Colt New service, and really confused

[Gundogblue]

Hi all,
This is my first post on this sight, I have a pre war Colt New Service in .45 Colt, it was my dad's gun, when he passed in 2000 i got the gun. I've never shot it before and would like to do so. Im very familiar with hand loading I've been at it for 30 plus years, but I've never come across anything like this. I load the run of the mill stuff like 9mm .45 acp, 308, 223 useing jacketed bullets. When I looked up the loadings for the .45 Colt in my Lyman manual it warned that pre war Colts have a bore diameter of .454. I had the local smith slug the barrel and it is a .455, I also measured the cylinder throats, I don't have a pin gage so I used my calipers, I measured each cylinder throat serveral times and came up with the same measurment two cylinder throats are .443, and four are .454. I was going to order some .454 bullets but the guy told me with the bore diameter of my gun (.455) a .454 bullet would'nt work, and that it would just lead up my barrel, he told me I need a bullet with at least a .457 diameter is this true? My dad used to cast and I still have some of his moulds, one of them is a Lyman 454190, but thats will only produce a .454 bullet, and if what I was told is true it will only lead up the bore. So as you guys can see Im pretty cornfussed, any help on this will be greatly appriciated.
Thanks,
Paul

[Der Gebirgsjager]

First let me say that I own 4 of these revolvers in various configurations, including two 1917 models that are virtually the same as what you've got.
Let me ask you, do you have any recollections of your dad shooting the revolver, and if so how well he shot it? It seems to me that if he had a mold for it and kept both the revolver and the mold he must have been reasonably pleased with the results. As for the measurements you've given, and the advice you've received, there is some truth to all of it but it is not necessarily the absolute last word. First, I would try shooting the revolver with some standard 230 gr. hardball ammo as "back in the day" that's what they were made to fire. Then I'd try the cast bullets (here they refer to them as "boolits" so don't be confused). You'll need to determine what grain weight they are and what diameter they cast to, and develop a load accordingly. I utilize a 225 gr. cast lead round nose with one lube groove over 5.5 gr. of Unique. Perhaps you will find that they cast unsized to .455-.457 and may get good accuracy shooting them that way. I would suggest that you mark (felt tip pen) the chambers that are undersized and keep track in your shooting of how they shoot compared to the four that are standard size. Perhaps they will shoot well, but if they don't you can have their mouths reamed out a few thousandths to match the other four. Or, you could even have all six opened to .455 to match the bore. Should you develop some lead in the bore during your testing it isn't the end of the world, just buy and use a Lewis Lead Remover--inexpensive and highly effective. I think the point is that you really won't know what results you will get until you try, and then you can go from there. Good shooting!

[jcren]

There is no point loading a bullet larger than the cylinder throat. Commercial hard cast may lead being slightly undersized, but a softer bullet will upset some when it hits the forcing cone and May well shoot fine. Bottom line, try .454 and see what happens, if you can't get it to shoot you May need the cylinder honed th use a larger bullet.

[dondiego]

Just because the mold number is 454190 doesn't mean that it will throw a bullet that is .454 in diameter. It likely may be a few thousandths larger depending on alloy used. Also, don't count on the throat measurements taken with calipers to be accurate. g

[leadman]

There is at least one commercial caster that sells fairly soft alloy boolits but the name escapes me now. Maybe others can remember.
A softer alloy boolit with the right load will bump up (expand or obdurate) the boolit to fit the bore. There is also a boolit with a base that is somewhat dished to aid in the boolit fitting the bore.

[Outpost75]

In my Colt New Service M1909 my best load is the Saeco #954 230-grain cowboy bullet cast 1:30 tin/lead, sized .454 with 6.0 grains of Bullseye or 7 grains of Unique.155325

[Gundogblue]

I want to thank all you guys for the fast and informative replies, this is very different from loading with jacketed bullets, I should have watched and listened to my dad more. I guess the best plan of attack is to first shoot some 230 gr hardball like what I shoot in 1911. Then go to some .454 cast boolits, if all is well I'll buy my casting equipment and the Lyman guid, hell I already have my dad's .454 Lyman mould. Can you guys recomend a good set of dies for loading .45 Colt with cast boolits?
Thanks again for all the info I greatly appreciate it
Paul

[Char-Gar]

This pre-war 45 Colt barrel groove of .454 causes some confusion. This applies to Single Action Army and not the DA Colts like the New Service. The New Service continued with the .452 of the WWI 1917s.

That said, the cylinder throats are the important dimension when determining the size of the cast bullet.

[SOFMatchstaff]

The one measurement of .443 makes me question the accuracy of the the number, either the method, or leaded and dirty throat, or typo,, .011 is a really big variation. I suggest a very thorough cleaning of those two chambers, so there's no chance of a errant reading. Char-Gar has it right, But I am wondering if your New Service might have been a .455 Eley at one time, its happened before.

If those two throats are THAT tight, I bet the target will be interesting, flyers ect. I have cleaned the crud from throats with a stainless bore brush in a drill motor(carefully) try that and then measure again. Hopefully you will see a change, if not then its time to have the cylinder attended to by an expert. New Service Colts deserve the best. I also would slug the bore again just to be sure, your Dads mold with pure lead. good luck..

[Char-Gar]

The one measurement of .443 makes me question the accuracy of the the number, either the method, or leaded and dirty throat, or typo,, .011 is a really big variation. I suggest a very thorough cleaning of those two chambers, so there's no chance of a errant reading. Char-Gar has it right, But I am wondering if your New Service might have been a .455 Eley at one time, its happened before.

If those two throats are THAT tight, I bet the target will be interesting, flyers ect. I have cleaned the crud from throats with a stainless bore brush in a drill motor(carefully) try that and then measure again. Hopefully you will see a change, if not then its time to have the cylinder attended to by an expert. New Service Colts deserve the best. I also would slug the bore again just to be sure, your Dads mold with pure lead. good luck..

You raise some good points. Over the years I have had four New Service Colts in 45 Colt and every one of them had .452 barrel groove diameter and .456-457 cylinder throats. These four Colts ran from 1921 to 1939 in production date.

For whatever reason, I feel confident that the numbers given are not accurate for a factory Colt New Service in 45 Colt. Trying to measure the ID of a round hole with calipers is just asking for bogus numbers.

[Char-Gar]

I want to thank all you guys for the fast and informative replies, this is very different from loading with jacketed bullets, I should have watched and listened to my dad more. I guess the best plan of attack is to first shoot some 230 gr hardball like what I shoot in 1911. Then go to some .454 cast boolits, if all is well I'll buy my casting equipment and the Lyman guid, hell I already have my dad's .454 Lyman mould. Can you guys recomend a good set of dies for loading .45 Colt with cast boolits?
Thanks again for all the info I greatly appreciate it
Paul

Lyman, Redding, RCBS and I suppose others make good dies in 45 Colt caliber. The only fly is the expanders are for hard jacketed bullets and can distort lead bullets. RCBS Cowboy dies come with correct expanders for cast bullets and separate larger expanders can be bought from several sources. I use the .452 (45 ACP) and .454 (45 Colt) expanders that come with Lyman 310 dies to do the job.

[Gundogblue]

You guys may well be right about the measurements, I took the gun to a local smith, but ive never before used his services, and I know calipers are not as accurate as a pin gage, but all I had to use was my calipers. Also my dad's gun was made in 1925 the same range Char-Gar has mentioned

[bedbugbilly]

I would try and get a more accurate/precise measurement of your throats before anything else. I really don't thin you can measure them accurately enough with a set of calipers. If you have a sizing die . . . say .452 . . . cast up a couple of boolits, size them and then see if they go in your throats . . then go from there. Yes . . .they might be tight . . or they might be loose but it will at least tell you what's going to happen if you use a .454 or .455 boolit.

I have a SAA that the bore measures .452 . . . the throats are larger than that . . around .454. I'm using a 454-190 mold (250 grain) and loading them "as cast" and they usually drop around .454 - .455. My chambers are very generous and the loaded cartridges fit just fine . . . they shoot just fine and are accurate.

As suggested . . . try some rounds and see what happens. The worst case scenario is if you boolet is too small . you may have to clean some leading out of the bore . . . and the initial results just may surprise you. As in most things . . . don't borrow trouble before you have to.

And welcome to the forum! I hope you will post what goes on with your Colt so we can follow the progress! Good luck!

[leftiye]

Check that groove size by slugging it. Have your (or do it yourself) cylinder mouths opened up to groove diameter plus one thou.

[Wayne Smith]

Dougguy here is the guy to send your cylinder to if you need the throats opened. Get or borrow pin gagues to find out what you actually have first.

[BwBrown]

Over on the Ruger forum, there has been quite a lot of discussion of throat diameter, it seems that Ruger is famous for their undersize cylinder throats.
A couple guys rent reamers, a couple more offer same day turn around to ream your cylinder. I bought a reamer set from Brownell's It took me less than hour start to finish (pun intended).

Made a world of difference in my groups. My Redhawk now shoots better than I ever will. Get the throats uniform, size your bullets to that size. Use soft lead, keep velocity down, use slow burning powders. Your experience might vary, but this is what works for me.

In the long run, don't waste time overthinking - it has already had a long life - just enjoy Pop's gun.

[.45Cole]

Gundogblue-

Post your (relative) location and I'm sure you're not very far from one of our members. You sound like you will be exploring the words "beagling" molds and learning about hollow-base boolits. Soft alloy boolits will be your friend. A machine shop will have pin/plug gauges, although you might want to go in and BS them a little before inquiring about their precision plug gauges.