Leading at the Forcing Cone

[gazpacho]

I'm loading .45 Colt 250gr Lead Flat Point Oregon Trail Laser Cast bullets into Winchester Brass with 7.0gr Win231 and Win LP Primers. No indications of over pressure on the brass or the primers, and no measurable bullet pull on the 6th loaded round after firing the first five (RBH 4.5"). After 50 rounds the barrel cleaned up fine with a single pass of a bore snake, except for the forcing cone, which was heavily leaded.

Can anyone explain the reason for this? How serious of a problem is this in terms of shooting pressures, etc.?

 

[HSMITH]

Cylinder throats not matched to the bullet size is my guess. Are the bullets you are shooting sized .452" or .454"?

Take a bullet and drop it into the cylinder, if it takes more than two fingers on a pencil to push it through the cylinder mouth the mouth is too tight for the bullet. Your Ruger should have a .451" bore, so .452" sized bullets should be the right ones but .454" bullets in light loads should shoot just fine. If the bullet just falls through the cylinder find some larger bullets.

Unique is a better choice for 45 Colt and lead bullets. Pick up a can next time you are at the gun shop. Leading is less in all cases I have seen than comparable powders including 231.

 

[ghostrider07]

I have seen this several times before and what I believe is happening is, the bullet is accelerating as it makes the jump from the case to the rifling. When it encounters the rifling, the bullet's momentum resists the rotational effects the rifling is trying to impart, so the bullets actually strip the lands for that first 1/2" until the bullet starts rotating. I had an 1894 Marlin with the microgroove barrel, and with my Redhawk loads of a 240 grain SWC HC over 24.0gr/H110, it would lead the entire length of the barrel, just on one side of the grooves. It was stripping the lands for its entire journey down the barrel. Right off the top of my head, your pressure should be fine for your bullet hardness, but I'm still with Mr HSMITH, there, I would try a slower burning powder than 231, maybe AA #5.

 

[brickeyee]

You can also check the forcing cone for tooling marks from being cut. If there are any they tend to be circumferential and catch lead very nicely. They can be polished out if present. The cone should have almost a mirror finish.

 

[Quantrill]

I once saw the same condition on a Colt used in PPC. What finally cured it was a trip to a GOOD gunsmith who rereamed the forcing cone. Quantrill