Issues with my slide Mount

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woody57
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Issues with my slide Mount

Post by woody57 » Tue May 11, 2010 8:08 pm

About a year ago I had a Clark slide mount installed in My 1911, for my red dot. After about 1800 rounds I noticed the mount was lose. When I tried to remove the screws one of them sheared off. I took it back to the gunsmith and he extracted the screw and replaced all the screws. Well now after about 4300 rounds the same thing happened. This time I extracted the broken screw myself.
My question is, why is this happening?
I am shooting 200grain SWC with 3.8g of Clays powder with a 14.5 pound recoil spring.
Should I be using a lighter spring? Should I be using a recoil buffer. Do I need stronger screws.
Thanks
Woody

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blue68f100
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Post by blue68f100 » Tue May 11, 2010 9:47 pm

It's called ineritia. The slide hammering forward jolts the mount every time. A fix, I do not know what would hold up. That is why some use a side mount. Maybe a lighter dot may help.
David

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Post by Bullseye » Wed May 12, 2010 6:50 am

Your mount is moving under recoil forces and straining the bolts that hold it to the slide. One way to help prevent this is to increase the surface area holding the mount in place. I like to apply some red (#271) Locktite sealant to the underside of the scope mount and then affix it to the slide. The extra surface bond provided by the sealant helps prevent shearing from stress.

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woody57
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Post by woody57 » Wed May 12, 2010 11:12 am

Thanks Bullseye I will try that. Would a lighter recoil spring and shock buffers help also?
Thanks,
Woody

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Post by stork » Wed May 12, 2010 11:34 am

Woody,
I've got about 40,000 rounds on my slide mounted wad gun. When my smith installed the clark mount, we didn't know which to get; with tuner cutout or without. We got it with the cutout which only has 3 screws insted of 4. I have never had a screw break or loosen, but we did apply red locktite to the screws.

My loads are 3.5 Clays with a 196 gr SWC for 50' and 25 yds; and 4.4 gr WST with a 210 gr SWC at 50 yds. I use an 11 # spring in the winter and a 13# spring during the outdoor season. I also use an Ultra Dot 1" which is on the lightest end of the spectrum.

I have never used a shock buffer, if you are using the correct spring there is no need.

One way of testing for the correct spring is to shoot a dirty gun (to simulate shooting at the end of a 2700) and if the slide fails to lock back after the last round (when shooting with a limp grip) you have the correct spring. My 13# is just at the maximum edge of function during the last couple of rapid fire sequences.

Stork
Last edited by stork on Thu May 13, 2010 10:09 am, edited 1 time in total.
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Post by woody57 » Wed May 12, 2010 11:33 pm

Thanks guys, I will switch to red loctite and try a lighter recoil spring.
Again Thanks for your help.
Woody

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Post by stork » Mon Aug 30, 2010 10:23 am

going over some of the posts I had a very brief moment of clairty.

Woody57, Is it the same screw that shears every time? What I'm thinking is that one of the screw holes is drilled a few thousanths off, resulting in most of the pressure being placed on just one screw.

Just a thought that may turn out to be nothing. But, thought I'd share it.

FWIW
"A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government.” – George Washington

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Post by woody57 » Fri Sep 10, 2010 11:52 pm

Hi Stork, Yes It was the same screw that broke, but since some of the others screws were lose I think that is the reason that it broke.
I put the slide mount back on with red locktite per Bullseyes advise, installed a 12 # spring. After 1200 rounds it is doing fine. Only time and rounds will tell the whole story. Thanks for your insights,
Woody

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