.303 British light loads

bsparker · Dec 27, 2021

I’m a little restricted on powder, having only 4064 on hand for this rifle.

Previously I’ve loaded .303 with 4064, using 150 and 174gr bullets. Test charges ranged from 39-43grs and 37.5-40.5grs respectively. All felt like they were hitting harder than PPU factory rounds.

Any recommendations for lighter loads using IMR4064?

AJC1 · Dec 27, 2021

bsparker said:
I’m a little restricted on powder, having only 4064 on hand for this rifle.

Previously I’ve loaded .303 with 4064, using 150 and 174gr bullets. Test charges ranged from 39-43grs and 37.5-40.5grs respectively. All felt like they were hitting harder than PPU factory rounds.

Any recommendations for lighter loads using IMR4064?

Not with that powder. Rifle powders can cause pressure problems below minimum loading. 4895 has a data sheet for reducing rifle loads and trailboss is intended for this exact purpose. There are a ton of loads with pistol powders as well. I would not force that powder to work in a reduced load.

bsparker · Dec 27, 2021

AJC1 said:
Not with that powder. Rifle powders can cause pressure problems below minimum loading. 4895 has a data sheet for reducing rifle loads and trailboss is intended for this exact purpose. There are a ton of loads with pistol powders as well. I would not force that powder to work in a reduced load.

I was afraid of that. I do have trailboss on hand and will do some research. I assume gas checked cast bullets.

JohnB-40 · Dec 27, 2021

I agree with AJC1. H4895 is the one I use for reduced .303 loads,it works well and Hodgdon has data

AJC1 · Dec 27, 2021

Tallinar · Dec 27, 2021

bsparker said:
I do have trailboss on hand and will do some research.

Speaking anecdotally, my dad and I had very good experience loading .30-40 Krag with Trail Boss and lead bullets. I would think Trail Boss would be a very good candidate for light .303 British loads.

25-20 WCF · Dec 27, 2021

Not with that powder. Rifle powders can cause pressure problems below minimum loading. 4895 has a data sheet for reducing rifle loads and trailboss is intended for this exact purpose. There are a ton of loads with pistol powders as well. I would not force that powder to work in a reduced load.

Interestingly, Hodgdon does not list a starting load with IMR4064 in the .303. Not sure how you’d work up a load from below….

bsparker · Dec 27, 2021

Lyman 50th has starting load at 39gr for 150gr bullet.

I’ve heard others state that a minimum charge can generally be found by reducing maximum charge by 10%.

Random 8 · Dec 27, 2021

Hornady lists a start load of 32.8 to a max of 41.1 using 150 grain bullets and IMR 4064. This seems quite mild compared to your loads and Hodgdon data. I've noticed Hornady data to be conservative with military cartridges.

I disagree that IMR 4064 cannot be downloaded. Just because they put the time and money into researching reduced loads with H4895, does not mean that that is the only powder in the whole wide world safe to download.

In my experience, ANY of the IMR series through 4350 can be safely downloaded slightly below minimum in the WWII battle rifle cartridges (haven't tried 4831, and I probably won't). Accuracy may range from great to iffy. IMR 3031 through W748 have start charges ranging from 29.1-35.3 gr with 150 grain bullets in the Hornady 5th.

Jerry M · Dec 28, 2021

P.O. Ackley has a chapter in his book about the dangers of downloading slow powders with pictures of blown up firearms.

Following powder distributors data is highly recommended. But it is your cheek in the stock...

bsparker · Dec 28, 2021

Random 8 said:
Hornady lists a start load of 32.8 to a max of 41.1 using 150 grain bullets and IMR 4064. This seems quite mild compared to your loads and Hodgdon data. I've noticed Hornady data to be conservative with military cartridges.

I disagree that IMR 4064 cannot be downloaded. Just because they put the time and money into researching reduced loads with H4895, does not mean that that is the only powder in the whole wide world safe to download.

In my experience, ANY of the IMR series through 4350 can be safely downloaded slightly below minimum in the WWII battle rifle cartridges (haven't tried 4831, and I probably won't). Accuracy may range from great to iffy. IMR 3031 through W748 have start charges ranging from 29.1-35.3 gr with 150 grain bullets in the Hornady 5th.

I'll have to get my hands on a Hornady manual. Haven't seen a starting load that low with 4064, but I'm intrigued. Thanks.

EDIT: Just found a copy of "The Complete Reloading Manual" for 303 brit. Starting load for 158gr bullets with 4064 is 32.8gr under Hornady at 2200fps; 38gr under Sierra at 2300fps; 39gr under Speer at 2315fps.

Not sure why Hornady bullet is so much less than the Sierra or Speer...Bullet construction maybe? Or, Hornady (as with the Hornady manual) allows for lower pressures in MilSurp?

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.303 British light loads

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