is this normal for an STI pistol?

[croc4]

So I took apart my boonies carry weapon for a basic cleaning today, low and behold the left front rail completely has been sheared off. It is a clean sheer so maybe it was a fault in the base metal that recoil only exacerbated?

I only run cheap Tula through it and it might have had maybe 250? or so rounds through it, so it was not abused in that fashion.

Anyone else had a failure like this that could comment?, it was an 80% if that makes any difference.

Croc4

[ar15barrels]

Who made the 80%?
Did you radius the front of the rails so that the slide is not impacting the rails?



The slide should be striking the area just forward of the slide stop pin where the guide rod seats in front of the barrel's standing lug and link.
The slide should NEVER be able to strike the front of the rails.

[Dr69er]

Have never seen such a bad failure on a 1911 or 2011 in 80% or 100% finished condition...

A few questions, what material was it made from and who made the
modular 2011 frame ?

Sometimes you will see something similar in a poorly cast frame using
low quality materials...

Glad no one was Injured as a result of the failure...

Well known quality brands/manufactures will always use high quality
materials and/or back-up their products...

Good luck.

[croc4]

Thanks for the replies.
No I didn't champ-fer the rails, it was(is) an aluminum frame, as I understand it with the recoil rod installed it would not be physically possible for the slide to hit the rails directly as the base of the recoil rod isolates the slide from the frame ~1/8". slide hits base of guide rod, guide rod hits frame, I could be very wrong on this though.

the frame was a limited 10 frame, but I don't think that is this issue.


croc4

[ar15barrels]

No I didn't champ-fer the rails, it was(is) an aluminum frame, as I understand it with the recoil rod installed it would not be physically possible for the slide to hit the rails directly as the base of the recoil rod isolates the slide from the frame ~1/8". slide hits base of guide rod, guide rod hits frame, I could be very wrong on this though.

You have the parts in your hand so play with them and see if there is any peening on the very end of the corner of the frame rails.
The inside of the slide has a radius where it would have struck the corner of the frame rails.
A radius is also put on the leading edge of the frame's rails SO THAT it's not possible for the slide to strike them.
The radius creates the clearance to make it impossible to strike the rails.

Did you ever drop the gun on carpet?

[pklin1297]

That is a clean break... Wow...

Talk to Eric at L-10 also and see what they think.

[dwalker]

I have literally thousands through my L10 aluminum frame and have no issues. I kinda have to ask how the railes were cut and the slide fitted?

[croc4]

rails were cut with a circular cutter and then hand filed to get the slide to freely slide.

croc4

[dwalker]

A circular cutter? A keyseat cutter in a mill? Or? The reason I ask is to me- although the picture is not terrific- it looks like the rail failed on a stress raiser, like a groove or deep scratch, possibly aggravated by "fitting" the slide to the rails using a hammer to force the slide down the rails. This is a pretty standard technique especially with steel frames, but one has to wonder about how much stress is applied on an aluminum frame.

[croc4]

it was done on a mill, using this bit

https://www.dremel.com/en_US/products/-/show-product/accessories/199-high-speed-cutter

Looking at the failure, I can mate the pieces together and there is no obvious
sign of damage, and there is no peening to the front of the rails, so I'm just baffled

[dwalker]

Almost has to be a a stress riser then.

[tr6guns]

Just as a guess, how much heat did you build up when cutting the rails?

[croc4]

I would say zero, the cutter I used required me to make many shallow cuts to get to the right depth and the feed rate was quite slow.

[oddjob]

I've never even heard of a frame failure like this.

Tag for future updates. I would be interested in what L-10 or a gunsmith (who inspects it) has to say.

[Limited-Ten]

This is the first failure we have seen on any of our frames. The cause will be tough to determine without knowing what happened every step of the build process and how the pistol functioned before the shear. I've got a few aluminum frames with tens of thousands of rounds downrange and one with north of 40k rounds of major PF ammo still going strong. But as dwalker mentioned, looks like a stress riser.

I have no experience with that particular cutter, but I use a keyseat cutter with a small radius in the corners to prevent risers. Also, excessive barrel lockup (think les baer), involving a hammer during any portion of the build, or a guide rod that doesn't sit flush with the frame impact abutment could all be contributors.

If it is ours we will replace free of charge