Time for a new test I have wanted to do for a while now. Recoil spring changes on full power 10mm ammo. SwampFox (Mike Willard) said a weak for the load spring can make a 50-75 FPS difference due to unlocking. With my Hunter I think it come with a 12lb and 14lb spring. I will try those in the Match with Delta-Lite Underwood 180gr reloads that tested in the 1250 FPS range and see if it proves out. Good test?
Willard was referring to a Glock. The Witness is more like a 1911, where the hammer spring and firing pin stop affect unlocking a lot more than the recoil spring. Slide mass makes a big difference too, but of course is a lot harder to change.
So do you think a 12lb or 14lb will show any signs in the Witness? I don't have a Glock to test with ;)
IMO you'd need to shoot about 10rds with each type and use the avg velocity. Factory ammo varies too much to get an accurate reading with less rds. ...for what your doing. Can also look at extreme spread.
I have to do this test myself again. Going to do with glock 20 with factory spring, 24lb ISM, 22lb wolff and 24lb wolff. (wolff of course is a round spring and the factory and ISM are flat springs)
You have the Glocks to do it with. You need a stock spring (18lb?) or even lower with some full house ammo and then change to the 24lb.
I burn up ammo anyway so I will try in the Witness with the 12lb and 22lb. I will do ten 180's@1250 FPS as a baseline and then ten with the 22lb spring. If that gives nothing to mention I will go to the 1600 FPS 155's from Underwood and that should tell us something.
BTW... Did the ammo arrive?
This person (drsjr1969 ) is also testing various ammo from a Stock Glock 20. He has several videos posted.
http://www.youtube.com/watch?v=nlONYodFh2c&feature=share (http://www.youtube.com/watch?v=nlONYodFh2c&feature=share)
Here is his spread sheet
https://docs.google.com/spreadsheet/ccc?key=0AjsXvXEryDJjdFhsRUcwSHRUcktCMmhOMTVFa25xa1E#gid=0 (https://docs.google.com/spreadsheet/ccc?key=0AjsXvXEryDJjdFhsRUcwSHRUcktCMmhOMTVFa25xa1E#gid=0)
Yea. David has an all stock Glock and his numbers have been different than mine on some things lately. Part of why I wanted to do this for my own info. An increased spring I think would help him but if it is the original I bet it is wore out pretty bad by now hurting things more.
I sent David another personal e-mail invite to the forum, I posted an invite on his Facebook page sometime back. The springs could be worn some but still stroking along!
He mentioned about Kevin's NEW 155gr offering @ 1500 fps in the video and it looks like they are running as advertised.
I did this test today too. I had two low power springs (11lbs/12lbs) and decided to just do the 11lb spring:
Underwood 180gr FMJ (Reloads) out of the Match with a 22lb spring as a baseline: 1269, 1279, 1246, 1262, 1294, 1270. Average = 1270 FPS/ 644.53 LBS.
Underwood 180gr FMJ (Reloads) out of the Match with a 11lb spring: 1263, 1241, 1272, 1249, 1229, 1276, 1246, 1272, 1231. Average = 1253.22 FPS/ 627.62 LBS.
Pretty much debunked the theory in a Match. Possibly different in a Glock.
I still wanted to do worse case so did Underwood 155's.
22lb spring: 1568, 1598, 1553. Average = 1573 FPS/ 851.44 LBS.
11lb spring: 1618, 1629, 1599. Average = 1615.33 FPS/ 897.88 LBS.
Yea. Blew this one out of the water it appears.
Sounds like the EAA runs the same with either spring velocity wise, how were the ejections with the lighter springs? ???
I am not familure with the way the EAA's work with regards to recoil and lock up.
I didn't pay close attention but I thought some of those 155's with the 11lb spring were closer.
If Mr.Redbull does a test like this with a much reduced spring it may tell us the other part of the story (Glocks).
Quote from: Intercooler on August 13 2012 05:37:40 PM MDT
Pretty much debunked the theory in a Match. Possibly different in a Glock.
You didn't "debunk" anything. Nobody said a stiffer recoil spring would change the velocity in a Witness, or in a 1911. You misunderstood the application.
Mike Willard stated that he saw differences in velocities same for Buffalo Bore. Yes debunked for the Witness but can't speak to the rest.
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.
Quote from: sqlbullet on August 14 2012 08:35:24 AM MDT
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.
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.
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.
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.