Relationship between popple holes and flatness

[Fo0]

31 minutes ago, vgdvc said:

Yes I recognize that theory, and I do have it set up that way on my limited gun. However if Cha lee's theory is correct a majority of the upward dot movement comes from the mass of the slide hitting harder at the rear position when firing. I'm going to play to see if the square-edged FPS has a better recoil sensation for (1)keeping it delayed and locked in battery longer so even more gas is burned prior to slide movement  and (2) slowing the slide momentum to create less reward impact. I know the common

thing seems to be using a higher contact point fps contact point with open guns but when this was mentioned a little while back to some very experienced shooters they actually said they have settled on a square FPS style in there open guns so I will need to try this myself.

 

i think it depends on how many popple holes you have

[racer-x]

52 minutes ago, Aircooled6racer said:

Hello: Buy a EGW square firing pin stop and try it. Then start filing a radius on the corner to see what it does. I made a fixture so I can mill an angle on the firing pin stop that works very well for me. It makes racking the slide easier so it cycles quicker. Thanks, Eric

 

Thanks Eric - interesting.

 

Could you post a picture showing the angle you ended up with on your FPS?

[echotango]

11 hours ago, vgdvc said:

Not to jump off topic but seeing how it could relate to the need or lack of for popple holes has Echo Tango or anyone else experimented with using an original design FPS with just a small radius at the bottom like the EGW standard unit( seen farthest back in above picture)? I have read on here before that many prefer the Cheely FPS profile but if the intent is to retard/delay rearward slide movement to allow a lighter recoilspring, which would reduce forward momentum of the slide going back into battery, wouldnt a square profile with slightly rounded bottom FPS make most sense?

I have tried all of those and more as I took that picture.  My current setup is a Cheely fps (2nd in pic) and a 9# ISMI recoil spring and a 17# ismi main spring.  Yes, brand of spring matters as they are all diff. Example, an ISMI 17# is lower than a Wolff 15#. 

FYI, the fps in the pic are f to b, Atlas, Cheely, Caspian and Harrison.  

 

 

Edited January 22, 2020 by echotango

[echotango]

11 hours ago, vgdvc said:

 wouldnt a square profile with slightly rounded bottom FPS make most sense?

Not necessarily. It is give and take.  It will be hard to unlock and that energy has to go somewhere such as muzzle lift.  I prefer easy/quick unlocking and tune the slide travel speed with springs.  Also have to keep in mind the closing and that your second shot doesn't go low/muzzle dip as stated previously. 

Edited January 22, 2020 by echotango

[zzt]

11 hours ago, vgdvc said:

Not to jump off topic but seeing how it could relate to the need or lack of for popple holes has Echo Tango or anyone else experimented with using an original design FPS with just a small radius at the bottom like the EGW standard unit( seen farthest back in above picture)? I have read on here before that many prefer the Cheely FPS profile but if the intent is to retard/delay rearward slide movement to allow a lighter recoilspring, which would reduce forward momentum of the slide going back into battery, wouldnt a square profile with slightly rounded bottom FPS make most sense?

 

Yes.  A lot of bullseye shooters like an almost square FPS, because it delays the rearward motion of the slide and felt recoil is reduced.  A side effect is it makes the slide a lot harder to rack.  It is definitely not something I want on my Open guns for just that reason.   However, it definitely did reduce slide caused muzzle rise.   I started with the EGW square with a 1/64" radius.  I kept increasing the radius a little at a time until I was past the 'normal' angle.  As you would expect, slide speed increased and the slide was easier to rack with each increase.

 

That being said, you have to tune everything to your individual gun.  For example, I started with Aircolled6racer's custom comp cuts, a standard Cheely Open FPS and a 17 lb. mainspring.  A 7 lb. recoil spring worked the best for that.  It didn't shoot as flat as I liked, so I had two 3/16" poppels added in a V2 configuration.  The gun shot flatter,  but everything else changed.  It hit my hand harder, slide speed increased and the slide hit the frame harder at the end of the stroke.  I ended up going to a 19 lb. mainspring and that helped.  I had a problem with minor ammo short stroking and stovepiping the case.  So I increased the angle on the FPS so it hit the hammer as high as possible.  That cured the stovepipe problem with minor ammo, but slide speed increased again.  Going to an 8 lb. recoil spring cured that.

 

I'm just finishing a dedicated minor Open gun.  When it is finished I'll go back to a Cheely standard FPS for the major gun and start over.  Not having to accommodate minor ammo should let me tune it a little better.

[CHA-LEE]

Since tuning all of these springs and FPS's is confusing for people I made a video of what all of this stuff does a while ago.......

 

 

[Dwbsig]

Thanks for the video you have helped me learn some good info.

[Posvar]

1 hour ago, CHA-LEE said:

Since tuning all of these springs and FPS's is confusing for people I made a video of what all of this stuff does a while ago.......

 

 

Great job. This is helpful 

[perttime]

19 hours ago, CHA-LEE said:

 

The recoil spring has an affect on the slide velocity but not as much as the hammer spring or firing pin stop angle. The recoil spring weight should be tuned to optimize the snapping forward motion of the slide so that the muzzle returns directly to level. If you put a heavy recoil spring in there to help reduce the slide velocity it will likely help in that part of the slide movement but it could also ruin the forward motion of the slide by making the muzzle dip low as the slide snaps back forward excessively hard.

 

Once again, observing the movement of the gun during the cycling process via slow motion video one frame at a time will tell you exactly what is causing "Movement" in the gun.

 

Recently, I discovered the notion that you can "stroke" the gun, or let the slide travel further back - and that is supposed to reduce muzzle flip.

 

Any experiences or opinions on that?

[shred]

Square firing pin stops were a thing in the days of 175PF Major.  Turned out they tended to egg-out the hammer pin hole in the frame if you ran them like that too long, so something to watch for.

 

"Stroking" 1911s was originally invented to increase reliability in STI guns to give the big stick more time to lift the stack and get the next round into place before the slide started trying to feed it.  Since then it's like CBD in as many things as it gets credit for improving.

 

 

 

[CHA-LEE]

1 hour ago, perttime said:

 

Recently, I discovered the notion that you can "stroke" the gun, or let the slide travel further back - and that is supposed to reduce muzzle flip.

 

Any experiences or opinions on that?

 

A "Stroked" gun simply provides a longer movement path of the slide which produces a larger window of opportunity for the recoil spring to resist the slides rearward movement. Think of it like giving a car a further breaking distance before it smashes into a wall. Its still going to smash into the wall but will be doing so with less velocity because it had a little more distance to slow down. This extra slide movement distance makes the felt recoil as the slide bashes into the frame "Feel" softer.

 

Realistically though, the same amount of felt recoil reduction "Stroking" does can be achieved using much cheaper methods. Such as adding more weight to the non-reciprocating parts (Barrel, Frame, Guide Rod, Grip, Magwell, etc). In my testing the same felt recoil reduction that "Stroking" produces is about the same as adding 2 - 3oz of weight to the gun. 2 - 3oz of weight can easily be achieved by switching to a tungsten guide rod or a steel magwell. 

 

The fun and frustrating thing about 1911/2011 guns is that there is an endless combination of parts available on the market today. Your testing with all of these different parts to see what they do to change the felt recoil is usually restricted to the thickness of your wallet.

Edited January 22, 2020 by CHA-LEE

[MikeBurgess]

The list of variables is so long with infinite possible combinations, I think the best thing for 99.9% of shooters is to pick a gun that you like develop a load that makes power factor, adjust your recoil spring so it returns to where it came from and shoot the crap out of it. 

 

variables include but not limited to

slide weight

barrel + comp weight

barrel length

barrel holes

comp design

frame weight

recoil spring

main spring 

FPS shape

hammer geometry

cartridge (9/38)

powder

bullet weight.

 

If you think anyone has scientifically tested all the above combinations and found the one best solution you are kidding yourself. 

 

 

 

[Posvar]

20 minutes ago, MikeBurgess said:

The list of variables is so long with infinite possible combinations, I think the best thing for 99.9% of shooters is to pick a gun that you like develop a load that makes power factor, adjust your recoil spring so it returns to where it came from and shoot the crap out of it. 

 

variables include but not limited to

slide weight

barrel + comp weight

barrel length

barrel holes

comp design

frame weight

recoil spring

main spring 

FPS shape

hammer geometry

cartridge (9/38)

powder

bullet weight.

 

If you think anyone has scientifically tested all the above combinations and found the one best solution you are kidding yourself. 

 

 

 

That’s how I started and that’s all I do. Those two things make a huge difference for me. 

[AverageJoeShooting]

So is there such thing as a gun that shoots flat, slide hits frame soft, and dot remains basically where it started? 

 

Is it possible to have it all in one build?

[zzt]

53 minutes ago, AverageJoeShooting said:

Is it possible to have it all in one build?

 

Yes, but not in 9mm unless you have a welder's grip.  A friend shot my gun and it did not move.  He can crush an apple in his hand, so that will give you some idea of the grip strength required  It is much easier to achieve in 38SC and 40sw with a more normal grip strength.

 

I'll also say that chasing perfect flatness is a waste of time IMO.  As long as there is not a lot of muzzle rise and the dot returns to the same spot very quickly, you are good to go.  If you are shooting snake eyes with .2 second splits or faster, your gun is set up perfectly, even if the dot rises.

[MikeBurgess]

38 minutes ago, AverageJoeShooting said:

So is there such thing as a gun that shoots flat, slide hits frame soft, and dot remains basically where it started? 

 

Is it possible to have it all in one build?

I have yet to see a slow motion video of a open gun where the dot could actually be staying in the glass through the full recoil cycle, I'm sure there is someone out there with monster arms that can do it but as a rule it doesn't happen. what IS important is that the dot is back where it started at the end of the recoil cycle. Chase the return don't worry about the rest

 

 

 

 

 

 

 

 

 

 

 

[CHA-LEE]

As zzt has stated already, it is possible to produce a near zero muzzle flip setup with an optimized gun/ammo/spring config along with a MAN level of grip pressure. I was able to produce exactly that on my 9Major shorty open gun setup. I thought that zero muzzle flip would be better than having muzzle flip because the dot "Should" simply stay where it started. What I found is that this setup became nearly impossible to call my shots effectively because the dot would explode into a super unpredictable pattern within the glass due to the vibration and concussion as the shot fired. All of the violence of the shot firing has to go somewhere. With that failed experiment I found that a minimal amount of muzzle flip is best as it allows the dot to stay a dot and also track up and down within the glass in a very smooth and predictable manner. A predictable vertical streak of the dot within the glass is much easier to call shots with.

 

Regardless of muzzle flip magnitude, what matters most is that when the slide snaps back forward the muzzle should return exactly to a level position with the dot centered in the glass.   

[CHA-LEE]

12 minutes ago, MikeBurgess said:

I have yet to see a slow motion video of a open gun where the dot could actually be staying in the glass through the full recoil cycle, I'm sure there is someone out there with monster arms that can do it but as a rule it doesn't happen. what IS important is that the dot is back where it started at the end of the recoil cycle. Chase the return don't worry about the rest

 

 

 

 

 

 

 

 

 

 

 

Here is my Atlas Chaos in slow motion. The dot is staying in the glass through the whole cycle of the slide. This blaster could be even "Flatter" with a heavier hammer spring and less angle on the FPS. I am waiting to get it back from getting Black DLC coated to continue my tuning and load development process. For what its worth, this gun is setup with no popple holes in the barrel and the Atlas 2 port comp.

 

https://www.instagram.com/p/B69vlgXpiKc/?utm_source=ig_web_copy_link

[Aircooled6racer]

Hello: A thing to remember is that Charlie(CHA-LEE) grips the crap out of the pistol. I have tested a bunch of comps and built a bucket full until I found what works best for me. I wanted less recoil and a dot that tracked straight up and down. My dot stays in the glass for me. I don't grip the pistol overly hard about the same as a firm handshake. I use a 5.5" barrel length with no barrel holes. I have a 9mm open pistol I am running now that has two barrel holes in line and over 60,000 rounds or so. Still shoots good with 115's. I will post some pics of the firing pin stop tomorrow. Thanks, Eric

[AverageJoeShooting]

2 hours ago, CHA-LEE said:

Here is my Atlas Chaos in slow motion. The dot is staying in the glass through the whole cycle of the slide. This blaster could be even "Flatter" with a heavier hammer spring and less angle on the FPS. I am waiting to get it back from getting Black DLC coated to continue my tuning and load development process. For what its worth, this gun is setup with no popple holes in the barrel and the Atlas 2 port comp.

 

https://www.instagram.com/p/B69vlgXpiKc/?utm_source=ig_web_copy_link

Damn that's flat

[zzt]

I don't have Cha-lee's grip strength, so I have to rely on gun configuration and tuning.  Without getting into detail, injuries prevent more than 75 lbs. of grip strength before serious pain sets in.  I started Open with 40sw.  I also thought the goal was total flatness.  So I worked up loads until I got to dead flat.  That was 188PF.  The 6 MOA dot on the upright slide ride exploded, just as Cha-lee describes.  It was also so loud and violent I feared for my hearing and the longevity of the gun.  So I dialed it back to 172PF and lived with the dot movement.

 

A lot later on I decided to experiment with slower powders.  I had been using Autocomp and Silhouette, because everyone else did.  When I switched to Major Pistol powder I had enough gas to seriously flatten the gun AND make it softer shooting at the same time.  I have yet to achieve those levels in my 9mm major gun.  I'm very close on flatness, but not softness.

[MikeBurgess]

15 hours ago, CHA-LEE said:

Here is my Atlas Chaos in slow motion. The dot is staying in the glass through the whole cycle of the slide. This blaster could be even "Flatter" with a heavier hammer spring and less angle on the FPS. I am waiting to get it back from getting Black DLC coated to continue my tuning and load development process. For what its worth, this gun is setup with no popple holes in the barrel and the Atlas 2 port comp.

 

https://www.instagram.com/p/B69vlgXpiKc/?utm_source=ig_web_copy_link

That looks very flat, I would love to see it in 900fps super slow motion to see the movement in some detail.

I did qualify my statement  and you did  go on to reinforce my main point, it just matters where it comes back to.  

 

15 hours ago, CHA-LEE said:

Regardless of muzzle flip magnitude, what matters most is that when the slide snaps back forward the muzzle should return exactly to a level position with the dot centered in the glass. 

 

In talking to a couple top 10 Open nationals shooters, and watching some slow-mo videos of Max,  who's dots all leave the glass I have come to the conclusion that it it isn't that important for them it probably shouldn't be for me.

 

 

[zzt]

Cha-lee's slomo video has prompted me to go to another range so I can be recorded from the side.  What I saw was a very, very slight dip when the slide returns to battery, and too much slide impact at the rear.  The heavier mainspring and a lower angle on the FPS he plans, should cure much of that.   I plan to do the same to the FPS as soon as I don't have to shoot minor out of the gun.

Edited January 23, 2020 by zzt

[CHA-LEE]

1 hour ago, zzt said:

Cha-lee's slomo video has prompted me to go to another range so I can be recorded from the side.  What I saw was a very, very slide dip when the slide returns to battery, and too much slide impact at the rear.  The heavier mainspring and a lower angle on the FPS he plans, should cure much of that.   I plan to do the same to the FPS as soon as I don't have to shoot minor out of the gun.

 

As I said in my post of the slow motion video, more tuning is needed on this config to make it optimal. When I get it back my primary goal is to eliminate the muzzle dip when the slide snaps forward (Recoil Spring) and to maintain a minimal amount of slide bashing to still create a little bit of muzzle flip (Hammer Spring & FPS) so that the dot moves in a smooth vertical streak while staying in the glass.

[Sfisch0311]

I bought my gun without popples and was using HS-6. Then I added 2 popples and I switched to AA7. I love the way it feels with the popples and how flat it shoots. Remember though, once you put popples in, you are stuck with them. My recommendation is to start with a small size hole, maybe 2 of them at 3/16” each, then if you want to later go up to 5/32”. You then will have to add more powder and if you’re shouting .38 SC that’s not that big of a deal but it is with 9 major.