Fire Formed Case Load ?

[Johnch]

Couldn't sleep

So I finished tumbling some 303 Brit cases
I had fired 200 rounds of Sellier & Bellot 180 gr FMJ ammo a year or so back out of my Enfield Number 4 Mk1

I plan on plinking and hunting with the rifle

But to get better accuracy and better case life
I am not planning on full length sizing
As the fire formed cases have a much larger shoulder and a LOT more case capacity than a full length sized case

Not planning on MAX loads
But I do want to be able to safely work up to a moderate load for hunting

Is there a way to figure what would be a safe starting load for the fire formed case ?
I was thinking H4895 and RCBS .30-180-FN
As the RCBS .30-180-FN my friend has drops a .313 bullet ( he opened up 1 cavity ) and my Enfield has a .312 bore

I was hoping for a about 2000 FPS load

Thanks
John

[Bills Shed]

I am a bit lost.
Are you saying that the rifle is not chambered for a 303Brit ?….or just that your chamber is a bit oversized and you do not want to work the brass to much? So some form of neck sizing only.
Why not just stick to book spec and keep it sane. A hunting load does not need to be anything to hot or over the top from book spec. Keep it simple and keep it sane.

Bill

[Wilderness]

Couldn't sleep

So I finished tumbling some 303 Brit cases
I had fired 200 rounds of Sellier & Bellot 180 gr FMJ ammo a year or so back out of my Enfield Number 4 Mk1

I plan on plinking and hunting with the rifle

But to get better accuracy and better case life
I am not planning on full length sizing
As the fire formed cases have a much larger shoulder and a LOT more case capacity than a full length sized case

Not planning on MAX loads
But I do want to be able to safely work up to a moderate load for hunting

Is there a way to figure what would be a safe starting load for the fire formed case ?
I was thinking H4895 and RCBS .30-180-FN
As the RCBS .30-180-FN my friend has drops a .313 bullet ( he opened up 1 cavity ) and my Enfield has a .312 bore

I was hoping for a about 2000 FPS load

Thanks
John

John

This may help in an oblique way ....

When my Ruger 77V .308 was new, I compared NS and FLS cases with the same load - got 50 fps more out of the FLS cases, i.e. equivalent to one grain load difference. That convinced me not to mix NS and FLS cases and expect the same result.

In your .303, what might the difference be between your fireformed cases and presumably new or FLS cases used tor published loads? One grain? Two grains? And this is only one of the fudge factors. Add in the complication of cast bullets going faster than jacketed and the case for a chronograph becomes compelling. With a chronograph, as few as three or four shots can get you near the required velocity level.

ADI lists starting loads for the Sierra 180 gn bullet - 34 gns 2206H/H4895 for 2178 fps and 35,200 psi. For 2208/Varget, the starting load listed is 37 gns for 2282 fps and 38,200 psi. Be aware however that cast bullets of the same weight may go 100 fps or more faster than jacketed with the same load. This is not a free ride, since pressure goes up also - see Lyman #46 .30-30 data.

If it were me, and I was looking for 2,000 fps, I'd try about 30 gns of something like H4895 or Varget. This will be a pretty tame load and easy on brass.

For perspective, with a 175 gn cast bullet in .30-30 I get 2150 fps from 30 gns 2208/Varget - putting it in a larger .303 case would bring that back to ??

[Wayne Smith]

John, do you have a chronograph? Choose your boolit and powder and do a ladder test is the way I would approach the problem. One boolit and two powders, two ladder tests, etc. If you don't have a chronograph I'm not sure how to advise you except to stay with the normal book loads in your larger cases.