Colt police positive, puzzling

T

tangolima

New member
I have an old police positive in 38 new police, which is same as 38 s&w. This revolver is old, a service revolver of the royal hong kong police almost 100 years ago. It has been puzzling me since I got it years ago.

The bullet diameter is supposed to be 0.361". The first thing I noticed was that 38 s&w factory cartridge doesn't always freely drops into the cylinder. I measured the throat to be 0.358", 0.003" smaller than the bullet. If the bullet is seated deep enough, the bullet ogive will allow the cartridge to go into with no restriction.

I then went ahead and slugged the bore. Groove diameter 0.354"!

All that is mysterious to me. I doubt the revolver is sized for 38 colt new police, or 38 s&w, even the barrel is clearly stamped as such. It is more like 38 short colt instead. That's exactly what I will feed it with.

The best bullet I could find would be 0.357" cast bullet for 38 spl target guns. The normal 0.358" cast bullet for 38 spl should also work. I can also step down to 0.356" for 9mm.

Your inputs and comments are much appreciated.

-TL
 
Colt did not always adhere to modern specs in those days. They made those guns for soft lead bullets and didn't worry overmuch about a few thousandths here and there. Also, of course, the chambers were made for the bullet ogive in use at the time, which is not necessarily what might be used today especially in reloads.

Stick to soft lead bullets of the right ogive, and the gun should shoot well.

Jim
 
Colt .38s were generally smaller in the bore than Smith to start with and they did not seem to bother with separate barrel specs between .38 Spl and .38 NP/S&WL.
 
Here is a good example of what might be called a "cavalier attitude."

Colt offered its Model 1889 to the Navy chambered for the old .38 Long Colt with a heel type bullet, which meant the bullet was about .380". The chambers were bored straight through and the barrel dimensions were about .380 groove. But when the Army adopted an improved model as the Model 1892, they designed a new cartridge with an inside lubricated bullet of .357" diameter and made ammunition of that dimension at Frankford Arsenal for issue for over 17 years. In spite of complaints about inaccuracy, neither Colt nor the Army chose to make any changes. When S&W came out with the .38 Special in 1899, Colt finally (c. 1903) put shoulders in the chambers and made the barrel dimensions to suit a .357" bullet so those guns would fire .38 Special. (They never changed the barrel marking, though!)

So all those years, Colt saw no problem with selling guns to the army that wouldn't fire the Army's ammo accurately, and the Army saw no problem in issuing ammo that wouldn't shoot straight in its service revolver! And no one seemed to care very much.

Jim
 
James,
I wonder how much of that attitude help push along S&W to surpass the rampant horse?
I think Colt was kinda indifferent because well after all they are Colt.
 
Thank you gentlemen for your inputs.

Given the measurements of this particular revolver, it is no point sticking to 0.361" bullets. So I will start with 0.358" cast bullets I have. Then I will try 0.356" next. Those are easy to get standard sizes, and I already have those in my stash.

-TL
 
I have slugged ".38 S&W" guns from .354"-.360"...

The currently available WW and Rem ammo (early 90's vintage actually) I have pulled, have dead soft bullets that come in at .358"...They have a hollow base in order to slug up to grooves if need be...

For my Albion Enfield I use any 158gr cast at .358" over a couple grains of Red Dot, and get excellent accuracy and no leading...
 
Hmm... Sounds like nobody is serious when they say 38 s&w has bullet diameter of 0.361", except Missouri bullet company, from whom I bought the bullets. Not only colt in the old days was off a few thousandths here and there, everybody was.

Thanks for the info!

-TL
 
0.361" is the SAAMI spec, so the bullet company is correct. Why the British made their bullets smaller, I don't know. Anyway, the difference is .004", the thickness of the paper in your printer. Nothing much is going to happen either way over .004" bullet diameter in a revolver.

Jim
 
I guess the saami standard must be based on something. They haven't been around that long, I don't think. They just put down some number that very few people are actually doing. That's comical.
I wouldn't worry if it is really 0.004". The bullet is 0.361" and the barrel is 0.354". That's 0.007". I know the gun won't blow up, as I have shot more than a handful of those already. But whether it is kosher? I wouldn't think so. It is part of the reason I hand load. I get to adjust some parameters to make things work better.

-TL
 
How did you measure the barrel? The .354" is right for the .38 S&W bore diameter. Groove diameter would be .361" with a groove depth of .0035. Bullet diameter is groove diameter.

Jim
 
See post #1. I slugged the barrel, and measured the slug with micrometer. I did it twice to confirm. The actual measurement was 0.3537" to 0.3539". I just rounded it up to 0.354". Groove diameter.

-TL

Edit: when come to think about it, the barrel never sees a bullet of 0.361". The throat will force it down to 0.358" before it hits the forcing cone. So the actual difference is 0.358" - 0.354" = 0.004". But still the throat shouldn't be doing any forcing down.
 
Last edited:
I fully believe that you have a .354" groove diameter, as I have seen it in other guns...

The Lyman 44th Edition Manual quite clearly calls for bullets from .354" to .360"...

Pg 121:

"As wide variations in groove diameters occur in guns chambered for this cartridge, we suggest that you slug your barrel before reloading. Bullets should be sized to as near groove diameter as possible"
 
Salmoneye said:
I fully believe that you have a .354" groove diameter, as I have seen it in other guns...

The Lyman 44th Edition Manual quite clearly calls for bullets from .354" to .360"...

Pg 121:

"As wide variations in groove diameters occur in guns chambered for this cartridge, we suggest that you slug your barrel before reloading. Bullets should be sized to as near groove diameter as possible"
Click to expand...
Thanks. Very useful information. Most appreciated.

-TL
 
I've seen ".38 S&W" revolvers with bore diameters running as large as .370 (very cheap late 1800s guns), and as tight as .352 (a Colt like yours).

Bullets back then were dead soft and the round works at low pressure, so it really didn't matter much to them...
 
Mike Irwin said:
I've seen ".38 S&W" revolvers with bore diameters running as large as .370 (very cheap late 1800s guns), and as tight as .352 (a Colt like yours).

Bullets back then were dead soft and the round works at low pressure, so it really didn't matter much to them...
Click to expand...
Got it. Thanks.

I only got into the practice of slugging bores recently. Before that I just took whatever printed in the book. Now I know better and will do better.

-TL
 
I simply gave up worrying about bullet diameter when I loaded for .38 S&W and ran into variable bores.

A soft hollow-base wad cutter in the .358-.359 range is often the answer to all of your prayers.

In guns with ovesized bores the hollow base allows the bullet to blow into the rifling, giving passable accuracy, and in an undersized bore it would easily swage down without leading the bore.
 
You must log in or register to reply here.
Back
Top