Lead ?

[Steve Anderson]

In a perfect world, what would the lead look like for a given cartridge. Would a black powder cartridge be any different than a smokeless cartridge? A friend has a 38-55 that appears to have no lead angle, just an abrupt jump from the throat to the rifling. Inquiring minds want to know. Steve

[Don McDowell]

Modern chambers have a 45 degree angle from the end of the case to the rifling, Ideally that's tapered off somewhere between 4 and 25 degree angle.
Hopefully Kurt pops in here with some chamber casts and drawings, or maybe Gunlaker or Iron Coyote can give some visual assistance..

[Kurt]

Here is a cast from a original Sharps .44-77

Here is another original .44-77

This is my .44-75 Ballard everlasting.

The left cast is an example of the standard Shiloh .44-2-5/8 BN chamber. It has the now used 45 degree chamber end that leads up into the lead.
The right cast is a cast I got from a like new condition 1877 #1 Sharps long range Creedmoor rifle. I had a reamer made from that cast. The original cast has a flat 3.5 degree chamber end like the other casts above but I changed that transition to a 5 degree, now wishing I left it as it was in the original.

I have seen a chamber cast of a .45-2.6 late model Borchardt I could not get this cast but it had a more blunt transition at the chamber end, guessing about a 18 degree. This came out about the time of the .30-40 Krag.
I made a cast of my .45-70 Trapdoors and both have a flat transition also.

Below is a chamber cast of a .22 rimfire. It is the only lead bullet chamber that has not changed since it's beginning



Kurt

[Kurt]

Here is a print of my chamber in the CPA 44-1/2 Stevens. I chambered it with a .44-75 Ballard as close to the original as I can.
It will not except a GG bullet unless I have a mould made that will cast a .399 ring bullet.

[Steve Anderson]

Kurt those all show at least some sort of transition. My friends has no transition and is just an abrupt change from throat to rifling. When would you want no transition? Thanks for the photo's and drawing. There are a big help. Steve

[Kurt]

Steve,

I'm not clear what you mean by no transition. Do you mean a 90 degree chamber end with a freebore that is groove diameter??

[Steve Anderson]

His bullet impressions seem to show no freebore. Rather an abrupt 90 degree jump to the rifling.

[SgtDog0311]

His bullet impressions seem to show no freebore. Rather an abrupt 90 degree jump to the rifling.

Soon as I get back from the range tomorrow I'll post a picture of the chamber cast. It's a Cody Ballard in 38-55 'for Black Powder'.

When I described it to Steve Garbe in an email he said it would have a 1.5 degree leade and no throat"... by which I took him to mean a tapered transition from freebore to groove diameter. Chamber cast reflects exactly that. I can't say its a 90 degree but if you tap an overized bullet into the leads there is a line around the circumference adjacent to the leade's shallow end that looks like it is cut with an exacto knife. In otherwords, right at the start of the groove diameter and start of the leade.

I assumed that maybe "for Black Powder" chambers got away without cutting a taper and that was due maybe to the bump up of BP and the potential for using less than groove size bullets.

Seems a 90 degree shoulder vs a taper would still create potential for creating lead rings or a number of other issues. But coupling what Steve Garbe said, with what I'm looking at by way of chamber cast, and an otherwise super Badger barrel/chamber, it does not look to me like there have been any changes made since it left the Ballard Rifle and Cartridge Company. Does not even look like it's been shot much at all if any... well at least once, enough to lead it good. But that all came out like it had nothing to stick to - two patches!

Currently shooting a groove size bullet and getting away with it but I told Steve I was surprised and asked him if that was a common thing with a "Black Powder" chamber.

John

[J.B.]

Just be sure you're looking at the lead and not the chamber end. The end of a modern cut chamber end is fairly easy to pick with the eye... the lead, not so much. That photo Kurt posted with the two 44/90 chambers shows the current 'standard' Shiloh 44/90 chamber with the 45 degree chamber end... there is still a lead there, possibly 2-3 degrees and of short duration..but it is there. The early guns, mostly used with paper patch, didnt seem to have the abrupt chamber ends that we consider standard today. The chamber mouth...appears to give way to the lead..and then the rifling in a smooth, constant transition. This is evident in the castings from the originals. Or that is how it appears to me.

J.B.

[Gunlaker]

I'd see if he could do a chamber cast to get a better impression. Some rifles have zero freebore and they can shoot very well. There are so many variations though. I have a CPA that has a .38-55 chamber with no freebore, just a 6 degree taper from the outside of the case mouth. It has shot some excellent targets, but also a lot of not so excellent targets.

For grease grooved bullets the Shiloh chambers seem to shoot very well, although they do get a bit of leading. I'll bet that they are really close to ideal for BP with greasers. The Browning Bpcr .45-70 chamber also shoots very very well. If I remember correctly it's a 12.5 degree cone from the outside of the case mouth.

Dan Theodore's chambers seem to do very well with greasers. I haven't got any guns with those chambers but I have some of the reamer drawings. I can post them if you like. Dan also wrote an article about reamer design on BPCR.NET that explained his philosophy.

Chris.