Case inspection questions

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djcantr

New member
I recently worked up a load for .40 S&W major. My goal was 960fps to make major with a little cushion. These are fired out of a Glock 35.

Load fired today:
180 grain MG JHP
CCI SP primers
4.7 grains Titegroup
1.135" OAL
.420" crimp

I tried working up to 4.6 grains but velocity was around 920fps. I loaded up some with 4.7 grains. I got velocities from 950fps to 1000fps today. I shot 20 rounds. I took the cases home for a little more detailed inspection. One case split. Almost all of them have a mark at the mouth of the case. Looks almost like a file swiped the case at the case mouth. The grain of the mark wasn't running the length of the cases but around them. The 4.6 grain load didn't do this. I shot some factory ammo at a match between the 4.6 and 4.7 grain load testing. I can't see anything wrong with the chamber. I've posted some pictures below. Thoughts?

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D

djcantr

New member
Upon further inspection of my 4.6 grain cases, they do have that mark. The mark is much less noticeable, though.
 
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1stmar

New member
Primers don't look right, looks like some cratering. How many x those cases been reloaded? Are you sure they were 4.7 gr? Id go back and check. I'd also look at your chamber see if something is making that mark.
 
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D

djcantr

New member
I'm as sure as I can be on the 4.7 grains. I knew I would be getting up there in pressure so I was quite careful. I adjusted the micrometer charge disk on my Lee Pro Auto Disk. I got it to where I was pretty certain it was throwing right at a 4.7 grain charge. Every charge I weighed was 4.7 grains on my Frankford Arsenal digital scale. I verified the weight with my Dillon balance beam scale. Then I threw ten charges and weighed them on the digital. 47.3 grains. Checked it with the balance beam and it was the same. Did that a couple times. I threw ten charges with shaking the powder measure as much as I could to ensure the powder didn't have a way of compacting to get a heavier charge. I got 47.4 grains and 47.6 grains. I was really shaking it and trying to get the powder to compact. My press doesn't shake the powder measure nearly as much as that when I use it. So, I'm fairly certain I was really close to 4.7 grains. Most the charges could have been was 4.76 grains.

The cases were range brass. Not sure how many times they were loaded. The case that split was one of my own once fired cases.

I looked at the chamber and couldn't see anything. There is a little bit of fouling where the case split, but I got most of it removed. You can just see a faint fouling line that matches the shape of the split. No gouges, scratches, etc in the chamber.
 
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1stmar

New member
You always get that rectangular mark on the primers? If the marks on the case didnt come from the chamber it may be coming from the inside of magazine. You may want to remove the spring and clean the inside of the mag. I believe glocks use a polygonal barrel, 4.7 gr is max load, you may get higher pressure in a polygonal bore. I think the primers show signs of high pressure. the split case could be from pressure or a combination of pressure and whatever is causing that wear mark. I'm guessing it's pressure.
 
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djcantr

New member
I always get the rectangular marks on the primers. It's from the striker channel in Glocks. I have thousands of .40 S&W range brass and I can always spot the ones fired through Glocks by the rectangular mark in the primers. Well, that and the bulged bases. I use a Redding G-RX die to resize before I load them.

I need to shoot some factory .40 S&W through this pistol again to see if I get the same marks on the cases. I took apart the magazine I used and found nothing out of the ordinary.

The primers aren't flattened any. What signs of high pressure are you seeing? Not challenging you on your evaluation, I'm still fairly new to reloading and am wondering what you're looking at.
 
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djcantr

New member
Lee Pro Auto Disk. I use a Frankford Arsenal digital scale and verify with a Dillon balance beam while setting the micrometer disk and occasionally while loading.
 
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1stmar

New member
Are you possibly over belling the case? Once fired that's would have to be a lot of pressure, seems unlikely. How did they feel? Stiff?
 
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Gerry

New member
Doubtful the split case was from pressure. A case can't expand more than your chamber dimensions no matter what the pressure. Looks like a brittle case to me. Once fired? I donno about that.... but stuff happens. The primers look fine to me. The elongated strikes are weird, but then again I'm not a Glock guy :p

The marks on the case mouths could be caused during ejection.
 
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djcantr

New member
I'm not belling the case too much. It's not visible. I'm just barely belling enough to get a bullet to sit on there. I have to hold my mouth just right to get the bullet to not fall over on the case. I should probably bell just a touch more, actually.

They felt fine firing them. Just about like factory ammo. Next time I ought to alternate factory and these reloads in the mag so I can compare them.
 
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rajbcpa

New member
I can't add much to this.

However, I got 1K of this once fired brass and about 5% would not chamber and the problem was at the base of the cases. Upon further inspection, the brass had bulged.

I now run all these type cases through a Lee Bulge Buster die and now all the rounds chamber corectly.

I did not realize that Glock cases have that distintive primer strike mark. Since these often have unsupported chambers, this fact is good to know. That way, you can tell which cases have been fired using a striker and which are probably Glock fired.
 
S

Sevens

New member
The marks on the side/mouth are of no concern, they come from getting dinged on the way out of the gun during ejection. I see them often, I don't give them a second thought and by the time they are loaded again, I either can't see/find them, or I don't care. They don't affect, well, anything, IMO.

The powder choice is BAD and is the limiting factor. Listen to WESHOOT2 as he knows. Titegroup is extremely fast and works best in small volumes at target ranges. You are using a heavy-for-caliber bullet and you are running a HOT load and this is precisely where a powder like Titegroup gets dangerous.

Power Pistol is better suited for this role, but will likely give you more blast, flash and recoil, none of which is what you want MORE of for competition...but if you want to run heavy bullets fast and you want to do it safely, you've got to pay the dues.

STOP running Titegroup this hard in .40 S&W unless you want to be part of the "don't let this happen to you" crowd.
 
N

Nathan

New member
I would measure the diameter of 10 bullets. Maybe something is off there.

I've picked up a lot of Glock 40 S&W brass. It never had the square mark as far as I know. It did have drag marks and your drag marks are about right for a max or near max load. Maybe the square marks are the next level of hot. Also, Glock's are famous for oversized chambers. Maybe it is time for a chamber cast.

Last, the crack seems to have stopped where the brass was "Glocked". . .weird.:confused:
 
M

Malaph

New member
Hey there,

Those "file marks" at the case mouth I get those too on my Glock 22.
Just a remark the amount of crimp you're using could be excessive in addition to the comments about the powder choice being too fast.

SAAMI specified maximum = .423
Tightest I've seen suggested = .421

From what I've read elsewhere I think a slower powder might be the answer though.

Safe shooting all
 
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