303 British

Rabble_Rouser · Sep 16, 2020

I have gotten excellent accuracy from two different Enfields with IMR-4064 and Alliant Reloader 15, both using 174g Sierra Match Kings. I remember trying 3031, 20ish years ago, without great success but have been developing an interest in trying a 150g bullet, which may have better results with the faster burn rate of 3031. Then again, maybe my rifles just don't like 3031..

GooseGestapo · Sep 18, 2020

My best accuracy is with the Hornady .312” 174gr Match BTHP. Only sold by GRAFS. It’s eve better than the Sierra Match King.
Favorite powder is BLC2 as it gets best velocities at lowest pressures, making it easier on brass. PPU is my far and away favorite brass.

Vern Humphrey · Sep 18, 2020

IMR 303 was developed specifically for the .303 Brit in WWI by US ammo makers that had contracts with the Brits. They later improved it a bit to produce 3031.

AJC1 · Sep 19, 2020

Vern Humphrey said:
IMR 303 was developed specifically for the .303 Brit in WWI by US ammo makers that had contracts with the Brits. They later improved it a bit to produce 3031.

That's some neat history. Where does one find bits like that.

Vern Humphrey · Sep 19, 2020

AJC1 said:
That's some neat history. Where does one find bits like that.

As I recall, it was published in Handloader magazine.

Rabble_Rouser · Sep 22, 2020

Vern Humphrey said:
IMR 303 was developed specifically for the .303 Brit in WWI by US ammo makers that had contracts with the Brits. They later improved it a bit to produce 3031.

I have heard this a number of times, probably more then once on this forum. Just my experience has shown slower powders to provide better accuracy.
Having started out originally as a black powder cartridge, I think they were trying to stay within the same pressure ranges/faster burn rate, maybe just so they didn't have to rework the sight graduations...? Total speculation there, but black powder being a much faster burn rate, first with Cordite then with 3031, I think they just stayed in familiar territory.
Having a much broader range of powders & burn rates now, I find the somewhat slower burn rates to work better in my rifles. My best groups with my SMLE MKIII were just under 2" at 100 yards with iron sights & 39g of IMR--4064. Bit of a cheat as the "iron sights" are a Parker Hale 5A Micrometer Apurature sight... But it's still not a scope. I did put a scope on my #4 recently and went sub MOA with loads I had made for the SMLE. Hopefully taking that to the range this weekend.

Vern Humphrey · Sep 22, 2020

Rabble_Rouser said:
I have heard this a number of times, probably more then once on this forum. Just my experience has shown slower powders to provide better accuracy.
Having started out originally as a black powder cartridge, I think they were trying to stay within the same pressure ranges/faster burn rate, maybe just so they didn't have to rework the sight graduations...? Total speculation there, but black powder being a much faster burn rate, first with Cordite then with 3031, I think they just stayed in familiar territory.
Having a much broader range of powders & burn rates now, I find the somewhat slower burn rates to work better in my rifles. My best groups with my SMLE MKIII were just under 2" at 100 yards with iron sights & 39g of IMR--4064. Bit of a cheat as the "iron sights" are a Parker Hale 5A Micrometer Apurature sight... But it's still not a scope. I did put a scope on my #4 recently and went sub MOA with loads I had made for the SMLE. Hopefully taking that to the range this weekend.

If a man has good eyes and a lot of practice, he can shoot an aperture sight as well as a scope -- or so they tell me.

Jim Watson · Sep 22, 2020

The powder sold surplus by Hodgdon as Ball C was made for WWII .303 contract ammo.

Vern Humphrey said:
IMR 303 was developed specifically for the .303 Brit in WWI by US ammo makers that had contracts with the Brits. They later improved it a bit to produce 3031.

I see no mention of an "IMR 303" powder by Phil Sharpe.
He says the WWI DuPont powder for .303 was IMR 17 which was a development of IMR 16. There was a whole series of MR and IMR powders with two-digit designations.
IMR 3031 was introduced in 1934 as a replacement for IMR 17 1/2 without the tin additive meant to reduce hard metal fouling.

303 British

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