200 gr Sedgwell 303 bullets
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I shoot Steve's 200 grain bullet out of my 303 Epps. Very accurate and decent velocities using Higginson's 47N powder [slightly faster than IMR 4350] Never shot any game yet, but possibly this fall. My lot of bullets is sized at .313" Eagleye.
It is a 303 brit P14 enfield that I had rechambered to take 300 win mag brass. I made up the name. I got a very good barrel, actually the famous Bevan King rechambered it for me years ago. This particular rifle shoots a lot better than I do, and I have found some quality 200 grain bullets for it, both from Steve Sedgwell and I bought some .311 200 gr speer Grand Slams back when they used to make them. I have been able to get velocity beyond what you would expect from a 300 win mag, as I said, I get over 2900 fps easily with a 200 grain bullet, and I was shooting 180 grain CIL bullets, round nose KKSP, at over 3150. The CIL's were just for fun, I am sure that they would explode at that velocity. I like the P14 action, yes, it is a bit heavy, but it does not kick much. I shot a smallish mule deer buck with it, and with a 200 grain speer grandslam, and it went right through both shoulders, and I had to come back the next day to find him. I have a very cheap 4x simmons scope on it, but it works well for me. I still have the 25 and a half inch barrel.
I am able to seat bullets after resizing in a normal 300 mag die, I do not even have an oversized neck expander.
I am able to seat bullets after resizing in a normal 300 mag die, I do not even have an oversized neck expander.
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Guys have been doing this conversion for 40+ years (it's often called a "303 Win Mag"), but not much lately as a 300 Win Mag can be had more cheaply than converting a P14 (sporterizing, rechambering, etc.). All you do is run a 300 Win Mag reamer into the 303 Brit chamber. The thing you need to watch is neck clearance - you're putting a 0.311"+ bullet into a chamber made for 0.308", and eating up a lot of the neck clearance in doing so.
If you "get velocity beyond what you would expect from a 300 Win Mag", that's because you're loading to higher pressures than a 300 Win Mag.
If you "get velocity beyond what you would expect from a 300 Win Mag", that's because you're loading to higher pressures than a 300 Win Mag.
You can also get higher velocities by using a fatter bullet.
Compare the German 7.92x57 and the original US .30 M1906:
154 bullet @ 2880 ft/sec versus 150 bullet @ 2700 ft/sec... and the heavier bulet came out of a shorter case with less volume AND less pressure by 10,000 PSI.
It might only by 4 thou, but the same principle holds.
Ellwood Epps chambered P-14s for his .303 Epps Magnum for many years: a .308 Norma case with a 303 slug.Works REAL good and feeds easy through a standard action. This was before the WinMag came out, of course, but it is stil a good cartridge.
There was also a .303 Magnum made in England in the 1920s, based on the P-13 casing opened out to handle a .303 slug: another monster-in-the-making, held in check only by the limitations of Cordite.
Dr. Frank Enfield, where are you when we need you??????
.
Compare the German 7.92x57 and the original US .30 M1906:
154 bullet @ 2880 ft/sec versus 150 bullet @ 2700 ft/sec... and the heavier bulet came out of a shorter case with less volume AND less pressure by 10,000 PSI.
It might only by 4 thou, but the same principle holds.
Ellwood Epps chambered P-14s for his .303 Epps Magnum for many years: a .308 Norma case with a 303 slug.Works REAL good and feeds easy through a standard action. This was before the WinMag came out, of course, but it is stil a good cartridge.
There was also a .303 Magnum made in England in the 1920s, based on the P-13 casing opened out to handle a .303 slug: another monster-in-the-making, held in check only by the limitations of Cordite.
Dr. Frank Enfield, where are you when we need you??????
.
What ever happened to the 303 (311) Imperial Magnum - I saw some brass and a rifle at a show once, and it was being billed as slightly better than the Second Coming, and then ........nothing. Sort of like the ammunition plant that was going to be built in the Fraser Valley (at about the same time).
303 Win Mag
When the P14 rifle is rechambered to 300 Win Mag is the barrel removed or is the rechambering done through the receiver? One person I talked to thought that the 300 Win with its sharp shoulder would be difficult to chamber through the receiver but a 300 H&H which is a more tapered case would be much easier. I have a 303 Epps, done at the Epps shop some time back and I think it was rechamered through the receiver but I am not sure. Any advice would be appreciated. Has anyone personally done this? Thanks.
When the P14 rifle is rechambered to 300 Win Mag is the barrel removed or is the rechambering done through the receiver? One person I talked to thought that the 300 Win with its sharp shoulder would be difficult to chamber through the receiver but a 300 H&H which is a more tapered case would be much easier. I have a 303 Epps, done at the Epps shop some time back and I think it was rechamered through the receiver but I am not sure. Any advice would be appreciated. Has anyone personally done this? Thanks.
