Leading in the first area of barrel

[cheese1566]

I am having trouble with two different semi auto handguns that are leading in the first 1/2" of the barrel. No leading past that...

i have tried Lars red carn after thinking it was the magma hard lube I was using. No remedy. I tried various loads that are pretty minimal and mild...no hot stuff. The lead is air cooled sorted clip on wheel weights. I have shot the same lead and lube in my 38, 45acp, .308, and 357. Never had a problem until these two guns.

whats leading in the first section of the barrel generally signal?

[btroj]

Not getting a good seal until into the barrel. Try a slightly larger bullet or maybe go 50/50 WW/Pb.

Years back I had the same issue and I was told by one of the wiser guys who ever perused these pages to overcoat very lightly with LLA to get a seal faster. It worked, and I owe bassakwards for that.

[geargnasher]

"New" semi-auto handguns? You mean ones made since the manufacturers decided it wasn't necessary to cut throats in barrels anymore? If your throat entrance is smaller than your bullet diameter, and your cases aren't centering the bullets exactly, you're likely getting shaving that powders under pressure and follows the bullet down the barrel a short distance before depositing itself in neat little lumps. Make a chamber cast and see what you have to work with, that is job #1.

Gear

[Thin Man]

Geargnasher's comments about no throats in barrels reminded me of a recent problem pistol. It was a S&W Sigma 9mm, very recently made and a one owner. The owner complained about 2 problems. First, the pistol would frequently fail to fire. Second, the slide was the devil to retract when a round was chambered (but not when the chamber was empty). I loaded the pistol and found the slide locked so hard on a cartridge it took excessive force to retract it. I also observed that the slide would occasionally fail to go completely into battery and the striker would not release. The pistol also misfired frequently. Apparently the owner was on target with his complaints. He said it had been like this since he bought it new. After several mis-fires I removed the chambered round and found the forward edge of the case was heavily compressed and shiny at the mouth (was not like this before). The primers had light striker marks, not enough to generate ignition. I removed the barrel and attempted a "plunk" test with various brands of ammo. All rounds stopped in the chamber with an excessive length of the web/groove/rim extending outside the chamber. There was a lot of unsupported web area in this condition. Close examination confirmed there was no contamination, debris, or other foreign matter in the chamber of this barrel. I pulled the barrel out of another Sigma (9mm) for the same test and got an appropriate "plunk" with appropriate depth in the chamber. What this showed me was that the original problem pistol had a barrel with headspace trouble - the chamber had not been cut to the correct depth. The complete pistol went back to S&W complete with a description of all observations, also the comparison against another of their Sigma barrels. They inspected and test fired this pistol, then returned it without making any changes or corrections to the pistol. Their announcement was "it is within our specs." I test fired the returned pistol and found it still had the same problems as before it was shipped back to the factory. Once the owner got it back in his hands, he sold it. As Mr. T would have said, "I pity the fool" who bought this pistol. This pistol is a "kaboom" waiting to happen.

Thin Man

[RobS]

As Gear mentioned a short/abrupt, sharp throat can scrape off small bits of lead for the next boolit to "iron on" into the bore. The degree on how much scrapes off is dependent on the boolit shape. Boolits with full diameter front drive bands extending outside the mouth of the case tend to make this situation worse.

[bhn22]

There's a thread in the handguns section on throating 1911 barrels. I remember opining when it started that having an abrupt throat could likely be the reason my XDs hated cast bullets so badly. I borrowed a throating reamer for my 45s from a gunsmith buddy, and just the difference at the origin of the rifling was worth the effort. The rifling origin in some barrels is just too abrupt, and it seems to cause bullets to cut rifling in the bullet instead of progressively engraving it. One of my 1911 barrels was so undersized that it almost appears that the reamer cut a Taylor throat in it. That sucker is way out of spec.

[milrifle]

I watched a You-Tube video on using a throating reamer in a .45 barrel. Looked easy enough, but is it really that easy? Or can you screw it up big time if you don't know what you are doing? I have two and maybe three .45 barrels that might benefit from using a throating reamer. I could probably buy the reamer and handle for what it would cost to have multiple barrels done. I'm just afraid to do it.

[DougGuy]

If you are not willing to invest in the pilot kit, having the reamer is pointless. It needs the proper pilots to center it in the rifling or it's just a guess whether the throat is in the center of the bore or not. Once it starts cutting it will follow wherever it starts, and if that first half turn is a tad off, the rest of it will follow that. I have the proper tooling and will be glad to help if necessary.

[cbrick]

I would start with sizing a bit larger but without more info it's only a guess. If the leade into the rifling is anything like this photo you do need a throating reamer. While this isn't a 1911 type action (it's my Winchester 94 30-30) it is proof that they do sometimes leave the factory without proper throats being cut. In the photo it's not that the throat wasn't cut deep enough, it wasn't cut at all. The edge is right where the neck of the brass ended and all bullets had to be very deep seated or chambering a round seated the bullet for you.

128855

Photo of this throat taken with a camera on a bore scope. You can imagine the quantity of material this sliced off bullets, both cast and jacketed. A throating reamer turned this into a fine cast shooter.

Rick

[cheese1566]

I didn't want to give too much info on the guns since that in itself leads to long debates of what's "wrong" rather than what the actual problem is. I have experimented with lubes, hardness, adding tin, sizes, in the one gun and it always ends in the same leading in the front of the barrel near the throat. This gun is a 20+ year old beretta 92FS that has had about 5000 through the pipe. The throat and lands are pretty mellow and gradual.
The other gun is a Glock 27 with a factory barrel. ( oh my! Did I say factory?!) yes, I have shot several factory Glocks with lead and no issues. I have shot hundreds of 45acp thru my BIL's Glock using 451 and 452" boolits with hard lube and no leading.

my next step will be back to402" for the glock 27 and .357 in the beretta with some other lubes coming in a pending trade deal.

Maybe be powdercoating would be my best bet.

[bhn22]

Fire lap the barrel if you're apprehensive about reaming it. The idea is to make the approach angle of the rifling origin a little gentler on the bullets.

[milrifle]

My wife's XDS has no leade whatsoever. The rifling starts full depth right at the end of the chamber, or at least that is the way it looks. It used to lead like a son of a gun, but got better after shooting a few plated Berry's bullets through it. I'd still like to open it up some so I don't have to seat bullets so deep. My XD looks almost as bad, but it doesn't lead and will take a longer OAL and still 'plunk'. Think I will get a gunsmith to do it rather than trying it on my own.