This guy chambered the same 9mm round 100 times...

[jtwilson3]

DON'T DO THAT!



Yep.

I will gladly stop but I do want more information on this first. Like is there a study about this? Any articles? Etc? Or is this just heresay and gun myths... I am also open to change so long as logic is what requires it.

 

[sloughfoot]

Some thoughts.

1. Your bullet should never be in contact with the feed ramp. Certainly never slammed into it.

2. The bullet is held by neck tension, not the crimp.

3. The crimp is to remove the bell and to promote reliable feeding. Nothing more.

4. If you feel the bullet hitting the feed ramp, you should fix this major problem.

 

[88E30M50]

Some thoughts.

1. Your bullet should never be in contact with the feed ramp. Certainly never slammed into it.

2. The bullet is held by neck tension, not the crimp.

3. The crimp is to remove the bell and to promote reliable feeding. Nothing more.

4. If you feel the bullet hitting the feed ramp, you should fix this major problem.

I always thought the feed ramp was there to guide the bullet upwards during the feed cycle. It seems to be hit on just about every pistol I own, from 1911s to Glocks. I know the animated sequences showing 1911 or Glock function are no authority on the matter, but those show the bullet being guided upwards by contact with the feed ramp. If not the feed ramp, is it the magazine lips that should present the bullet at an angle that takes it cleanly into the chamber?

I love learning new stuff, but just want to be sure I'm understanding what it is I think I'm learning

 

[SERparacord]

I always thought the feed ramp was there to guide the bullet upwards during the feed cycle. It seems to be hit on just about every pistol I own, from 1911s to Glocks. I know the animated sequences showing 1911 or Glock function are no authority on the matter, but those show the bullet being guided upwards by contact with the feed ramp. If not the feed ramp, is it the magazine lips that should present the bullet at an angle that takes it cleanly into the chamber?

I love learning new stuff, but just want to be sure I'm understanding what it is I think I'm learning

Bullets contact feed ramps. Crimps hold the bullet tighter. Any mag fed ammo should be crimped.

 

[rvb]

the last time we talked about this.....

https://www.indianagunowners.com/forums/handguns/301236-chambering-same-round-multiple-times-3.html

-rvb

 

[USMC-Johnson]

Ok guys here are my results from my sig. I am about to do the same with a glock 23.

Its up to you to decide whether the loss in height is from the hollow part of the round collapsing or the bullet getting pushed back into the case.

 

[USMC-Johnson]

Here are the results from the g23 gen 4. Much less change. All rounds were chambered from the slide locked to the rear and sent forward with the slide release.

I stopped after 75 times on the g23 because i stopped seeing any change.

 

[Lebowski]

Ok guys here are my results from my sig. I am about to do the same with a glock 23.

Its up to you to decide whether the loss in height is from the hollow part of the round collapsing or the bullet getting pushed back into the case.

Wow, big difference! I wonder how if the results would be similar with a non-HP round. Looking forward to seeing what the Glock does too.

 

[USMC-Johnson]

I'm gonna do both with FMJ rounds later tonight.

 

[ArcadiaGP]

Graph form of your current tests:

Same axis

 

[midget]

If you want to see a really scary change in OAL, do the same test with a 1911 and 230gr hydroshocks. Edit, if I get the chance tonight, I will do this one...

 

[Tombs]

I will gladly stop but I do want more information on this first. Like is there a study about this? Any articles? Etc? Or is this just heresay and gun myths... I am also open to change so long as logic is what requires it.

The reason you don't want to do it is the stresses this places on your extractor.

It depends on a few things of course. Almost every handgun I know of is pretty much controlled feed, meaning the round's rim goes under the extractor as it's leaving the magazine.

The extractor is not designed to snap over the rim of a casing. This will absolutely screw up a 1911's extractor tension and result in malfunctions, or a broken extractor.
For most other firearms, it creates stress at a few points on the extractor that were not designed to experience those stresses. This will eventually result in breaking or chipping your extractor.

It's important that you never do this again. If you've been doing it every day for years, you should consider replacing your extractor now, before it fails on you when you need it.

-------

As for bullet set back from chambering rounds... You should try a 1911 with a 24 pound spring and a tight chamber. (Clark 460 rowland kit build)
When I first started reloading 460 rowland for it, I didn't realize it'd require such a ridiculous crimp to keep the round from having massive setback even after chambering once. That said, it never blew up on me and I'm sure some of those rounds had to be set back far enough to compress the charge after chambering.
I don't think it's as dangerous as it's made out to be. I would never trust a questionable firearm to handle such a thing though, nor would I trust a firearm without good chamber support.

I've rechambered the same round of federal HST 147gr 9mm in my USP countless times now, and there's still no setback at all according to the calipers. Some guns are very gentle on ammunition, that USP doesn't even seem to leave a mark on the bullet.

 

[millsusaf]

I chronoed a set back bullet vs a fresh bullet once. I only saw maybe 20 fps difference. I will say I didn't fire a lot of those rounds so 20 fps could have been normal between cartridges.

The only time I think setback matters is on really hot loads.

 

[chezuki]

Here are the results from the g23 gen 4. Much less change. All rounds were chambered from the slide locked to the rear and sent forward with the slide release.

I stopped after 75 times on the g23 because i stopped seeing any change.

I'll try this with Critical Defense 9mm in my M&P. I bet the cone shape of the CD helps minimize setback vs the wide hollow point 9mm pictured.

 

[USMC-Johnson]

My big thing is its very hard to measure with that stupid little plastic insert.

 

[sloughfoot]

Consider this. You just loaded up a mag and chambered a round into your EDC. You then holstered your pistol, ready to face the day.

How do you know that this round was not pushed back into the case?

Nobody worries about it unless they have lots of spare time while sitting in front of the computer.

 

[chezuki]

Consider this. You just loaded up a mag and chambered a round into your EDC. You then holstered your pistol, ready to face the day.

How do you know that this round was not pushed back into the case?

How could it possibly? According to you, the bullet never touches the feed ramp.


I do have to ask though, what do you think the feed ramp is for?

 

[sloughfoot]

How could it possibly? According to you, the bullet never touches the feed ramp.


I do have to ask though, what do you think the feed ramp is for?

You mis-understand but it is more likely that I am not clear. The bullet should never be slammed into the feed ramp. You can feel that. It does not feel good. I have had 1911's that did that. I fixed them.

The side of the bullet can certainly slide up the feed ramp. This feels good. This cannot push the bullet into the case.

Edit to add: none of us can see what actually happens in the feeding process. But we can feel it. It should feel smooth no matter what is coming into contact with the feed ramp.

 

[chezuki]

You mis-understand but it is more likely that I am not clear. The bullet should never be slammed into the feed ramp. You can feel that. It does not feel good. I have had 1911's that did that. I fixed them.

The side of the bullet can certainly slide up the feed ramp. This feels good. This cannot push the bullet into the case.

Gotchya. Here is my M&P with a 9mm Critical Defense (the narrowest angled bullet profile I'm aware of) showing where the bullet impacts the feed ramp.

I actually stopped using Gold Dots because I could feel the wide mouth hang up on the ramp for a split second. It never failed to feed them, but I could feel it when chambering a round.

 

[Lebowski]

INGO Members on Reddit! Same round chambered 100 times, with caliper measurements (Sig P226) : guns

Someone suggested / asked:

If he's got some, I'd like to see what a Federal HST looks like after 100 chamberings. It's got the crimp behind the bullet that is supposed to lessen setback and I'd like to see one put to the test.