Why .311 and .312 ???

rmckeon

rmckeon

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Hey guys,

I'm wondering why there are both 311 and 312 calibre projectiles for the 303 (british)? ...I have a minty barrel, so I'm wondering if I should stick with the 311's ... does it make a difference? ...and if so, why??

Thanks for your feedback!!
 
my opinion .311 and .312 for an enfield don't really make a difference. Some guys load .308 for their enfields.

Most enfields will slug out over .312 and up to .315 in some cases.

I would just pick one bullet that works and go for it.

If your really concerned slug your barrel
 
Here's the skinny on those 303 bores. If you have a milsurp 303, the groove diameter will vary from about .3125" up to as big as .316" However, if you buy an aftermarket barrel made in the USA, the groove diameter will be .311" It is a good idea to "slug" the bore of any milsurp, so you have an idea what the groove diameter really is. I have 2 - P14 rifles, one is stock 303 British, and one has been opened up to 303 Epps. The groove diameters on both these rifles is very close to .313", so larger bullets are used by choice. They shoot smaller bullets OK, particularly the Sierra 180 spitzer, but given a choice I opt for the larger diameter. I have some 200 grain flatbase semi-spitzers from
303.com that are sized right at .313" and they shoot great in both rifles. Regards, Eagleye.
 
Thanks to you all for your insight.

I've been switching between 311 and 312's, and I think I'm getting the message that it won't harm a new barrel (mine has less than 500 rounds through it) if I stick to the 312's.
 
You probably won't harm the barrel but you should slug the barrel and use the proper diameter for best results.
bigbull
 
rmckeon said:
I wonder if continually using oversized bullets will hasten barrel wear...
Click to expand...
The short answer is no. The wear on a barrel caused by the bullet is so miniscule that it is almost never taken into account when discussing barrel wear. It is hot gases that erode the barrel in the throat area. I have seen barrels with 4" of the throat eroded away, accuracy fading, and the rifling still looked very good at the muzzle area. Since bullet speed is greatest at the muzzle, if bullets were responsible for any substantial wear, the muzzle would show that. Regards, Eagleye.
 
You should never harm a barrel, or get worse accuracy with bullets that are oversize ( though pressure will be higher). The same can not be said for bullets that are undersize.
Mike
 
I'm glad I posted this question - a lot of excellent knowledge transfer from many experienced CGN'ers.

Thanks to you all for you input!
 
Calum said:
Over pressure in old actions...bad idea.

If in doubt have a gunsmith slug the bore.

Over pressure in old actions...bad idea.

If in doubt have a gunsmith slug the bore.
Click to expand...

So .312 bullets in an Enfield will cause dangerous pressures?
 
Then why is that guy saying he's worried about excess pressures in this thread I don't get it.
 
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