Jam That Won't Die -- Please Help!!

[ehowell12]

18 minutes ago, Benji said:

Is there any chance that the recoil spring isn't trimmed correctly and that's not allowing the slide to travel back far enough to give the round time/space to move up to be loaded? 

 

Not in this case. From the recoil system perspective, it's just a plain ol' 5" 1911/2011. 

[ehowell12]

UPDATE

 

My RN bullets arrived - hand cycling with half-full and full mags feel much better. I haven't been able to replicate the malfunction my hand with these bullets - that wasn't the case for the JHPs. It'll be tested at a local match Saturday, because I like to live dangerously . 

STI Gen2 mags will arrive either Saturday or Tuesday - I'll report back with results. 

 

Thanks to all who took the time to read and respond. Even if RN makes the problem go away, I still want to fix the root cause, and will be taking a look at all the things that @caspian guy, @Nolan, and others recommended. 

[Benji]

On 8/30/2019 at 11:05 AM, ehowell12 said:

 

Not in this case. From the recoil system perspective, it's just a plain ol' 5" 1911/2011. 

That doesn't mean it's not trimmed properly. Different guns and different springs don't always play well with each other. I have to trim all my recoil springs for my 2011... if it's not that then cool though!

[ehowell12]

UPDATE

Well, folks, I think my issue is resolved. Thank you to everyone who made suggestions - hopefully this will help others that fight similar issues. 

 

In a roundabout way, all the mags went back to MBX for testing. The tubes seemed to be in spec, and in their current configuration ran 2-250 rounds in two test guns. In my case, the MBX tubes do seem to like MBX followers the best, even though many replace them with other followers.

 

Three of four STI G2 mags with grams guts had the same nose dive issue (2x140 and 2x170). The 170s have gone to Grams for tuning, and I haven't gotten them back yet.  

 

What I found: 

The gun / mags / system hates the typical JHP profile - PD, Hornady XTP, etc. I hate this, but luckily there are lots of good options for jacketed bullets. 

115gr PD JHP @ 1.16" - NOPE

115gr PD JHP @ 1.18" - NOPE

115gr MG CMJ @ 1.16" - NOPE

115gr MG CMJ @ 1.18" - Better, but NOPE

At this point I decided to abandon the 115s, and go to 124s only to be able to load longer, since that with a RN bullet seemed to be the first sign of positive results. 

124gr Everglades RN JHP V2 @ 1.16" - NOPE

124gr Everglades RN JHP V2 @ 1.18" - Better than 1.16", but NOPE

124gr Everglades RN JHP V2 @ 1.20" - Best results so far - only one nosedive in 150 rounds. This is up from at least 1 per mag.

Since the MG CMJs are much more RN that even the Everglades RN JHP, I decided to try those in a similar manner as the Everglades RN JHP.

124gr MG CMJ @ 1.20" - WINNER!!! (at 170pf)

**Note: I do have to use an undersized size die to get sufficient neck tension at 1.20". Redding or EGW have worked. 

**I do not get any bullet setback on multiple chamberings, while pushing it into the bench, or when forcing a nosedive. The crimp is unchanged throughout all the mentioned loads. 

 

Solutions: 

1) So far, I'm 350 (live) rounds into this load, with (knock on wood) zero nosedives! Additionally, I have not been able to recreate the malfunction by hand cycling, neither slow or fast.

2) Also, I have employed a trick on loading mags recommended by Beven Grams - every 10 or so rounds:

        1. Use your thumb to press down on the rim of the top round on the mag to slightly compress the spring 

        2. While holding #1, tap/smack the bottom of the basepad with your other hand.

        3. Feel the rounds settle into a cleaner stack in the mag, and watch the gap between the 1st and 2nd round go away. 

        So far, I've had no problems using this trick with an uplula or loading by hand - again, only 500 or so rounds into it, but that's way better than where I was. 

3) I've settled on an untrimmed 9lb variable recoil spring through most of the above testing - might try an 8lb variable in the future. At this point I'm reasonably confident that the recoil spring weight was not the culprit. 

 

Now, time to go shoot some matches!!  

 

[Sarge]

Glad you found a band aide that works for now but something is wrong with the gun if it only feeds one specific bullet at one specific oal. 

[ehowell12]

8 minutes ago, Sarge said:

Glad you found a band aide that works for now but something is wrong with the gun if it only feeds one specific bullet at one specific oal. 

 

I'm still open to suggestions - I've investigated all of the ones thus far, and have found "non-issue" results.

I agree, I shouldn't be limited to one bullet profile, but how often do we hear "I only use X bullets" or "It only like Y bullets" 

[Sarge]

1 hour ago, ehowell12 said:

 

 how often do we hear "I only use X bullets" or "It only like Y bullets" 

Or, “a properly built gun should run damn near any bullet”?

[ehowell12]

4 minutes ago, Sarge said:

Or, “a properly built gun should run damn near any bullet”?

 

Cool, thanks for your help  

[JimF38sup]

If the MG 125 CMJ is a winner you should try their 125 JHP for 357 Sig. It has a longer body. They work well in 38 supper and 9x25 Dillon.

[Ssanders224]

Ethan, 

 

While it's good that you found a "band-aid", a system that is THAT picky about cartridge length and bullet profile is almost certainly going to cause you headaches again in the future, or worse, not truly run 100%. You don't want to operate on the ragged edge of reliability. 

 

To be honest, I'm betting this is an easy fix, but It's all but impossible to diagnose here. Have you tried someone else's mags in the gun? Your mags in someone else's gun? 

[d_striker]

Shoot a couple of rounds in a mag that's mostly loaded.  Then remove magazine and look at how far forward the top round in the magazine is.  If the top round is pretty far forward, this could be your problem.  At least it has been for me in pretty much every Open gun I've ever shot.  Once that top round gets dragged forward by the bottom of the breach face or rough/sharp edges on the disconnector rail, the round is far more likely to nose dive as it's not being correctly supported by the magazine feed lips.  This is completely irrespective of whether your mag lips are correctly spaced or not.

 

Break the sharp edge at the bottom of the breach face with a needle file and slight bevel on it.

 

Then take the needle file to the disconnector rail surface.  Keep file as flat as possible so it just hits high spots and any rough portions.  Then sand with increasingly finer grades of sandpaper and then polish.  

[ehowell12]

1 hour ago, Ssanders224 said:

Ethan, 

 

While it's good that you found a "band-aid", a system that is THAT picky about cartridge length and bullet profile is almost certainly going to cause you headaches again in the future, or worse, not truly run 100%. You don't want to operate on the ragged edge of reliability. 

 

To be honest, I'm betting this is an easy fix, but It's all but impossible to diagnose here. Have you tried someone else's mags in the gun? Your mags in someone else's gun? 

 

I agree with all of that. I have tried a few different mag configurations - 

MBX - 170s, 155s, 140s, with all MBX guts, with Grams guts, with Grams springs and Taran followers

STI Gen2 - 140s and 170s, with Grams guts. The 170s are currently with Beven being tuned. 

I do know of someone with some old skool SV mags that I could try, but were a few hours apart and haven't landed at the same match in a few months, unfortunately. 

 

With normal length 9major ammo (1.16"-1.17") I had nosedives in all of the above. In all of the above cases, a more RN profile bullet than a JHP helped, even at 1.16", but did not go away. Even at 1.20", with Everglades RN JHP still nosedived 1/~100 rounds or so. 

 

Right now, with the MG CMJ 124 at 1.20" I've yet to have a nose dive in 500 rounds. MBX mags with MBX guts and STI Gen2 140s with grams guts. 

 

Trust me, I reallllly don't want to be tied to one bullet from one manufacturer . 

 

1 hour ago, d_striker said:

Break the sharp edge at the bottom of the breach face with a needle file and slight bevel on it.

 

There's, what I would call, a sufficient bevel at the bottom of the breech face. I'll get a pic uploaded of it shortly. 

 

With the shorter ammo, I did notice the top round being pulled forward. Enough to potentially cause a problem. However, I do not see it nearly as much with the long ammo. Maybe because it physically can't be pulled far enough forward to cause a problem. 

[CHA-LEE]

Load up a mag fully and take some close up pictures of the top round from the side and from the front. This will give us a good understanding of how the brass is shaped and how the rounds are stacking in the magazines.

[Aircooled6racer]

Hello: I just found this today and I have not read all of it yet(just 4 posts so far). How much overhang does the barrel have into the magazine tunnel? Thanks, Eric

[ehowell12]

On 10/22/2019 at 4:06 PM, CHA-LEE said:

Load up a mag fully and take some close up pictures of the top round from the side and from the front.

 

170mm MBX full at 29 rounds - MBX guts. The pics are after doing the "Grams" trick I mentioned above. Before that there is a slight gap, but it always goes away afterwards. The gap seems to grow with shorter ammo. 

 

On 10/22/2019 at 2:11 PM, d_striker said:

 

Break the sharp edge at the bottom of the breach face

 

Pics attached! Excuse the dirty gun. 

 

22 hours ago, Aircooled6racer said:

How much overhang does the barrel have into the magazine tunnel?

 

Very little, if any. This was my first thought when the malfunctions started - We removed material until there was no overhang while in battery. Even very little overhang when the slide is locked back.

[Aircooled6racer]

Hello: Looks like the bottom of the slide could use a radius and the extractor could have a lead put on it to help the round get under it. Thanks, Eric

[d_striker]

That disco rail looks pretty rough.  

[TONY BARONE]

As Eric stated your extractor needs work.

[CHA-LEE]

Based on those pictures here is what I see needs fixed.....

 

1 - Try using magazine spacers and a normal "Short" OAL. The metal magazine spacer in the back of the tube will bias the rounds forward which will help minimize nose diving.

 

2 - The angle cut at the bottom of the breach face looks like it still has a sharp angle that can catch on the brass. Round off the sharp angles to make the transition from the breach face to the disconnctor rib smooth. While you are at it, smooth out and polish the under side of the disconnector rib from the breach face angle all the way to the back of the slide were the disconnector notch is cut. This rib needs to be flat and smooth as butter.

 

3 - If the tips of the bullets are flaring out just below the top round after you load the magazine then you are dealing with a brass wall straightness issue. Are you using an undersize die in your press that would give the brass a coke bottle shape? The coke bottle shape promotes nose diving as the top round slides across the brass case underneath it. The best way to verify this is to get some factory 9mm ammo (which will not have a coke bottle brass shape) and load up the magazine to see if the tip of bullets fanning out issue still happens.

 

4 - The third picture from the top shows the front of the magazine and tip of bullet. The top left diagonal angle of the front of the tube has a divot beat into it. This is evidence of the bottom of the barrel feed ramp is bashing into the front edge of the magazine every time the barrel unlocks and drops down and back while cycling. This "Bashing" every shot between the barrel feed ramp and mag tube does a great job of changing the front to back registration of the rounds within the magazine. If the front to back registration of the rounds are inconsistent then you are going to get inconsistent feeding because the breach face is picking up the next round at a different front to back position. The evidence of this bashing will also be seen on the bottom right corner of the barrel feed ramp. You can fix this issue two ways. First, cut the bottom of the barrel feed ramp forward so that its depth matches the inside of the frame when the barrel is in the fully down and back position. That should have been done by whoever built the gun in the first place. The Second fix is to cut the diagonal portion of the magazine tube down far enough so that the barrel feed ramp can't hit it. To me the second option is a band aid fix to a barrel fit that wasn't done right in the first place, but it should also work. 

[CHA-LEE]

The extractor likely needs tuned as well, but that needs to happen AFTER you figure out the Nose Dive jams. On most Nose Dive jams the rim of the case isn't even high enough to start engaging the extractor hook as the rim is still at the bottom of the breach face/disconnector rib and still needs to clear the magazine feed lips.

[Kema]

How it looks like if you install barrel without slide(just the link)?

 

Alignment of the first round vs. chamber?

 

What main spring? 

 

I don't think it's the magazine, to rule the extractor out, just use very little tension on extractor, probly you get extraction issues but that's easier to fix after all. Extractor issue usually puts rounds nose up.

[ehowell12]

On 10/24/2019 at 1:22 PM, CHA-LEE said:

Based on those pictures here is what I see needs fixed.....

 

1 - Try using magazine spacers and a normal "Short" OAL. The metal magazine spacer in the back of the tube will bias the rounds forward which will help minimize nose diving.

 

2 - The angle cut at the bottom of the breach face looks like it still has a sharp angle that can catch on the brass. Round off the sharp angles to make the transition from the breach face to the disconnctor rib smooth. While you are at it, smooth out and polish the under side of the disconnector rib from the breach face angle all the way to the back of the slide were the disconnector notch is cut. This rib needs to be flat and smooth as butter.

 

3 - If the tips of the bullets are flaring out just below the top round after you load the magazine then you are dealing with a brass wall straightness issue. Are you using an undersize die in your press that would give the brass a coke bottle shape? The coke bottle shape promotes nose diving as the top round slides across the brass case underneath it. The best way to verify this is to get some factory 9mm ammo (which will not have a coke bottle brass shape) and load up the magazine to see if the tip of bullets fanning out issue still happens.

 

4 - The third picture from the top shows the front of the magazine and tip of bullet. The top left diagonal angle of the front of the tube has a divot beat into it. This is evidence of the bottom of the barrel feed ramp is bashing into the front edge of the magazine every time the barrel unlocks and drops down and back while cycling. This "Bashing" every shot between the barrel feed ramp and mag tube does a great job of changing the front to back registration of the rounds within the magazine. If the front to back registration of the rounds are inconsistent then you are going to get inconsistent feeding because the breach face is picking up the next round at a different front to back position. The evidence of this bashing will also be seen on the bottom right corner of the barrel feed ramp. You can fix this issue two ways. First, cut the bottom of the barrel feed ramp forward so that its depth matches the inside of the frame when the barrel is in the fully down and back position. That should have been done by whoever built the gun in the first place. The Second fix is to cut the diagonal portion of the magazine tube down far enough so that the barrel feed ramp can't hit it. To me the second option is a band aid fix to a barrel fit that wasn't done right in the first place, but it should also work

@CHA-LEE, Thank you for all of the recommendations! I'll look into these for sure. So far, here's what I have:

 

1) I've also been curious about this - I do plan on looking into spacers with the STI G2 tubes and my old 1.16" ammo when I get them back from Grams.  

 

2) A couple days ago I did round that edge some and polish the disco rail down to 2000 grit. I do think this helped a lot, but I haven't seen real results yet - I've only shot the long 1.20 ammo (that ran before) since. Again, I do plan on doing more testing with short, JHP ammo. 

 

3) This makes a lot of sense. I do use an undersized die currently, but only recently went to that from a Mighty Armory size die. I saw more of a gap before the U-die and long ammo somehow. 

 

4) One of the first things the gunsmith and I did was cut the feed ramp as you described. That particular mag tube is an old one that has had a previous life in a lot of different guns (one of which was basically a bolt action), so  that's likely where that came from. Similar marks don't exist on the other mags, and there aren't any signs of mag to feed ramp contact on the barrel 

 

5) Agreed on tuning the extractor as well. Also agreed on the timing of doing so.

Side question: What kind of tension is to be expected and "spec" for an Aftec extractor? The standard 2-4lbs for other extractors seems to be entirely too much tension, and extraction pattern is normal and consistent at ~1.25lbs. 

 

[CHA-LEE]

From your response the number one issue sounds like the Undersize die in your press. If the brass has an excessive coke bottle shape you will ALWAYS battle nose dive issues. This correlation also fits nicely into what you have observed where you are having the same nose dive issues using varied vintage/brand magazines, bullets and OAL's.

 

From a Extractor feeding perspective there are three important elements that need to be tuned.....

 

The first is the lead in angle on the bottom of the extractor hook. The bottom of the extractor hook needs a slight forward angle so the rim of the case can get under the extractor while the base of the case is climbing up the breach face at an upward tilt angle. Most extractors have a very minimal angle and the inner edge of the case rim can get caught on the bottom edge of the extractor as the case is climbing up the breach face. For AFTEC's I always had to add a little more angle on the bottom corner of the extractor hook.

 

The Second tuning component is how the hook engages the rim of the case. For 9mm I have had the best luck with tuning the hook so that when a case is retained both the tip of the hook and the base of the hook are both touching the case. Most 9mm extractors are made so that only the base of the hook engaged the outer rim of the case and this dramatically reduces the overall "Grab" the hook has on the rim of the case. With 9mm Major you need as much case rim engagement as you can get so its best to tune the hook so the tip is engaging the inner portion of the case rim. Having both the tip and the base engage at the same time reduces the overall friction when the case pushed up into the extractor. Also keep in mind that 9mm brass varies dramatically from one manufacture to the next when it comes to the depth of the inner case rim cut or the height and angle of the forward relief cut. Shooting random mixed head stamp brass in 9major is a recipe for failure. 

 

The third tuning component is the extractor pinching pressure on the rim of the case. With 9mm Major ammo you usually need much more extractor Pinch force than 38 Super/Comp. This is because the 9mm case is being exposed to insane levels of pressure (Well beyond SAAMI Spec) and the case length is shorter which translates to a crazy amount of friction between the outer sides of the case and the inner portion of the chamber when it is being extracted. Its essentially "Harder" to pull the case out of the chamber due to the increased friction between the brass and chamber. The other sub optimal factor with 9mm brass is that the overall case rim depth is much less than 38 Super/Comp. So you are dealing with a scenario where it takes a lot more effort to pull the case out of the chamber due to the increased friction and there is less case rim to pull on during that process. Both of these "Issues" usually translate to needing more extractor pinch force than normal. The biggest challenge with using an AFTEC is that tuning the pinching force isn't easy due to the solid design of the whole extractor. Some people have had luck with bending the front portion of the AFTEC to change the pinch force but that weakens the metal and you also risk breaking it during the bending process. Some people like to play around with using only 1 spring instead of 2, but that is also not optimal because it usually causes the spring cup to break because there is uneven pressure on the "Wings" of the cup. Then there is the proper tuning of the firing pin stop to extractor so that the AFTEC can move freely in and out while NOT moving in a clocking direction. This last portion is what most people screw up when installing an AFTEC.

 

I used AFTEC's in my Limited and Open guns for several years and they worked great. But they also required tuning to get them setup properly in whatever gun I put them in. At some point the durability of the AFTEC's started going south as the edge of the extractor hook tip would get rounded off way faster than the "Older" vintage ones. When that happened I switched over to the EGW HD Extractors and have had ZERO issues with them. The EGW HD extractors are high quality and much easier to tune in all aspects versus the AFTEC. They also hold their pinch depth and pressure settings much better than standard extractors. The EGW HD extractors are not drop in with no tuning needed. They still need to be tuned but they usually require much less tuning than most other extractors. Basically, they start off much closer to where the optimal setup will be, especially in the hook area.

 

With all of this being said, there are a bunch of Extractor tuning threads on this forum already. Do some digging and you will find a lot of good information on how to set them up properly for whatever caliber you are using. Or let a competent gunsmith get it figured out for you.

Edited October 28, 2019 by CHA-LEE