipers go south on me a few years back by a few thou. Didn't realize it until a fresh set of known reloads wouldn't group any longer...
But I have heard of some Enfield bores varying from .309 to .312 when measured with strong to new rifling. Probably wasn't a big issue to the manufacture of combat rifles of that time. 2 m.o.a. was quite acceptable & probably could be achieved with the slight variances in both bores & calibers. Desperate times!
 
Yes, that's correct. GP1890 is .304" and GP11 is .308".

Come to think of it, the French 7.5x54mm also uses a .308" bullet.
 
The actual nominal bullet diameter for most old SMLE's and P14's is right at .313" [Bore is 303, groove depth is .005(x2)= .313"] However, most North American made barrels are at .311" As for bullets, I have a slew of pulled Military bullets from 303 Cartridges back to the 20's. The diameter varies from .3085" right up to a few at .314" [AP rounds] Sierra and Speer bullets for the 303 usually mike up at .3106-.3112", while Hornady offerings are about .001" larger. I have some Winchester Power points here that mike .3102" I also have some 180 grain Norma bullets that mike .3125" This diameter also works with the 7.65 Mauser rifles, and the 7.7 Japanese offerings. Not much consistency here, but the best way to determine what to use is to slug your barrel. I have 2 303's in P14 rifles, one is a 303 Epps. Both groove diameters are close to .313" However, I once slugged a SMLE barrel for a friend that looked quite good inside, but did not shoot well with anything. Imagine our surprise to find that the groove diameter was .317" Regards, Eagleye
 
Why not? said:
Yessirree Bob, and I know more than one guy who has loaded the 220 gr Sierra .308" round nose in his Lee-Enfield when there were no more 215 gr .311" bullets available. :)

Ted
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That's true Ted, I regularly use 220 Hornady (.308 diameter) bullets in my Enfields. Some show better accuracy than others due to the different internal sizes of the barrels.
 
Variances

Hey guys.

Well seems there are mixed feelings - I am still confused myself as I know that .303 br should be around .311-.312 (atleast from what more experienced guys have told me) - also about the caliper being out - I actually did have to replace it recently because I know it was giving me messed up readings, but since I know the .30 cal bullets were pulled from 30-06 and .308, the measurements were obviously coming out right.... a while back I also got the same measurements with my last caliper (but didn't think much of it). Strange too since I got similar readings from both war time and commercial .30 cal/303 br. The only one like I said before that measured different was a round nosed .303 round from 1905 measured at .304.
 
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Yup, ask any old enfield fan and they will tell u of the .308-.312ish varience and to slug ur bore.

What surprised me is that nobody has yet mentioned that .308Win is a shortened .30-06 and thus the same bullet diameter.

Why winchester decided to shorten the case can probably be found in wiki somewhere
 
slushee said:
What surprised me is that nobody has yet mentioned that .308Win is a shortened .30-06 and thus the same bullet diameter.

Why winchester decided to shorten the case can probably be found in wiki somewhere
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Winchester didn't do it, the US Army did (Springfield Armory, actually). Winchester "civilianified" the military round. As to why - a case that is half an inch shorter, will allow a rifle that is one inch shorter (from the M1 came the M-14).

There are actually a few other differences between the .30-06 and the .308:
- the ejector groove is different (wider for the .308)
- the neck is shorter for the .308
- the case body taper for the .308 is less.
 
The .308/7.62x51 was developed because improvements in powder since the .30-06 was developed made it possible to get the same ballistics as service .30-06 ammo in a smaller case.
 
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