jolague Posted October 10, 2020 Report Share Posted October 10, 2020 I have Jap Lewis Type 92 (Aircraft style) that is a lot of fun to shoot. I replaced all that I could with British parts. Nonetheless, my Lewis runs a little on the fast side. I always use 150gn FMJ ball .311 with 38 grains of IMR 4895. It's a decent load. I set spring tension to 12lbs. Anyway, I would like to get to the 450-500 range? Currently, I'm a 600+. Link to comment Share on other sites More sharing options...
DougStump Posted October 10, 2020 Report Share Posted October 10, 2020 Probably too obvious, but do you have the gas regulator on the small hole? You could also try a different powder that has different burn characteristics, my Lewis is quite happy with IMR-3031. Link to comment Share on other sites More sharing options...
jolague Posted October 10, 2020 Author Report Share Posted October 10, 2020 Probably too obvious, but do you have the gas regulator on the small hole? You could also try a different powder that has different burn characteristics, my Lewis is quite happy with IMR-3031.Yes, actually...,my gas regulator is further modified. In addition to the original "S" and "L" setting my gunsmith added "B" smaller than "S," and "A" smaller than "B." I put my setting to A. My gas regulator has four options. Link to comment Share on other sites More sharing options...
hatrick Posted February 26, 2021 Report Share Posted February 26, 2021 Standard .303 Mk7 ball is 174gr. I wonder if your lighter 150gr is causing it to run faster Link to comment Share on other sites More sharing options...
Ivan Posted February 27, 2021 Report Share Posted February 27, 2021 IMR 3031 was developed for the 303 cartridge and has a little faster burn rate than IMR 4895. Not sure how much that would effect ROF.The spring weight is not written in stone.Some guns like 14 lb setting, some like 12 or less. Perhaps try 11 lb setting.Each firearm has it's own peculiarities. You may be lucky and have an operating rod that is in good shape and close fit to gas tube. A cylinder and gas plug that are not worn and allowing gas to escape.The 100 year old clock springs are part of it too. The Jap guns were usually used in aircraft with a booster and were tuned to give a high ROF for shooting at other aircraft. My limited experience with the Type 92 left impression that the normal ROF was about 800 or so RPM. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now