.303 help needed

O

OctaRon1

Regular
Rating - 100%
93   0   0
Location
Sussex, New Brunswick
I thought I would see if anyone nows this for sure.
I'm reloading for some old .303 Enfields I know they make bullets in .310 & .311 & .312 diameter.
But in the 1940s what was the actual diameter of the bullets they used ?
My thought being I might get a bit better accuracy with the correct diameter.
Also anyone know of a good supplier ?
Thanks Ron
 
First thing you need to do is "slug" your barrel to determine what the real groove diameter is.

In surplus 303 rifles, this varies greatly. I have seen as small as .3122" right up to .3166"
Most will be around .3125" to .3135"
If your groove diameter is over .315", it is unlikely that your rifle will shoot well with any bullet.

The nominal bullet diameter should be bore diameter plus .005"x2, so technically, if the bore
[not groove] diameter is .303", then groove diameter should be .303" + 2 x .005" = .313"

Therefore, most 303 Lee Enfields and P14 shoot the larger .312" bullets best.

However, Many also shoot the smaller .311 bullets well. I have a P14 303 Epps, with a groove
diameter of .3134", and it shoots the 180 Sierra SPFB [.311"] very well indeed.

Muddying the water somewhat is the fact that practically all custom barrelmakers make 303
barrels with the .303" bore diameter and a .311 groove diameter. My experience with these barrels
is that they seem to shoot all diameters well, including the .308, 30 cal bullets over 150 grains.

Hornady makes .312" bullets in 150 Spitzer, & 174 RN persuasion. All other NA sources are .311"

There used to be a Canadian source for .313 & .314" bullets, but I believe he has stopped production.
I have a few of his [Steve Redgwell] 200 grain .313" bullets, and they do shoot in my P14.

Be careful with older Winchester component bullets. Most are .3105 or smaller.

Hope this info is some help. Eagleye.
 
Standard bullet size for a .303 was .311", but chances are it's worn past that now.

It's quite likely that a .312 bullet will do what you need it to.

A flat base bullet typically works better because it will obturate to fill the barrel when shot, for this reason stay away from boat-tail bullets.

Look for posts by smellie on this board, he has wise words when it comes to loading for the .303 British.

Cheers.
 
My understanding is that the original milspec Mk 7 ammunition was in fact .312". I've used nothing but Hornady .312" 174gr BTHP in my No.4 Mk2, SMLE, Mosin and Arisaka Type 99 with excellent results. But, as has been mentioned, slug your bore to optimize your own results.
 
I have a couple of dozen 303 British bullets pulled from military surplus ammo.

Most are FMJ, around 174 grains, but a couple are tracers, and a couple are AP.
I just measured them up with my Vernier Micrometer.

They vary slightly, but the smallest is .3119, the largest .3123.

Regards, Eagleye.
 
Just for the record, the Hornaday bullet I've seen referred to here as a BTHP is actually a FMJ-BT, and it is .3105" not .312". Not trying to split hairs here, but it could save someone looking for a .312" BTHP that doesn't exist. ;)

Mfg. specs were different. I have a battle-worn Maltby No.4 Mk.I that slugs out at .3125. I own a mint condition, never issued, brand new, 1943 Long Branch with bore that slugs out to a .317". I still have to slug my Jungle Carbine...

Manufacturers produced barrels that have been reported as .309" - .324".

Here is my issue. With my LB, it has a big ol' .317" bore. What tells me is that a little .3105 FMJ-BT is going to rattle down that barrel and oscillate without stabilizing. We are talking about bullet deformation, gas blow-by, excessive copper fouling, throat erosion, and horrible accuracy.

WRONG!

My barrel like many Enfields, is a 2 groove. That means that I have 2 very thin grooves that only affect 10% (approximately) of the bullet's ogive, and the other 90% (approximately) is hitting the lands.

The lands in my rifle slug out to a perfectly concentric .3031 diameter.

So instead of a .3105" bullet rattling down a .317" bore, we have a .3105" bullet being squeezed and swaged .0074" down to .3031". Part of this tight swage forces more jacketing material into the grooves lessening the amount of blow-by, and creating a tighter seal.

The proof is iin the pudding. At 100m, I shot those "undersized" bullets into a 2" group.

Alec
 
I've never seen those; discontinued perhaps?

I looked on the Hornady website and they list a .312" 150gr. SP, a .3105" 174gr. BT-FMJ, and a .312" 174gr. RN. No BTHP that I saw. I also looked in my #8 manual, and I saw no load data or reference to a 174gr BTHP.

Maybe it was a past model, or maybe they just came out with it. Maybe I just missed it as well.

Alec
 
Hornady makes BOTH .311" and .312" in 174gr BTHP, but their catalog and website only mention the .311". CGN sponsors Budget Shooter Supply and Trade Ex both carry the .312" 174gr BTHP.
 
Longshot338 said:
I've never seen those; discontinued perhaps?

I looked on the Hornady website and they list a .312" 150gr. SP, a .3105" 174gr. BT-FMJ, and a .312" 174gr. RN. No BTHP that I saw. I also looked in my #8 manual, and I saw no load data or reference to a 174gr BTHP.

Maybe it was a past model, or maybe they just came out with it. Maybe I just missed it as well.

Alec
Click to expand...

Hornady 8th page 605 has it as bt-fmj which the data i use.

Purchased from Budget shooter supply.
 
There are TOLERANCES in anything manufactured. The theoretical ideal bullet for the .303 was .311" with a MAX diameter of .312".

Problem was that in almost every case tested, the .312" bullet shot better than the "correct" .311".

The Specification remained the same but anybody who wanted the MOST accurate ammo looked for a Lot with .312" slugs and grabbed all they could of that Lot number. This goes for Wartime Snipers as well as for shooters in the old Service Rifle class.

My own Test load for the .303 is a 180 Sierra Pro-Hunter bullet hed of 38 grains of 4895 powder. This comes in at 2250 ft/sec out of the SMLE or the Number 4, 100 ft/sec quicker out of a Ross with a full-length barrel. This is the by-test most accurate VELOCITY for this weight of bullet in a .303. Military ammo used 174 FLAT-based bullet at 2440 ft/sec MV.

ENFIELS rifling (used in ALL Lee-Enfields, P-14s and US M-1917s) has a decided preference for FLAT-based bullets.

Older rifles with worn bores can be made to shoot nicely with that same charge, but substituting the Hornady 174 RN bullet for the Sierra.

For 150 bullet, try the Hornady 150 .312" Spire Point.

Seating for ALL these is to a Cartridge Overall Length of 3.05"; you can use a Ball round to set your seater.
 
You must log in or register to reply here.
Back
Top Bottom