Thread: .303 reloads

I now have some redundant 7.62x39 (THANKS JACINDA ) after some searching it seems to reload this to 303 British all that needs to be done is size and prime the 303 case, pull the bullet and powder from the 7.62x39 and dump it in the 303 case. I would have assumed there would be air space between powder and bullet due to different case sizes but this seems to not be a problem. Any comments advice welcome.

Originally Posted by Tasbay

I now have some redundant 7.62x39 (THANKS JACINDA ) after some searching it seems to reload this to 303 British all that needs to be done is size and prime the 303 case, pull the bullet and powder from the 7.62x39 and dump it in the 303 case. I would have assumed there would be air space between powder and bullet due to different case sizes but this seems to not be a problem. Any comments advice welcome.

It sounds simple but this approach can be problematic. The projectile is fine its the powder where problems can begin.
The russian round is designed for a shorter barrel than the 25 inch enfield so the powder is reasonably fast think adi 2207 and is 25-28 grains. The case is full.
The 303 uses 40 -44 grains of 2206h for a similar weight 125 gr pill and the case us full.
Using a smaller charge of fast powder in a larger case can cause serious pressure issues, as the powder lays flat exposing a larger than normal surface area so it can ignite in mass not progressivly and cause a massive pressure spike.
It is not safe to transfer load data from one case to another as the dynamics of ignition are case size dependent.

Originally Posted by Marty Henry

It sounds simple but this approach can be problematic. The projectile is fine its the powder where problems can begin.
The russian round is designed for a shorter barrel than the 25 inch enfield so the powder is reasonably fast think adi 2207 and is 25-28 grains. The case is full.
The 303 uses 40 -44 grains of 2206h for a similar weight 125 gr pill and the case us full.
Using a smaller charge of fast powder in a larger case can cause serious pressure issues, as the powder lays flat exposing a larger than normal surface area so it can ignite in mass not progressivly and cause a massive pressure spike.
It is not safe to transfer load data from one case to another as the dynamics of ignition are case size dependent.

Thanks Marty : That's about what I came up with, have loaded a lot of subsonic rounds over the years and cartridges like the 303 needed at least a filler between the powder and bullet so as not to get detonation or a squib load. May need to look at a Ruger American in 7.62x39 if they are aloud across the boarder as a huge pay out should be coming my way (Cough Cough) will believe it when I see it.

Using a smaller charge of fast powder in a larger case can cause serious pressure issues, as the powder lays flat exposing a larger than normal surface area so it can ignite in mass not progressivly and cause a massive pressure spike. It is not safe to transfer load data from one case to another as the dynamics of ignition are case size dependent.[/QUOTE]

You have it wrong it is small amounts of SLOW burning powder that is supposed to cause Secondary Explosive Effect it has never been done in lab tests so is concidered an urban myth, Though it will happen with a double charge
of FAST burning powder,
it you want plinking loads use Trail Boss 70% fill the case and you are good to go, 27.0 Grains of 2206H is a favourite light load in the .303 and .308 with cast bullets and should work with jacketed work down to it rather than up
Start at 40.0 grains and go down .5 grain at a time.