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(NERD) Physics of Slide Lightening Cuts


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I've been doing some thinking around the concept of reciprocating mass and center of gravity of that reciprocating mass. I am an engineer with machining experience so this sorta stuff is fascinating to me, but I don't have enough real world experience tinkering and testing with firearms to know if any of it really matters.

 

My question is really 2-fold.

 

1) Knowing that [Force = Mass * Velocity^2], by reducing the mass of the slide by ~10% and making adjustments to the recoil spring to keep ejection distance appropriate, is there a tangible difference in recoil of a pistol with just slide lightening?

 

2) If said slight lightening also lowers the vertical center of gravity by ~10%, that should also reduce the force felt at the grip.

 

Ultimately, what I am confirming is, taking as much weight out of the front and top of the slide as possible is theoretically the most effective at reducing felt recoil, but does the theory line up with real-life experience to those who have done it?

 

Just for kicks, the 3D model for the slide I am playing around with is attached.

BullShadow Assembly Tapered Scallops Iso.PNG

BullShadow Assembly Tapered Scallops side.PNG

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I started a thread about this topic several years ago when I was going through my slide lightening R&D phase. My BE Forum search Kung-Fu is weak today and I can't seem to find it. I believe all of your questions are answered in there.

Edited by CHA-LEE
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48 minutes ago, CHA-LEE said:

I started a thread about this topic several years ago when I was going through my slide lightening R&D phase. My BE Forum search Kung-Fu is weak today and I can't seem to find it. I believe all of your questions are answered in there.

 

36 minutes ago, HoMiE said:

 

 

Thank you both!! Excellent info!

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I lightened the slide on my Limited gun and it made very little difference.

 

Slide lightening on an Open gun is mandatory IMO.  So much gas it directed up through poppels and/or the comp that little remains jetting out the front.  So there is little impetus given to the slide.  I had the slide lightened to 10.5 oz on my two newest builds.  One is a 2011 9mm major gun.  To get enough slide velocity with a major load I had to go down to a 17 lb main spring, raise the pick up point on the firing pin stop up to the firing pin hole, and go to a 7lb recoil spring.  Even so, the brass only flies about a foot.  If I had left the slide at 13 oz, it would not have worked at all.

 

Here is my take on slide lightening.  I have three slides done this way.  Metal is removed where possible and left full strength where needed.  No shown in this view are two rows of vertical holes drilled into the rear scallop cut.  BTW, the barrel is also fluted to reduce mass.

100_1175.thumb.JPG.0b18896291bf618f77b79171d7d55c0f.JPG

Edited by zzt
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Just to be picky, Force = mass x acceleration

 

Energy equals ½mass times velocity squared.

 

Momentum, used in finding the gun velocity in recoil calculation, or the slide velocity if the slide mass is used instead of the gun mass, is mass times velocity.

 

Lightening the slide will increase the slide velocity.  This may or may not be good depending on the "feel" you like.

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On 3/20/2019 at 10:02 PM, Guy Neill said:

Just to be picky, Force = mass x acceleration

 

Energy equals ½mass times velocity squared.

 

Momentum, used in finding the gun velocity in recoil calculation, or the slide velocity if the slide mass is used instead of the gun mass, is mass times velocity.

 

Lightening the slide will increase the slide velocity.  This may or may not be good depending on the "feel" you like.

correct.

M1xV1=M2xV2

1 before changing weight

2 after. 

to find force  f=ma.    a -it's acceleration of the slide from rest to moment of battering the frame.

and real force is the impact of the slide to frame  f=mv/dt......................😉

and not always u can feel this physics with your body.😀

Edited by yigal
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