Ruger Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
189 Posts
Discussion Starter #1 (Edited)
I'm aware of what bullet setback is, how it occurs and what the danger is but would like everyone's opinions on what to do with a setback cartridge.

I've heard one YouTuber I respect indicate he checks constantly and closely for setback and puts any noticeable cases aside for the range. The implication is if I see minor setback, the cartridge is safe for practice but not for SD. How would I know if one cartridge is safe and another isn't? What do you guys think?
 

·
Registered
Joined
·
189 Posts
Discussion Starter #3
Yeah, I'll consider that. Wasn't sure what was best. Thanks.
 

·
Registered
Joined
·
89 Posts
I read an article in a gun rag on this very subject just recently. I am trying to find the magazine, but am not having much luck.
Basically, the author said that setback, if extreme, can blow up your gun. He advises that when you unload each night, the round that was chambered goes into the practice pile. To me that is extreme. I look at my rounds regularly and any noticable setback is put in the practice pile. I rarely unload my EDC, except to swap out practice rounds.
With the scarcity of ammo now, no one can really afford to throw out good quality ammo. Use your best, educated judgment, and always err on the side of safety.
 

·
Banned
Joined
·
402 Posts
Set back of a round should not occur but unfortunately it does. It happens when a round is chambered, and due to small anomaly's in the feeding process the round is driven deeper into the case. How dangerous is it ? that depends on a few things.
-------------------------------------------------
How far back was the bullet pushed into the case ?
How hot was the load ? ( how close to max pressure to begin with )
How many times the round is cycled in the pistol ?
Also how bad the alignment of the round was, that caused the problem in the first place.
Some pistols can set a bullet back enough one time to make it dangerous, and some pistols may take two or three times to create an unsafe condition. The deeper the bullet is set into the case from it's original position the more the pressure can rise inside the case.
There are some things that can be done to help avoid the problem.
DON"T load and unload the pistol, Think about why you are doing this and perhaps you can find a way not to do it so much.
Read your owners manual, depending on the type of extractor your pistol uses you may be able to load by dropping right into the chamber. A 1911 pistol has an internal extractor and it's not advisable to load the chamber and drop the slide allowing the extractor to jump over the round ( ruined trigger job ) some 1911 pistols S&W for one use an external extractor and so do some Berettas ( 92 and 96 for two) If so you can drop a round in the chamber and close the slide, then insert the Mag. ( no set back )
Why ? cause the bullet tip did not contact anything on it's way into the chamber.
( check your manual to see if you can single load )
But the best practice is to not load and unload the pistol if your pistol is prone to set back bullets.
 

·
Registered
Joined
·
838 Posts
My EDC weapon is never unloaded except when reloaded with range ammo, but i have never encountered any personal defense ammo having setback occur. If i ever have a round that is seated to deep or had setback for any reason, i use an RCBS bullet puller to partially pull the bullet then adjust it to proper depth and recrimp it. When i encounter a dud round i pull the bullet replace primer and reload powder and bullet.
 

·
Registered
Joined
·
189 Posts
Discussion Starter #7
I read an article in a gun rag on this very subject just recently. I am trying to find the magazine, but am not having much luck.
Basically, the author said that setback, if extreme, can blow up your gun. He advises that when you unload each night, the round that was chambered goes into the practice pile. To me that is extreme. I look at my rounds regularly and any noticable setback is put in the practice pile. I rarely unload my EDC, except to swap out practice rounds.
With the scarcity of ammo now, no one can really afford to throw out good quality ammo. Use your best, educated judgment, and always err on the side of safety.
Thanks. This is exactly the insight I'm looking for. Sounds like there might indeed be three stages: no setback, minor setback (practice pile), major setback (discard).
 

·
Registered
Joined
·
189 Posts
Discussion Starter #8
Set back of a round should not occur but unfortunately it does. It happens when a round is chambered, and due to small anomaly's in the feeding process the round is driven deeper into the case. How dangerous is it ? that depends on a few things.
-------------------------------------------------
How far back was the bullet pushed into the case ?
How hot was the load ? ( how close to max pressure to begin with )
How many times the round is cycled in the pistol ?
Also how bad the alignment of the round was, that caused the problem in the first place.
Some pistols can set a bullet back enough one time to make it dangerous, and some pistols may take two or three times to create an unsafe condition. The deeper the bullet is set into the case from it's original position the more the pressure can rise inside the case.
There are some things that can be done to help avoid the problem.
DON"T load and unload the pistol, Think about why you are doing this and perhaps you can find a way not to do it so much.
Read your owners manual, depending on the type of extractor your pistol uses you may be able to load by dropping right into the chamber. A 1911 pistol has an internal extractor and it's not advisable to load the chamber and drop the slide allowing the extractor to jump over the round ( ruined trigger job ) some 1911 pistols S&W for one use an external extractor and so do some Berettas ( 92 and 96 for two) If so you can drop a round in the chamber and close the slide, then insert the Mag. ( no set back )
Why ? cause the bullet tip did not contact anything on it's way into the chamber.
( check your manual to see if you can single load )
But the best practice is to not load and unload the pistol if your pistol is prone to set back bullets.
I'm fortunate in this regard as there are no children in the house (my wife would say 1). I'm going to think through that idea some more. Still a rookie. Thanks.
 

·
Banned
Joined
·
402 Posts
Your welcome.
I wonder how many people can detect .010 set back, and if it's just a little ?
how do you know the next time you chamber the round it wont be to much ?
If you choose that way to go, and I sure don't advise it . then at least get a cheep dial caliper and compare the OAL of the round to an UN-chambered round.
The worst thing new folks can do, ( people with little experience ) is to make things up as they go along. But hey ! have at it.
 

·
Retired Moderator & Gunsmith
Joined
·
16,479 Posts
Revolver7, I moved your thread to this more appropriate "Ammo" topic.

Just a little history .... Back in the mid-90's, many law enforcement agencies changed to 40 S&W cartridges in Glock pistols. A very high incident rate of "Kabooms" was noted nation wide so a commission was organized to determine the source. This commission included the Glock factory, an ammo company (I think it was Federal), a SAAMI lab, and about 20 independent gunsmiths nation wide (including myself). Our tasks were to investigate police procedures, inspect actual guns that were used by law enforcement agencies, test ammo, report findings, and recommend changes. The initial issues were the ammo itself and the pistol's design.

During the course of this study, the initial reports indicated the incident rate was much higher with Glock pistols but Kabooms also happened with other brands of pistols and 9mm pistols as well. Part of the conclusion was ... more Glock pistols were used by LEAs so it would only make sense that incident rates would be higher with Glocks due to shear numbers.

As more data was compiled, the investigation expanded to include "police procedures". It was discovered ... the general procedure used by most law enforcement agencies was to unload and clear the pistol at the conclusion of each shift, store the pistol unloaded, then load it again at the beginning of the next duty shift. This procedure revealed two major issues ... the cartridge was often dropped on the floor when the slide was jacked to clear the weapon and more importantly .... the ejected live cartridge was placed back in the magazine and chambered again for the next duty shift. Samples of "recycled" ammo were sent to a SAAMI lab for pressure testing. The results were ... if the bullet was seated just .030" deeper than factory specs (about the thickness of a fingernail), chamber pressure with both 40 S&W and 9mm ammo would elevate far beyond the SAAMI standards of 35,000 psi. In some test ammo with deeper seated bullets, chamber pressures were as high as 65,000 psi. Further, nearly all "Kabooms" showed up at the range during the LEO's semi-annual qualification. Most LEAs used previous "duty ammo" for qualification then issued new ammo to the LEOs to keep duty ammo "fresh".

Meanwhile, gunsmiths inspected the pistols themselves. This revealed two specific issues, both involving the feed ramp. Turns out, all pistol brands in both 9mm and 40 S&W with "built in feed ramps" shared the same problem. Because of the design of the feed ramp, it would leave a void at the bottom of the cartridge where the case walls of the cartridge were not fully supported. This resulted in a weak area where the thin case wall could blow out when chamber pressures were excessive. This was especially noteworthy with Glock pistols as evidenced by the expanded area on a spent cartridge. The expanded area looked like a "smile" and was located at the junction where the case wall meets the solid case head. Nearly every brand of pistols with built-in feed ramps were inspected and found to have chambers that were not fully supported (including Ruger pistols).

The second issue with feed ramps was the angle of the feed ramp itself. This varied a lot from brand to brand but Glocks typically had the steepest feed ramp angles. A steeper feed ramp angle could cause the bullet to be jammed deeper into the case as the cartridge fed from the magazine to the chamber. When the same cartridge was loaded multiple times (or dropped), the bullet would loosen and be driven deeper into the case, which in turn would elevate chamber pressure.

Conclusions and remedies: Based on the findings from the commission, there were several contributing factors ... the design of the pistol, the design of the cartridges, combined with the procedures used by LEAs. LEAs were advised to change their procedures. Ejected ammo was not to be loaded back into the magazine and especially if it had been dropped. Glock redesigned their pistols (second generation) with a more gradual feed ramp. Ammo manufacturers changed their case designs on 40 S&W ammo where the web of the case (area between the case wall and solid head) were shaped more like a "U" than squared, which had already been implemented in 9mm cartridges decades before. Further, ammo manufacturers designed their 40 S&W cartridges with more neck tension to help prevent bullet setback. After these changes were made, the incident rate with Kabooms reduced dramatically in the law enforcement community.

Addressing the OP's question ... here's some recommendations: If you chamber a cartridge then later eject it or drop it, do not use it until you measure the cartridge's overall length. Using a fresh cartridge as a reference, if the bullet has been pushed back in the case .010" or more, do not try to use it again.

Pulling a loose bullet then reseating it to the proper COL is not recommended because once the bullet breaks loose from the case, neck tension is reduced and may not hold the bullet tight enough to survive another chambering without being set back again. Removing the bullet and sizing the case should restore neck tension.

Applying too much taper crimp to any case when reloading will actually reduce overall neck tension because the case will expand slightly, leaving only the crimp holding the bullet. In a properly sized and crimped case, about 90% of the neck tension comes from the slightly undersized case and only 10% should come from the taper crimp.

If you note "smiles" in any spent cases, discard them and do not attempt to reload them. The weak area where the case web expanded is much more likely to blow out should it again align with the non-supported area of the chamber.

Reloading 40 S&W or 9mm is no more dangerous than any other cartridge providing you follow good procedures. Never "hot rod" any pistol cartridge. Toss "smiley" cases in the trash. Never seat bullets deeper that the recommended seating depth (COL) as noted in your reloading manuals. Never substitute brands of bullets, even if they are the same weight and style. As an example ... a 9mm Speer 115 gr JHP is seated to a COL of 1.125" whereas a Hornady 115gr JHP is seated to 1.075" (.050" difference). Using Hornady specs with a Speer bullet will result in a dangerously high chamber pressure ... enough where you can damage your pistol or worse. Test each reloaded cartridge for neck tension by holding the case and pushing the bullet nose against a solid work bench. If the bullet seats deeper as indicated on a caliper, the case has lost its ability to maintain neck tension and should be discarded.

Here's an example of a "smiley case". It happens to be a once fired 45 ACP from a STI 1911 with a ramped barrel. Not a good photo but if you look close, you can see the expanded area at the lower front.

 

·
Retired Moderator & Gunsmith
Joined
·
16,479 Posts
Here's a couple more photos. The first one is a 40 S&W case that has a cut away area to test for a fully supported chamber.



Here's a Beretta Mod 96, 40 S&W barrel (shown upside down) with the cut away case inserted so the open area aligns with the feed ramp (top). A blue LED was used to illuminate the barrel. As you can see .... blue light emanates between the ramp and case, indicating the chamber is NOT fully supported. I used this cut away test case (and another in 9mm) to check many different brands of barrels (to include Rugers) and none of the pistol barrels with a built-in feed ramp were fully supported. Older Generation 1 Glocks were the worst ... newer Gen 2 & 3 Glocks are not as bad. Ruger P-guns (P-944 in 40 S&W and P-94 in 9mm) tested about the same as the below Beretta barrel.

 

·
Registered
Joined
·
189 Posts
Discussion Starter #14 (Edited)
Your welcome.
I wonder how many people can detect .010 set back, and if it's just a little ?
how do you know the next time you chamber the round it wont be to much ?
If you choose that way to go, and I sure don't advise it . then at least get a cheep dial caliper and compare the OAL of the round to an UN-chambered round.
The worst thing new folks can do, ( people with little experience ) is to make things up as they go along. But hey ! have at it.
Not me. I stand corrected. Between you and Iowegan I think we have a consensus and that's why I asked the question. Thanks.
 

·
Registered
Joined
·
396 Posts
On another forum there was a discussion about cartridge length, so I measued a whole bunch and found that in a box of factory ammo, the lengths differed from a couple thousanths to .010 or even .015 in a sample of 10 per box from various brands. I go in and out of IL all the time so I load and unload regularly. If I see any noticable setback I set that one aside for practice rather than have it get worse and cause a KB.
 

·
Retired Moderator & Gunsmith
Joined
·
16,479 Posts
Nothing much to do on a rainy day so I dug into my ammo stash and grabbed 4 boxes of factory and a box of reloaded 40 S&Ws. I ended up measuring all cartridges in each of the boxes, adding the total and dividing by 50 to get the average length. 2 boxes of factory WWB had a +or- .005" variation in COL. 2 boxes of Federal Lawman was +or- .003". The reloads off my Dillon RL550 were +or- .002". What does that tell me? Factory ammo is not held to very precise standards. Some cartridges come from the factory with bullets seated too deep so if there is just a token amount of setback, it could drive chamber pressures well above limits.

Currently, I only own one 40 S&W pistol ... a Glock Mod 35 (2nd generation). I do not carry this gun nor do I ever plan to so my situation is different than those using a 40 for a carry pistol. Personally, I don't think it is worth the risk of "setting cartridges aside for practice when there is a notable setback". I value my guns and my body more than the cost of a box of ammo. If you have ever seen the results of a Kaboom, you would likely change your mind.
 

·
Registered
Joined
·
256 Posts
40 S&W 165 gr Gold Dot setback data

I'm appending these data to this older thread because the posts here (especially Iowegan @ post 10) explain the problem.

This was an informal test done over a couple of years.
- gun is a Gen3 Glock27
- ammo is a 20 round box of 165 gr Speer Gold Dot, their product 23970.

I treated the gun as a bedside table gun … loaded @ 9+1, occasionally unloaded by dropping the mag, ejecting the round in the barrel, and reloaded by inserting the mag, slingshot, top off the mag with the ejected round. This would correspond to SD storage with occasional unloading to clean or to render safe for visitors.

Measurements are cartridge OAL using 6" dial calipers checked to a Mitutoyo Gage block set over 0.0625" to 2.000". These calipers read @ 0.001". Fourth place shown below is essentially +/- 0.0005 by eye. Data below show the minimum measurement for each round as there is some positional variation @ each round due to irregularities in the bullet nose.

8 unused, unchambered rounds:
1.1225, 1.1215, 1.1220, 1.1210, 1.1205, 1.1220, 1.1230, 1.1210
Avg: 1.1217
Max: 1.1230
Min: 1.1205

10 rounds, magazine use only … these were never chambered:
1.1205, 1.1210, 1.1210, 1.1205, 1.1220, 1.1210, 1.1200, 1.1200, 1.1230, 1.1210
Avg: 1.1210
Max: 1.1230
Min: 1.1200

2 rounds, noticeably short … these are the rounds that were ejected and chambered repeatedly:
1.1010, 1.0860

For someone with access to QuickLoad:
Speer lists this product as 1150 fps (muzzle) with a 4" test barrel.
tnoutdoors9 has chronographed an example of this product at 1137 fps (@10 ft, 5 shot avg) from a G23 (4.01" barrel). See: youtube v=s8dezgRVqs0
 
1 - 17 of 17 Posts
Top