Help with 357SIG FTF diagnosis pls

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I recently acquired an Aero Survival Rifle with 9mm and 357SIG barrels. The PO warned me that the 357SIG converision had never run right and he would help me resolve it with the dealer if I desired. Since he is the original owner who ordered and purchased the gun and conversion I assume they will make it right if we send it in his name. However I thought I'd take a crack at it first, or more accurately, get you guys to take a crack at it first. ;)

So what's happening is it's FTFing, nosing into the side of the barrel to the left of the feedramp. It is sensitive to magazine spring tension. It will typically fire the last 5 rounds or so malfunction free, but 10 or more rounds in the mag guarantees one or more (usually more) FTFs. I'm using stock G22 .40S&W mags, that have always worked for 357SIG for me in the past, and I used 2 different ones with precisely the same behavior. The rounds miss the feedramp by so much I can't imagine that the .40 mags are the problem but I'm not ruling it out. The conversion consists of the barrel and a .40/10mm bolt face, so if it's not the mags it's likely to be one of those things. I'm betting it's a mag or bolt face issue.

Anyway here's some pics and a short vid: Any expert advice before putting a stamp on it and shipping it in?

Twice it did this:

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But many times it did this:

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FTF in Action!:

 
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What about your support hand? Could it be weird pressure, or additional pressure, when firing? When you're low in the mag it may be a moot factor, but full or Fuller mag may experience it? Same idea as a G26 with the pinky extension getting squeezed.
 
Yes my finger was against the mag release and my weak hand was halfway gripping the mag. Ideally I shouldn't have done those things but I never put any pressure on the button and I hold it the same with the low round count in the mag when it runs good, and with 9mm. I've had other Glock mag PCCs (JRC, Sub200) in 9mm and 40 and they weren't sensitive to gripping the mag when firing. Good thing to point out though I should try shooting it without doing those things just to make sure.
 
I guess it has something to do with the 357 pressure which would point back to timing?
 
I’m thinking that the feed lips are different shapes for 40 and 357sig. First thing I’d do is try a proper mag.
 
Mag well is of the wrong angle.

Poor design.
Works fine with 9mm which uses a different barrel and bolt. These have been selling for years, I think a design flaw of that magnitude would have killed it or have been resolved by now.

The trigger housing and mag well are a separate piece so you can swap it out for the larger mag one to run 10mm or 45. There is some adjustment possible of the tension between the mag well and the body via the screws that the pins engage to hold it on. I may try playing with that, but again it runs fine with 9mm.
 
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Did you try different ammo? My AR9 that runs Colt mags will NOT run the German IMI 9mm that is really nice stuff because the bullet is a very short, round nose. My CZ Scorpion and Glocks chew the stuff up and spit it out. But the AR9 doesn't like the feed angle and will pretty much jam up just like the OP's pictures.

OP, try a .357 round with a larger/longer bullet and see if the problem persists. If it does, then I am with everyone else in that it is a combination of bad angle and pressure.
 
Thanks for all the replies.

Just for grins, there are a couple of things in the video that I thought someone would mention:

1) 1600fps! You can hear me state the velocities for the rounds that didn't jam. This was GA Arms 124gr FMJ rated at 1300fps. Can't wait to load some rounds with the 90gr 380 bullets I have laying around. :D

2) In the very last segment you can see the spent case sail away looking through the dual ejection ports. Thought that was kinda cool.
 
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Works fine with 9mm which uses a different barrel and bolt. These have been selling for years, I think a design flaw of that magnitude would have killed it or have been resolved by now.

The trigger housing and mag well are a separate piece so you can swap it out for the larger mag one to run 10mm or 45. There is some adjustment possible of the tension between the mag well and the body via the screws that the pins engage to hold it on. I may try playing with that, but again it runs fine with 9mm.

Your solution to my statement is right. And my statement supports your solution.

Think about it.
 
So what's happening is it's FTFing, nosing into the side of the barrel to the left of the feedramp. It is sensitive to magazine spring tension. It will typically fire the last 5 rounds or so malfunction free, but 10 or more rounds in the mag guarantees one or more (usually more) FTFs. I'm using stock G22 .40S&W mags, that have always worked for 357SIG for me in the past, and I used 2 different ones with precisely the same behavior.
I think @JBoyette is right. One problem with angled mags is that the first rounds out of the mag may not be angled up, or have as much pressure pushing the front of the round up, as do the last rounds in the mag. From what you describe, it sounds like this may be the problem. I would try tweaking the feed lips so that the front of the rounds are riding a little higher.
 
I think @JBoyette is right. One problem with angled mags is that the first rounds out of the mag may not be angled up, or have as much pressure pushing the front of the round up, as do the last rounds in the mag. From what you describe, it sounds like this may be the problem. I would try tweaking the feed lips so that the front of the rounds are riding a little higher.
The Glock 357SIG mags are the same as the 40s except for the follower that angles them up slightly more. The only problem anyone has reported using the 40 mags is if loaded to 100% full capacity the very first round would not feed. It sounds like my problem is just a worse manifestation of this. I have two 357SIG followers on order.
 
Here's one other thing to consider, look at the chamber. There's no hint of a feed ramp going in. Look at a stock Glock barrel and you'll see what I'm talking about.
 
Here's one other thing to consider, look at the chamber. There's no hint of a feed ramp going in. Look at a stock Glock barrel and you'll see what I'm talking about.
Oh there is, it's just not showing in the pics because the round hits the barrel face to the left of the feed ramp. I should have taken a pic or two from the other side.
 

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Got my 357SIG followers today. Will test this weekend. They do angle the round up more than the 40. The sig is on the left in the last 2 pics.

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So frustrating. :mad: I contacted TNW weeks ago about this and they ran the serial number and wanted me to try a new ejector that they shipped to me. I know, I know it's a feeding issue but they said something about the way it could affect feeding too, so I had to play by their rules so I installed it and of course no difference. So it cost me $45 to ship it to them in Oregon, and it appeared that they sent it back the same day they got it. Keep in mind it takes a week or more each way. I picked it up today, the invoice said they replaced everything but the receiver, lower, barrel, stock (I took that to mean they replaced the bolt, bolt carrier and buffer tube) and fired 60 rounds without issues. I take it out of the box, load a mag (the same one I had sent them) and the 2nd round jams vertically in the feedramp like the first pic above. 4th round same thing. Load different ammo, no better. About 40% of the rounds jammed.

I do believe they did something because it used to have two feeding issues shown above and now it's only the vertical jamming in the feedramp, but the overall frequency of jamming is the same. I find it hard to believe their claim of 60 rounds with no issues. I'm going to find out what ammo they used and see. I'm not sure where we go from here, but so far I'm sorely unimpressed with their customer service. If they can't make a 357SIG carbine run right they just need to come out and admit it.
 
Works fine with 9mm which uses a different barrel and bolt. These have been selling for years, I think a design flaw of that magnitude would have killed it or have been resolved by now.

The trigger housing and mag well are a separate piece so you can swap it out for the larger mag one to run 10mm or 45. There is some adjustment possible of the tension between the mag well and the body via the screws that the pins engage to hold it on. I may try playing with that, but again it runs fine with 9mm.

So I take it you are now removing emotions from my post so many moons ago and see my point here right?
 
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So I take it you are now removing emotions from my post so many moons ago and see my point here right?
What the hell are you talking about John?

Edited to add:
You know, your first post was not helpful because as usual you didn't provide any supporting evidence or explanation. I responded with facts that supported why I thought differently, and as usual you didn't respond directly. Your second post I could not decipher as anything other than psychobabble.

I'm sorry if not taking your abrupt unexplained conclusion as the word of God offended you. Us mortals typically discuss things and share our ideas and explanations to come to a conclusion.

So let's try this again. Please explain how the magwell could be at the wrong angle when all other firearms that swap between these calibers use the same magwells to feed 9mm, 40, and 357 from Glock mags with just a barrel and/or mag swap and as I said it feeds 9mm 100%. I sincerely want to know how you came to that conclusion. You could absolutely be right but you don't convince people without explaining why. I admit I don't know everything, please put your instructor hat on and teach me something.
 
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Success! So I called and spoke with customer support and they actually were very helpful, even said they would order some Ga Arms ammo to try and sent me a prepaid return label. They had used Remington FMJ. So now having a little more confidence in them I decided to try some different ammo before sending it back and I'm glad I did. I purchased 3 more types of 357SIG and all of them fed well, other than one of the Hornady hollowpoints but it was the last round in the mag, so don't know what that was about. So it was essentially my ammo all along, or at least since they replaced the parts because the previous owner also had problems with it. I was using two kinds of ammo and thought that was enough, but they were both from the same manufacturer.

There are two things about the ammo I was using which could have been the issue. Left to right below: Hornady 147gr FTX, Sig Sauer 125gr, American Eagle 125gr, and the two that were giving me problems, GA Arms 125gr and GA Arms 125gr Speer HP(GD). The three on the left feed well, the two on the right don't. First and obvious in both pictures is the GA Arms ammo had larger meplats than the rest. I didn't select on meplat size, this is just what Mace Sports in Mebane had in stock, so I think maybe the GA Arms FMJ may have a larger Meplat than normal. Second, look at the second pic at the difference in neck length between the GA Arms rounds and the others. I measured them and the other three are right on the money as to what the spec calls for, while the GA Arms have 3.5 mm less distance between the base of the case and where the shoulder starts. So they have that much less contact with the follower and it's shifted to the rear which could affect not only how it sits on the follower but how it comes off of it when feeding. I got the spec numbers from Wikipedia and there was no acceptable range given, just absolute values and the other three brands were as close as I could measure to the spec so I don't know if the GA Arms are technically "out of spec" but it sure looks like they are out of the ordinary compared to the other 3 brands.

Edited to add: Something else I just notice in the pic below (yeah I'm no Sherlock Holmes). Both the GA Arms also have shorter OALs than the rest. This combined with the wider meplats would naturally make them less likely to feed well.

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I haven't tried large wide mouth hollowpoints like the Speer GD in cases that look to be in spec yet, but to be honest I won't be that upset if they don't feed well now that I know I've got many other options, and frankly now I'm broke after buying all this 357SIG, lol. I plan on buying dies and experimenting with various bullets, should be easy to break 2000fps out of this carbine especially with lighter bullets. Now I can begin since I know it won't all be in vain. I'm stoked! Thanks for all the attempts to help. I certainly learned something.
 
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