Mike, 240 FPE with a 29" barrel in .257 at 3500 psi is VERY impressive.... The "lofty goal" is only 219 FPE, so you are beating that by a fair margin.... I don't think even Doug Noble, with his highly modified Condors, has made those kind of numbers, even shooting a heavy bullet.... Whoops, I see the barrel is 35.5" long, so that bumps the "lofty goal" to 268 FPE.... Still the 245 FPE you reported in the other thread is 91% of that, which is VERY impressive at nearly Mach 1.... I'm thinking that with a 120 gr. bullet in the high 900s you could easily top 250 FPE.... Congrats for sure.... Bob
My old Edgun R3 is the first gun I ever saw with a 2mm stem. But it was regulated, typically at 150 bar or less. The edgun throat was only .250 or so. After my experience with the Edgun, 2mm stems became the norm for my builds, but again they were mostly regulated and relatively smallish valve throats.I do have a 2mm stem in one unregulated 3kpsi fill gun, a 70fpe .25, again a smaller valve throat.If I do try a 2mm stem on this gun, it will be pushing one harder than I ever have, in both pressure and throat area. There is definitely potential of failure. At least the Bulldog has a bleed screw incase I drive the stem through the poppet to the point of no stem protrusion, lol...I am hopeful that the long barrel helps with the less than bore area porting. It will be late next week before I can exchange my nitrogen cylinder, so no full fill testing until then.
Quote from: mackeral5 on April 07, 2021, 07:58:52 AMMy old Edgun R3 is the first gun I ever saw with a 2mm stem. But it was regulated, typically at 150 bar or less. The edgun throat was only .250 or so. After my experience with the Edgun, 2mm stems became the norm for my builds, but again they were mostly regulated and relatively smallish valve throats.I do have a 2mm stem in one unregulated 3kpsi fill gun, a 70fpe .25, again a smaller valve throat.If I do try a 2mm stem on this gun, it will be pushing one harder than I ever have, in both pressure and throat area. There is definitely potential of failure. At least the Bulldog has a bleed screw incase I drive the stem through the poppet to the point of no stem protrusion, lol...I am hopeful that the long barrel helps with the less than bore area porting. It will be late next week before I can exchange my nitrogen cylinder, so no full fill testing until then.Using PEEK poppet would be a good idea. Alternatively metal poppet and PET-P or delrin seat.
Do try the 2mm stem, I'd really like to hear the results.