Replicating .303 Brit Mk I-VI

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flashman2

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Anyone done it? Have a ME .303 AC 1 that I want to shoot and hunt with period correct loads ie a 215 gr RN at about 2000 fps.

Using the Woodleigh 215 gr RN you could effectively duplicate the Mk II Special, Mk III, IV and 5. CBE seems to have a 215 gr mould to cast to replicate No II and VI ball, which you could do quite well and very cheaply with a PC bullet.
 
Would be pretty simple to replicate that ammo performance. Get some bullets - cast, PC, jacketed or whatever. Many different powders would work, esp anything in the 3031 - 4895 range. Not really too complicated.
 
I have a NOE 311 202 RN mould on the way. Between sizing dies and PC I can make any dia from .311 to .316. This is really a cast your own or shoot Woodleighs situation... I dunno anyone else making 215 grain jacketed bullets
and no one selling cast.

H4895 doesn't seem preferred but I have lots on hand. Pretty sure it'll achieve load density without going over 2000 fps.

British ML did the same thing, but never seen it done with a 215 grain RN jacketed bullet. Pretty tame energy but penetration would be nuts.
 
I have used a 210gr RN (or so) cast bullet in the L.E. and found it shot very well, and better than the others. 3031 and 4895 would make excellent full power loads. Or use 10 -15 gr of shotgun powder for a 50 yd plinker.
 
OP it looks like you've done some due diligence and are willing to go the cast bullet route.

Most folks just keep experimenting and hope.

The first thing that does come up and does make a difference is the bullet construction and the propellant used at the time.

The propellant is fairly to replicate as far as performance curve with several different powders.

The biggest problem is the type of bullets available during the period the rifles were designed.

The jacketed bullets had EXPOSED LEAD bases. I believe the intention of this was to allow the pressures to work directly against the lead and help it to obdurate the jackets into the rifling.

I used to have a good supply of these bullets and they definitely seem to be more accurate than the offerings available today. Also, the bullet diameters need to match your bore. There was a time when manufacturers like CIL made bullet diameters from .310 to .315 to accommodate different bore diameters. To my knowledge this is no longer the case.

That's why I like your cast bullet idea. If your bullets are cast hard enough with gas checks, you should be able to push them to 2000+ fps without much problem and likely will have a tough time to recover them from any game as they will likely pass all the way through.

I have a 1888 MKI Metford factory sporter that I'm going to be developing a load for in the spring and of course after a winter complete overhaul. I do have some exposed lead bullets with round lead noses but they are only 175 grains. I don't have many but enough for a spring Bear hunt.
 
bearhunter said:
OP it looks like you've done some due diligence and are willing to go the cast bullet route.

Most folks just keep experimenting and hope.

The first thing that does come up and does make a difference is the bullet construction and the propellant used at the time.

The propellant is fairly to replicate as far as performance curve with several different powders.
Click to expand...

Yeah, I can only replicate the external performance really. The Mk I load was a highly compressed cylinder of 70 grains of BP. It's tough compressing 70 grains into a .45-70 with heavy bullets; 71.5 grains in a .303 case would be like a rock. The case was final formed after the powder had been inserted, so they're effectively impossible to replicate without having a lot of custom equipment made.

The biggest problem is the type of bullets available during the period the rifles were designed.

The jacketed bullets had EXPOSED LEAD bases. I believe the intention of this was to allow the pressures to work directly against the lead and help it to obdurate the jackets into the rifling.

I used to have a good supply of these bullets and they definitely seem to be more accurate than the offerings available today. Also, the bullet diameters need to match your bore. There was a time when manufacturers like CIL made bullet diameters from .310 to .315 to accommodate different bore diameters. To my knowledge this is no longer the case.

That's why I like your cast bullet idea. If your bullets are cast hard enough with gas checks, you should be able to push them to 2000+ fps without much problem and likely will have a tough time to recover them from any game as they will likely pass all the way through.
Click to expand...

Mk I and II had a 215 grain cupro FMJ RN. Performance at 1850/1950 fps was underwhelming. The Mk III, IV and V had the soft and hollow point bullets. Mk VI was back to the 215 grain FMJ RN. So they switched back and forth between open and closed base bullets. The HP designs were made like FMJ with the HP punched in... problems with cores blowing through jackets ensue.

No one I know of makes 215 grain FMJ RN. I'd have to cast. NOE has a 311-218 RN mould that is closer in dimension and profile to the Mk I and VI bullet than the 202 grain mould BML uses so I ordered one of those too. PC ing a .311 bullet will give me .315. I can size down to .314, or size the bullets to .309 and PC them to. 313. Plus other combinations, but I should be ok to make the right diameter bullets. I suppose the Woodleighs could be PC'd up too if they're too small.

Mk III, IV and V are easy, use the Woodleigh 215 gr bullets.

I have a 1888 MKI Metford factory sporter that I'm going to be developing a load for in the spring and of course after a winter complete overhaul. I do have some exposed lead bullets with round lead noses but they are only 175 grains. I don't have many but enough for a spring Bear hunt.
Click to expand...

You need a BP load...
 
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Ganderite said:
I have used a 210gr RN (or so) cast bullet in the L.E. and found it shot very well, and better than the others. 3031 and 4895 would make excellent full power loads. Or use 10 -15 gr of shotgun powder for a 50 yd plinker.
Click to expand...

I'm not sure what other option I'd have, H4895 is on the slow end, but it's also the only one suitable for reduced loads to get down to sub 2000 fps. Shotgun powder loads don't get it quite fast enough.

And the appropriate charge of H4895 to get 1950 fps should be about the exact same weight the cordite charge was, funny enough.
 
If the mold I am using casts .315 diameter bullets, they are good to go as is with some lube IMHO. Even with a .310 bore they would be good to go and IMHO will be very accurate. Cast lead is very forgiving.

Cast lead with 15% pewter or lino mix has appx a 22 bnh reading, depending on how quickly it gets cooled. Good lube is the trick.
 
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