cferree Posted January 14, 2017 Share Posted January 14, 2017 I'm using STI tubes with Grams followers & springs, Hardy style steel spacers and TTI base pads. Three 140's and one 170 all run great until the last 2-3 rounds. I then get nose dive FTF's. It doesn't matter if I load 10, 15, 20, or 22 rounds (springs are still tight, and 23 rounds are really tight right now). The gun is a Match Master. It has an Aftec, Brazos fire control group, etc. The slide stop has been modified to prevent premature slide lock and so has the Grams followers. With the slide off, the rounds are not contacting the ejector, or slide stop. I'm out of things to look for or try. Any suggestions? Link to comment Share on other sites More sharing options...
Sarge Posted January 14, 2017 Share Posted January 14, 2017 New springs? I change mine once or twice a year depending on how much I shoot. Link to comment Share on other sites More sharing options...
cecil Posted January 14, 2017 Share Posted January 14, 2017 I had a similar issue .. I too use STI tubes with Grams springs & followers... changed springs... problem went away.. Link to comment Share on other sites More sharing options...
cferree Posted January 14, 2017 Author Share Posted January 14, 2017 The spring are brand new. I just built the mags. Link to comment Share on other sites More sharing options...
Sarge Posted January 14, 2017 Share Posted January 14, 2017 37 minutes ago, cferree said: The spring are brand new. I just built the mags. OK. Move on to feed lips then. Probably too tight in front. Link to comment Share on other sites More sharing options...
Yeti Posted January 14, 2017 Share Posted January 14, 2017 Since you are 100% certain mag springs are good to go. Check for follower binding at top 1/3 of mag tube, feedlip dimensions & extractor tension. Link to comment Share on other sites More sharing options...
Glk21C Posted January 14, 2017 Share Posted January 14, 2017 after you check the items above AND you still have a problem you'll want to adjust the double-stack to single stack transition area. Might require some squeezing of the ribs in that area, making sure to keep the tube square as well. That transition area controls the presentation of the rounds and when it gets too wide you can get the problems you describe. Link to comment Share on other sites More sharing options...
mikev49 Posted January 16, 2017 Share Posted January 16, 2017 I have found that the TTI base pads and the Hardy spacers dont work all that great together. If the feed lips are tuned correctly, and you keep having problems try different base pads. Link to comment Share on other sites More sharing options...
cferree Posted January 16, 2017 Author Share Posted January 16, 2017 Thanks for all the suggestions. Two of the three 140's ran 'til empty yesterday during a practice session. I'm wondering if what Glk21C offered is the issue since they're running good until almost empty. Link to comment Share on other sites More sharing options...
mikev49 Posted January 16, 2017 Share Posted January 16, 2017 Are you using the 4g or 7g basepads for your 140mm mags? I have noticed that the 7g let the spacer drop down too far and it causes me problems. Link to comment Share on other sites More sharing options...
mikev49 Posted January 16, 2017 Share Posted January 16, 2017 And if the transition area were out of spec, the mags would almost definitely stick in the gun. Do they drop free? Link to comment Share on other sites More sharing options...
cferree Posted January 16, 2017 Author Share Posted January 16, 2017 They drop, so maybe that's not it. Link to comment Share on other sites More sharing options...
Glk21C Posted January 16, 2017 Share Posted January 16, 2017 Not necessarily. Link to comment Share on other sites More sharing options...
z40acp Posted January 16, 2017 Share Posted January 16, 2017 Are they hard to load? Like said, check the front to back measurement on top by the taper. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted January 16, 2017 Share Posted January 16, 2017 Hello: Check the mags front to back and side to side measurements. Check the feed lips front to back and make them parallel. Bevel the Grams follower. Check the tension on the Aftec like I told you before. Thanks, Eric Link to comment Share on other sites More sharing options...
cferree Posted January 16, 2017 Author Share Posted January 16, 2017 The feed lip dimensions are set to the number you gave me Eric (-0.000/+0.001). The rounds are hitting the feed ramp before they have a chance to slide up the breach face. They feed fine until the last 2-3. I posted earlier that 2 out of 3 140's are working now and the 170 is 50/50 feeding 'til empty. Link to comment Share on other sites More sharing options...
mikev49 Posted January 16, 2017 Share Posted January 16, 2017 9 or 38? Did anyone fit the aftec? Sometimes you have to bevel the bottom edge a little bit. There may be enough upwards pressure with the mag full to force the rounds in the correct place, but when you get down to the last 2-3 rounds it doesnt have enough. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted January 16, 2017 Share Posted January 16, 2017 Charles: It must be either Aftec tension is too tight or the springs need to be bent. Bring them to River Bend match and I will look at them. Thanks, Eric Link to comment Share on other sites More sharing options...
sitw Posted January 18, 2017 Share Posted January 18, 2017 " The rounds are hitting the feed ramp before they have a chance to slide up the breach face. " " The feed lip dimensions are set to the number you gave me Eric (-0.000/+0.001). " If the mag feed lips have been tuned, start next by tuning the extractor. What are you setting the rear of the mag lips at? Picture the rim of the round as it comes up from the mag and bangs into the extractor, it is at an angle not straight on. The more the angle, the more force required to get it up into the the extractor. Tune the mags so the angle is shallower and/or tune the extractor so the round slides up into the extractor easier. If it is an Aftec extractor, tuning means pre-compressing the springs and putting a very slight radius on the bottom of the extractor hook. Careful, it is all a balancing act. Go too far with either and you have other problems. If you go too far with the mags you can bend them back. Go too far with the extractor and you get to try again with a new extractor. But learning is half the fun! Link to comment Share on other sites More sharing options...
cferree Posted January 28, 2017 Author Share Posted January 28, 2017 (edited) Update: The 140's are feeding great until the last 1-2 rounds. They all have TTI 7mm base pads. So Mikev49's suggestion regarding the spacer dropping, might be the issue. The thing that I'm looking at most is the transition area. I have one 170 that won't feed at all. Immediate nosedives from the 1st round 'til the 28th. The taper area on this mag is so tight, the follower stops 1/2" short. My 140's aren't near as bad, but the followers on them are all "tight" near the top of tube. I had 3 nose time stoppages yesterday out of 300. All hit the feed ramp low, and before the base of case had gotten to the extractor. Question: How do I open the transition area, mainly the front rib, on both sides? The pliers that come with Dawson's tuning kit won't go deep enough into the tube to expand it. My first idea was to cut a furring strip, 1 5/8" x 5/8", down so it fits in the tube (take the 1 5/8" side down under 1 1/2"), and then bevel the sides to match the taper of the tube. Put the tube in a vice, and tap the wood with a hammer to expand the transition area. If I check it frequently with a follower, I can stop before opening it too much. Thoughts? Edited January 28, 2017 by cferree Link to comment Share on other sites More sharing options...
Glk21C Posted January 28, 2017 Share Posted January 28, 2017 At this point I would contact sti for warranty replacements. Link to comment Share on other sites More sharing options...
Glk21C Posted January 28, 2017 Share Posted January 28, 2017 Your stick idea may work but you are forcing wood into a steel tube that must be moved past it's present shape so that when you remove the stick it still stay a little bigger. Almost fighting a losing battle which is why hydraulics and steel mandrels are used for extreme reshaping of tubes. Seriously, good luck, it would be easier to contact sti to have them replaced. Link to comment Share on other sites More sharing options...
cferree Posted January 28, 2017 Author Share Posted January 28, 2017 STI isn't going to replace tubes they didn't make correctly to begin with, and do I want to fight another set of tube. I have 5 tubes, 3-140's and 2-170's. NONE had the same side to side or front to back measurement. NONE had the same feed lips dimensions. NONE were square along the entire length of the tube. And at least 3 had burrs on the feed lips. Several gunsmith make good money annually taking these and making them work. If STI had the same Q/C specs that SV has, this post wouldn't exists. I ran an Infinity IMM for 2 seasons with factory SV mags (6-140's and 3-170's), with no issues. Take them out of the box and run them. No polishing, no bending, no hammering just load and shoot. Hopefully MBX will be a long time solution for those of us shooting STI based 9mm, open guns. Link to comment Share on other sites More sharing options...
mookman Posted January 28, 2017 Share Posted January 28, 2017 No really..If you bought any other product than a magazine you would have sent it back....I have an Svi..Bought a genuine Svi Magazine...Doesn't fit in the Genuine grip...It's what I accept..Why is this... Link to comment Share on other sites More sharing options...
billy396 Posted January 29, 2017 Share Posted January 29, 2017 I had the same problem with my STI 2011 in 9MM. Of course the 140MM mags were actually 38 Super mags so I had to get spacers which seemed to help a little. What I found during steel challenge matches is, if I take a micro fiber cloth and wipe off the feed ramp between stages I don't get the nosedive FTF's anymore. While I know this isn't a perfect solution it works for me and I don't see any need to try to throw money at a set up that already cost me $3,500.00. At the time I bought it, I was shooting steel challenge matches once a month but over the last couple of years my arthritis has become so bad that if I shoot centerfire pistols I have several days if not a week afterwards where I have almost constant pain in my right hand and wrist. I'm going to break down and try to sell this STI and start confining my handgun shooting to 22LR. Good luck with your problem. I hope my solution works for you as it only takes a few seconds. Link to comment Share on other sites More sharing options...
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