Griffel Fourie wrote:Manne, dankie sovêr - ek sal moet hulp vra - wat is "epps"?
Dis 'n "Improved" 303, doppie is uitgeblaas vir groter inhoud
Hierdie het ek op die internet gekry
The 303 British suffers from "droopy shoulders". Good in its day, the shallow angle was designed to help in loading and placement of the long stranded propellant "cordite", within the case. While good for factory production then, it's a real problem for the reloader today.
Any cartridge with shallow shoulders is more prone to case stretching, case wall thinning and thickening around the neck. Maximum loads fired from these cases accelerate the process.
Canadian gunsmith Ellwood Epps saw the problem and corrected it. He knew that steeply angled shoulders helped modern spherical and extruded powders burn more within the case and less up the barrel. His solution was to increase the shoulder angle to 35 degrees from 16. At the same time, he decreased the body taper by over 50 thou. The resulting improved cartridge showed a 15 % velocity enhancement over the standard 303 British when fired from the P-14.
After consulting with PO Ackley, Mr Epps reformed the cases with minimal body taper and sharply angled shoulders. Reduced body taper lessens the rearward pressure effects on the bolt and lugs (bolt thrust). Sharp shoulder angles inhibit forward brass flow, which reduces the need to trim cases as often.
Originally, the improvements were made to increase brass life, not to produce a higher velocity round. Mr Epps knew that reshaping the case into a more efficient design would yield this secondary benefit, but considered improved case life to be the most important factor.
A short review before we carry on.
With older case designs, lots of taper and shallow shoulders present problems for reloaders. They allow more case stretching and shorten case life.
The primary advantage to improved cases is increased case life. The secondary benefit is additional velocity. Normally, older designs benefit more from these enhancements.
When Mr Epps created his improved cartridge, he wanted it to be a simple chamber reaming with no other required alterations. He wanted to be able to fireform new cases using existing 303 British ammunition. He accomplished this handily, and began modifying rifles at his gun shop in Ontario, Canada.
At first, he "Eppsized" No 1s, No 4s and P-14s. He found however, that because the action strengths were different, loads developed in P-14s were dangerous to use in modified Lee Enfields. He preferred the P-14 action, and told anyone wanting their Lee Enfield reamed to 303 Epps not to expect the same velocities. Case life would still be vastly improved though.
He also warned customers not to use 303 Epps reloading recipes unless they could absolutely confirm that they were safe. He regularly gave owners of Lee Enfield conversions handouts for the proper load levels in their rifles. Since he talked with anyone getting this job done, Mr Epps was sure that the right reloading information was being distributed.
- self post tot so vêr terug as 2012 - ek ek leer (en lees) dat die spoeg so spat. Dankie vir 
