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We all enjoy the easy rackability of the PK.380, and I'd like for someone to explain exactly why it is so easy to rack, as compared to 99% of other handguns. A couple of you-tube videos mention the term 'Blowback', and infer that it has something to do with the difference between the PK and others that are much more difficult to rack. They don't go on to explain exactly what 'Blowback' is.. and I was wondering if anyone could please clear this up for me. Thanks
 

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Locked breach:

The barrel is locked together with the slide and travels with it as a unit for a short distance before being unlocked by a camming action of differing varieties. It unlocks and swings down to let the slide continue back for extraction and ejection. The advantage is that it can be used with nearly all power levels of cartridges.

Blowback:

Just as it sounds. The barrel is fixed and the fired cartridge pushes the slide to the rear for extraction/ejection. The slide must be heavy enough to counteract the force of the cartridge. This means that blowback is limited to fairly low powered cartridges such as .25 ACP, .32 ACP, and 9x18 Makarov or the weight of the slide, or strength of the recoil spring, or some combination of slide weight and spring strength, becomes outrageous.
 

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"I'd like for someone to explain exactly why it is so easy to rack ..."


The PK's stranded recoil spring has less "spring load" when operated slowly,
as during racking; with more "apparent spring load" during the fast recoil.

A stranded coil spring acts a bit as a shock absorber. (and it heats up more)
For some guns with single-wire coil springs, problems are sometimes
reduced by swapping it for a multi-strand spring.
[note: the link at "shock absorber" was auto-generated.
I don't doubt that we all know what a shock absorber is.]


From www.spring-makers-resource.net/advanced-spring-design.html :
"Long springs with many coils subjected to high rates of load applications, as in
automatic weapons, encounter shock-wave motion or displacement of spring coils.
Stranded wire springs are often the solution to such problems. This is because
of the frictional resistance set up by the selective movement between strands.
The helix of the spring must be opposite in direction to the helix of the strands.
This will allow the strands to bind together when the spring is compressed."

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