Buffer Tube Shimming

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Buffer Tube Shimming

Postby CxK-ArthurDent on Fri Nov 30, 2012 10:53 am

Hi,

i am wondering how a cylinder/ Buffer tube is shimmed "right".

"you should use some foce to split the receiver" is not a value to work with.
-> and it confuses me that systema says the contrary (if its locks without excessive foce, it opens without it too)
what is the current value for "excessive force, some foce" ?

Is the cylinder shimming "ok" when the cylinder does not move while fireing ?
(by looking in the magwell without a mag)

Facts / or better "Systema says" :
-> that the buffer tube should recessed by ~2mm
-> the "nub" on the cylinder should line up and fully seat with the opening of the upper
-> the (upper)receiver should "lock" in place without excessive force

can someone supply me with the right procedure here ?

kind regards

Arthur
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Re: Buffer Tube / Cylinder Shimming

Postby Tackleberry on Fri Nov 30, 2012 2:50 pm

The simple fact is it makes little if any difference to how the gun shoots. The idea is that when the upper and lower are closed there should be just enough pressure to prevent the cylinder from rattling around.

Too little and the cylinder moves and you will drop FPS slightly.
Too much and you exert too much pressure on the weakest point of the lower receiver.

Ideally it should be enough that when closed it should gently snap shut without too much force involved.

And before you question my knowledge, just remember how many 100's if not 1000's of PTW's I have worked on over the years !
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Re: Buffer Tube / Cylinder Shimming

Postby CxK-ArthurDent on Fri Nov 30, 2012 3:05 pm

thanks @tac, that is what my conclusion is too
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