Chamber Shearing

[thx997303]

It's possible fire or hand lapping the throat could fix that problem.

[lwknight]

Is the leading something I have to live with until I can get a different gun?

You can beat the leading in most guns. Some are just more persnickety than others. Some just don't want to lead at all unless you shoot under sized bullets in them.
I bet that once you isolate the problem , the fix won't be all that difficult.

[BulletFactory]

This thing is really ing me off.

I've been trying to get the lead out since October. I have become really quite good at cleaning the barrel though. Should have picked "Edison" for my screen name.

[243winxb]

243,

Explain to me exactly HOW an oversized boolit caused the damage to those barrels please.

I've seen damage like that attributed to cast boolits several times, and it looks more like a pressure issue or slide battering to me.

Also, what kind of gun did those barrels come out of?

Link to thread & photos > http://castboolits.gunloads.com/show...amber+1.089%22 Over pressure is my guess. Shooting bullets that were very large in diameter, not sized. Do you think a lead bullet .008" larger than the groove will increase pressure? I do.

[dla]

I hate to be a party pooper but that lead IS TOO SOFT FOR THE PRESSURE! It is turning into a putty ball before leaving the case.
How in the world do you start with 8.7 BHN and go to 29.9 with water dropping? Something is not right!

Bingo! That is 1st problem. That is way soft for .40S&W. The 2nd problem looks either (a) you aren't flaring the casemouth enough or (b) your taper crimp die is set wrong (based on the picture).

[BulletFactory]

I am now at 13.4

The shearing isn't being caused by the case. The crimp is as such that it won't swage the bullets, but it gets hold of the bullet well enough that I can do a BHN test on a loaded round. That tells me that it can hold to at least the 60 pounds the BHN test requires.

[BulletFactory]

That's what happened to mine! Now, why did that happen?

[BulletFactory]

Why would they NOT have replaced the recoil spring assembly though?

I loaded up 25 today with 7.3 gr, sized to .403 or so, and lubed with LLA only. Still had leading, but it seemed to be concentrated towards the muzzle more. Still at 13.4 BHN, should I try to go harder?

Tomorrow, I'll loas another set at 7.3, 13.4 BHN, and try the BAC lube and a coat of LLA, while sizing to .403.

I'm still having a noticable buildup of lead on the chamber area where the cartridge mouth headspaces from after only the 25 rounds I shot today.

[462]

BulletFactory,
When experimenting, make only one change per session. If you change both the lube and boolit's size, and get the result you are looking for, which of the two produced the result?

Muzzle leading is an indication of a poor lube for the job.

[truckboss]

bullet fac.,are shooting rounds like the one you have pictured?if so you do not have your cases expanded enough.i can see alot of lead at the case mouth.this should be very clean,you should be able to,with barrel out of gun,put the round in the chamber and have a little wiggle room.also try reducing your load,seat the bullet bout .020 or less out of the case, and like someone said before try one thing at a time.what others have said about bullet hardness i would have to agree on.good luck,let us know how it works.

[BulletFactory]

No, I'm shooting these now.

[243winxb]

http://www.saami.org/PubResources/CC...40%20SandW.pdf If you look at the chamber drawing, you will notice the minimum throat diameter is .401" Your cast/sized bullet at .403" is to fat. Causing shearing of lead as the round chambers.To fix the shearing, seat the bullets deeper, shorter COL, Or size them to .401" Your 2nd problem-BHN is to low, you need at least 16 or more, with tin if air cooled. Your 3th problem is lube. Fill the grease grooves of the bullet.

[thx997303]

Link to thread & photos > http://castboolits.gunloads.com/show...amber+1.089%22 Over pressure is my guess. Shooting bullets that were very large in diameter, not sized. Do you think a lead bullet .008" larger than the groove will increase pressure? I do.

Re-read that thread, you will notice that I posted in it.

Also note that the general consensus was that the owner of the pistol hadn't changed his recoil spring often enough.

Will oversized lead boolits break a barrel? Not if the load is worked up properly.

[243winxb]

Re-read that thread, you will notice that I posted in it.

Also note that the general consensus was that the owner of the pistol hadn't changed his recoil spring often enough.

Will oversized lead boolits break a barrel? Not if the load is worked up properly.

I think he used Berry"s plated bullet for 2 years without a problem. When he started casting, he broke 2 barrels. Why? Your guess is as good as mine. The 40 is a high pressure round, may not take much to push it over its limits?? This guy, bullet factory, also has broken a barrel.

[BulletFactory]

I'm sure that I had gone over limits though, I was reading the wrong chart.

However,

The breakage happened several hundred rounds AFTER I had identified the overcharging mistake.

[thx997303]

I think he used Berry"s plated bullet for 2 years without a problem. When he started casting, he broke 2 barrels. Why? Your guess is as good as mine. The 40 is a high pressure round, may not take much to push it over its limits?? This guy, bullet factory, also has broken a barrel.

Battering due to a weak recoil spring. Very simple.

Aside, overpressure rounds don't break off a locking lug unless shot frequently, overpowering the recoil spring, causing battering.

I don't believe for a second it's due to cast boolits.

[BulletFactory]

I didnt think it was the lead, but the loader.

[BulletFactory]

http://www.saami.org/PubResources/CC...40%20SandW.pdf If you look at the chamber drawing, you will notice the minimum throat diameter is .401" Your cast/sized bullet at .403" is to fat. Causing shearing of lead as the round chambers.To fix the shearing, seat the bullets deeper, shorter COL, Or size them to .401" Your 2nd problem-BHN is to low, you need at least 16 or more, with tin if air cooled. Your 3th problem is lube. Fill the grease grooves of the bullet.

I thought I was supposed to size +.002. When I sized them at .401, I got really heavy leading throughout the length of the barrel.

I thought BAC lube from white label lubes was supposed to work in a .40.

[lwknight]

Generally speaking , I think that SWC style bullets are not exactly ideal for autoloaders anyway. I do well with hard bullets ( 15bnh or better ) in my 9mm and I think that the 40 should be about the same.
Revolvers are just so much more forgiving when everything is right.

[BulletFactory]

I know, but I don't like to carry outdated weaponry with inadequate capacity.