Do all semi's beat up the bullet during chambering? - Page 2

RsqVet · October 6, 2015, 11:27 AM

Setback is something to be aware of, to watch for and to consider in sop's and administrative handeling of your guns and ammo. One need not live in fear of it and you sure as heck can chamber a round more than once before tossing it out.

One of the bad set back stories I read went something along these lines....

It was DOE as I recall, officers report in obtain weapons from armory and load, go on duty. At end of shift go off duty clear weapons and turn in.

This occurs for some number of months... Then it came time for qualiications at the range and one of the guns kb's inspection reveals serious set back in other unfired rounds.

As I recall subject guns were 40 cal glocks.

Obviously this is a bit of an extream case. If you do some quick math with some wild assumptions with this scenario you get something like a minimum of 100 chamberings of a round. So don't do that... In a glock... In 40 cal... Change any variable and it likely is not an issue

9x18_Walther · October 6, 2015, 11:51 AM

Some ammo is more sensitive to setback than others.

Corbon DPX I believe will start to setback after just a couple re-chamberings. Corbon might have fixed this issue.

**44 AMP** · October 7, 2015, 10:25 AM

Quote:

It was DOE as I recall, officers report in obtain weapons from armory and load, go on duty. At end of shift go off duty clear weapons and turn in.

This occurs for some number of months... Then it came time for qualiications at the range and one of the guns kb's inspection reveals serious set back in other unfired rounds.

As I recall subject guns were 40 cal glocks.

That sounds like a perfect storm situation for a KaBoom!

Repeated chamberings from duty carry
(the setback issue)

.40 S&W
(a high pressure "keg of dynamite" cartridge)

Glock pistol
("generously" unsupported chamber)

Am not so sure about DOE, though. I spent 30+ years working at DOE guarded facilities, and never saw the regular officers, nor the TRT guys carry any GLock. Its not impossible, I have no idea what DOE used at other sites. I would tend to doubt any difference though, Govt is pretty big on standardization, at least within agencies.

Might it not have been some other alphabet agency? Or something other than a GLock? possible either way.

Stuff happens. One of the guards shot himself in the foot (and no, it was NOT a holstering accident), another fired a round from his UZI into a lunchroom ceiling. If you look at enough people handling guns over a long enough period of time, you will see all kinds of stuff.

I could tell you some stories, but then, I'd have to kill you, and I'm feeling lazy today.

Blackbook · October 7, 2015, 11:23 AM

Quote:

Originally Posted by Mike_Fontenot

I've gotten the impression that the chambering process for all 1911's is very chaotic, with frequent bullet-push-back, and "whops" to the bullet (and also the case). I've seen that on my 10mm Kimber Eclipse, and I've also seen some copper deposits on the small FRAME feed-ramp that is immediately underneath the barrel-mounted feed-ramp ... that's a LONG way below where I'd like the bullet to be during feeding. I also occasionally see some tiny copper fragments left on the feed-ramp, and once even in the upper lug area. Since my gunsmith throated my chamber (several hundred fired rounds ago), I haven't had any more failures to feed or eject, but I still don't like that chaotic feeding precess. In contrast, when I chamber the first round by SLOWLY moving the slide forward (with only a single round in the mag), the feeding is like melted butter ... absolutely smooth and controlled. But when live-firing, or when slingshotting the first round, it's clearly not smooth, even though it doesn't ever seem to jam now.

Do other semi-auto's have chaotic feeding, with bullet-push-back, etc?

I've deliberately chambered the same round in my Sig p320c for a month now to observe wear. So far all I can see is a minor blemish to the finish. No deformation to the casing at all.

Hornaday Critical Duty JHP 9mm.

**JohnKSa** · October 7, 2015, 10:07 PM

Different guns put differing amounts of wear on a chambered round. The straighter the shot from the magazine into the chamber, the less wear and tear on the round and the less potential for setback.

Also, different types of ammo tolerate the stresses of chambering differently. Some will tolerate a lot of re-chamberings with no issue while others will setback after a relatively small number of trips from the magazine to the chamber.

Webleymkv · October 8, 2015, 12:46 AM

In my experience, bullet setback is more likely to occur with non-premium "practice" ammo like FMJ than with premium self-defense ammo. For example, I've experienced significant bullet setback before with CCI Blazer Brass .45 ACP 230 gr FMJ. However, out of curiosity, I repeatedly chambered and measured the same round of premium SD ammo to see if setback would occur. I tried this experiment with Federal .45 ACP +P 230 gr HST, Winchester 9mm +P+ 127 gr Ranger-T, and Winchester 10mm 175 gr Silvertip. With all of those loadings in the guns I tried them in (S&W 1911, CZ-75B, and S&W 1076 respectively) I found a couple thousandths of setback within the first one or two chamberings and none thereafter out to 20 chamberings.

Mike_Fontenot · October 8, 2015, 11:30 AM

I picked up my 10mm 1911 from my gunsmith's yesterday afternoon, and I'll test it this Saturday. He said the problem is caused by the top cartridge in the mag (in last Saturday's jams, it was the only round left in the mag) being slid forward when the previously-fed round is fired, purely due to the heavy recoil of the full-spec 10mm. When the round is fired, the slide is closed (of course), and the top cartridge in the mag is being pressed down lower by the bottom of the slide above it than it would be if the slide were all the way back. He says the round was being slid all the way forward by the recoil until it is in contact with the junction between the barrel-mounted feedramp and the frame feedramp. It was hanging up at that point due to the upper feedramp being very slightly aft of the lower feedramp (the offset at the junction is tiny, but it's enough hang up the bullet). When the slide then comes aft and then forward, it hits the rear of the round, but because of the low position of the bullet, the rear of the case misses the extractor, and rotates up in front of the slide, and ends up getting hit by the bottom edge of the slide at roughly the midpoint of the case, pinning it against the aft end of the chamber. His fix was to re-contour the lower part of the barrel-mounted feedramp, so that it is very slightly forward of the top of the frame feedramp (instead of being in the opposite direction), and won't hang up the bullet. And if there is any subsequent buildup of copper in that area, I'm probably going to leave it alone.

That's my understanding of what he said, anyway. I'm hoping for the best at the range.

Walt Sherrill · October 8, 2015, 03:35 PM

I wonder if you can stronger mag springs from Wolff... if you're not already using the strongest ones available? THAT extra force pressing UP on the topmost round might help, too.

Mike_Fontenot · October 8, 2015, 03:44 PM

I've thought about that, also. But the last time I looked, Wolff didn't have recoil springs in 10mm for either the original Kimber mags (Metalform, rounded follower) or Checkmate (9-round mags with a "collapsing" follower). I've previously emailed Metalform and Checkmate several times (asking about buying new (and perhaps stronger) springs for my magazines, and I've never received a reply from either of them. Likewise for Kimber, itself.

It's possible also that the "preemptive" sliding forward of the next round (due to recoil when the previous round is fired and while the slide is forward) might not necessarily be a bad thing, IF the feedramps are smooth enough (and shaped right) to not snag the bullet.

745SW · October 8, 2015, 04:01 PM

" His fix was to re-contour the lower part of the barrel-mounted feedramp, so that it is very slightly forward of the top of the frame feedramp (instead of being in the opposite direction), and won't hang up the bullet. And if there is any subsequent buildup of copper in that area, I'm probably going to leave it alone."

I find the lower part of the ramp on the barrel to be useless. Can be reduced substantially. Once reduced the ramp on the frame can be extended forward.

Best to keep case head support at the ramp of barrel untouched IMO.

Mike_Fontenot · October 8, 2015, 05:08 PM

Quote:

Originally Posted by 745SW

Once reduced the ramp on the frame can be extended forward.

Seems like what you'd want is for the lower feedramp to be extended AFT a bit, to make the upward slope of the ramp less steep. It's already to the point that, when the bullet is that low (with the rear of the case higher once the slide has gone aft), that the axis of the cartridge is getting dangerously close to being perpendicular to the ramp (and it won't want to go either up or down when pushed along its axis by the slide). Adding material AFT on the lower feedramp is what I'm going to try to accomplish by leaving any copper deposits on the lower ramp right where they are, instead of cleaning them off. But who knows ... maybe I won't see any more of those deposits.

pete2 · October 9, 2015, 11:30 AM

You can open the lips on the mag a little to allow an earlier release of the cartridge. I would try a different bullet before jacking with the mag. Target shooters shoot SWC ammo, it won't feed at all in a gov. model bbl. The guys that built target guns rampped the bbl and tuned the mags so the flat tip of the bullet doesn't hang on the ramp. Some hollow point bullets hang or stub on the ramps of some guns. Of 7 1911 guns the only problem I've had is the 9MM with the Wilson mags and I'm told they have now redesigned them so they will work. Recently shot a friends Kimber with my 185 Hornady bullets, first round hung on the ramp. They work fine in my guns including my Kimber.

SpareMag · October 10, 2015, 03:59 PM

I am afraid I haven't discerned the issue here. Is the OP complaining of fairlures? If so, I am not picking that up.

If the OP is complaining about the way feeds are done during fire, then I would ask who cares, barring this being a high-end race gun of some type.

There is a lot of force, and a lot of critical timing employed with these gizmos. If it is working satisfactorily, call it a day. If you want Korriphilia performance out of a Tisas, you are gonna be working on that for a while.

**JohnKSa** · October 10, 2015, 05:27 PM

Quote:

You can open the lips on the mag a little to allow an earlier release of the cartridge.

I'm not saying that adjusting mag feedlips is impossible, but it's not a simple thing. Most of the time, for most people, "adjusting mag feedlips" = "buying a new magazine".

Walt Sherrill · October 10, 2015, 05:58 PM

Quote:

Originally Posted by JohnKSa

Most of the time, for most people, "adjusting mag feedlips" = "buying a new magazine".

As JohnKSa notes, there's not much adjusting allowed. The metal in most mag feed lips is pretty brittle. Bend the lips too much and you break them; if you bend them too far and try to bring them back a little they'll break, too. (Once bent, they're not all easily unbent.)

Maybe using a file to open the feed lips (moving the file rom front to back) would let you open up the gap a bit....but do it carefully, as you can't replace that lost metal.

Mike_Fontenot · October 25, 2015, 02:39 PM

Update: Long story short, after the previous gunsmith work (which involved removing some material near the bottom of the barrel-mounted feed-ramp, to remove the discontinuity between the upper and lower feed-ramp), the problem with the jam on the last round in the mag didn't recur at the next range trip, but a new problem surfaced: I got numerous horizontal jams when slingshotting the first round out of a mag. Back to the gunsmith, and I think he has now solved all the problems: he recut the barrel-mounted feed-ramp, so that it has the same constant slope as before the previous feed-ramp work, but positioned slightly forward of its original position (which was slightly aft of the lower frame-mounted feed-ramp, which created a hang-up junction). This slightly increases the unsupported area at the bottom-rear of the chamber, but Kimbers are known for having the most chamber support of any 1911, and so it could afford to gave up a slight amount of support in return for feeding reliability. The cases I shot look OK ... no bulges in that area (even with my full-spec 10mm DoubleTap carry rounds, which is all I ever shoot). I'm cautiously optimistic, and hoping that I've finally got a reliable 10mm 1911. I love the way my Eclipse handles, but I've got to be able to quit wondering on every shot if it's going to jam or not ... may take a while with no failures to learn to trust it.

October 7, 2015, 10:07 PM	#30
JohnKSa Staff Join Date: February 12, 2001 Location: DFW Area Posts: 24,994	Different guns put differing amounts of wear on a chambered round. The straighter the shot from the magazine into the chamber, the less wear and tear on the round and the less potential for setback. Also, different types of ammo tolerate the stresses of chambering differently. Some will tolerate a lot of re-chamberings with no issue while others will setback after a relatively small number of trips from the magazine to the chamber. __________________ Do you know about the TEXAS State Rifle Association?

October 6, 2015, 11:27 AM	#26
RsqVet Senior Member Join Date: February 20, 2005 Posts: 2,474	Setback is something to be aware of, to watch for and to consider in sop's and administrative handeling of your guns and ammo. One need not live in fear of it and you sure as heck can chamber a round more than once before tossing it out. One of the bad set back stories I read went something along these lines.... It was DOE as I recall, officers report in obtain weapons from armory and load, go on duty. At end of shift go off duty clear weapons and turn in. This occurs for some number of months... Then it came time for qualiications at the range and one of the guns kb's inspection reveals serious set back in other unfired rounds. As I recall subject guns were 40 cal glocks. Obviously this is a bit of an extream case. If you do some quick math with some wild assumptions with this scenario you get something like a minimum of 100 chamberings of a round. So don't do that... In a glock... In 40 cal... Change any variable and it likely is not an issue

October 6, 2015, 11:51 AM	#27
9x18_Walther Senior Member Join Date: June 2, 2015 Posts: 500	Some ammo is more sensitive to setback than others. Corbon DPX I believe will start to setback after just a couple re-chamberings. Corbon might have fixed this issue.

October 8, 2015, 12:46 AM	#31
Webleymkv Senior Member Join Date: July 20, 2005 Location: Indiana Posts: 10,446	In my experience, bullet setback is more likely to occur with non-premium "practice" ammo like FMJ than with premium self-defense ammo. For example, I've experienced significant bullet setback before with CCI Blazer Brass .45 ACP 230 gr FMJ. However, out of curiosity, I repeatedly chambered and measured the same round of premium SD ammo to see if setback would occur. I tried this experiment with Federal .45 ACP +P 230 gr HST, Winchester 9mm +P+ 127 gr Ranger-T, and Winchester 10mm 175 gr Silvertip. With all of those loadings in the guns I tried them in (S&W 1911, CZ-75B, and S&W 1076 respectively) I found a couple thousandths of setback within the first one or two chamberings and none thereafter out to 20 chamberings.

October 8, 2015, 11:30 AM	#32
Mike_Fontenot Senior Member Join Date: March 7, 2009 Posts: 568	I picked up my 10mm 1911 from my gunsmith's yesterday afternoon, and I'll test it this Saturday. He said the problem is caused by the top cartridge in the mag (in last Saturday's jams, it was the only round left in the mag) being slid forward when the previously-fed round is fired, purely due to the heavy recoil of the full-spec 10mm. When the round is fired, the slide is closed (of course), and the top cartridge in the mag is being pressed down lower by the bottom of the slide above it than it would be if the slide were all the way back. He says the round was being slid all the way forward by the recoil until it is in contact with the junction between the barrel-mounted feedramp and the frame feedramp. It was hanging up at that point due to the upper feedramp being very slightly aft of the lower feedramp (the offset at the junction is tiny, but it's enough hang up the bullet). When the slide then comes aft and then forward, it hits the rear of the round, but because of the low position of the bullet, the rear of the case misses the extractor, and rotates up in front of the slide, and ends up getting hit by the bottom edge of the slide at roughly the midpoint of the case, pinning it against the aft end of the chamber. His fix was to re-contour the lower part of the barrel-mounted feedramp, so that it is very slightly forward of the top of the frame feedramp (instead of being in the opposite direction), and won't hang up the bullet. And if there is any subsequent buildup of copper in that area, I'm probably going to leave it alone. That's my understanding of what he said, anyway. I'm hoping for the best at the range.

October 8, 2015, 03:35 PM	#33
Walt Sherrill Senior Member Join Date: February 15, 1999 Location: Winston-Salem, NC USA Posts: 6,348	I wonder if you can stronger mag springs from Wolff... if you're not already using the strongest ones available? THAT extra force pressing UP on the topmost round might help, too.

October 8, 2015, 03:44 PM	#34
Mike_Fontenot Senior Member Join Date: March 7, 2009 Posts: 568	I've thought about that, also. But the last time I looked, Wolff didn't have recoil springs in 10mm for either the original Kimber mags (Metalform, rounded follower) or Checkmate (9-round mags with a "collapsing" follower). I've previously emailed Metalform and Checkmate several times (asking about buying new (and perhaps stronger) springs for my magazines, and I've never received a reply from either of them. Likewise for Kimber, itself. It's possible also that the "preemptive" sliding forward of the next round (due to recoil when the previous round is fired and while the slide is forward) might not necessarily be a bad thing, IF the feedramps are smooth enough (and shaped right) to not snag the bullet.

October 8, 2015, 04:01 PM	#35
745SW Senior Member Join Date: August 25, 2011 Location: California Posts: 776	" His fix was to re-contour the lower part of the barrel-mounted feedramp, so that it is very slightly forward of the top of the frame feedramp (instead of being in the opposite direction), and won't hang up the bullet. And if there is any subsequent buildup of copper in that area, I'm probably going to leave it alone." I find the lower part of the ramp on the barrel to be useless. Can be reduced substantially. Once reduced the ramp on the frame can be extended forward. Best to keep case head support at the ramp of barrel untouched IMO.

October 9, 2015, 11:30 AM	#37
pete2 Senior Member Join Date: May 15, 2012 Location: Texas Posts: 2,566	You can open the lips on the mag a little to allow an earlier release of the cartridge. I would try a different bullet before jacking with the mag. Target shooters shoot SWC ammo, it won't feed at all in a gov. model bbl. The guys that built target guns rampped the bbl and tuned the mags so the flat tip of the bullet doesn't hang on the ramp. Some hollow point bullets hang or stub on the ramps of some guns. Of 7 1911 guns the only problem I've had is the 9MM with the Wilson mags and I'm told they have now redesigned them so they will work. Recently shot a friends Kimber with my 185 Hornady bullets, first round hung on the ramp. They work fine in my guns including my Kimber.

October 10, 2015, 03:59 PM	#38
SpareMag Senior Member Join Date: February 7, 2012 Posts: 514	I am afraid I haven't discerned the issue here. Is the OP complaining of fairlures? If so, I am not picking that up. If the OP is complaining about the way feeds are done during fire, then I would ask who cares, barring this being a high-end race gun of some type. There is a lot of force, and a lot of critical timing employed with these gizmos. If it is working satisfactorily, call it a day. If you want Korriphilia performance out of a Tisas, you are gonna be working on that for a while.

October 25, 2015, 02:39 PM	#41
Mike_Fontenot Senior Member Join Date: March 7, 2009 Posts: 568	Update: Long story short, after the previous gunsmith work (which involved removing some material near the bottom of the barrel-mounted feed-ramp, to remove the discontinuity between the upper and lower feed-ramp), the problem with the jam on the last round in the mag didn't recur at the next range trip, but a new problem surfaced: I got numerous horizontal jams when slingshotting the first round out of a mag. Back to the gunsmith, and I think he has now solved all the problems: he recut the barrel-mounted feed-ramp, so that it has the same constant slope as before the previous feed-ramp work, but positioned slightly forward of its original position (which was slightly aft of the lower frame-mounted feed-ramp, which created a hang-up junction). This slightly increases the unsupported area at the bottom-rear of the chamber, but Kimbers are known for having the most chamber support of any 1911, and so it could afford to gave up a slight amount of support in return for feeding reliability. The cases I shot look OK ... no bulges in that area (even with my full-spec 10mm DoubleTap carry rounds, which is all I ever shoot). I'm cautiously optimistic, and hoping that I've finally got a reliable 10mm 1911. I love the way my Eclipse handles, but I've got to be able to quit wondering on every shot if it's going to jam or not ... may take a while with no failures to learn to trust it.