[Quigley]

Can anyone suggest a cast bullet load for the .303. I am trying to develop a load that will give me 1400-1700FPS.

I have been experimenting with HRBC 303 Copper Hawkes (with gas check) and several powders in both a 1942 SMLE Range Rifle, and a 1898 Martini Enfield.

Both shoot the same .311 Sierra Matchking HPBT bullets very very well, but neither handle the HRBC 180gn .311 FP cast projectile. Target looks like a shotgun has fired tumbling bullets at it!

I have just ordered the Lyman 314299 mould (.314 dia, 200gn)to see if a larger diameter cast bullet helps.

[bullbarrel7.62]

YOu really need to know the size of your bore to establish projectile diameter.however the 314299 is an excellent bullet. Bore sizes vary a bit in the old 303s

[PeterD]

Aside from slugging the bore to get your appropriate projectile size, is there a reason why you want 1400-1700fps? I don't have a 303 yet so I know buggar all on its cartridge limits but if you are twisting at 1 in 10 you'll have about 100,000 to 122,000 RPM to stabilise the cast bullet with which may not be the correct spin rate. In extreme simplification you could say that depending on alloy hardness used (14-18 bhn for example) and the powders burn rate (slower to medium powder preferred), the cast bullets will have an RPM range where they give their best accuracy, deteriorating either side of that range. The general idea is to develop the accuracy load for a given cast projectile, my preference being for a tiny bit understablised heavy projectile rather than aiming to develop specific fps load where the cast projectile is a poor match and you obviously have stabilisation issues that need to be sorted out, bore size first and looking at RPM range for your cast bullet used next.

[bullbarrel7.62]

PeterD, on 19 Apr 2012 - 05:34 PM, said:

Aside from slugging the bore to get your appropriate projectile size, is there a reason why you want 1400-1700fps? I don't have a 303 yet so I know buggar all on its cartridge limits but if you are twisting at 1 in 10 you'll have about 100,000 to 122,000 RPM to stabilise the cast bullet with which may not be the correct spin rate. In extreme simplification you could say that depending on alloy hardness used (14-18 bhn for example) and the powders burn rate (slower to medium powder preferred), the cast bullets will have an RPM range where they give their best accuracy, deteriorating either side of that range. The general idea is to develop the accuracy load for a given cast projectile, my preference being for a tiny bit understablised heavy projectile rather than aiming to develop specific fps load where the cast projectile is a poor match and you obviously have stabilisation issues that need to be sorted out, bore size first and looking at RPM range for your cast bullet used next.

Spot on the money there Peter! I am beginning to think a Chronograph may be very useful for cast bullet load development.

[Quigley]

Thanks for the responses to date............

The velocity range was for two reasons - one may be an old granny porky - the other is range regulations.

I was 'told' that a 20:1 lead:tin projectile would strip and lead the barrel if pushed faster than this. The second is that to shoot metal plate the range restriction is 1700FPS.

The view down the barrel of the Martini Enfield is black, but clear, rifling. I pushed a moly lubed patch down the barrel, then belted a .311 cast bullet bullet down from the muzzle end. Hard work until about six inches from the breach, were it virtualy fell through. It came out with very prominent rifling engraved on it. There is obviously some obduration of the projectile due to the belting down the barrel.

How do you measure the groove diameter when a groove is opposite a land? My vernier tips are not quite fine enough to fit into the groove.

I am a bit concerned about the sloppy six inches from the breach. My Seargents Tool view shows a clear chamber and then rifling. I pushed a projectile up the breach with a bamboo skewer until it stopped. Measuring revealed that the projectile would be about 1.25 inches from the case mouth as it engaged the lands. Obviously that first few inches of the barrel is a bit worn!

[Jaximus]

Hey mate, I put this in a diff thread too, but I recently got some data for HBRCs in 303 and 308.
This is the reccomended loads direct from ADI for a 303. Hope it helps some

LOADING DATA
FOR LEAD PROJECTILES
.303 BRITISH
BARREL LENGTH: 24 INCHES
BULLET DIAMETER: - .312 CALIBRE (.312 SIZED DIAMETER)
TWIST RATE: - 1: 10 INCHES

BULLET POWDER STARTING VELOCITY MAXIMUM VELOCITY

WT. TYPE C. W. APPROX. C.W. APPROX.

(GRAINS) ______MIN_(GRAINS) / (FT/S) / MAX_(GRAINS) / (FT/S)
185 grain ____AP50N____ 9.50 / 1375 / 13.50 / 1550
Round
Nose

185 grain ____AP70N____ 10.50 / 1325 / 14.00 / 1585
Round
Nose