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mscott

STI Trubor help, please .... won't run with major ammo

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Hello: Did you radius the firing pin stop like Aftec suggests? I would look at recoil spring coil bind also. It may be hitting so hard against the recoil spring it is bouncing when shooting major. Cut 3 coils off and try again. I would try the 8lb spring or a 9lb if you have one. Thanks, Eric

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Yes, firing pin stop has radius per Aftec instructions. I have not tried cutting coils on recoil spring. Have mixed feeling on that, but really can't hurt much at this point.

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Tried cutting three coils off of 8 pound spring. Ran 3 mags. No better

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try your OAL @ 1.23

That's pretty dang long for 9mm. Sounds like what 38 supers load to.

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I was actually thinking about that. Not sure if I could do it with 115s though. I thought about removing the spacers in a couple mags and seeing how long I could load them. It seems like 38 super guns about always run, so maybe the longer ammo helps? I don't know, but it's something to try.

One other thing is I'm going to order and load some 147s to major and see if that does anything for me.

I really don't know at this point.

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On the major ammo, is all the the ones that jammed the same head stamp?

It might be some of the brass is softer than others, and the higher chamber pressure is causing the brass stick in the chamber

Enough to slow the slide down and not eject.

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try your OAL @ 1.23

That's pretty dang long for 9mm. Sounds like what 38 supers load to.

yes sorry that OAL is for 38sc

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try to remove a bit from the inside of the extractor so it cams in a little more if it hits the extractor tunnel you can give as much tension you want

make sure there is a 9mm extractor in your gun (on a STI extractor the caliber is on the inside)

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I'm going a little different. Seems like you've done a lot with extractor and ejector as everyone is suggesting. I think the key to your problem lies in that it always runs perfect with minor loads and won't ever run well with major loads and has an erratic ejection pattern.

I'd look at the culprit being the combination of your chamber and loads. The major loads with your particular barrel could be causing the brass to stick in your chamber and slow slide action. Have you played with function testing down from 174 pf or up from 130 pf to see where the malfunctioning begins? Have you ever had total failures to extract?

Edited by theWacoKid

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I'd look at the combination of your chamber and loads. The major loads with your particular barrel could be causing the brass to stick in your chamber and slow slide action. Have you played with function testing down from 174 pf or up from 130 pf to see where the malfunctioning begins?

+1 Gotta be the ejector or the ammo.

Have you tried any other major ammo? :cheers:

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I'll get a couple pics of the ejector. It is pinned and fits tight. Nothing broken. The other one I shortened was pinned as well.

As far as ammo goes I did load about 100 rounds of 115s with 8.0 of HS6. I'm sure that's below major, but didn't chrono it. Gun didn't like that either. I don't know where the threshold is where the jams start happening, but I know it runs on 6.5 of HS6 with the 115s.

I also have some major ammo loaded with 124s and AutoComp, but it is no more reliable. I thought the powder burn rate of bullet weight being different might help, but it didn't.

No problem with extracting from chamber (except 1 single time in the guns life and with the stock extractor). It's pretty much always the case caught by the slide while feeding the next loaded round.

Guess I could use some Flitz and polish the chamber.

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Have you checked your ejector to make sure it is not too long? If the ejector is too long, the increased blow back from the hotter loads could cause timing issues, resulting in erratic ejection. I had a similar problem with one of my open guns and the problem was solved by filing down the ejector and tuning it. With the shorter ejector, the problem was solved.

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Couple of ejector pics below. Stock one is in the gun and another one I shortened.

On the short one, I went to the range and tried it when I shortened it a little and still no good. I shortened it some more and tried it. Still no good. It's down to about .130 long, ejected brass is all over the place including jamming between slide and barrel hood. Short one was pinned as well.

Also have the Brazos tuned ejector, which did nothing for my problem.

post-7061-0-15472200-1440465024_thumb.jp

post-7061-0-35690600-1440465039_thumb.jp

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My first thought was coil bind. Since you check that, try running the gun as a single shot. load round remove mag and shoot. Make sure the top round in the mag isn't too high hitting the ejector. Something is slowing your slide down to cause that jam with a 90* mount

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Does it run without the scope mount?

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Couple of ejector pics below. Stock one is in the gun and another one I shortened.

On the short one, I went to the range and tried it when I shortened it a little and still no good. I shortened it some more and tried it. Still no good. It's down to about .130 long, ejected brass is all over the place including jamming between slide and barrel hood. Short one was pinned as well.

Also have the Brazos tuned ejector, which did nothing for my problem.

That is extremely short. I only took about about .016" off mine as that was all that was needed.

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