Early Colt Police Positive dimensions?

[flintlocke]

In the past I've had some frustrations with Colt New Service revolvers circa 1910, same old story, big cylinder throats, tight forcing cone, and correspondingly small groove diameter barrels. All that adds up to targets that you really don't want anyone to see. I am now interested in acquiring an early Police Positive in .38 S&W (.38 Colt Police) with some exterior issues but supposedly an 'excellent' bore, for a price I consider fair. But, I worry that I might run into the same grief encountered in the New Services, and I'm told, SAA's from the same era.
Do any of you folks have any experiences with the Police Positives and their as issued dimensions?

Nice fellow he seems, but he doesn't sound like he's real comfortable with a micrometer, if he had one.
Flintlocke

[Outpost75]

My Colt Police Positive .38 Colt New Police was made in 1930.

Cylinder throats are .359", barrel bore diameter .344", groove diameter .354", cylinder gap is pass 0.004"/hold 0.005"

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[flintlocke]

Outpost, Dimensions be damned, it looks like you are making it work for you. So, where does your bullet diameter fall? Toward the .359 throat or toward the .354 groove?
And just as an anecdote, the aforementioned New Service that I had in .45 Colt with the problematic dimensions of .455 throat/.452 groove liked a .452 swc with a bevel base just like your bullets pictured. Popular doctrine seems to suggest, for best results, flat base, fit the throat and resize the bullet when you jerk the trigger. Guns are as individual as the folks that shoot them I guess. Thanks for your help.

[Guesser]

My 1913 and 1920 PP38 get my soft cast 147 grain # 358246 and 360271 sized to .360. Both molds drop at .361 with soft alloy. My accuracy mirrors what you show on the target. My S&W 1920's Regulation Police and my 1953 pre Model 33 do quite well with the same bullets.
I haven't measured or slugged anything on any of the 4 revolvers, I've had them for several years and they satisfied me right from the top so I just continued on; just as if I knew what I was doing...........

[Outpost75]

Outpost, Dimensions be damned, it looks like you are making it work for you. So, where does your bullet diameter fall? Toward the .359 throat or toward the .354 groove?... Thanks for your help.

In revolvers ALWAYS make the bullet fit the cylinder throats! IGNORE barrel groove diameter!!!!

Ideal fit is so that you can push a lubricated bullet through all six charge holes using the eraser end of a pencil and hand pressure only, and wipe a film of lubricant on the throats. That requires a bullet about 1/2 thousandth under throat size.

My bullets from Accurate molds drop .360-.361" from the mold, when cast out of wheelweights with 2% of tin added.

I lubricate with Lee Liquid Alox, using a thin film only enough to turn the bullets a uniform brassy color, making no attempt to fill the lube grooves. Attempting a heavy coating of LLA enlarges groups and is not necessary at subsonic revolver velocities or for cowboy rifle loads with plain based bullets which are below 1350 fps and therefore do not require a GC.

I use the Lee .358 push-through sizer in the loading press and the .360-.361" bullets come out of the sizer at .3585-.3587, which is a perfect fit for the .359 throats. In my Webley & Scott MkIV and S&W Model 32-1 Terrier I load these bullets as-cast and unsized to better fit their .362" cylinder throats.

A charge of 2.5 grains of Bullseye, 2.7 grs. of W231 or 3 grains of Unique or Universal are a full charge load in .38 S&W brass.

You mentioned .45 Colt. Your poor accuracy was caused by following the old Lyman mythology and folklore of sizing bullets to barrel groove diameter, which is absolute horse manure!

My Colt New Service M1909, my S&W .45 Hand Ejector and my Webley MkVI all have cylinder throats which are .4555-.4560 and in those I use the Accurate 45-262H bullet, which drops from the mold from the above alloy at .457". The same bullet without the bevel base is 45-240H1, which works well in the .45 Auto Rimmed to shoot to its fixed sights.

I lube similarly and size in a Lee .454 sizer, from which the .457 bullets emerge at .455". I load 3.5 grains of Bullseye in the .455 Webley with 262H for 600 fps, 4 grains of Bullseye in the .45 Auto Rim with 240H1 for 700 fps, 5 grains of Bullseye with 262H in the .45 Schofield for 750 fps and 6 grains of Bullseye with 262H in the .45 Colt for 850 fps. Same formula...

If you want a traditionally shaped bullet for the .38 S&W, Accurate 36-151H is a near dead ringer for the original .38 Colt New Police. It is of the same length and profile as the .45 Auto Rim bullet 45-240H1, simply reducing base diameter to .360" for the .380 Rimmed and .38 S&W, being optimized for the Webley & Scott MkIV.

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[smkummer]

I shoot Lyman's 454190 as cast in my 1920 7 1/2 barrel 45 Colt. It drops out at 454-455. 9 grains unique and I can hit a 30" plate at 200 yards.
My colt bankers special shoots any .358 lead bullet just fine and while I have a old Bridgeport single cavity mold that casts a 150 bullet and is stamped 38 S&W, I will probably go with Lyman's 358477 DC at 150 grains and older data with red dot or bullseye.