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  #1  
Old 11-23-2015, 04:06 PM
canrunin canrunin is offline
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heavy main spring, firing pin stop

when it is talked about using the main spring and FPS to slow the slide down, is this done to only help with recoil?i understand the slide needing to hesitate for the magazine to feed the next round.i just hate how it feels when i pull the slide back against the hammer and how hard it is. my first instinct is to find a happy medium with main spring and recoil spring so when racking the slide its a nice smooth motion. so i thought i would ask because maybe on the 1911 you dont want it to be a smooth motion. thanks
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  #2  
Old 11-23-2015, 04:30 PM
drail drail is offline
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The full power mainspring and square FPS only slow the slide down while it is traveling to the rear. When the slide reaches the end of its rear travel and stops those parts are out of the picture. The feed cycle takes place when the slide goes forward. That is one of the problems with using too much recoil spring - the slide can be driven forward faster than the magazine spring can get the next round up in position to be picked up by the slide. The slide does not "hesitate" for a round to feed. If it is difficult for you to rack the gun with the hammer down just cock it first - and then rack the slide. Soldiers complained about the force required to rack the pistol with the hammer forward during WW I and the FPS was changed to make it easier to rack.
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  #3  
Old 11-23-2015, 04:44 PM
Steve in Allentown Steve in Allentown is offline
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As you say these two things slow down the rearward speed of the slide. This allows the use of a lighter recoil spring which causes the slide to hesitate a bit longer before it comes forward. This means the magazine spring has more time to push the column of rounds up into solid contact with the feed lips. The result is enhanced feeding reliability and less muzzle dip as the lower barrel lugs are stopped by the slide stop pin. There is also a varying amount of recoil impulse reduction depending on the individual shooter's perception and the way the pistol unlocks.

The price to be paid is that it's not as easy to pull the slide back.

All of this is esoteric, 1911 enthusiast kind of stuff. It's fun for guys like me to think about and experiment with. But a 5" steel frame 1911 shooting standard pressure loads should run like a scalded dog without resorting to square bottom firing pin stops and heavier than standard mainsprings.

Last edited by Steve in Allentown; 11-23-2015 at 04:52 PM.
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  #4  
Old 11-23-2015, 04:50 PM
Paxson Paxson is offline
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A solution looking for a problem.
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  #5  
Old 11-23-2015, 04:58 PM
Thomgetch Thomgetch is offline
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You will always have some resistance initially to overcome the hammer when racking the slide, this is the general design. You can lighten the hammer spring and there are hammer designs intended originally for lighter loads like a 22 that can make it easier. You did. It mention if you have a standard or flat bottom FPS, nothing wrong with the standard. If it is hard to rack the slide how are you doing that? Try this. Grasp the slide not with fingers but with the palm of your hand on top of the slide grasping the whole slide firmly. Then grip the frame as normal but holding the slide firmly, push the frame forward with your trigger hand. Then release the slide. You will find this much easier.
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  #6  
Old 11-23-2015, 05:02 PM
drail drail is offline
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I was not referring to non-standard parts. I was referring to the original specs in the blueprint as drawn up by John Browning. He didn't change the FPS profile - the Army did. His original FPS stop radius was almost square. I also have to think he probably tried just about every combination of springs possible until he found the best and most reliable setup. He specified a specific strength recoil and mainspring to balance the system out. You can use better steels than were available to him at the time and you can certainly hold tighter tolerances than most factories want to deal with but the real reason the pistol runs like a scalded ape is because Browning's original design work was just about perfect on every gun he built. He had plenty of competition on the new pistol for the War Dept. - and none of the others even came close to what he achieved.

Last edited by drail; 11-23-2015 at 05:09 PM.
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  #7  
Old 11-23-2015, 05:09 PM
ortho32 ortho32 is offline
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Cock the hammer before racking the slide
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  #8  
Old 11-23-2015, 05:10 PM
drail drail is offline
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Yup. Or go to the gym.
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  #9  
Old 11-23-2015, 05:32 PM
DArBad DArBad is offline
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I think............the perfect combination was already worked on by JMB. 23 lbs mainspring with a 16 lbs recoil spring and flat bottomed FPS. The " rounded " FPS came only later at the behest of the military.
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  #10  
Old 11-23-2015, 05:53 PM
canrunin canrunin is offline
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ok let me reword the question.what is the purpose for slowing down the slide? the only reason i can think of is to help with recoil? thats all i want to know,sorry for the confusion.
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  #11  
Old 11-23-2015, 06:05 PM
DArBad DArBad is offline
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Quote:
Originally Posted by canrunin View Post
ok let me reword the question.what is the purpose for slowing down the slide? the only reason i can think of is to help with recoil? thats all i want to know,sorry for the confusion.
I think so too, that is.... to help with the perceived strong recoil.
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  #12  
Old 11-23-2015, 06:26 PM
Steve in Allentown Steve in Allentown is offline
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Quote:
Originally Posted by drail View Post
. . .the real reason the pistol runs like a scalded ape is because Browning's original design work was just about perfect on every gun he built.
Absolutely 100% in total agreement.

By the way, I wasn't adressing anything you wrote. I didn't see your post until I had finished mine. We must have been writing at the same time. I was just slower than you.
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  #13  
Old 11-23-2015, 07:07 PM
drail drail is offline
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WOW. I didn't think anyone could be slower than me.
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  #14  
Old 11-23-2015, 07:50 PM
beretta92 beretta92 is offline
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I will be ordering a couple EGW Firing Pin Stops my next order to just have a couple on hand..
In fact being they are different between series 70 & 80 & 9/38/40 v.s. 45 & then stainless or carbon blued there are several different ones available..
In my opinion getting one of these setup correctly might just be the single best $15-$20 you could ever spend on your 1911..
I have been wanting one for my Compact/Officers Colt & 20+ years ago got it running 100% by increasing the mainspring & recoil springs + Wilson/Rogers magazine..
I might have to back off on the recoil spring & plan on trying a single flat type spring that wasn't available in the early 90s..
As far as trouble with racking the slide, either grow a pair or cock the hammer first & go on with it..
Here's the Link to EGWs FPS -----> http://www.egwguns.com/firingpinstops
I'm also gonna keep an eye out for pre 1918 FPSs at the gunshow in the old parts bins made to JMBs original specs..
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  #15  
Old 11-23-2015, 10:29 PM
airwing8404 airwing8404 is offline
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The Old Guy

OK you guys that can swing through the tree's like Tarzan, give us old guys a break, besides doing what you guys said "grow a set or cock the hammer" I do that plus I have a flat Firing pin stop, 14 lb recoil spring ,18 lb mainspring and I use a claw full finger grip on top the slide to rack it when it's necessary.

Now for the angry old man words. I've probably been and done a few things that would make you girly boys cry, and that was just in training. SO STUFF IT
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  #16  
Old 11-24-2015, 02:48 AM
beretta92 beretta92 is offline
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OH YEAH!! HaHa..

No Offence intended but I think you get my point..
BTW I'm 50 & can't do the Tarzan stuff anymore & arthritis pain makes it tough to even play the guitar/bass anymore BUT we improvise adapt overcome

Here's a link to Midway USA for a Wilson FPS for Series 70s 1911s
http://www.midwayusa.com/product/107...-acp-series-70
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  #17  
Old 11-24-2015, 07:53 AM
Magnumite Magnumite is online now
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Quote:
Originally Posted by DArBad View Post
I think so too, that is.... to help with the perceived strong recoil.
Many use it as a tuning aid for faster follow up shots. If you slow the slide down there is less impact on the frame and a lighter recoil spring may be used. Using a lighter recoil spring causes less front sight dip when the pistol goes back into battery. It has been discussed many times in the forums.

I use firing pin stop radius, how close to parallel the hammer face is to the firing pin stop surface, putting cutouts in the hammer face and mainspring/recoil springs to achieve the operating nature of the pistol for a given load. Even grip pressure can cause small changes in the nature of the pistol. When shooting the action sports recovery is time. I am not the fastest but I can feel the differences.

As an experiment take an old firing pin stop and extend the top of the radius up to about the bottom of the firing pin hole. Then shoot a ball load or two. The amount of muzzle flip with be greatly increased. The square bottom fps takes the nature in the opposite direction. The square bottom fps also as a tuning aid in more powerful loads...say 45 Super and 10 mm.
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  #18  
Old 11-24-2015, 12:16 PM
airwing8404 airwing8404 is offline
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I can't get away from it

Quote:
Originally Posted by beretta92 View Post
OH YEAH!! HaHa..

No Offence intended but I think you get my point..
BTW I'm 50 & can't do the Tarzan stuff anymore & arthritis pain makes it tough to even play the guitar/bass anymore BUT we improvise adapt overcome

Here's a link to Midway USA for a Wilson FPS for Series 70s 1911s
http://www.midwayusa.com/product/107...-acp-series-70
OK but quoting Clint Eastwood, that's not fair. And what I called flat Firing Pin Stop is a Square Stop, I happened to use a Fusion.
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  #19  
Old 07-04-2018, 02:50 PM
Cousin Vinnie Cousin Vinnie is online now
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Quote:
Originally Posted by canrunin View Post
ok let me reword the question.what is the purpose for slowing down the slide? the only reason i can think of is to help with recoil? thats all i want to know,sorry for the confusion.
I came across this old thread and wanted to share why I need to slow down my slide. I have a Sig C3 and am experiencing inertia feeding issues. Meaning when I get to the last round in the magazine, the slide will lock back and the last round floats on top of the magazine. I did change to the magazines and that helped until I go to +P ammo, than the inertia feeding will occur sporadically. My C3 is completely stock, and I was led to believe that if I can slow down the slide a little, this may not occur with +P ammo. So, I ordered the 25 lb mainspring and a 22 lb recoil spring and a heavier firing pin spring to balance things out. This is a Commander length slide and it currently has a 20 lb recoil spring. As a proactive option, I also ordered the Wilson Combat Bullet Proof slide stop with the dimple to also provide an additional measure. I should have everything this week and will report back after I make the changes and do a range test.
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  #20  
Old 07-04-2018, 03:53 PM
log man log man is offline
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Quote:
Originally Posted by drail View Post
I was not referring to non-standard parts. I was referring to the original specs in the blueprint as drawn up by John Browning. He didn't change the FPS profile - the Army did. His original FPS stop radius was almost square. I also have to think he probably tried just about every combination of springs possible until he found the best and most reliable setup. He specified a specific strength recoil and mainspring to balance the system out. You can use better steels than were available to him at the time and you can certainly hold tighter tolerances than most factories want to deal with but the real reason the pistol runs like a scalded ape is because Browning's original design work was just about perfect on every gun he built. He had plenty of competition on the new pistol for the War Dept. - and none of the others even came close to what he achieved.
Here is a profile of the 1911-1918 firing pin stop changes.

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  #21  
Old 07-04-2018, 03:57 PM
Striker2237 Striker2237 is offline
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Quote:
Originally Posted by canrunin View Post
ok let me reword the question.what is the purpose for slowing down the slide? the only reason i can think of is to help with recoil? thats all i want to know,sorry for the confusion.
Keeps it locked slightly longer if using very powerful loads too, really helps keep the slide velocity sane as well for the smaller guns.
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  #22  
Old 07-04-2018, 04:07 PM
Steve in Allentown Steve in Allentown is offline
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Quote:
Originally Posted by Cousin Vinnie View Post
. . . I need to slow down my slide. I have a Sig C3 and am experiencing inertia feeding issues. <snip> So, I ordered the 25 lb mainspring and a 22 lb recoil spring <snip> and it currently has a 20 lb recoil spring.
I think the C3 comes with flush fit 7 round magazines even though the standard capacity for an Officer's size frame is 6 rounds. Flush fit magazines that stuff more rounds in them than standard capacity can wear out springs much more quickly than those that only accept the standard number of rounds.

In addition to everything else you may want to consider picking up a Tripp Cobra 7 round mag which has a longer tube than a flush fit mag. You can also get Tripp Government size 8 round mags with a baseplate thae prevents over insertion. I have several of these and they work fine. They're my reloads for CCW when I carry my CCO.
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  #23  
Old 07-04-2018, 06:44 PM
Magnumite Magnumite is online now
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The small radius of a flat bottom firing pin stop can be over done or misapplied. In a heavier recoiling gun it definitely is an attribute. In something like a full size 9mm it isn’t needed. Full size stock steel gun, 9mm caliber, the small radius actually increases felt recoil, though more affecting followup shot speed than any discomfort. This was used as part of the build. The character and manner of the recoil was bothering me. Changing main and recoil spring combinations only got me so far. So I used the firing pin stop radius to smooth out and lessen the push against my hand. Extending the radius to about 1/4” radius softened the impulse, smoothed the recoil character of the pistol and gives me faster followup and double tap times. I typically use this technique for specific loads.
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Last edited by Magnumite; 07-05-2018 at 09:34 AM. Reason: grammar, content, maingey spelling
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  #24  
Old 07-04-2018, 07:08 PM
Geologist Geologist is offline
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I run a Harrison small radius FPS, 20# MS and 12# recoil spring in my SA loaded. Not that hard to pull the slide back. Gun cycles fine even using 750 FPS/230 gr match ammo. Feels good when I shoot it and allows me to get back on target a bit more predictably and faster. YYMV.
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  #25  
Old 07-05-2018, 08:38 AM
Martensite Martensite is offline
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I recently built a 7.62x25 Tokarev 1911 using a J&G Conversion barrel. I'm using corrosive surplus Bulgarian, Romanian and Polish ammo. This ammo has really hard primers. Last range session, I had a 26Lb mainspring and a 12 Lb recoil spring installed in the pistol in conjunction with a flat bottom firing pin stop. The slide failed to lock back a maybe five times out of 240 rounds but the real problem was that the mainspring still wasn't strong enough to successfully light-off the surplus rounds every time. Often times, I had to re-cock the hammer for a second successful hit.

Next range session, I'll be switching to a 28 Lb mainspring and potentially an 11 Lb recoil spring if the slide doesn't lock back on the last round. We'll see how she runs then. You've got to understand the power of the 7.62x25 Tokarev round to understand the spring combo...
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