Here you go Rick.
“Long Cartridges in Short Chambers”,
Field, Jan. 30, 1892
https://books.google.com/books?id=in...page&q&f=false
2 1/2” chamber 12g
3 Dr. “E.C.” with 1 1/8 oz. shot in 2 1/2” case 1” pressure – 5,475 psi by LUP (+
10-14% for modern transducer numbers)
3 1/2 Dr. with 1 1/4 oz. in 2 1/2” case – 6,200 psi
3 1/2 Dr. with 1 1/4 oz. in 2 3/4” case – 6,600 psi
“Mr. Griffith on Shotgun Patterns”, 1897 Lecture
https://books.google.com/books?id=in...page&q&f=false
p. 243 “Turnover” - case longer than the chamber
No. 9 2 1/2” case with 1/8” turnover
No. 10 3/8” turnover
No. 11 & No. 12 with 2 3/4” and 3” cases in 2 1/2” chambers = “…patchy patterns, clustering, and frequent balling…” Pattern examples on p.244
p. 245 “balling or clustering”
p. 247
Summary of patterns;
Field, March 5, 1898
No. 9 - 1/8” turnover better pattern % than 10, 11 & 12
Pressures with 3 Dr. “Schultze” with 1 1/8 oz.
No. 9 – 2.13 tons = 6,040 psi (
converted by Burrard’s formula)
No. 10 – 3.03 = 9,060 psi
No. 11 – 3.22 = 9,700 psi
No. 12 – 3.71 = 11,345 psi
“When long cases are used in short chambers, the paper overlaps the cone and causes greater resistance to passage of the shot and wads. The pressure then goes up considerably, while muzzle velocity and recoil are both increased.”
We all understand the studies used (thick) paper cases; not modern plastic cases and polyethylene wads
Threaded Mode