Bullet Sizing Clarification

[Coyote Roper]

I have 2 Pietta 1858's with R&D 45 Colt conversion cylinders.

I bought the sample pack of Big Lube bullets and slugged the barrels with the 250 grain bullets and they measued at .446 and .447 with dial calipers.  Is this a normal size for the1858 or is my measurment off somehow?

I have some BP lead bullets (.452) and I loaded up 100 rounds to try out the cylinders.  I have experienced some lead being shaved off of the bullets when they enter the barrel.

The question I have is; if I get the Big Lube mold which casts at approximately .453 I believe, will I be able to size them down to use in these revolvers?

And how far down should/can they be sized? 

The Lee website sizing chart shows .451 as the smallest 45 caliber die they have, though they may make custom sizes.

Would .451 be small enough?

[Montana Slim]

Better reuslt from slugging will be with .454 RB, pure lead, lube the bore with ballistol, Kroil or other (first).
All my Piettas (and my Pas) slugged out (groove) around .450 - .451, making a .452 bullet the best choice.
Good idea to have the forcing cones reamed on these guns. They shoot much better.

Regards,
Slim

[Flint]

The Pietta has 7 lands and 7 grooves, an odd number, which is almost impossible to measure with a caliper.  You are measuring across one land and one groove.  You can only directly measure diameter when you have even numbered rifling.

If you are shaving lead at the barrel, you have a forcing cone problem, and Piettas very often have almost none.  Mine had a convex rounded "cone" that may be somewhat acceptable with a pure soft lead round ball, but certainly is not with a harder, heavier conical fired from a cartridge.  Have a gunsmith check your barrel's forcing cone angle (if it has any).

.45/.452 is a proper size for hard lead bullet in a modern 45 caliber bore.  The deeper rifling of the Italian cap & ball might go a bit more in groove diameter, and smaller in the land diameter than a barrel made for cartridges, as they have to deal with soft lead and fouling.  .453 sounds like the bullet is designed to be soft lead in a sometimes oversized bore.  Some seem to be as much as .458.

The original Colt bullet diameter was .454, and it was changed to .450 for the second gen SAA after WWII, when they apparently used the boring/rifling equipment of the 1911 auto.

[Fox Creek Kid]

Actually, the original SAA for the military was ordered with a groove diam. of 0.450 according to the "Bible", i.e., the Kopec & Graham Colt book. But, then as now specs varied wildly and as Flint correctly pointed out it soon varied all the way up to 0.454.

[Mako]

Actually, the original SAA for the military was ordered with a groove diam. of 0.450 according to the "Bible" i.e., the Kopec & Graham Colt book. But, then as now specs varied wildly and as Flint correctly pointed out it soon varied all the way up t 0.454.

Yep, They are all over the place.  A 1st gen from '96 has a Ø.454 Barrel (see below)  and a couple of 20th century Colts are both about Ø.451.

I think the USFAs are running Ø.451 as well, at least the Rodeos are...

You might mention the cylinder chamber lead and the mouth diameter is as important or more important than the bore diameter with the lead bullets we're shooting.  That's what should drive most of your bullet diameter selection if you're concerned about accuracy.

~Mako

(Modified 7/13)

[Driftwood Johnson]

Howdy

I have a bunch of Smith & Wesson revolvers and most of them have an odd number of rifling grooves. If you have an odd number of grooves you can get a pretty good approximation of your groove diameter by measuring across the slug from high spot (groove depth) to low spot (land diameter) and then taking the depth extension at the base of your calipers and measuring the height from groove mark to land mark on your slug. Then add it to the number you read across the bullet. This is not an exact method, and usually takes a few tries, but you can at least get a closer idea of your groove diameter, even though it won't be perfect. And you don't absolutely have to use pure lead to slug a barrel. I have used all kinds of things, from pure lead, right up to hard cast bullets. You just have to whack them harder to get them started.

I have two Remmies that I shoot with R&D cylinders. One is an old EuroArms import that I bought way back around 1975 or so. It has a very tight bore, only about .449, but I shoot .452 soft lead bullets through it all the time with no problems. Remember, these guns were not designed to shoot 45 Colt, it is only dumb luck that allows us to do so.

As far as the groove diameter of the 45 Colt is concerned, with all due respect to Mr Kopec, the 19th Century groove diameter for 45 Colt was .454. I'm looking at a reproduction of a 1882 US Ordinance spec sheet on the Colt Army Revolver, Caliber 45 right now. It lists the groove depth as .454 min, .455 max. When the SAA was reintroduced by Colt in 1956, groove diameter for 45 Colt was changed to .451 in order to be the same as 45 ACP.

As far as how far you can size down bullets from their as cast diameter, you can go .002 or .003 without too much trouble. After that, you can shove them through the sizing die OK, but you start wiping off the surface features. Your crimp groove will start getting shallow and may blend into the ogive. My Lee molds drop both my PRS 250 grain bullets and my J/P 45-200 bullets out at about .453-.454. I size them all down to .452 with no problems.

Also bear in mind, the actual alloy you use when you cast will have an effect on the diameter your bullets drop out of the mold. As it cools, pure lead shrinks the most. When you start adding some tin, you get less shrinkage. I cast all my 45 caliber bullets using an alloy of about 25/1 lead/tin. Bullets made from this alloy shrink slightly less than if I use pure lead.

Also, bear in mind that despite what they say, not all Lee molds are exactly the same. When I designed the original J/P 45-200 bullet I had several conversations with Lee when designating the diameter. Lee has a tolerance range of .003 and still considers their molds to be in spec.

In short, it's a bit of a crap shoot. You get the mold, and you start experimenting with alloy mixes until your bullets start dropping out the diameter you want. If you don't have to size them down at all, that's fine. You can just lube them and load them. If you have to size them, try and keep the sizing around .002 or .003 or so.

[Fox Creek Kid]

...As far as the groove diameter of the 45 Colt is concerned, with all due respect to Mr Kopec, the 19th Century groove diameter for 45 Colt was .454. I'm looking at a reproduction of a 1882 US Ordinance spec sheet on the Colt Army Revolver, Caliber 45 right now. It lists the groove depth as .454 min, .455 max...

I believe you Driftwood, however Kopec was referring to the original 1873 specs. Something must have happened after the military bought the first batch in 1873 that warranted a change in specs later.  Interestingly, the Colt SAA had a higher rejection rate during inspection than the S&W Schofield as well. Usually it was for cylinder holes not indexing correctly.

[Mako]

As far as the groove diameter of the 45 Colt is concerned, with all due respect to Mr Kopec, the 19th Century groove diameter for 45 Colt was .454. I'm looking at a reproduction of a 1882 US Ordinance spec sheet on the Colt Army Revolver, Caliber 45 right now. It lists the groove depth as .454 min, .455 max. When the SAA was reintroduced by Colt in 1956, groove diameter for 45 Colt was changed to .451 in order to be the same as 45 ACP.

Driftwood,
I went and re-measured that 1st Generation .45 of mine.

I had cleaned my guns and I was emptying out the gun cart when I found one of my Ø.454 balls that had fallen out of my loading kit, so I decided to slug that 1st Generation .45 of mine again.  It was made in 1896 commonly attributed to be the Black Powder transition year.  It has a SN of 1647XX which puts it in the 1st half of the SAAs produced that year.  It has the newer style Base Pin retainer which I understand appear on some guns and the screw still showed up on some SAAs after 1896.

I was surprised when the O.D. of the ball that was engraved by the bottom of the rifling grooves only measured Ø.4515 -.4520, I thought I had remembered them being Ø.454 as I reported yesterday.  To make sure I got a good reading I grabbed a larger Ø.457 ball and slugged it again.  It measured the same.

I have a set of gage pins on the bench so I measured the rifling diameter.  I could only get a Ø.442+ pin to go in about half and inch, a Ø.441+ pin slides freely through the bore.  So I'll call it a Ø.442.  This is what it should be if it is a Ø.452 bore.

So it looks like Colt wasn't following the dimensional requirements of the 1882 Army ordnance requirement of  Ø.454-.455 and the Rifling land diameter of .445 in at least part of the 19th century.  I looked up the smaller diameter in Kuhnhausen's book where it lists the '82 requirements you referred to.

This pistol is in really, really excellent shape and I trust the dimensions coming from it.  I'm going to include a couple of pictures from today to show you just what kind of shape it is in and what I did.

Regards,
Mako

[Driftwood Johnson]

Howdy Mako

It is not unusual for individual guns to vary a couple of thousandths from the specified numbers. Tool wear to the rifling tool could account for a groove diameter a couple of thou tighter than the specifications.

[Mako]

Howdy Mako
It is not unusual for individual guns to vary a couple of thousandths from the specified numbers. Tool wear to the rifling tool could account for a groove diameter a couple of thou tighter than the specifications.

Driftwood,
I don't think that was the case. They were using cut rifling or more likely broaching at the time.  Neither one will have both the lands and grooves move together like that.  They drilled the barrel then reamed it, then they cut the rifling.  The land diameter doesn't change in either case. If the broach wears, then  the rifling just gets shallower.  If a cut rifling hook gets worn the same thing happens, the rifling gets shallower.  The original bore doesn't get smaller.

No, I wouldn't bet on this being a "worn" reamer.  The bore is perfect. It's shinier and smoother than a lot a modern weapons I have.  The gun is pristine Driftwood.

They hadn't discovered button rifling yet (the mistake that led to the discovery hadn't happened yet), they didn't have ECM or roto-hammer forging, I'd have to say the bore was drilled and reamed at Ø.442 nominally and then the standard .005" grooves were cut.   That pretty much covers the rifling methods.  The rifling tool may have been undersized for whatever reason, but a conscious decision had to be made to drill and ream the primary bore to match.

Regards,
Mako

[Coyote Roper]

Thanks to all for the input.

I will put it to good use.

Thanks Agian
CR

[Fox Creek Kid]

Again I refer to the "Bible" for the SAA, the Kopec book, whereas it states that the FINAL MODEL of the SAA approved by the military (after the .44 American test models, etc.) called for a "bore" diameter of 0.445 and a "front chamber"
diameter of 0.450. Bore in this regards re the nomenclature for the times is what we now commonly call "groove" diameter.

[Mako]

Again I refer to the "Bible" for the SAA, the Kopec book, whereas it states that the FINAL MODEL of the SAA approved by the military (after the .44 American test models, etc.) called for a "bore" diameter of 0.445 and a "front chamber"
diameter of 0.450. Bore in this regards re the nomenclature for the times is what we now commonly call "groove" diameter.

FCK,
I think you meant to say that the bore diameter of Ø.445 is the land diameter, not the groove diameter.  That is when you are speaking of the barrel.  The groove would be the deepest or largest diameter.

~Mako

[Fox Creek Kid]

FCK,
I think you meant to say that the bore diameter of Ø.445 is the land diameter, not the groove diameter.  That is when you are speaking of the barrel.  The groove would be the deepest or largest diameter.
~Mako

Nope. Not to appear a wise guy, but re-read my post. A 0.450 chamber mouth with a 0.454 groove barrel would shoot garbage can lid sized groups. As little as 0.002 can cause that. This I know as I had an ASM SAA with a 0.432 groove & 0.430 chamber mouths. Accuracy was pathetic UNTIL I had the chamber mouths opened up to 0.432 and it shot a ragged hole.

[Mako]

Nope. Not to appear a wise guy, but re-read my post. A 0.450 chamber mouth with a 0.454 groove barrel would shoot garbage can lid sized groups. As little as 0.002 can cause that. This I know as I had an ASM SAA with a 0.432 groove & 0.430 chamber mouths. Accuracy was pathetic UNTIL I had the chamber mouths opened up to 0.432 and it shot a ragged hole.

FCK,
I don't think you're cracking wise, I'll just say two more things

First, I doubt seriously Colt was making revolvers with a .450 Groove diameter and a  .445 land diameter.  The specifications I have seen call for a .005" groove depth .  A .450 Groove diameter would give you a .0025" groove, which is much too shallow for soft lead bullets .  You might as well make them smooth bores.
 
I think you are misinterpreting what Kopec was relating.  Below is what Kuhnhausen says on the subject.  This is in direct reference to the Army Ordnance spec of 1882 for the Colt Army Revolver, Caliber .45.  I won't list all of the specs, only the pertinent ones.

And I quote (page 15)

• Bore diameter (lands diameter) (notes 1, 5)                                                  .445"
• Groove Depth (notes 1 , 6)                                                                          .005"
• Groove (groove to groove) diameter (notes 1, 6)                                           .454" min., .455" max. 
• Chamber diameter at throat (notes 1,4)                                                       .450"

Note 1:  Original ordnance barrel and chamber specifications for the .45 caliber Colt S.A.A. Revolver
Note 4:  Workable with hollow base bullets. Current industry specified throat diameter is .452"min. and .4595" max.  To prevent chamber throat bullet extrusion with solid bullets, chamber throat should not be smaller than bullet diameter.  Bullet diameter should also match barrel groove diameter.  See pages 39 and 112 for additional data.
Note 5:  By comparison, current industry bore (lands) diameter is .442" min and .446" max.
Note 6:  Original barrel rifling lands/groove specifications for black powder were maintained through about 1910. .454" groove diameter was standard in .45 S.A.A.'s through 1940.  Groove Diameter was changed to .451"-.452" (same as .45 ACP specs.) circa 1956.  These specifications have been maintained as factory standard to date.

close quote
Look at note 4 and the reference to hollow base bullets.

Secondly I only know what I have.  I have an 1896 Colt with a perfect bore and when slugged it measures  .452" and .442".  I can't speak for Kopec or Kuhnhausen I can only relate what I have read.  But I can guarantee you that the measurements I took are accurate .  I just measured the throats on all six chambers and they will accept a Ø.455" gage pin.  So I can say I have a revolver produced in the 19th century with rifling and chamber dimensions that one source says didn't come into effect until 1956.  The gun has been in the family since the 20s given to my grandfather by the original owner who wanted to keep it away from his son.  My grandfather was a rifleman and had little use for a pistol, it was in his sock drawer for as far back as I can remember.  So unless an agent from Colt snuck into his bedroom and swapped this revolver for a 2nd generation pistol (but with 1st generation features like hammer, firing pin, ratchet, etc.   I'd have to say that it just shows once again people (authors)  are just recounting things they read from a singular source which may or may not have been accurate.

Nothing surprises me anymore FCK, especially when it comes to specifications and what was really produced.  Especially from Colt, I have never dealt with anyone faster to change things just to be able to use what they have in inventory.  Then they want you to change your supplied components to match the bastardized parts they are holding.

Regards,
Mako

[Fox Creek Kid]

Mako, I think you're right here & I'm wrong. I'll bow to Kunhausen. I forgot about the ctgs. having HB bullets. Still accuracy had to have been bad. No wonder W.B. Franklin tried to talk the military in using the .44 Russian ctg.

[Mako]

Mako, I think you're right here & I'm wrong. I'll bow to Kunhausen. I forgot about the ctgs. having HB bullets. Still accuracy had to have been bad. No wonder W.B. Franklin tried to talk the military in using the .44 Russian ctg.

Well you know the saying, even a blind hog finds an acorn every once in a while... Now if I could just find pecans.

Anyway it's more of an information exchange than anything else.  You've taught me a thing or two over the years.

Regards,
Mako