How much bullet setback is dangerous?

[weaverftw]

Just curious how much a bullet can be setback before it would cause dangerous pressure spikes. I noticed a .40sw round that I had chambered only twice in my Sig was slightly shorter than a fresh round, so I measured it and it was 1.11235 vs 1.11265 for an unchambered round. At what point should I throw a round away, rather than shoot it at the range when I cycle rounds out of my mags?

I'm particularly worried about the .40sw rounds since I've read that it's particularly susceptible to over-pressure (especially the 180gr loads).

Thoughts?

[highpower790]

You have a couple too many numbers.Get rid of them and youll be fine,provided you are following a manual.

[weaverftw]

Oops, I added a digit. It was actually 1.1235 vs 1.1265. Some fresh rounds measure as short as 1.1255. How much setback would make the round dangerous to shoot? Just to be clear, I'm not reloading, just measuring the bullet setback from chambering a round several times.

[highpower790]

.010 shoulnt make a difference.

[Catch]

Something felt off while loading these today. To be fair, they were from a blemished box of PPU 165gr.

[RTE]

Something felt off while loading these today. To be fair, they were from a blemished box of PPU 165gr.

Use one of these and put that round in the for range use box.

[RR.44]

.10 shouldn't hurt, anything more than that and pressures will start to rise.

[deerdeerdeer]

Kaboom!

[weaverftw]

.10 shouldn't hurt, anything more than that and pressures will start to rise.

Do you mean 0.10, or 0.010? Ie, if 1.1255 is the average for a fresh round, would 1.0255 be the cutoff or 1.1155? I could visually detect the 0.002 difference (which is what led me to measure), so a full 0.10 seems like a huge amount.

[uhlan1]

Reloading 9mm at least I don't worry if within .005.

1.1235 vs 1.1265 I personally wouldn't worry about. There are variations even in factory ammo.

[cgates]

I would add that it also depends on how close the load is to max. With factory ammo you cant say for sure. A more sensitive round like the above poster mentioned that is already running at max could be dangerous even with a small amount of setback.

OP - in your specific case right now a small amount of setback shouldn't be cause for concern, but that might not always be the case.

[357magnum]

Do you mean 0.10, or 0.010? Ie, if 1.1255 is the average for a fresh round, would 1.0255 be the cutoff or 1.1155? I could visually detect the 0.002 difference (which is what led me to measure), so a full 0.10 seems like a huge amount.

Are you sure your reading your calipers right, a common piece of paper has a thickness of .003-.004
You have incredible eyes if you can see COAL difference of .003-.004
Are you sure its not .030-.040

[weaverftw]

Are you sure your reading your calipers right, a common piece of paper has a thickness of .003-.004
You have incredible eyes if you can see COAL difference of .003-.004
Are you sure its not .030-.040

Yes I'm positive it's .003 difference, I double checked twice with calipers. I do have good eyesight, but I didn't notice the difference in length by looking at the total length of each round, I noticed it by comparing how much of the base of the bullet was poking up above the case head. It's easier to see the difference when the total length you're comparing its less.

[357magnum]

Yes I'm positive it's .003 difference, I double checked twice with calipers. I do have good eyesight, but I didn't notice the difference in length by looking at the total length of each round, I noticed it by comparing how much of the base of the bullet was poking up above the case head. It's easier to see the difference when the total length you're comparing its less.

However you are determining the OAL difference, .003-.004 is not going to matter at all.
Factory ammo OAL varies more than .003-.004
Check and measure several different boxes of factory ammo, you will find they are all over the place in OAL.

[CK_32]

There is no real number to give.

A lot of factors come into play to have a set number.

If it's more than a littler, throw it away. Saving $0.26 is not worth risking $600 and more in injury and med bills.