New test full power 10mm with spring swaps

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Pretty sure Mr. Willard was speaking about Glock pistols when he made that statement.  I don't have time to go track down the info and confirm that.

But, regardless of what he made the statement about, if he applied it to 1911 designs we was certainly wrong, and I believe wrong about the CZ/Witness design.  The only way to slow unlocking in these guns I beleive is to increase the slide mass or barrel mass or mess with the geometry of the hammer and firing pin stop.

Ned Christensen found no difference in unlock timing and he went to extremes in his test.  By extremes I mean firing without a recoil spring.  Unlock was no faster.

The Glock has a different geometry, and different, though derivative, locking system.  Spring rates may have an impact on Glocks.

[Yondering]

But, regardless of what he made the statement about, if he applied it to 1911 designs we was certainly wrong, and I believe wrong about the CZ/Witness design.  The only way to slow unlocking in these guns I beleive is to increase the slide mass or barrel mass or mess with the geometry of the hammer and firing pin stop.

Yep. You could think of the CZ/Witness as a linkless 1911 mechanism, in relation to unlocking. One significant difference though, is the location of the hammer pivot relative to the slide; it is lower on the Witness than the 1911, enough that I'm not sure a flat bottomed firing pin stop would make much difference. A stiffer hammer spring would be my first approach to slowing down the slide on a Witness.

[Intercooler]

Tim Sundles Buffalo Bore

If you are firing this 10mm ammo from an autoloader and experience high extreme spreads in velocity, it is not the ammo. Here is why and how to remedy the situation.

Full power 10mm ammo has always generated enough recoil and pressure to require a pretty stiff recoil spring in your handgun - this of course depends on several variables such as your slide weight, etc. When the cartridge fires, it generates enough pressure/recoil to prematurely open your breech face in some guns. When this happens, the opening breech face has an effect on the burn rate of the powder. This can result in some fairly high extreme spreads in velocity. If you are experiencing extreme velocity spreads of more than 50 fps, simply install a stiffer recoil spring. For example, I have an original Colt Delta Elite. This gun with the factory spring runs extreme spreads of about 35fps with both of these 10mm loads. I am happy with 35 fps, so I leave the Delta Elite as is. I also have a custom built Para Ordinance with a Nowlin barrel. It runs extreme spreads of about 70 fps with its original recoil spring. When I install a spring that is 4 lbs stiffer, the extreme spread drops to about 35 fps. The new Glock model 20 comes with a recoil spring that allows the breech face to open too soon and my new Glock model 20 will get extreme spreads of about 100fps with the factory spring installed. When I go to a stiffer recoil spring, the extreme spreads drop to about 50 fps in my new Glock model 20. Of course none of this will be an issue in a revolver.


The Para and Colt Delta are both 1911's. Glad I did the test and the feedback I received has been good.

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That is an interesting report on the Para with a Nowlin barrel.  Sounds like the lower lugs are cut time it very differently from spec.

Yondering may have some other thoughts on what else may allow the breech of a 1911 style to behave different than design.  But the timing of the lower lugs and link are all I can come up with.

[Yondering]

The above info from Buffalo Bore goes against everything I know about the 1911, and everything I've read from other people that really know the 1911. I'm not sure what to think about it, except that there's probably more to the story. (There always is.) Maybe he's got extra light hammer springs in his 1911's, so the minimal effects of a heavier recoil spring are noticeable? FWIW, it's not uncommon to find lighter hammer springs in 1911's with trigger jobs; that's not necessary for a good trigger though, and is totally the wrong direction for a 10mm. Works fine in a .45 wadcutter gun shooting light loads at paper.