Leading in the first 4 inches of carbine barrel

[gvanzeggelaar]

Good Day Folks.

Hoping to get some onsite into some leading issues I have been having. I have shot thousands of rounds through various 9mm handguns and carbines and have never been more than a bore snake away from a clean barrel.

I tried a new bullet out. The lee 124gr TC with a bevel base. LLA or Hi-Tek it leads the first 4” of my Carbine something awful.

So here is what I am dealing with.

CZ Skorpion Evo with 18.5” barrel
Lee 124gr as cast. About .356-.357 LLA or Hi-Tek
4.0gr of bullseye
Alloy. Range Scrap

Taper Crimp

I suspect the bullet may be too small and the rifling is stripping the bullet.

Would a slower powder be the ticket? Odd that it is just leading the first few inches of the barrel

[Wheelguns 1961]

Does it lead with other loads?

[Dusty Bannister]

CZ Skorpion Evo with 18.5” barrel
-------------
Groove diameter?

Lee 124gr as cast. About .356-.357 LLA or Hi-Tek
-------------
This tumble lube bullet does not have a strong reputation for not leading.

4.0gr of bullseye
-------------------
Upper end for bullet weight. Bullet actual diameter and is it seated into the lands or short of the lands. A longer throat designed for a heavier bullet will give excessive bullet jump. What is the max cartridge OAL for the bullet of your choice that will chamber? Dusty

[gvanzeggelaar]

I probably should do a chamber cast. I will get back to you guys with groove diameter

[sigep1764]

I am pretty sure that boolit has a long body that needs either a deep enough case expander to seat deep or a generous enough throat to seat it out longer. The Lee 120 TC lube groove boolit might be a better choice. Accurate has a nice copy of the Lyman 356402 called the 35-120B that can be had in 5 cavity. It has a longer nose moving some of the weight out of the case.

[winelover]

I have access to a Hawke Bore Scope. My CZ scorpion gets minor leading, in the first couple of inches, also. The leading disappears when I switched to gas checked bullets. Had a bunch of PB 120 TC's already cast, installed aluminum PB checks.

Also have a Lab Radar unit and velocities out of the carbine are 200-300 faster than out of pistols. I have recorded some loads, just under 1500 fps...............treading on gas check ground.

BTW, I'm sizing to.358 diameter and using Carnuba Red for a lube.

237306

Winelover

[Wayne Smith]

Generally leading at the beginning of the barrel indicates a boolit too small. Leading at the other end of the barrel suggests running out of lube.

[winelover]

Tried .359 bullets, also, same result. Any larger and they won't chamber, due to case bulging. Gas check designs are my only option, unless I want to clean barrel, more frequently.

[gwpercle]

Generally leading at the beginning of the barrel indicates a boolit too small. Leading at the other end of the barrel suggests running out of lube.

Wayne nailed it . That boolit is small and range scrap is soft....it takes 4 inches for the boolit to slug up. Bevel base isn't a big help either.

Try a .357 sized boolit if you have a mould and throat that will accept it.
I have a sneaking hunch the larger boolit will do the trick .
I use that same Lee 124 gr. TC boolit , cast softish and sized .357 , in my Walther P38 w/ generous throat and bore , with great results.

To really solve the leading problem I ordered a 124 grain TC - Gas Check mould from NOE . I use the softish alloy GC boolits to load 9mm Luger, 38 Special and 357 Magnum, all with no leading...best mould I ever bought .
Gary