Jump to content
Brian Enos's Forums... Maku mozo!

STI .40 Single Stack Problem


Theo Carter

Recommended Posts

  • Replies 79
  • Created
  • Last Reply

Top Posters In This Topic

Single Stack .40s can be a little picky about ammo length and mags. The guns as set up by STI are designed to work with factory length ammo and the supplied mag with the spacer in the back that puts the round far enough forward that it can't nosedive. Because of that, the ramp is a little farther forward than it would be if they were setting it up to run .40 loaded long with 10mm mags. The Tripp mags you have are probably 10mm right? If you're using factory length ammo it's pretty likely for this problem to crop up. If you load long .40 try going even longer. I experimented loading as long as I could and still have them fit the mag. Once I ran them out to about 1.240" they seemed to work perfectly and even longer didn't seem to change anything, but it will depend somewhat on the shape of the bullet you're using. Curiously, Precision Delta's 180gr FMJ is almost a round nose and seems to feed smoother than MG 180 FMJs or either MG or Zero 180gr JHPs. I tried a few Hornady Action Pistol 180gr JHP's and those fed very nicely as well....very much like a roundnose with a small cavity.

I tried Wilson 47NX, McCormick 10mm mags and Trip 10mm System mags. Of all those, the Wilsons fed the best and the McCormick was a very close second. I will note that the nosedives I had were only from slide lock with a full mag and never while actually shooting the gun.

In talking this over with a few top gunsmiths and a top barrel manufacturer the ideal solution is to either have the ramp welded up and recut so that it's closer to the magazine or go with a quality aftermarket barrel. Mine is running perfectly now, but I do have a Schuemann Classic AET that's going in the gun when I get around to sending it off to Derek. I know there are a lot of variables there, but I hope it helped a bit. R,

Link to comment
Share on other sites

I have an STI .40 singlestack with Tripp mags and the bullets keep nosediving during feeding. What is the problem? Does anyone have solutions?

Theo the same thing happened to me until I switched to Wilson 47NX's. The problem magically disappeared for me.

Link to comment
Share on other sites

I was having the same problem with all OAL from 1.135-1.1230" out of the #47NX mags. It was suggested to widen the feed lips to about .430". I have mine out to .40" and it has taken care of about 90% of the hand cycling nose down jams. These mags run 100% when firing live fire though. :wacko:

Link to comment
Share on other sites

The 45 mags place the top round higher which makes it nose down higher on the ramp and gives it a better chance of getting in the chamber before all motion is lost. It usually works. Loading long usually works. If those don't work and it won't run with the factory mags and factory ammo send it back and have it fixed.

Link to comment
Share on other sites

I was having the same issues with a tripp mag. THe problem seemd to be that the rim of the top round was catching in the extractor groove of the second round draggin the second round forward, and tilting the first round forward.

A few things seemd to fix it (tripp 10 rounder 10mm mags for 40).

1) don't seat the top round fully back so things don't get hung up. This is pretty lame.

2) load maximum capacity-1. Which kind of sucks.

3) The mag spring ends on what ammounts to a half coil. I figured I'd fold it up flush with the next coil. This helped a little. Loading and unloading the magazine about a bajillion times while testing my extractor setup and to just to break the mag in, and that mag seems to be running fine now and feeding 165gr precision deltas loaded to 1.75" pretty slick now.

Link to comment
Share on other sites

If you are shooting single stack, major, and are limited to 8 rounds in the mag, do what HSMITH said and try some good .45 mags loaded out to 1.2". Wilson 47Ds, or Wilson ETMs work fine out of my Trojan, but, only if I load them long. :cheers:

Link to comment
Share on other sites

If you are shooting single stack, major, and are limited to 8 rounds in the mag, do what HSMITH said and try some good .45 mags loaded out to 1.2". Wilson 47Ds, or Wilson ETMs work fine out of my Trojan, but, only if I load them long. :cheers:

I didn't notice any improvement with mine when I tried Wilson 47Ds and ammo loaded from factory length out to at least 1.250"...it worked about identically to the 47NXs. That could be my gun, my mags or both....hard to say, but it didn't seem to be any better. R

Link to comment
Share on other sites

I think a lot of us have a pile of 45 mags from 'back in the day' though, I have a shopping sack full of CMC PowerMags and the old Shooting Star mags, a few Wilson 47D's, and a pile of real GI 7 round mags all in 45. Not having to buy another 10 mags and keep them separated is nice.

Link to comment
Share on other sites

I just bought an stock early STI 40 Trojan and have the mag that came with it an 4 new Wilson 47NX mags. It will feed factory forty and various bullets loaded to 1.18, except the Berrys 180 HP which feeds if I only load 7 in the mag.

Link to comment
Share on other sites

This problem in the 40 Trojan is well documented here on the gunsmithing forums, I think.

The Trojan 40 I shoot did the same exact thing. You can fool with different mags, and bullet OAL but the actual problem is the steep angle of the ramp.

The best permanent cure for this is to have your ramp rewelded (yes what a pain).

I sent my Trojan 40 to Virgil Tripp to have the ramp re done (he had it like 2 weeks) and it cost $75 plus SH. He told me he had done about 60-70 of these now and he stayed pretty busy rewelding ramps in Trojans.

Virgil guaranteed that this pistol would be very reliable and would become my "go to' gun.

He was right on both counts.

If you are going to run this blaster with regularity you can run 8 rounds in the mags, which seems to help the problem or you can get the gun fixed.

I decided to hang in there with single stack shooting, so I bit the bullet and had the Trojan ramp re done.

If you get the gun fixed, you will not regret it.

Link to comment
Share on other sites

This problem in the 40 Trojan is well documented here on the gunsmithing forums, I think.

The Trojan 40 I shoot did the same exact thing. You can fool with different mags, and bullet OAL but the actual problem is the steep angle of the ramp.

I'm not sure it's really a "problem" since the guns seem to work perfectly with factory ammo and the factory mag with the spacer....it's when we change things with 10mm mags and long ammo that the problem can show up.

It's not actually the angle of the ramp (see above about working with factory ammo and mag), but more the placement of the ramp. To work with 10mm mags and long ammo the ramp needs to extend back farther into the magwell, i.e. towards the magazine. When the ramp gets welded up, it's being moved back towards the magazine, which prevents the nose dive since the round hits it before the nose can get low. Building up the ramp has to change the angle somewhat since you add more to the bottom than the top, but that's more of a byproduct than a goal. R,

Link to comment
Share on other sites

I'm not sure it's really a "problem" since the guns seem to work perfectly with factory ammo and the factory mag with the spacer....it's when we change things with 10mm mags and long ammo that the problem can show up.

A

When I got mine, it wouldn't run w/ factory ammo and the Mec-Gar .40 mag that came with the gun (ie, with spacer).

It's not actually the angle of the ramp (see above about working with factory ammo and mag),

Not sure what yours looks like - mine was more of a "feed wall", as shred called it. STI "recut" it for me - it would then run with 5 or fewer rounds in the factory mag, but not loaded with more than that. Virgil welded and re-cut mine, and it now runs very well on factory and reloaded ammo, up to 1.185" OAL or so... It doesn't seem to like ammo longer than that.

My understanding, though, was that STI had corrected the issue and was properly angling feed ramps on these guns, now?

Link to comment
Share on other sites

I'm not sure it's really a "problem" since the guns seem to work perfectly with factory ammo and the factory mag with the spacer....it's when we change things with 10mm mags and long ammo that the problem can show up.

A

When I got mine, it wouldn't run w/ factory ammo and the Mec-Gar .40 mag that came with the gun (ie, with spacer).

It's not actually the angle of the ramp (see above about working with factory ammo and mag),

Not sure what yours looks like - mine was more of a "feed wall", as shred called it. STI "recut" it for me - it would then run with 5 or fewer rounds in the factory mag, but not loaded with more than that. Virgil welded and re-cut mine, and it now runs very well on factory and reloaded ammo, up to 1.185" OAL or so... It doesn't seem to like ammo longer than that.

My understanding, though, was that STI had corrected the issue and was properly angling feed ramps on these guns, now?

I guess I never really paid much attention to the barrel/feedramp on the one I got last summer, but, I've used Chip McCormick, 10mm mags, Tripp 10mm mags, and Wilson Elite .45 mags with ammo loaded to 1.2 without any issues. :cheers:

Link to comment
Share on other sites

I'm not sure it's really a "problem" since the guns seem to work perfectly with factory ammo and the factory mag with the spacer....it's when we change things with 10mm mags and long ammo that the problem can show up.

A

When I got mine, it wouldn't run w/ factory ammo and the Mec-Gar .40 mag that came with the gun (ie, with spacer).

It's not actually the angle of the ramp (see above about working with factory ammo and mag),

Not sure what yours looks like - mine was more of a "feed wall", as shred called it. STI "recut" it for me - it would then run with 5 or fewer rounds in the factory mag, but not loaded with more than that. Virgil welded and re-cut mine, and it now runs very well on factory and reloaded ammo, up to 1.185" OAL or so... It doesn't seem to like ammo longer than that.

My understanding, though, was that STI had corrected the issue and was properly angling feed ramps on these guns, now?

I got mine around Sep of 07 give or take.....not sure if they've changed things before or after that...they may have fixed it.

What's interesting is that it's the same barrel that they put in 2011 bushing guns and nobody seems to have problems with them nose diving (at least that I recall hearing). Mine fed fine as it came from the factory with factory ammo. Matt M. very slightly shallowed the angle when he did the trigger job and reliability package, but any major change eats into case support and he didn't weld it up and recut it so this was a minor change. Mine is fine now with long ammo, but short stuff is still pretty iffy from a full mag. There are a fair number of guns with pretty vertical feed ramps and they work fine, but the bullet has to be pretty close to them when it's in the mag.

I think they could come up with a barrel that has the bottom of the ramp moved back a bit and still be able to use mags with spacers and get the best of both worlds.

Link to comment
Share on other sites

yeah if you have a feed WALL like mine was, you will have problems with factory ammo of all different types.

The length of the round did not have much to do with helping relieve the problem because I tried all different lengths of ammo and bullet profiles.

Hey if your STI Trojan 40 runs fine, don't worry about it.

If yours does not, call Virgil Tripp.

Link to comment
Share on other sites

yeah if you have a feed WALL like mine was, you will have problems with factory ammo of all different types.

The length of the round did not have much to do with helping relieve the problem because I tried all different lengths of ammo and bullet profiles.

Hey if your STI Trojan 40 runs fine, don't worry about it.

If yours does not, call Virgil Tripp.

How long an oal did you try? I went out to around 1.260 but I didn't notice any real change for the good beyond 1.230-1.240 (can't remember which). If the round is close enough to the ramp it really can't nose dive, no matter how steep the ramp is. If it's a flat or sharp shaped bullet it could hang up on a steep feed ramp without nose diving, but that's a different problem.

Again, these are the same barrels they put in 2011 bushing barrel guns and they aren't known to be a problem in those frames, so it has to be a geometry issue with distance between the mag and the ramp. They may have changed something since they were first introduced to help alleviate the issue in SS guns, but they haven't made different barrel lines for the different frames so it's interesting how this is happening.

Better yet, I have a friend that owns a barrel company...he sent me a barrel for the Trojan but haven't gotten around to sending it to the smith ;)

Link to comment
Share on other sites

yeah if you have a feed WALL like mine was, you will have problems with factory ammo of all different types.

The length of the round did not have much to do with helping relieve the problem because I tried all different lengths of ammo and bullet profiles.

Hey if your STI Trojan 40 runs fine, don't worry about it.

If yours does not, call Virgil Tripp.

How long an oal did you try? I went out to around 1.260 but I didn't notice any real change for the good beyond 1.230-1.240 (can't remember which). If the round is close enough to the ramp it really can't nose dive, no matter how steep the ramp is. If it's a flat or sharp shaped bullet it could hang up on a steep feed ramp without nose diving, but that's a different problem.

Again, these are the same barrels they put in 2011 bushing barrel guns and they aren't known to be a problem in those frames, so it has to be a geometry issue with distance between the mag and the ramp. They may have changed something since they were first introduced to help alleviate the issue in SS guns, but they haven't made different barrel lines for the different frames so it's interesting how this is happening.

Better yet, I have a friend that owns a barrel company...he sent me a barrel for the Trojan but haven't gotten around to sending it to the smith ;)

I dont remember the OAL (long) that I tried but it was the OAL for long 40s that a friend who is a GM runs in his guns.

They were really long. EIther way I got mine running and when I spoke with Virgil prior to mailing it to him, he said that he had been very busy rewelding the ramps on trojan 40s. I figured he would know the deal, since he started STI

Link to comment
Share on other sites

Mine was one of the first Trojan 40s and did the same thing ('cept it wouldn't run with Virgil's mags, Wilson's, Chip's, or anybody elses and OAL didn't matter). A guy actually GAVE me this gun in exchange for doing some AR work for him. He was that frustrated with it. I tried all different OALs, 40 mags, 10 mags, 45 mags. I even went to one of the JP Elevated Mag Catches that raises the magazine very high in the magwell.

Finally, I swapped out the barrel, going to a Kart. It now runs like a scalded dawg.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×
×
  • Create New...