Welcome to M1911.ORG
The M1911 Pistols Organization Forums Site


John needs your help
Please read this message.


Sponsors Panel
If you intend to buy something from the companies advertising above, or near the bottom of our pages, please use their banners in our sites. Whatever you buy from them, using those banners, gives us a small commission, which helps us keep these sites alive. You still pay the normal price, our commission comes from their profit, so you have nothing to lose, while we have something to gain. Your help is appreciated.
If you want to become a sponsor and see your banner in the above panel, click here to contact us.

Page 1 of 18 1234511 ... LastLast
Results 1 to 10 of 176

Thread: Magazine Function: The Dimple

THREAD CLOSED
This is an old thread. You can't post a reply in it. It is left here for historical reasons.Why don't you create a new thread instead?
  1. #1
    Join Date
    1st June 2004
    Location
    Lexington, North Carolina...or
    Posts
    11,260
    Posts liked by others
    29

    Magazine Function: The Dimple

    I think this one's been posted somewhere...but it bears repeating. El Comandante may delete at a later time if he deems it best to do so.
    *********************

    Inertia! Just no way to get around Newton's Laws regarding motion.
    Remember the old trick of jerking a tablecloth out from under a table setting? This is the principle at work here.

    We have a round in the chamber and one round in the magazine.

    Bang! The slide starts to move as the pistol torques up and back. The slide holds the last round slightly below the feeding position until it moves far enough to uncover it. Just as the magazine spring is struggling to move the round into position, the round is in a sort of "Limbo" while the pistol continues to move backward in recoil. The round obeys Newton, and stands still while the gun is moving away from it.

    The magazine spring catches up, and gets the round up and into the underside of the feed lips, but because the pistol pulled backward away from it (Even though the pressure from the slide drags the round backward in the magazine)...it settles down forward of the feeding position. At this point, if the magazine spring is strong enough to keep it there, the slide pushes it ahead of the extractor. The pistol either fails to go to battery with the round fully chambered, and the front of the extractor rammed against the back of the rim. Extractor breakage is an eventuality.

    If the spring isn't strong enough, the round is forward of optimum feeding position just as the slide smacks the impact surface in the frame, and triggers a second recoil impulse. The gun makes a short, hard jerk upward and backward...and the round is in limbo once more because the mass of the round has caused the magazine spring to compress slightly. The round...already too far forward in the magazine...jumps the follower, and is free of the magazine. The follower pushes the slidestop up as the slide moves forward, and the slide locks. If the magazine spring is weak enough, the next to last round will be ejected from the magazine, and the last round feeds. Ever found live ammo among your brass? Heeere's yer sign!

    The problem is two-fold. One is the spring that has fewer coils to make room for the extra round. There is ample tension to feed until it gets to the last round...and tension is at a mimimum...but sometimes it can happen before the last round. Upping the spring rate helps, but doesn't address the other issue.

    The other part of the problem is the smooth follower. Browning knew how
    inertia would affect things, and he put a small dimple on the top of the magazine follower. The dimple's function is two-fold. It adds a small amount of height to the follower in order to give it a "Leg Up"...and it stops the forward movement of the round. More accurately, it keeps the pistol from moving out from under the round in recoil. In this function, it's basically a back-up for the spring as it fatigues, and provides a better opportunity for the round to stay in position to be stripped from the magazine by the slide instead of being pushed ahead of it...or... in the extreme cases, escaping from the magazine completely.

    John Moses designed a 7-round magazine and he put a dimple on the follower for very good reasons. Whenever we try to change things in order to "improve" the gun...we very often cause problems. There just ain't no such thing as a free lunch, I'm 'fraid.

  2. #2
    Join Date
    1st June 2004
    Location
    Virginia
    Posts
    2,094
    Posts liked by others
    0
    More physics, uuuuuuhhhhhhh....

  3. #3
    Join Date
    1st June 2004
    Location
    Lexington, North Carolina...or
    Posts
    11,260
    Posts liked by others
    29

    Physics

    Quote Originally Posted by stans
    More physics, uuuuuuhhhhhhh....
    stans....Are you followin' me?

  4. #4
    Join Date
    4th October 2004
    Location
    Used to be N.C.
    Posts
    531
    Posts liked by others
    0

    Was eventually gonna ask

    Thanks Tuner,
    Printed it to save for later enlightenment!

  5. #5
    Join Date
    8th November 2004
    Location
    Manassas, Virginia
    Posts
    110
    Posts liked by others
    0
    Quote Originally Posted by 1911Tuner
    John Moses designed a 7-round magazine and he put a dimple on the follower for very good reasons. Whenever we try to change things in order to "improve" the gun...we very often cause problems. There just ain't no such thing as a free lunch, I'm 'fraid.
    I'm a bit old fashioned, and I've been accused of purism, so it should come as no surprise that all of my mags are of the gov't issue, 7 round, welded floor, dimpled follower variety. My RIA came with an 8 round job with a smooth follower. I don't use it, but my son likes that one because it's easier(read that as 'less technique sensitive') to load. But he wondered why he got 2 instances of the slide coming slightly short of going into battery, both of which occured on the last round out of that mag. I have to work on his mag packing skills! Once I get a few more gov't mags, I'll probably sell the 8 round job.

    Thanks again, Tuner, for another great technical post. You should write a *******' book!
    Paul X. Danner
    NRA Life Member
    Email me

  6. #6
    Join Date
    19th November 2004
    Location
    alberta,kanada
    Posts
    88
    Posts liked by others
    0
    i am in awe
    the more i learn about the 1911(and other browning designs)the more i realize what a genius the man was.
    Tuner, you must run a close second in order to make a simpleton like me be able to understand these concepts/funtions

  7. #7
    Join Date
    1st June 2004
    Location
    Lexington, North Carolina...or
    Posts
    11,260
    Posts liked by others
    29

    Simple-ton?

    Canuk...I beg to differ. A simpleton wouldn't have been able to understand
    that explanation...or wouldn't have seen the logic behind it.

    F'rinstance...Several years ago, my uncle (Retired Navy armorer) told me that
    that the dimple had a very good reason for being there without explaining why. He knew that I was the hard-headed type that had to touch the
    wall to see if the "Wet Paint" sign was lying...and that I'd be obliged to
    find out for myself. I guess he figured that a hard-learned lesson would be
    less likely to fade...so he dropped that on the table and waited for me to
    file the dimples off a few followers...which I did. basically...He baited me to
    file the tops of the followers smooth to see what would happen.

    After all...Ken Hallock said it was the right thing to do...right? RIGHT??

    Last round malfunctions began to show up almost immediately in two pistols,
    but two others seemed to run fine. "Seemed to" is the key. They did run...
    but a couple thousand rounds into the exercise, I noticed that the extractors
    began to lose tension...something that they hadn't done before over the course of 20,000 rounds collectively. (Heeeere's your sign!)

    I shrugged it off, reasoning that they were just ready for adjustment anyway. I reset the tension and continued on. One lost tension quickly...and one snapped off flush with the breechface. I STILL didn't make
    the connection.

    Somewhere in that time frame, my uncle called me to ask if I had removed any dimples. I answered in the affirmative, and his next question was: "Lost any extractors yet?" I could "hear" the little wiseassed grin on his face over the phone. After about a 30-second silence, he said: "I'll let you go...I guess you've got some followers to replace."

    Quote:

    "There are three kinds of people. There's them that learn by readin' and there's them that learn by watchin'. Then there's that third type that's gotta whizzz on the electric fence for themselves."

    --Will Rogers--
    Last edited by 1911Tuner; 21st December 2004 at 08:47.


  8. #8
    Join Date
    1st June 2004
    Location
    Virginia
    Posts
    2,094
    Posts liked by others
    0
    stans....Are you followin' me?
    Zzzzzzzzz....

  9. #9
    Join Date
    15th January 2005
    Posts
    176
    Posts liked by others
    0
    Can somebody explain how Wilson mags get away with no follower and have a very favorable reputation??

  10. #10
    Join Date
    29th May 2004
    Location
    Athens, Greece, Earth
    Posts
    28,076
    Posts liked by others
    204
    Blog Entries
    2
    No follower???? I seriously doubt that with Wilson's mags you load the rounds on the spring's top coil, maybe you mean no dimple?

    Rgds
    John Caradimas SV1CEC
    The M1911 Pistols Organization
    http://www.m1911.org

Page 1 of 18 1234511 ... LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  



Sponsors Panel
If you intend to buy something from Brownells, please use their banners above. Whatever you buy from them, gives us a small commission, which helps us keep these sites alive. You still pay the normal price, our commission comes from their profit, so you have nothing to lose, while we have something to gain. Your help is appreciated.
If you want to become a sponsor and see your banner in the above panel, click here to contact us.

Non-gun-related supporters.
Thank you for visiting our supporters.