.303 British or .303 Epps?

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Macd
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.303 British or .303 Epps?

Post by Macd »

While waiting for my .303 sporter I have been researching the Epps wildcat designed by the late Elwood Epps. His sons continued his store and gun smithing business and offer the conversion at a reasonable price. As a re-loader/hand loader I can see the advantages in case life the Epps chamber offers over the stock .303 one. The sharper shoulder and reduced case taper also mean a bit more powder room. Anyone had experience with this wildcat? Here is a link with an explanation of the modifications.
http://www.303british.com/id20.html
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Re: .303 British or .303 Epps?

Post by Ranch Dog »

Good evening MACD, I enjoyed the information about the 303 Epps, but after reading it, I'm not sure you would gain much in improving the cartridge for an SMLE. In fact, I think that if you use a Lee Collet Die for your sizing, you will gain near the same based on my experience. At least that is what I see with both my No. 4 & No. 5, and from what I have been told and read about the SMLE, my experience isn't uncommon.

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I keep very detail records of my brass lots, and I've seen a 1.4-grain gain in case capacity in living with the SMLE chamber vs. resizing back to CIP/SAAMI case dimensions. The H2O capacity for the cases went from 56.0 to 57.4-grain, a 2.5% increase. With my bolt rifles, I work with small lots of cases, typically 25, and I annealed the 303 British cases after the first firing. To date, my No. 5 has eight cycles on the brass and the No. 4 three. I have felt no need to run the cases back through the full-length sizer as they chamber fine. I do anneal the brass every third cycle.

The velocity gain from a full length sized case vs. the Collet neck sized case has been a 1%. It goes from 2455 FPS to 2480. I'm not sure the extra capacity is worth the reward because it takes more powder to get there while achieving the same pressure. In real measure, not H2O, using H100V to produce 47.0K PSI, it takes 50.0-grains with the full-length sized case (2455 FPS) and 51.6-grains to get to the same pressure and that 2.5% increase in velocity (2480 FPS). Nutshell 1.6-grains of powder to go 25 FPS faster.

I'm not sure what you would gain performance wise in any of this. Both of my SMLEs get sticky as they push past 47.0K PSI (as determined by QuickLoad), so that is where I keep them. At this pressure level, there is no way to make a 303 British equal a 308 Win. By "improving" if further, it will just take more powder to match its current performance with little gain in velocity as we have a relatively low-pressure limit for a bolt action rifle.

Not sure if this makes sense, but I'm skeptical of "improved" cartridges. I worked a couple of years with the 30-30 AI and decided, in practical terms, it was all smoke and mirrors.
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Re: .303 British or .303 Epps?

Post by Macd »

Thanks RD. That is the first hand experience I need to help with my deliberations. I think, based on your pictures, I will wait till I have a fired case to compare with SAAMI spec. Should have rifle in two weeks and hopefully weather will cooperate.
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