Barsto and Jarvis assure me that thier aftermarket barrels have better support than stock GLocks.
I had the feed ramp of a Kel-Tek P32 TIG welded up and I re cut the feed ramp and re reamed the chamber. The point at which case bulge starts improved dramatically.
I measured case support by holding a barrel and putting in a case and
scribing a line with a needle on the case as far forward as the chamber
will allow. With dial calipers I then measured the distance from the
base to the mark. To measure web thickness [the rear wall of a
cartridge] I sectioned cases with a cut off wheel in a Dremel tool. I
then measured the thickness with a dial caliper. I measured as many
pistols as I could take apart. If you could measure your Glock 20 after
market Federal Arms barrel, I would appreciate the data.
PISTOL SUPPORT WEB MARGIN RATING
Patriot 45acp .180" .180" 0" 21,000psi
Colt 1911 45acp .225 .180 -.045 21,000psi
Para Ordinance 45acp .235 .180 -.055 21,000psi
Glock 20 10mm .250 .180 -.070 37,500psi
Glock 22 40sw .235 .180 -.055 35,000psi
Glock 19 9mm .190 .160 -.030 35,000psi
Kel-Tek P11 .190 .160 -.030 35,000psi
Star Firestar .165 .160 -.005 35,000psi
CZ52 9mm .145 .160 +.015 35,000psi
Tokarev 9mm .160 .160 0 35,000psi
CZ52 7.62x25mm .185 .185 0 42,000cup
Tokarev 7.62x25mm .170 .185 +.015 42,000cup
Berretta 1934 .380 .170 .175 +.005 17,000cup
Kel-Tek P32 32acp .250 .150 -.100 20,500psi