Had to do a double take.

[DizzyJ]

When I saw these on the floor. 9mm fired cases.

Figured out the answer, but thought it might be a thought provoking question for you guys.

These were not "hot" but they were the top of the load range being tested at that time.

Any guesses as to what you're seeing?

Read More

 

[po18guy]

Hi-Point blow back rounds? Correct chambering? 9 won't go into 380, or parts of the gun would likely still be there if it did.

 

[Member 34319]

Something to do with the Bullet canulure?

 

[Stomper]

It looks like a machined square-cut groove turned on a lathe….

 

[Nosferatu]

.357 Sig fired in a .40 S&W

 

[Ura-Ki]

9 mm fired in a .40/10 mm pistol?

 

[DizzyJ]

All good thinking. These were the aluminum 9mm cases I reloaded and tried out. At first I thought it was the beginnings of head separation, but it never got worse among the top three loading steps.

Then I remembered reading about a "stepped" chamber in the Walther PDP. A quick google search showed pictures of the very same thing in brass casings fired out of a PDP chamber.

Thought it was quite interesting.

 

[ageingstudent]

All good thinking. These were the aluminum 9mm cases I reloaded and tried out. At first I thought it was the beginnings of head separation, but it never got worse among the top three loading steps.

Then I remembered reading about a "stepped" chamber in the Walther PDP. A quick google search showed pictures of the very same thing in brass casings fired out of a PDP chamber.

Thought it was quite interesting.

What is it about the shape of the chamber that makes them fire form like that? Can you see it with the flashlight or a borescope?

 

[DizzyJ]

What is it about the shape of the chamber that makes them fire form like that? Can you see it with the flashlight or a borescope?

I might have to take a look when I get a chance. My guess is it's literally a "step" in the chamber. I believe I read somewhere it is done to create better accuracy but don't quote me on that.

 

[Certaindeaf]

Looks like it was done to increase lock time.

 

[DizzyJ]

Looks like it was done to increase lock time.

Interesting.

 

[DizzyJ]

 

[po18guy]

No points for guessing the cause of these odd case markings.



What is it with "German engineering"? OK, technically Spanish, but the point remains.

 

[Certaindeaf]

No points for guessing the cause of these odd case markings.

View attachment 1133561View attachment 1133560

What is it with "German engineering"? OK, technically Spanish, but the point remains.

Remember the VP70Z where they purposely cut the rifling so deep the blow by effectively increased "lock" time (it was a straight blowback).
oof

 

[arakboss]

Looks like you have a cannelure for the next reloading.

 

[DizzyJ]

No points for guessing the cause of these odd case markings.

View attachment 1133561View attachment 1133560

What is it with "German engineering"? OK, technically Spanish, but the point remains.

Fluted chamber for reliability. And when fired out of a loose chamber they're a real B to resize!

 

[osprey]

As a reloader I could not abide by the Hk91 I had for awhile. Between the fluted chamber and just being generally hard on brass I settled on the Fal and never looked back.

 

[osprey]

Don't get me wrong though , the HK is one hell of a battle rifle and would serve that purpose very well.

 

[Ura-Ki]

As a reloader I could not abide by the Hk91 I had for awhile. Between the fluted chamber and just being generally hard on brass I settled on the Fal and never looked back.

I have a couple of the Century built stainless barreled CETME rifles with out the fluted chambers, sure makes them run nice with out mangling my brass! I got them as cheap and reasonable rifles to pass off to those who needed and didn't have! Complete with a couple of 5 gallon buckets of $1.00 mags all loaded with surplus M-80! Bought them from Keith's back when there was a rush on AR type rifles, nobody cares about these or the pile of FALs in the racks next to them! Bought a couple of those as well and never looked back! Shot them each to function check cleaned and packed in grease with 12 loaded mags each, and forgot (not really) where I stashed each one!

I much prefer the FAL over any other semi auto but beggers can't be choosers when SHTF, so I got these stashed all over the place for everyone else!

 

[CLT65]

As a reloader I could not abide by the Hk91 I had for awhile. Between the fluted chamber and just being generally hard on brass I settled on the Fal and never looked back.

Same here. Many years ago I also had a Hakim rifle in 8mm Mauser. It doesn't have a fluted chamber but it sure was a brass mangler. I kept my FN49 and sold the Hakim. I'm kicking myself on that one though, since Hakims are now worth many times what they were back in the '90s.