Bullet Setback, Multiple Chamberings

[Donny1]

On occasion I will unload my carry gun and a few times without thinking I reloaded the same round back in the chamber a few times. Since I had a second thought about the round having setback I started rotating to a different round each time. I measured all the rounds in my 2 mags I carry and found only one had any setback but it was significant.

I try not to unload often, holster and pistol are removed together daily but for cleaning every month or two for lint and debris it's gonna happen.

These are my reloads (not interested in opinions about that).

M&P Shield 9mm
Xtreme XDEF 124gn HP
5.4gn CFE Pistol
1.120
1050fps

The one in question now measures .980.

I'm due to rotate these out but I'm wondering if I should pull this round apart or just shoot it off, what increase would I expect from .040 setback, dangerous?

[pacrat]

On occasion I will unload my carry gun and a few times without thinking I reloaded the same round back in the chamber a few times. Since I had a second thought about the round having setback I started rotating to a different round each time. I measured all the rounds in my 2 mags I carry and found only one had any setback but it was significant.

I try not to unload often, holster and pistol are removed together daily but for cleaning every month or two for lint and debris it's gonna happen.

These are my reloads (not interested in opinions about that).

M&P Shield 9mm
Xtreme XDEF 124gn HP
5.4gn CFE Pistol
1.120
1050fps

The one in question now measures .980.

I'm due to rotate these out but I'm wondering if I should pull this round apart or just shoot it off, what increase would I expect from .0140 setback, dangerous?

FIRST ..... recheck your math. That is significant. And could likely be dangerous overpressure in such a small capacity high pressure cartridge.

You can use an inertia bullet puller to "bump" the bullet back into proper position. Or lacking a puller, pull the barrel, chamber the round, and bump the muzzle on a soft piece of wood for repositioning the bullet.

When loading your EDC. Drop round in chamber. Lower slide. Then insert loaded mag.

Gives you +1 round capacity. And does away with repeated bullet contact with feed ramp, which cause the "short round" issue.

[Donny1]

FIRST ..... recheck your math

Yes I made a typo, 1.080 so .040.

[ar15barrels]

9mm
Xtreme XDEF 124gn HP
5.4gn CFE Pistol
1.120
1050fps

The one in question now measures .980.

I'm due to rotate these out but I'm wondering if I should pull this round apart or just shoot it off, what increase would I expect from .040 setback, dangerous?

I don't have CFE pistol in Quicjkload, but using Unique, a 31,100psi load with a 124gr plated hollowpoint seated to 1.120" oal will become a 73,000psi load when the bullet is seated to 0.980" oal.

[Donny1]

I don't have CFE pistol in Quicjkload, but using Unique, a 31,100psi load with a 124gr plated hollowpoint seated to 1.120" oal will become a 73,000psi load when the bullet is seated to 0.980" oal.

You skipped over where I said I made a typo. 1.120 to 1 .080, total setback .040.

[tabascoz28]

Just found one of these reloading. Reloaders hate these as there is less case capacity and could even stop a press but it's meant to stop setback. This one is made by ZQI but IMT is also another brand that makes it. Some steps are lower than others, this one seems about perfect.

Capture.jpg

[bigbossman]

Just found one of these reloading. Reloaders hate these as there is less case capacity and could even stop a press....

Naw..... I load mid-range rounds and have never had an issue with these "stepped" casings. I don't mind them, and frankly don't pay them much attention.

[tabascoz28]

This one went through my press just fine but I am loading near max. I'd rather not but I have seen the other ones that have a much harder step that stops my press.

[the86d]

Do you load max-charges?

Load to mag-length?

Crimp?

[ptmn]

You already reload, just be extra safe using the one and done method for carry. Once you've loaded that round and have to extract it to clear your weapon, just toss that round in a coffee can for your range training day. That can will have a significant amount of ammo over time.

As for your .980" round, I wouldn't fire it. You're a reloader, you can easily pull it down and reload again properly. Why risk a damaged gun(or worse) over a single round when you probably crank out batches of rounds?

[Donny1]

Do you load max-charges?

Load to mag-length?

Crimp?

Not max

Xtreme XDEF 124gn HP
5.4gn CFE Pistol
1.120
1050fps

Light crimp with FCD, just enough to straighten the case

[Donny1]

As for your .980" round, I wouldn't fire it. You're a reloader, you can easily pull it down and reload again properly. Why risk a damaged gun(or worse) over a single round when you probably crank out batches of rounds?

Corrected above

You skipped over where I said I made a typo. 1.120 to 1 .080, total setback .040.

[JoyfulJoker]

The question is : Is .040 enough set back to be dangerous?

I just went and measured 6 mags I had loaded with factory defense rounds ( Sig, Hornady and Federal). and seperated them by brand. Some had fluctuations within .010-.030 plus or minus. Some were right on. Sig V crown was the most consistent. It was hard to find OAL info. From now on, I will measure OAL when I buy and write it on the box. All oddballs were set aside . Most, sorted by brand were within .020-.030 of average. The worst were .080 short.

What is the depth below average that set back becomes dangerous?

[ar15barrels]

You skipped over where I said I made a typo. 1.120 to 1 .080, total setback .040.

I didn't skip anything.
I responded to the first post.
I didn't GET to your correction until today...

A 31,100psi load at 1.120" becomes a 37,047psi load when the bullet is seated 0.040" deeper.

[JoyfulJoker]

Correction: Just checked my rejects again. The worst was Hornady critical defense with one seated .60 deeper. I'm glad I checked.