Understanding semi-auto calibers in full-length revolver chambers.

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My personal experience is that anything less than 100fps difference can be attributed to the individual gun/ammo combination.

The precise fit of the bullet in the chamber and barrel is an individual thing. While most guns will have their velocity with a given load fall in a fairly narrow range (with equal barrel lengths), if you test enough guns you will find ones that are noticably "faster" or "slower" than the average. And while a difference of as much as 100fps is unusual and uncommon, it is not impossible.

I have seen a "fast" 4" clock slightly higher velocity than a "slow" 8" revolver. It's rare, but it does happen.

So,don't get your knickers in a twist if gun A is 50fps faster than gun B, or a 3" gun shoots faster than a 4" one. Those differences are insignificant.

 

[Sevens]

Sevens, the Encore thing is a totally different animal.

I understand these things of course, I am quite familiar with them. My post regarding the T/C Encore and the testing of barrel length done by BBTI was in response to 1911Tuner's own testing by cutting down a rifle barrel. A very similar test.

 

[1911Tuner]

Encore

Sevens, the Encore thing is a totally different animal. That platform does not have the pressure venting cylinder gap of a revolver or the pressure absorbing recoil mechanisms of a semi auto.

There isn't any pressure-absorbing mechanism in a semi-auto, either, and there is no difference in the way that a locked-breech autopistol functions during the acceleration/recoil phase.

With a locked-breech pistol, the slide and barrel assembly is the gun. The frame is essentially the gun mount. Here, the gun is mounted on rails, with a spring that returns it to battery.

Because the breechblock...the slide...is mechanically connected to the barrel for a brief time...just like the barrel and breechblock on a single-shot TC Encore, when the slide is driven backward by recoil forces, it grabs the barrel by the locking lugs and hauls it along with it.

The Encore...or a revolver...does exactly the same thing, except that it doesn't drop the barrel.