"limp wristing" cured by Dr R. Spring
Clark Magnuson
necessary to get a semi auto to cycle with the stock spring and also the
amount of powder with the heaviest spring available. What I have found
is that only a fraction of the momentum of the bullet is reflected in
the momentum of the slide and barrel. It seems that most of the recoil
is transferred to the hand before the bullet leaves the barrel.
click on the pistol
click on technical issues
click on recoil spring selection tips by Bill Wilson
"As a rule of thumb, you should use the heaviest recoil spring possible,
which does not interfere with the pistol functioning."
I use AA#5 as you can see it has a very predictable powder to pressure
ratio
1) 45 acp 185 gr 1100 fps 10.2 gr AA#5 18,000 psi
2) 45 acp +P 1200 fps 10.8 gr AA#5 21,700 psi
3) 45 Super 1312 fps 12.4 gr AA#5 28,000 cup
4) 460 Rowland 1500 fps 14.5 gr AA#5 38,800 cup
Example:
Patriot 45acp
http://www.republicarmsinc.com/
15 pound to start and 42 pound spring at the rear [home made spring
assembly], is just right for 10.3 gr of AA#5. That is, it is just enough
powder to keep the Patriot from jamming with that spring.
The bullet leaves the gun at 1100 fps.
The bullet weighs 185gr = 185/7000 = .026 Lb.
The slide weighs .5 Lb.
The barrel weighs .1 Lb.
The spring is 15 Lb to start.
The spring is 42 lb at back.
The momentum of the bullet equals the momentum of the slide and barrel.
[1100][.026]=V[.5+.1}
V=47.7 feet per sec
Velocity of slide and barrel = velocity of slide
Energy of slide = .5mVV= one half mass velocity squared
Es=.5[mass of .5 pounds][47.7][47.7]
Mass = [wieght]/gravity= .5/32.2=.0155
Es=.5[.0155][47.7][47.7]=17.64 foot pounds of energy
The energy required to pull back the slide = [force][ distance]
Force = average force = [15+42]/2 = 28.5 pounds force
distance = 1.656"=1.656/12=.138 feet of slide stroke
Eslide = [28.5][.138]=3.93 foot pounds
BUT WAIT A MINUTE! 17.64 DOES NOT EQUAL 3.93!
Not all of the bullet momentum went into the slide and barrel.
Some of it accelerated the hand.
Only 3.933/17.64= 22% went into the slide and barrel.
What does this mean to someone who wants to calculate the spring needed
for a semi auto pistol?
Heavy firm hands need stiffer springs than soft light hands and there is
no good way to measure how light and soft one's hand is.
So, you cannot accurately calculate the spring you need.
However, a CZ52 9mm pistol takes 4.7 gr AA#5 to cycle with a 125 gr .357
bullet. Put in a Wolff +10% spring and it takes 5.3 gr AA#5 to cycle. So
you can calculate spring requirements over a small region of already
known spring requirements.
The 22% finagle factor [above] will go up for heavier slides with
lighter springs. The above example is an extreme case of light slide and
heavy spring. The numbers are usually around 30~33%.
Never say "limp wristing" again. Say, "If the gun jams, get a lighter
spring. If the slide slams the frame, get a heavier spring."
Clark
-------------------------------------------------------------------------
Please find out about rec.guns at http://doubletap.cs.umd.edu/rec.guns
Sqzeplay9
FJT
phil burton
lighter one?
Nick Hull
burton) wrote:
# Then why does a heavier bullet seem to produce more recoil than a
# lighter one?
#
Actually, heavier bullets seem to produce LESS recoil since they generate
less noise.
--
Committees of Correspondence Web page:
http://www.geocities.com/CapitolHill/5357/
- free men own guns, slaves don't
Bill Oertell
#
# In article <8ik4qo$q6l$1...@xring.cs.umd.edu>, ful...@webtv.net (phil
# burton) wrote:
#
# # Then why does a heavier bullet seem to produce more recoil than a
# # lighter one?
# #
#
#
What does noise have to do with recoil? Yeah, I can see a possible
connection between noise and flinching (actually, I don't really buy
this either, but it's become so widely accepted I don't really want to
argue with it), but noise and recoil...even felt recoil? I'd like to
see the explanation for that.
Bill
John Abatte
phil burton wrote:
> ...
--
John Abatte
jab...@wt.net
"I have come here to chew bubble gum and kick ass... and I'm all out of
bubble gum."
Roddy Piper in: "They Live"
Nick Hull
<oer...@pacbell.net> wrote:
# Nick Hull wrote:
# #
# # In article <8ik4qo$q6l$1...@xring.cs.umd.edu>, ful...@webtv.net (phil
# # burton) wrote:
# #
# # # Then why does a heavier bullet seem to produce more recoil than a
# # # lighter one?
# # #
# #
# # Actually, heavier bullets seem to produce LESS recoil since they generate
# # less noise.
# #
# What does noise have to do with recoil? Yeah, I can see a possible
# connection between noise and flinching (actually, I don't really buy
# this either, but it's become so widely accepted I don't really want to
# argue with it), but noise and recoil...even felt recoil? I'd like to
# see the explanation for that.
#
Ask any woman
--
Committees of Correspondence Web page:
http://www.geocities.com/CapitolHill/5357/
- free men own guns, slaves don't
-------------------------------------------------------------------------
Douglas Trabue
# What does noise have to do with recoil?
#
# Bill
#
Well it did come from a gun periodical, and it wasn't a scientific
study.
In reference to shooting the 16 1/2" barrel 14lbs Harris Desert Rhino
..50BMG
I quote, "Those of us who shot the Desert Rhino really couldn't
accurately assess felt recoil because we were too occupied coping with a
muzzle blast that broke strobe lights on a camera setup 10 feet away..."
Guns & Ammo Sept. 98.
Doug T
Mike in Oregon
The reason your momentum calculations don't work out is because your assuming
that all the momentum should be imparted to the barrel & slide, and that is
just not true in a locked breech design. It might be so with a true blow back
design but not a locked or delayed design. As you conclude: when selecting
recoil springs, there is no substitute to trial and error. I totally agree!
All you pistols shooters should invest in Wolff's calibration recoil packs,
just try them all and then install the one that works best for you with
favorite load.
I shoot a locked weaver stance and I tend to really take command of the
pistol with a high hold. I find a 22lb Wolff variable spring in my Kimber
..45 is perfect for my major power handloads. Cases only fly about a yard. I
hand my pistol to someone else who shoots an isosceles stance with not so
high a hold, and the pistol jams for them. Nothing wrong with their hold, nor
my pistol. It's just that it's tuned for me and my style of hold.
Talk to ya later,
Mike in Oregon
NW Shooters Support
Beaverton, Oregon
"Mike in Oregon"<Mike.W....@tek.com>
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