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STI Aluminum Grips - CRACKED


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To shed some light on the issues at hand.

The key to grip failures in the key way tolerance of the frame and grip.

The key ways on the sti frame are horribly oversized from the original design. (sti frames I have measured to be .644 or more) The original design was .637-.638 with the grip keys in a .636-.638. We used a moly grease when installing the grips to assist in the tight interference fit necessary for the modular grip frame design.

When the keys are loose the frame rotates around the keys loading the front of the grip. The grip will not withstand this load and cracks in the thin cross section as you see in the photo. The polymer grips often did not hold this load either and cracked in a similar fashion.

We have pin pointed the issue, increased the cross section width and now offer a grip with larger keys to correct the poorly held tolerance of the sti frame.

Rick Dirt Diver had two early sv grips which failed due to the loose tolerance of the keys.

Rick Dirt Diver can supply feedback over the long term on the grips being cut to fit the oversized keys. We have seen it correct the issue on several sti frames.

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To shed some light on the issues at hand.

The key to grip failures in the key way tolerance of the frame and grip.

The key ways on the sti frame are horribly oversized from the original design. (sti frames I have measured to be .644 or more) The original design was .637-.638 with the grip keys in a .636-.638. We used a moly grease when installing the grips to assist in the tight interference fit necessary for the modular grip frame design.

When the keys are loose the frame rotates around the keys loading the front of the grip. The grip will not withstand this load and cracks in the thin cross section as you see in the photo. The polymer grips often did not hold this load either and cracked in a similar fashion.

We have pin pointed the issue, increased the cross section width and now offer a grip with larger keys to correct the poorly held tolerance of the sti frame.

Rick Dirt Diver had two early sv grips which failed due to the loose tolerance of the keys.

Rick Dirt Diver can supply feedback over the long term on the grips being cut to fit the oversized keys. We have seen it correct the issue on several sti frames.

This explaniation certainly makes sense. It explains why some individuals with a certain gun (frame) regularly need a new grip while others have no problems for thousands of rounds. However due to the sensitivity of the parts fit, I think I would only go with the steel model ..

Edited by P.Pres
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I am not trying to stir anything up here. What are some estimated round counts on Aluminum grips that have not cracked, I'm curious?

EG

Read post #32

Interested in round counts of grips that have NOT cracked. Maybe no one can get over 2000rds without cracking...

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To shed some light on the issues at hand.

The key to grip failures in the key way tolerance of the frame and grip.

The key ways on the sti frame are horribly oversized from the original design. (sti frames I have measured to be .644 or more) The original design was .637-.638 with the grip keys in a .636-.638. We used a moly grease when installing the grips to assist in the tight interference fit necessary for the modular grip frame design.

When the keys are loose the frame rotates around the keys loading the front of the grip. The grip will not withstand this load and cracks in the thin cross section as you see in the photo. The polymer grips often did not hold this load either and cracked in a similar fashion.

We have pin pointed the issue, increased the cross section width and now offer a grip with larger keys to correct the poorly held tolerance of the sti frame.

Rick Dirt Diver had two early sv grips which failed due to the loose tolerance of the keys.

Rick Dirt Diver can supply feedback over the long term on the grips being cut to fit the oversized keys. We have seen it correct the issue on several sti frames.

B. Diddy is correct, the frame key ways were a different size or several thousandths oversized. SV fit the grip to the frame and all is good today. I only have about 1k or so rounds thru the gun...weather has not allowed practice. I'll keep you updated.

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I am not trying to stir anything up here. What are some estimated round counts on Aluminum grips that have not cracked, I'm curious?

EG

Read post #32

Interested in round counts of grips that have NOT cracked. Maybe no one can get over 2000rds without cracking...

My STI has about 15 thousand without a crack. The other gun about 5 K (both aluminium grips.

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  • 1 month later...

Just noticed cracks in mine under the trigger guard. I'm leaving for SC on Thursday after work so there's no time to get another one and install it before SC Sectionals and Area 6. Anyone out there have any idea how many rounds I'm likely to get before it becomes un-shootable? Please tell me several thousand rounds....

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  • 2 weeks later...

Read post #32

Interested in round counts of grips that have NOT cracked. Maybe no one can get over 2000rds without cracking...

My STI has about 15 thousand without a crack. The other gun about 5 K (both aluminium grips.

Update to my previous post - I just noticed a hairline crack at the bottom of the trigger guard. It could had been there earlier, I just looked closer this time. :wacko:

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besides all the cracked grips. can any of you guys that are shooting with the aluminum grips really feel a difference between the the plastic and aluminun? is really worth the headache. just curious. i dont have one and was think about getting one.

Mick :cheers:

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besides all the cracked grips. can any of you guys that are shooting with the aluminum grips really feel a difference between the the plastic and aluminun? is really worth the headache. just curious. i dont have one and was think about getting one.

Mick :cheers:

Yes! big time. I did that and bought both my open gun

and had my buddies try the STI aluminum grip open gun and the STI Polymer grip open.

Difference is night and day. Has something to do with Vibration and frequency or the frame

when you fire the gun. Its like shooting an Eaa or CASPIAN(all metal gun) versus XD or Glock?

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besides all the cracked grips. can any of you guys that are shooting with the aluminum grips really feel a difference between the the plastic and aluminun? is really worth the headache. just curious. i dont have one and was think about getting one.

Mick :cheers:

Mick,

Until you shoot an open gun with metal/aluminum or stainless steel the feel is amazing. The gun sits down in your hand, solid as a rock. You eliminate, and I mean eliminate the mag sticking or hanging up during a reload. The mag seems like it jumps out of the grip when you touch the mag release button. After having the grips fitted by SV, (I shoot a STI frame with a SV grip)the cracks have stopped...hopefully forever. I've shot about 5k thru one open gun and about 7,5k thru my practice gun. So maybe the fitting of the grip solved the problem....only more rounds downrange will tell. My OPINION and my opinion only is that you will improve your skills with the introduction of the metal grip.

Rick

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My STI small aluminum is cracked pretty bad after about 4K. I called and talked to Chris and they are very willing to exchange it for either a new aluminum one or two plastic in my choice of colors. I like the aluminum grip but was considering the plastic to eliminate the cracking but kinda feel two isn't quite enough compensation. Anyway, are the large/normal aluminum grips cracking still? I'd try one of those instead of the small if they seem to be more durable.

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My STI small aluminum is cracked pretty bad after about 4K. I called and talked to Chris and they are very willing to exchange it for either a new aluminum one or two plastic in my choice of colors. I like the aluminum grip but was considering the plastic to eliminate the cracking but kinda feel two isn't quite enough compensation. Anyway, are the large/normal aluminum grips cracking still? I'd try one of those instead of the small if they seem to be more durable.

Glad they will exchange for plastic, but I'd want 3 or 4 plastic grips...

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My STI small aluminum is cracked pretty bad after about 4K. I called and talked to Chris and they are very willing to exchange it for either a new aluminum one or two plastic in my choice of colors. I like the aluminum grip but was considering the plastic to eliminate the cracking but kinda feel two isn't quite enough compensation. Anyway, are the large/normal aluminum grips cracking still? I'd try one of those instead of the small if they seem to be more durable.

Glad they will exchange for plastic, but I'd want 3 or 4 plastic grips...

Me too Matt. I specifically asked about exchanging it for plastic and he said sure I can send you two in your choice of color. Guess I should have said um, how about 3 or 4? I'm sending back a $300.00 plus dollar grip. Oh well, live and learn huh?

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besides all the cracked grips. can any of you guys that are shooting with the aluminum grips really feel a difference between the the plastic and aluminun? is really worth the headache. just curious. i dont have one and was think about getting one.

Mick :cheers:

Better balanced, firmer feel when gripping, softer recoil....at least in my experience.

After using the grip for over a year, I don't plan to go back to polymer. :cheers:

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Do the regular size grips seem to hold up longer than the smalls? I'm about to take my small off and send it back for exchange. I'd be willing to try the regular size if they hold up better.

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Can folks with shooting experience with metal grips chime in at little more on the advantages of Metal vs Polymer?

I understand the Mag change advantage. Also, Some have said softer shooting or firmer grip.

At first, It seems counter intuitive that stiffer grip would be softer shooting but would love to hear what folks say about it.

I dont understand the better balanced concept as with a few tricks you can balance an STI anyway you want it.

Also, of the folks that like the way metal grip feels, I would love to know if they favor a certain hand position over over shooters hand positions. Also if the Metal Guys favor a smoother or more textured.

And thanks in advance to those early adopters who are pushing the envelope. You are blazing trails others may follow. That is kind of what racing is all about.

Edited by Aloha Robert
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I put one on Susan's Open 9 and she loves it. The gun is flatter which I think is because the Al grip is more rigid and doesn't flex under recoil. I also put one on a 6" 9mm gun. Haven't gotten to shoot it that much but the little I have done was really sweet.

I wrote a quick tutorial on fitting the Al STI grips here http://www.brianenos.com/forums/index.php?showtopic=105554

Edited by kgunz11
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  • 5 weeks later...

Ok...but here's the rub.

How long can STI afford to keep sending "free" replacement grips...?

There obliviously is a problem...I'm sorry at $ 500 a copy up here in Toronto the grip should last for years..if not a lifetime of shooting.

Ciao.

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Harmonics will destroy the aluminum. Stainless is the way to go. Those who remember when we use to shoot with the PDP3s and other aluminum scopes which would develop cracks/failure and there was NO stress in the failure area. Same thing, certain frequencies will create cracks unless isolators/dampeners are used. This was seen big time in the marine industry more so when the Detroit 2 cycle diesels were used. The harmonics would cause cracks in aluminum fuel tank mounting joints/gussets whether it had a radius or not. The tanks had to be completely isolated from the hull.

I would make a WAG that the failure would be highest to lowest from 115 grain bullets to 180/200 grain because of the recoil impulse (Major PF). I remember how the Tangfoglios with a PDP3 mounted on them felt like you had a tuning fork in your hand. Get that boing, boing, every shot from the aluminum mount/optics.

Combine both stress and harmonics and you are going to have a high failure rate. Sucks!

Jack

JT Engineering

Edited by Jack T
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OK then......let STI get on the ball and give us the New and Improved Gen 2 Aluminum Grip!!!!

I'll gladly buy one and put it on my .40 Eagle!

Ciao.

Edited by Carmine
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