Shot my first cast reloads today.. little issue

[bsctov]

I seem to be getting excessive leading on the chamber throats, and as a result it binds up when I try to pull the trigger for the next shot. Is it just a gun/bullet issue? or is it something I'm doing wrong.

It's not an issue of the bullets backing out from recoil, as I tried rounds that have not yet been inside the gun, and still the same problem occurs.


It's extreme bullets .38 special 158gr cast LSWC on 4.6gr of CFE Pistol @ 1.475in with a tight roll crimp.

Primer: Winchester Small Pistol
Brass: Mixed Headstamp X-treme brass
Powder: Hodgdon CFE Pistol

Probably around 1000 fps

X-treme bullets .38 158 LSWC

 

[loose noose]

What type of gun, and what are the velocities you are loading the cartridges. Or at least what are the components you are using to reload what caliber?

 

[LiveLife]

Glen Fryxell's ebook has an excellent chapter on issues related to leading as to cause/prevention/removal, especially for revolvers - http://www.lasc.us/Fryxell_Book_Chapter_7_Leading.htm

 

[redbullitt]

That sounds like bad leading... definitely not something that should be happening or that I see in mine.

I would look into bullet fit first. What does your bore and chamber measure? Might be a good idea to slug it. Whats the actual diameter of the bullets? .01 to .02 over bore size usually works well in pistols. Sometimes your chamber ends up being smaller than bore... that can be annoying.

How is the timing on the revolver? Could you be shaving lead?

 

[bsctov]

I have updated original post to add more info, its a Ruger SP101.

 

[rcmodel]

Perhaps you are over-crimping and wrinkling the case to the point they don't drop in all the way in freely?

Also, clean under the ejector star with an old toothbrush.
Unburned power under the ejector can hold the round up far enough to make cylinder rotation difficult.

rc

 

[bsctov]

they drop in freely, just like factory ammo, with a satisfying *Thunk*, the star is pristine,

 

[mdi]

Measure! Measure the bullets. Measure the cylinder throats. Best starting point is both bullets and throats be the same diameter. If the bullets are much larger than the throats, the throats will swage the bullets down and often spews lead out of the cylinder gap. But, for such severe leading, something is definitely not fitting. Mebbe the bullets are way undersize (like .355"-.356") and gas cutting leads the throats/cone.

 

[moxie]

Probably closer to 850fps.

Are you sure it's lead? It could be lube.

You say it's on the chamber throats. Do you mean on the cylinder face? Simply "in the throats" won't bind the cylinder. Something has to be on the cylinder face hanging up on the forcing cone.

What is the OD (outside diameter) of the completed rounds at the case neck, measured with a caliper?

 

[bsctov]

It's in the throats I beleive, but I'm not sure really, I checked the forcing cone gap and it still looked clear, and it didn't happen when I shot my XTP loads.

 

[TimSr]

Have you shot other ammo through this gun? I cannot mentally connect leading from cast bullets to depositing anywhere that would keep a cylinder from turning. I think something else is going on.

 

[Sunray]

Lose the crimp. 4.6 of CFE is a tick below minimum(only .2 of a grain. No big deal. Start load of 4.8 runs at 960 fps.), but you really do not need a crimp, of any kind, for .38's out of a revolver.
Very much doubt you have a leading issue either. Certainly not enough carbon build up with a few rounds. As mentioned, leading in the throat won't cause any issues.

 

[Reefinmike]

I'd guess poor bullet to gun fit. what do the bullets measure? measure your chamber throats, do bullets(just the projectile) freely drop through the cylinder throats, or are they a snug (proper) fit?

if your throats are over sized for the bullet, you will get gas blowby/gas cutting that will deposit lead spatter on the face of the forcing cone which could be leading to your problems.

 

[blarby]

About the only thing I can think of, given the description, is low pressure primer backing.

Severly underpressure loads can cause primers to back out, making rotation of the cylinder difficult.

Only thing I can think of that could actually cause cylinder rotation issues. short of an obstruction of some sort out the chamber and into or between the chamber and barrel.

Can you check your primers for us ?

 

[bsctov]

My apologies, I was looking at the wrong load label.


The rounds in question are as follows:

Bullet: X-treme 158gr LSWC measure (.357 caliper confirmed)
Case: Mixed brass (X-treme)
Primer: Winchester Small Pistol
Powder: Hodgdon CFE @ 5gr
OAL: 1.475

Measurement at crimp/case neck: .371 in
Primer: Slightly below flush

 

[bsctov]

It's a strange problem, because when this occurs, just looking at the gun, there isn't anything that appears to be binding up the works, and when I put the lead cartridges in, the same problem occurs, but with the XTP loads, it was smooth sailing.

This occured even when I inserted cartridges that had not been along for the ride, so to speak, when being fired.

The rounds definitely do not protrude out far enough to bind the cylinder in that manner. Stumped here


everything worked fine until the gun got a little hot and dirty, and even then, as mentioned before, it functioned flawless with my xtp loads.

 

[blarby]

Hmm...

So, just putting the cartridges in makes the cylinder not rotate ?

 

[bsctov]

They shoot and rotate beautifully until the gun gets hot/dirty.

 

[BSA1]

Measure the barrel / cylinder gap. As stated leading inside the chambers will not cause binding. However binding is not uncommon with tight b/c gaps when shooting lead bullets due to lead build up on the front of the cylinder. I personally like a b/c of .006 - .008".

 

[bsctov]

How would I go about measuring that gap? Also, what can I do to reduce leading?

 

[Walkalong]

Feeler Gauge

 

[Walkalong]

The alloy has to be hard enough to grip the rifling without skidding at the velocity you are shooting. The alloy has to be soft enough to bump up from pressure to seal the gases from flame cutting the bullet as it passes through the throats and barrel. The pressure must be high enough to bump the bullet up.

If your throats are .001 or .002 above bore diameter, your bullets fit your throats, and the alloy is hard enough to grip the rifling on its journey while being soft enough to bump up and seal everything, it won't lead at all.

Nothing to it, right?

Undersized bullets, unless they have enough pressure to bump up and fill the bore, will cause gas cutting and leading when the hot, high velocity gases "cut" lead off the bullet on its way between the bullet and the throat and/or barrel. Leading will be mostly at the throats and forcing cone, but will continue until it fills the whole barrel if you keep shooting the offending load.

Properly sized bullets that fit the cylinder throats will generally not suffer from gas cutting unless they are too soft/too hard.

Bullets that are too hard will not bump up and seal the throats and barrel well, even when sized properly, causing leading.

Bullets that are too soft to hold the rifling at the velocity they are driven at, will break loose from the rifling and "skid", breaking the seal and causing leading galore all the way down the bore.

If the bullets are sized properly, you can get away with them being a little harder than needed.

If the bullets are soft enough to bump up easily with the pressure used, you can often get away with them being a hair undersized, as long as they are hard enough to hold the rifling for the trip down the bore.

Hmm....did I miss anything? Probably.

Oh yea. Bullets that do not have enough, or good enough, lube, will tend to lead towards the end of the barrel.

 

[blarby]

I think you caught it all, Walkalong.



I really misunderstood the problem, no matter how many times I read it.

 

[moxie]

Probably has nothing to do with this problem, but I notice your OD at the case mouth is .371". That is one hefty crimp! Normal OD should be in the .375-.378" range.

Also, you state, "They shoot and rotate beautifully until the gun gets hot/dirty." Have you pulled the cylinder out and given the ejector rod, etc., a real thorough cleaning? Perhaps there's some gunk in there that binds things up when it gets hot. I know gunk on the ejector rod can bind a Security Six.

 

[BigBore45]

i'm going to go with undersized bullet and a dirty gun.