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38SC to 9mm major help


R.Elliott

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Good morning all:

I have recently made the decision to switch to 9mm major from .38 Supercomp.  I simply cannot handle the cost of the brass or the headache of sourcing it anymore in Canada and while I have been reticent to make the change, everything I'm reading on-line (mostly here) seems to indicate that the magic ju ju has been worked out now so it's safe to proceed.  However, I'm having issues that are stumping me and could use some assistance from the enos hive-mind. I really want get this sorted out before the major match season really gets underway so

I can focus on shooting and not on equipment.  Tried searching but I'm not finding what I'm looking for.

I have recently converted both of my Open guns to 9mm major and I am having trouble getting them dialed in to run correctly.

In primary gun the issue is inconsistent extraction/ejection.  I end up with an empty in the chamber and a double feed, only intermittently.  Most brass ejects about two feet to the right with some just falling out of the gun.

Primary gun: 5.5" Sheuman hybrid barrel with no ports, 3 port comp, I've tried Aftec and EGW extractors so far, SVI 140 and 170 mags.  RTS2 on DoubleTap mount.  8lb standard Wolf recoil spring and 17lb mainspring.

170's caused the most failures at last match and the do sit higher than the 140's.  They were bringing the top round in the stack and the mag feed lip into contact with the ejector. This has since been clearanced for top round and mag clearance but the problem persists.

Backup gun is set up the same way but in addition to extraction and ejection failures I'm also getting stoppages when going into battery.  Last .25" it will stop.

All rounds have been chamber checked and roll sized.  All punk in both barrels no problem.

Load is:

8.0 gr. HS6

125 gr. Zero

1.175" oal

170 power factor

9maj2.rv

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Mine had a lot of issues going into battery. It would hang up occasionally and always felt like it chugged a round in rather than a smooth feed. I was loading long because everybody says too. I now load at 1.150 and all my issues are gone and it cycles so smooth you can't tell it it's dry or picking up a round. 

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17 minutes ago, ShortBus said:

Mine had a lot of issues going into battery. It would hang up occasionally and always felt like it chugged a round in rather than a smooth feed. I was loading long because everybody says too. I now load at 1.150 and all my issues are gone and it cycles so smooth you can't tell it it's dry or picking up a round. 

That sounds pretty nice.  No issues on ejection?

I've wondered about loading shorter but the gun ran beautifully in 38SC @ 1.235" and of course I was aiming for a longer oal to keep pressures down.  You would think the shorter round would make the breakover too steep but.....perhaps the tapered case changes the geometry enough.  I notice a lot of folks here are loading to 1.65" or 1.70"  I guess maybe I should eliminate that as a variable.

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I think my gun was a bit of an oddball and the stroke was weird. 

 

Never had a lot of FTEctract issues. I had a few, then bought new springs for the aftec and it's ran great since. 

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Check out the Atlas Gunworks videos on YouTube. Magazines should be checked first. Then test extractor tension following their guidance. I had a similar issue with feeding, bullet was hitting low on the feed ramp. There was too much tension on the extractor and the extractor hook needed some work and then polishing in the bottom side of the extractor. Essentially when the slide was moving forward the bullet was not able to slide up the breech face smoothly.

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Did you convert the guns with new barrels?  Are the Schuemanns AET's?  All failures to extract and failures to go into battery I've dealt with have been my AET barrel. 

 

As for the ejection it will just take the right tune of mag catch, extractor, and ejector. 

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New barrels, AET's.  Sure hope I don't have to replace those.

Will look for the Atlas stuff.  Aftecs are new with new springs.  EGW extractors have been fitted and polished per usual protocols for 9mm extractors. 

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before touching the extractor, check to see if the round is touching the extractor?    if the round is hanging up on the ramp, it may not be near the extractor.

so then...try a shorter OAL and see if that works.   back off the powder charge and try 1.160

 

good luck

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So I've found AET 'finished' chambers are very snug in the 9x19 variety. I found it unacceptable. I have been reaming both the chamber and throat in increments with much improvement but not yet to perfection. It's something about their specs and it's the same problem as you're having. 

 

The previous owner loaded much shorter, but I don't do that. However it is a shortcut to help the problem. 

 

I also *think* running cmj's will eliminate the issue. I was on the route to trying that until MG didn't wanna take my money. The few CMJ's I have run were flawless but my sample size is too small to really know. 

 

 

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I should note that my problem rounds case gauge and plunk in the barrel depending on orientation. So the same round that stops my gun may run flawless if tried again. 

 

Also so some of the rounds plunk perfectly if the chamber is clean but get tight with just a touch of fouling. 

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May not of understood what you said above about re-reaming your chamber. So with that in mind take this with a big grain of Salt.

IS your chamber properly reamed for headspace of the cartridge?

Is it throated deep enough for the bullet and oal you're using?

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Yes, headspaced and chamber reamed and polished.
Boiling it all down I think I will shorten the round down to 1.165" and see if I can sweet-spot the extractor.  As noted before, both of these guns ran perfectly in .38 SC with Aftecs and I've got no problem tuning those or any other extractor.  Seems the feed problem may be related to 9mm case rim and groove dimensional variances, but I definitely do not want to get into having to sort brass by headstamp.  If i have to do that I might as well go back to Super.

 

It's very weird.

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But he did work on it beyond the 'finished' chamber provided with AET's?

 

Do you know how much he lengthened the chamber?  How much fluting was removed?  

 

I'm interested because I'm looking for the complete solution. 

Edited by theWacoKid
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  • 2 weeks later...

So the complete solution for both guns:

A little more polish in both chambers. 

Aftecs both with new springs. 

Some slight magazine feed lip adjustments to assist feeding. 

Shorten ejectors to. 250".

 

Primary issue was the chamber. Everything is hunky-dory now in both guns. 

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