Barrel Leading

Here is a question for KC, Jerry, Jon,or whoever thinks they can give me an answer to this question. On all of 4 of my 45s I get leading between 4 and 6:00 right where the chamber ends and the lands start. The leading extends about 1/4" to 3/8" up the barrel in this area. Nowhere else. I shoot both cast SWC and Zero SWC with 4.0gr of bullseye. The cast are hard cast (cannot scratch them with your thumbnail). Question is --Why do I get leading in just this area and nowhere else? I have been wondering about this for a while, so I thought that I would throw it out here for discussion. Has anyone else noticed this on their 45s?
Thanks, Paul

It is a known phenomenon with 22 rifles.  Which is why the consensus is now to clean 22s in International level shooting.the thought is a small internal yaw at bullet engraving is causing this.

Could it be as simple as the effects of gravity and Newtons 1st law of motion? Gravity pulling it down to the 4:00-6:00 area and the speed of the bullet still slow enough at engraving to leave lead. It would be easy to test.

Len

My model 19 revolver does the same..  im guessing its just as was said...  speed still a little slow, and it is still kinda wiggling around there till it locks into the rifling.

What brand of barrels? How far you seating edge of bullet past rim of case? I normally see leading problems on bullets seated out to far. Which brings up headspace; shorter headspace not as forgiving on bullets seated out too far.
Jon

Jon: The barrel brand is Kart. The bullet is seated .035 past the case rim. Headspace on all the Kart barrels that I have is .901-.904 and the chambers have never been recut from the manuf. The cast bullet is an H&G 130.

The Kart chamber must be finish reamed for lead bullets! Their throat isn't lead friendly. Every chamber I've seen not reamed leaded. The .035 is excellent.
Jon

With the head space already setting at .901-.904, would that not give the barrel excessive headspace?

No. Headspace can be cut to nearly those exact dimensions. Most BE smiths build to .905". Jerry is typically less.
Jon

Jon: Thank you very much for the information. I was always under the impression that headspace on a 45 ideally would be .895. I will try this and see if it makes a difference. Thanks again for the info. Maybe I will see you at Perry this year.

For years I ran the guns at .903, now I have several at.898 and I going to give .895 a try very soon. SAAMI spec reamers are, well, SAAMI spec and contribute little to accuracy. After market chambers are too big..and the 45 runs much better with some free bore blending into the lands @ 1& 1/2degrees. Many problems disappear with a well designed chamber.

I'll provoke this subject a little more.Typically, chambers receive very poor attention.
Throw the barrel in a vise , reamer in a tap wrench, and it is cut by hand, if it gets cut at all. No effort to insure concentricity on either  axis. No human can cut the chamber by hand and keep the reamer concentric.. Pilot or no..

+1^

Jerry, do you single point it?

james r chapman wrote:Jerry, do you single point it?

It's not possible with most barrels.. Not enough stock left in the chamber after  manufacture.. KKM usually has the most and a light single point is sometimes possible..The reamer then has minimal material to remove, and if the single point cut is aligned on both the x and z axis, the reamer will cut true to that axis..

Paul, I have a Manson reamer, and you can cut the chamber without increasing headspace. It's cutting the taper of the leade before you start lengthening the chamber. It has a pilot that rides on top of the lands, so maybe not as precise as Jerry does. You can give it a try if you want.

Ralph,  I have a Clymer finish reamer and gave the barrel a touch the other day. I'll go out to the range tomorrow and run a hundred rounds and see if the problem still shows itself. I would also like to thank Jon and Jerry for the suggestions as to what could be causing my problem and for the headspace dimensions.  Paul

All good stuff listed above.

But for little to no cost you could try loading .453" lead bullets and maybe a softer bullet.

FIT IS KING!

Jerry Keefer wrote:I'll provoke this subject a little more.Typically, chambers receive very poor attention.
Throw the barrel in a vise , reamer in a tap wrench, and it is cut by hand, if it gets cut at all. No effort to insure concentricity on either  axis. No human can cut the chamber by hand and keep the reamer concentric.. Pilot or no..

Cutting centered under power after a single point truing pass makes for a beautiful finish.. 70/100 RPM is what I usually turn.


Here the free bore is evident..as is the gentle 1-1/2 degree leade.  The benefit of this can be evaluated by tapping a lead bullet thru a standard chamber
and a chamber done like this, with a wooden dowel. Inspect and compare the surface disruption, under magnification. The scarring and ripping of the lead by the lands of a standard barrel,
is very apparent. I use a bore scope to insure the leade is centered in the groove.. If the Z axis is not true, it can be off..and it's easily seen with the scope.. If the projectile starts
off center,  it never corrects itself from the center of gravity shift that takes place....

A picture or two is worth a thousand words.