Bulging .40 cases

[bigedp51]

If the true Glock bulge is resized the case will deform and blow out at the weakened point at the base.

I still run all my .40 S&W range pickup brass through a Lee bulge buster. This is like using a small base die and returning it to minimum SAAMI dimensions.

I also bought a Lee 9mm makarov carbide factory crimp die as a bulge buster for 9mm. "BUT" it reduced the rim diameter .002 and none of the range pickup brass benefited or needed this treatment.

 

[BLUEDOT37]

SAAMI has chamber dimension specifications but that doesn't mean some aren't looser than others. As I mentioned in my previous post, my Ruger has a much tighter chamber than my 4013TSW and it chambers just fine without bulging the cases. My 4013TSW measures out-of-spec and I could not get S&W to answer my question as to whether their chambers are supposed to meet SAAMI specs....

One of the things I do with any new/used purchase is to go thru it & document clearances/dimensions. I too noticed my 4013TSW & 4056TSW pre-rails have noticeably larger chamber openings (the case head end) at .438" & .437" respectively using pin gages. Much larger than my 4006, 4013, or Shorty 40, at .429", .430" & .429" respectively.

Maybe by the late 90's, when these were made, those good reamers from the early 90's were all worn out.

That said, I've never experienced any negative side effects from it with mine. I see SAAMI specs are .4284" +.004".

.

 

[427mach1]

One of the things I do with any new/used purchase is to go thru it & document clearances/dimensions. I too noticed my 4013TSW & 4056TSW pre-rails have noticeably larger chamber openings (the case head end) at .438" & .437" respectively using pin gages. Much larger than my 4006, 4013, or Shorty 40, at .429", .430" & .429" respectively.

Maybe by the late 90's, when these were made, those good reamers from the early 90's were all worn out.

That said, I've never experienced any negative side effects from it with mine. I see SAAMI specs are .4284" +.004".

.

Those dimensions look similar to what I measured and I haven't noticed any side effects, either. My 4013TSW was very early in the TSW production, November 1996 and I don't know if they used the same reamers as the earlier, non-TSW chambers. With TSW production going through 2005, I would think they would have replaced worn out reamers at some point as they aren't that expensive! I think they intentionally ran the chambers big on the TSW.

 

[hdwhit]

Thank you for the photograph bigedp51.

My concern with "Glocked" brass, whether or not a Bulge Buster die is used or not, is that the brass was stretched out and thus made thinner in the unsupported area and that thinning cannot be uniformly restored by simply applying conpressive force from outside the case.

That's why I measure the case diameter of all brass just above the head and discard those cases that exceed SAAMI maximum dimensions.

The way I look at it, 9mm, 40S&W, 45ACP are all common enough and cheap enough that I'd rather throw out 25% of an order of brass than take my chances being maimed by a Kaboom.

 

[bigedp51]

Thank you for the photograph bigedp51.

My concern with "Glocked" brass, whether or not a Bulge Buster die is used or not, is that the brass was stretched out and thus made thinner in the unsupported area and that thinning cannot be uniformly restored by simply applying conpressive force from outside the case.

That's why I measure the case diameter of all brass just above the head and discard those cases that exceed SAAMI maximum dimensions.

The way I look at it, 9mm, 40S&W, 45ACP are all common enough and cheap enough that I'd rather throw out 25% of an order of brass than take my chances being maimed by a Kaboom.

If you do not know what the case diameter was before it was fired what you are doing could be over kill. At the Brian Enos's Forums many of the competitive shooters use range pickup brass. They load these cases until they split or have over sized primer pockets.

And most reloaders use their rifle brass until they have over sized primer pockets or a cracked neck. And rifle calibers are loaded to much higher pressures and we use small base dies to size the base more just like a bulge buster die.

Base diameter after firing is used to judge pressure, "BUT" the amount the base expands depends on the hardness of the brass. I have had factory loaded Federal .223 cases with over sized primer pockets after the first firing.

If your resized case pass a "plop" test in a case gauge the case is not over sized.

 

[NJM15]

Update

Recently I have noticed some bulging about 3/16" above the rim
I am using starting loads , 155 gr Extreme lead, usually power pistol, stock barrel.
I have found bulges on range brass fired by early gen Glocks but never noticed it on my fired rounds. the only thing I can think of is having too tight crimps increasing the pressure.
any other ideas ?
thanks

The only different thing I did was increase the crimp, so I went back to a lighter crimp and the cases have only a very small bulge just above the rim that was always there. they run through the buster with little or no resistance. I don't know if that is feasible or not but it worked for me. the moral of the story is leave everything the way it is if it works, experimenting can lead you in a different direction. I will try to post pictures if I can get a good close up.

 

[pdg45acp]

Sorry,
forgot to say I am shooting a S&W M&P 40
I have the Lee .40 bulge buster and never felt much
resistance pushing one through as I have recently.
I have a storm lake ported barrel I will try next time to eliminate that possibility

I'm using the bulge buster also. It works. The only thing I worry about is weakening the brass at the point the bulge was swaged back. I toss brass that has been through the bulge buster after the 4th loading.

 

[Dennis]

As a side note;
My brand-new Shield 9mm shows the same bulge on brand-new IMI 115 gr. EX-STAR rounds.
Maybe the rnds are a little hot for the Shield.
Gonna sell the Shield when I get around to it anyway.

 

[rwsmith]

Seating depth.....

Seating will raise pressures very quickly if seated to deep. Crimp MAY raise the pressure a little in a bullet crimped over the shoulder (revolvers) but nowhere near as much as too deep seating will.

 

[bigedp51]

Looking at the SAAMI chamber and cartridge drawings you can have .0114 difference between maximum chamber diameter and minimum case diameter above the extractor groove.

I do not have any .40 S&W photos but below is a example of case base diameter.

Below are two .303 British cases fired in the same Enfield rifle. The Greek HXP case on the right is a smaller diameter than the Prvi Partizan case. And the HXP case had further to expand to meet the chamber walls and "bulged" more when fired.

The Prvi Partizan case has a larger base diameter and is .010 thicker in the base area and did not bulge. Meaning case construction and its base diameter governs how much the case can bulge when fired.

Bottom line, if your cases are at or near minimum SAAMI diameter you will see more bulge around the entire base of the case. And measuring the cases with a vernier caliper will give you more information.

When the OP said he pushed these cases through his bulge buster with little resistance it tells a story. If you have a fat chamber and skinny brass you will have a bulged case. And if for some reason you have higher than normal chamber pressure it will increase the amount of bulge.

 

[hdwhit]

bigedp51 wrote:
If you do not know what the case diameter was before it was fired what you are doing could be over kill.

I acknowledge that I'm erring on the side of caution.

It is not necessary for me to know the "before" diameter of the case. If the brass is larger than SAAMI maximum for the case diameter at the head, it has stretched beyond its elastic limit. And that means it has stretched by a greater amount than I care to deal with.

At the Brian Enos's Forums many of the competitive shooters use range pickup brass. They load these cases until they split or have over sized primer pockets.

So?

Pistol cases that aren't oversize at the head enter my reloading stream and are reloaded and shot until they split or are lost in the weeds.

Apart from saying that some anonymous shooters on another forum apparently don't measure their cases before putting them into their reloading streams and then do exactly the same thing that I do, I fail to see your point.

And most reloaders use their rifle brass until they have over sized primer pockets or a cracked neck.

Again, whether someone uses a case until the neck cracks has nothing to do with whether the case is expanded at the case head.

Rifle cases that aren't oversize at the head enter my reloading stream and are reloaded and shot until they split at the neck, have loose primer pockets or are lost in the weeds. Most are lost in the weeds before their fifth firing so I rarely encounter any neck splits with rifle cartridges.

But, I think you miss the point of the process. It has nothing to do with how long brass is reloaded, it has to do with the dimensions it has when I first receive it.

As indicated in the post you take issue with, I am familiar with the Lee Bulge Buster die and the concept of its operation. Because of the thinning of the case wall that occurs when brass is stretched more than it should, I do not believe that conventional resizing or the Bulge Buster is a reliable, safe approach to dealing with oversize cases. I measure them using SAAMI maximum as the maximum amount of deformation acceptable to me. Any brass fired in an unsupported chamber (i.e. Glocked brass) will not pass this test. Brass fired from an open bolt will likely not pass the test. Other cases fired in abnormally loose chambers likewise will not pass the test.

I've been reloading for 38+ years and have never had a case-related failure, so if proceeding out of an abundance of caution keeps me and my guns safe and intact, it seems a small price to pay.