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Im not sure what happened!


Greg Thomas

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I bought a new STI USPSA SS in 9mm and have abought 200 rds thru it,the first prob. i had was that it was double feeding when i called STI for help they showed me a video on there site on how to addjust the tension on the extractor and that should fix prob. well it did! So im doing some ld testing and im using a lead 125gr rn with 4 gr of VVn320 ld was consistant and showed a PF of 133 thru my chrony so i figured i was good and started to adjust sights when i was happy with the hits i loaded up 10 rds in the mag(metalform,which is new) and shot very fast( well for me ) when i saw a rd jump thru the ejection port stright up and landed 2' in front of me, so im thinking thats weired i stop and pick it up, IT WAS A LOADED RD!!!! Now i saw this happen so it wasen't a rd that was droped.

I have a lot of questions and have looked thru this sites search function but haven't seen this discussed so does anyone know what happened?From my understanding when the slide goes back the mag spring pushes 1 rd up but the next rd stops at the feed lips so somehow 2 rds got thru because when i stoped i cleared the gun and there was an unfired rd in the chamber.

The other powder im using is Titegroup and it has more felt recoil to it than the VV n320,so did i induce this prob. buy slowing down the slide speed? Or is this a mag prob?

Now to be fair i called STI but it was right at closing time so i expect they will call me tomorow.

I haven't done any thing to gun other than cleaning and addjusting tension on extractor so it has all of the factory parts.

Thanks for your help in advance, looking foward to getting this fixed Greg.

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I have always found Metalform mags to be pretty marginal. People usually buy them to scrimp on cost, which turns out to be poor economy in the long run.

I have had excellent luck with the Wilson 10-rounders.

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I have always found Metalform mags to be pretty marginal. People usually buy them to scrimp on cost, which turns out to be poor economy in the long run.

I have had excellent luck with the Wilson 10-rounders.

Im using Metalform 10 rd mag Brownells part #620-000-013 these cost $50 a piece I wasn't trying to save any money, maybe i got some bad ones but i will try to find somw wilson and order some Tripps but i don't know of any local shooters that use them.

Thanks for the replies Greg.

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I have always found Metalform mags to be pretty marginal. People usually buy them to scrimp on cost, which turns out to be poor economy in the long run.

I have had excellent luck with the Wilson 10-rounders.

Im using Metalform 10 rd mag Brownells part #620-000-013 these cost $50 a piece I wasn't trying to save any money, maybe i got some bad ones but i will try to find somw wilson and order some Tripps but i don't know of any local shooters that use them.

Thanks for the replies Greg.

Funny, I went to Metal Form after problems with Wilson :( Price had nothing to do with the decision. The recommendation of a well known shooter was my reason for the change.

Is it one mag Greg or all of them? If it is one, send it back to Brownell for a replacement.

Edited by Round_Gun_Shooter
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9mm magazines that have the spacer at the rear leave limited feed lip surface to retain the round. In some magazines, with each round fired the magazine spring tension is reduced and the rounds move forward due to recoil until a live round squirts out the top or causes a double or even triple feed. Factors that contribute to the problem include: the out of spec feed lips already mentioned (sorry, don't have the correct specs available), inadequate magazine spring tension and cartridges with a short overall length. I've had good results from the Wilson magazines already recommended as well as the Metalfrom front ramp magazines. I've been able to salvage traditional 9 rd. magazines by substituting Wolff extra power magazine springs but don't know if they would be compatible with your 10 rd. magazines. I would guess that your 125 gr. rn loads are pretty short. If this is the case, a longer bullet might be the simplest solution.

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I have found with 9mm 1911 mags, who knows what will work for you and your gun.

I have had great luck with Wilson ETM 10RD mags up till my Trojan. Though it does have some other issues so they may still work... fingers crossed.

I had bad luck with metalform in the past myself. I am planning to try some Tripps at some point.

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Definitely sounds like a mag lip issue. make sure they are no wider then .350

Dawson Precision makes awesome 9mm mags, they are all around .325-.330

Have you seen the Dawson and Metal Form 10 round mags side by side Mike? They look the same to me. I will measure feed lips on my Metal Form tonight. Thanks for the measurement info (luckily no problems with mine)

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I wouldn't just buy one mag, by several different manufacture's mags and try them. Most know that I've settled on Tripp Research mags for all my 1911s and I typically don't have a magazine related issue unless I let my maintenance lapse. <_<

Also, on 9mm 1911s make sure that the rail under the slide that makes contact with the next round in the magazine is polished up nice and shiney. It could have a ruff spot and is moving the rounds forward then out.

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I thought STI had mag lip specs on their website?

Also, since you adjusted the extractor tension, you may have made it such that the round won't slide up under it easily. The slide still grabs it and pushes it forward, but it doesn't go where it is supposed to.

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The best feeding I've had were the Metal-Form 9rnd "Springfield" at 100%. The 10 rnd Metal Form did ok (not 100%)as did the Tripp (not 100%). Wilson ETMs were the worst at nose diving - always 1st round from slide lock. A heavier recoil spring (14#) increased reliability of all over the recoil master but changed its shoot-ability. 9mm 1911s are just tricky and require a full vocabulary of adult language and some compromise.

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First off thanks to everyone that is trying to help :cheers:

I got a call from STI warranty department today, after describing my prob.

The first suggestion was measure the feed lips he said should be .330 up to .350

The next suggestion was to bump up the powder charge thinking that the slide is short stroking

Also need to recheck the tension on the extractor,

He also suggested to move the o.a.l. out to 1.150 saying the 1.120 that im curently using may be to short,

When i get back home im going to look at the disconecter rail as Steel1212 and Flexmoney have suggested and will order some Wilson ETM's and see if i can get a few of the Tripps..

I wonder if i should try one of the tuned extractor from Brazo's or an Aftec?

I will also try to get some pics up of the rail and the feed ramp if that would be helpful.

Greg

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Ok here is one of the slide, not sure if you can tell in this pic but on the edge of the disconecter rail on both sides there looks to be cut at a different angle right at the edge not sure if its supposed to be like tha or not??????????

post-17832-0-92133700-1332608605_thumb.g

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I measured the feed lips on (10) of my metalform mags:

four were 0.33

six were 0.34

I measured the feed lips on (5) of my Tripp mags and they were all 0.34.

Never had a problem with any of these mags in my Springfield Loaded Stainless Target 9mm with a 5" barrel.

IMHO I think you are loading too short. Try 1.14 to 1.15 OAL before investing in any mags. Have a good gunsmith tension your extractor.

My load is as follows: Load is a little snappy.

Mixed Brass

4.1gr. Titegroup

Federal SPP #100

115gr. Berry Plated Bullet

OAL is 1.142

1128 FPS

129.7 PF @ 50 deg. F

If you are going to purchase other 9mm mags, I would recommend Tripp mags over any others.

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Well I have good news the gun is running good, I rechecked the extractor tension and it was good, and then measured the feed lips on the mags they were good,so I looked at the disconnecter rail and saw some small marks on the edge but didn't seem to be it, so the only thing left was the loaded ammo I pushed out the OAL to 1.150 and went back to titegroup powder tried a few different charges and low and behold the it never had 1 problem!

I guess i should have only changed 1 thing at a time but didn't think by pushing out the OAL that the same powder charge would work. I think that it was the combination of both but i'm just glad its working I put 100 rds thru it and it showed a power factor of 134 it's a little on the snappy side but it's consistentnt and it's grouping great so I adjusteded the sights and will shoot 1 more local match before the Battle In The Bluegrass.

Thanks to all that have helped Greg

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I have always found Metalform mags to be pretty marginal. People usually buy them to scrimp on cost, which turns out to be poor economy in the long run.

I have had excellent luck with the Wilson 10-rounders.

+1

Get better mags

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