Linstrum
02-18-2006, 06:07 AM
I just got my “dream gun”, an arsenal-rebuilt Walther P1 from the West German Army (now Re-Unified Germany). As far as I can tell it is the same as a Walther P38 but with an aluminum frame instead of an iron one. Several of us went in together to get a $10 discount from the regular price of $259 and out of the five that we purchased I got the lemon. The way the other four shoot vary from a fantastic 2" group at 25 yards to a still fantastic 3 inches. Mine puts ten shots into a cool 12-inch pattern that looks like the proverbial shotgun blast with 00 buckshot. I swapped my barrel and slide with my buddy’s pistol that does 2-inch groups and it does the 12-inch pattern trick with that frame, too, while my frame with his barrel and slide still does 2-inches, so it is somewhere in my barrel and slide assembly where the problem lies.
These pistols are new with the exception of their frames; the frames were checked over and rebuilt with new steel inserts installed in them. New barrel, slide, trigger assembly, etc. I checked the sights and the barrel-to-slide lock-up to see if anything was loose, but the barely-noticeable slack between the barrel and slide when they are locked together in no way would cause a foot worth of inaccuracy at 75 feet. I did the geometry calculations and found that for that to happen, the slop would have to be a whopping 1/16-inch of wiggle and play to cause that much trouble. I checked the play with a dial indicator and it is .015”, which gives a theoretical 2-inch group at 75 feet. That is what the other P1 I shot has!
I slugged the bore and found that it has a 0.358” groove diameter with 0.348” land diameter, the groove diameter being two-thousandths over the 0.355”-0.356” that the 9mm Parabellum is supposed to run. I don’t know how much effect that has on accuracy since I quite often run 0.356” boolits in my three Smith & Wesson .357s and they don’t go nuts spraying shotgun type patterns. With boolits that are 0.002” undersize for my Smith & Wessons, the groups do open up very noticeably to double the size, but they only open up one or two inches at 25 yards, they don’t increase to a whopping 14-inches! The same goes for my rifles, I run 0.308" boolits in my 0.312" bore Mosin-Nagants and they go from 2-inch groups to four or so inches at 100-yards, not to 48" groups that is the equivalent of what this Walther P1 does!
The cartridges that cause the most trouble are store-bought 115-grain full metal jacket round nose Winchesters. Because I am waiting for a Lee 0.356” 124-grain truncated cone mould to arrive, I bought some already cast boolits to get started reloading with real boolits for my P1. Those boolits shoot a much more realistic group, ten shots making only a 10-inch shotgun-like pattern instead of the abysmal 12-inch group. I have been loading them with 5-grains of Unique, which is the only pistol powder I have right now here where I am. I also re-crowned the barrel; I cut it back about 0.003” with a large 60° lathe center drill to clear any small nicks and dents at the end of the bore and then went in with a #2 Morse Taper reamer and cut an additional slight chamfer a few more thousandths to clean up the ends of the land tops. Doing the re-crowning got things down to a more reasonable 9-inches at 75-feet! The bore is just as pretty as can be, being brand new fresh cut with a mirror shine. When I slugged the bore the lead slug pushed down through the barrel nice and smooooooth, no hang-ups or tight spots at all. Of course I have a few guns with crappy sewer pipe bores that are pretty good shooters, too. Go figure!
I also just bought a new Cz85B (same as a Cz75 but with ambidextrous controls) and it is one of the finest 9mm Parabellum autoloader pistols I have ever shot, right up there with that OTHER Walther P1 that does 2-inch groups at 75-feet and my Browning High Power. My Cz85B does 4.25-inch groups at 75 feet with store bought ammo and with the 115-grain cast ammo loaded with 5-grains Unique it does an honest 2.5-inches! It feels good, to. That is important. My new Walther P1 has got the "feels good" part just fine, IT JUST DOESN’T SHOOT!
I’m out of tricks that I know how to do, what should I look at next to turn this Walther P1 back into my dream gun instead of the rotten nightmare it is right now?
These pistols are new with the exception of their frames; the frames were checked over and rebuilt with new steel inserts installed in them. New barrel, slide, trigger assembly, etc. I checked the sights and the barrel-to-slide lock-up to see if anything was loose, but the barely-noticeable slack between the barrel and slide when they are locked together in no way would cause a foot worth of inaccuracy at 75 feet. I did the geometry calculations and found that for that to happen, the slop would have to be a whopping 1/16-inch of wiggle and play to cause that much trouble. I checked the play with a dial indicator and it is .015”, which gives a theoretical 2-inch group at 75 feet. That is what the other P1 I shot has!
I slugged the bore and found that it has a 0.358” groove diameter with 0.348” land diameter, the groove diameter being two-thousandths over the 0.355”-0.356” that the 9mm Parabellum is supposed to run. I don’t know how much effect that has on accuracy since I quite often run 0.356” boolits in my three Smith & Wesson .357s and they don’t go nuts spraying shotgun type patterns. With boolits that are 0.002” undersize for my Smith & Wessons, the groups do open up very noticeably to double the size, but they only open up one or two inches at 25 yards, they don’t increase to a whopping 14-inches! The same goes for my rifles, I run 0.308" boolits in my 0.312" bore Mosin-Nagants and they go from 2-inch groups to four or so inches at 100-yards, not to 48" groups that is the equivalent of what this Walther P1 does!
The cartridges that cause the most trouble are store-bought 115-grain full metal jacket round nose Winchesters. Because I am waiting for a Lee 0.356” 124-grain truncated cone mould to arrive, I bought some already cast boolits to get started reloading with real boolits for my P1. Those boolits shoot a much more realistic group, ten shots making only a 10-inch shotgun-like pattern instead of the abysmal 12-inch group. I have been loading them with 5-grains of Unique, which is the only pistol powder I have right now here where I am. I also re-crowned the barrel; I cut it back about 0.003” with a large 60° lathe center drill to clear any small nicks and dents at the end of the bore and then went in with a #2 Morse Taper reamer and cut an additional slight chamfer a few more thousandths to clean up the ends of the land tops. Doing the re-crowning got things down to a more reasonable 9-inches at 75-feet! The bore is just as pretty as can be, being brand new fresh cut with a mirror shine. When I slugged the bore the lead slug pushed down through the barrel nice and smooooooth, no hang-ups or tight spots at all. Of course I have a few guns with crappy sewer pipe bores that are pretty good shooters, too. Go figure!
I also just bought a new Cz85B (same as a Cz75 but with ambidextrous controls) and it is one of the finest 9mm Parabellum autoloader pistols I have ever shot, right up there with that OTHER Walther P1 that does 2-inch groups at 75-feet and my Browning High Power. My Cz85B does 4.25-inch groups at 75 feet with store bought ammo and with the 115-grain cast ammo loaded with 5-grains Unique it does an honest 2.5-inches! It feels good, to. That is important. My new Walther P1 has got the "feels good" part just fine, IT JUST DOESN’T SHOOT!
I’m out of tricks that I know how to do, what should I look at next to turn this Walther P1 back into my dream gun instead of the rotten nightmare it is right now?