dam , I broke a few also when experimenting with MSP p17 ideas.. anyway ,I wonder how long a barrel would be max efficiency on the 17.. would it be 14 inches, 18 inches, a 24 incher?? no one has really tried above 10 inches iirc.
Quote from: Rob M on January 15, 2018, 03:54:40 PMdam , I broke a few also when experimenting with MSP p17 ideas.. anyway ,I wonder how long a barrel would be max efficiency on the 17.. would it be 14 inches, 18 inches, a 24 incher?? no one has really tried above 10 inches iirc.Rob, Scot Laughlin did a P17 (marksman 2004) with a 14" barrel... got over 500 fps with the 7 gr pellets. He also did some valve work but I don't know the details. At that length (14"), I believe he also had to modify the trigger guard to get clearance for cocking.I've done two so far... both 9.7" long which is what I got from cutting the port off the 10.1" LW from Crosman. They both averaged a 30 fps gain with the extra 3" length. A gain of 10 fps per inch of barrel is pretty solid, but even moreso at 7000' elev and going from un-choked to choked barrels. My guess is that you would gain well beyond 14" but the geometry will limit the length.Nice job miksatx and Robert on the longer barrels!Wyo
fwiw I've got a 14.5" modified crosman barrel on my P17 carbine. Went from averaging 400 fps to 483 fps with H&N sniper lights. Crosman heavies average 412 fps. The trigger guard and grip had to be modified to allow this length of barrel to cock.
Ouch! OH well a little bondo and she will be fine. Dang RobertMcC what weight pellet?
7.9s and got 421.
Quote from: RobertMcC on January 20, 2018, 09:49:36 AM7.9s and got 421.RobertMcC mine with the oem barrel shot 7.9s 385 fps. Not a bad bump to 420+ I think. Looks like there's room for a 11" barrel. The old HF lathe sounding like it might be on it last rpm lol.