Why are there reliability differences in tuned guns?

[MemphisMechanic]

Hey. I found the sarcastic retort...

 

Lets return back to the original topic - Apologies to the OP for the side show.

Edited February 10, 2017 by MemphisMechanic

[SCTaylor]

Wow, that went south quickly.

 

A lingering question of mine is why my particular gun with a PD 13 hammer spring (tested at 13.2 by PD) and stock hammer is (knock on wood!) major match reliable with hard primers versus other guns with PD13 or PD14 (tested at 13.8 by PD) hammer springs with the Titan hammer and total polish? Is that just a tolerance issue? 

 

Just as an aside my pull weights were 6lb 110z DA and 3lb 14 SA, tested just after the partial polish & PD springs. 

 

 

[MemphisMechanic]

Your gun has different timing than a gun with the Titan / Bolo combination, obviously. I wonder if it's advantageous.  In simple terms, I'm wondering if the hammer is cocked back further in DA before it is released and you get more oomph from the same springs.

 

I still have my factory disconnector and hammer. It would be interesting to swap those in and see if I need as much hammer spring, or less, or more.

Edited February 10, 2017 by MemphisMechanic

[IronArcher]

I think it is because different people are doing different things and describing them similarly.
When I did my "polish job", a lot of the parts I stoned square or flat before polishing. Some just polish what is there.
Some do every pin and hole, some just large surfaces.
The guns also don't start as equals.

I ended up with a VERY light SA pull for the springs I run, but my travel is longer than others as well.
No all hooks, sears, disconnectors are the same, so there are infinite variables within a range.

Different springs, and variability on each of those springs add to the possibilities.

We don't know where it will end up, but we know the DA can get between 7.5 and 5 pounds DA and be reliable... it's just where will you sit in that range.





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[IronArcher]

I think it is because different people are doing different things and describing them similarly.
When I did my "polish job", a lot of the parts I stoned square or flat before polishing. Some just polish what is there.
Some do every pin and hole, some just large surfaces.
The guns also don't start as equals.

I ended up with a VERY light SA pull for the springs I run, but my travel is longer than others as well.
Not all hooks, sears, disconnectors are the same, so there are infinite variables within a range.

Different springs, and variability on each of those springs add to the possibilities.

We don't know where it will end up, but we know the DA can get between 7.5 and 5 pounds DA and be reliable... it's just where will you sit in that range.





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[johnbu]

^^ words of wisdom. 

[MissionaryMike]

I wish there was a little device that we can stick to the inside of the breech face that would measure the force of the firing pin.  Then we could have a strategy on how to set up each gun based on data.   Someone invent this, please.

[V2plus25]

Hah I thought that device was commonly known as a pencil?

[MissionaryMike]

2 hours ago, V2plus25 said:

Hah I thought that device was commonly known as a pencil?

Sure, but it's hardly scientific. 

[MrPostman]

Sure, but it's hardly scientific. 

That being said, it does work. Just get your handy pencil, yard stick attached to wall, put cell phone camera facing yard stick, set to slow motion and voice activation, place barrel with pencil installed where tip of pencil starts at bottom of yard stick, pull trigger in double action, then repeat in single action, review footage, log height in inches for both double and single action pulls. Now you have a base line if you did this with the gun in stock form.

Very scientific

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[johnbu]

^^ in stock form you need more than 36" .

[IronArcher]

Yet we here about people with guns like Glocks that don't launch more than 1' and they punch primers all day.
A pencil with a thin brass cover over the eraser might be more fitting.
The faster the pin is moving, the more it will dig into the eraser, giving a false reading.
I'm actually thinking of making something a bit more reliable and repeatable.


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[MemphisMechanic]

22 minutes ago, IronArcher said:

Yet we here about people with guns like Glocks that don't launch more than 1' and they punch primers all day.
A pencil with a thin brass cover over the eraser might be more fitting.
The faster the pin is moving, the more it will dig into the eraser, giving a false reading.
I'm actually thinking of making something a bit more reliable and repeatable.


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Someone here said they cut down a plastic coat hanger. Ingeniously simple, readily available.

 

I'll be using that next time.

 

For whatever reason, I think there's little correlation between striker guns and hammer ones in "pencil testing"

Edited February 11, 2017 by MemphisMechanic

[IronArcher]

Actually, that was me.
Thanx!


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[MemphisMechanic]

 I have a full round of hammer springs to pencil test. I'll launch the same rod with my M&P and G34 when I check them all.

 

Thanks for making me curious and - getting me doing more work.  

[MrPostman]

^^ in stock form you need more than 36" .

Tape measure works too

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[SCTaylor]

So, yeah, I have some ideas on how to run some super non-scientific, non-empirical tests with the Tanfo's.  A new-to-me Stock 2 should be here by Wednesday that currently has a Titan hammer and a few other goodies installed.  If the new S2 has any issues w/ the S&B primers (that are effectively 100% in my old S2) then I am going to swap the Titan hammer to the factory hammer only for a re-test. This will be using a 14lb PDO hammer spring

 

I'm starting to wonder if there are two ways to achieve the "most reliable" gun with a decent trigger.

  1) Mostly stock internals with a polish job & moderate hammer spring (13/14lb PDO)

  2) Full blow aftermarket internals (Titan, bolo, 1pc sear, etc.), mirror polish job, and "heavy" hammer spring (~16lb)

 

This last part is pure conjecture that I will never test, unless I will the lotto.  Anyone know if Henning or Bodkin perform any proprietary work? Are we missing that secret sauce?

[PatriotDefense]

22 minutes ago, SCTaylor said:

 Anyone know if Henning or Bodkin perform any proprietary work? Are we missing that secret sauce?

I can tell you everyone has their own way of tuning, tweaking parts in the gun, and of course their own set of problems that arise when guys push the envelope of what the gun can reliably run set up a certain way. We're starting to see that there are just to many variables in play to have a constant baseline of what works in a "tuned gun". Ammo and primers of course are a huge variable as everyone has seen lately in threads saying "you have to seat deep!!!". The cast parts that are inside of these guns certainly do not help out as well as tolerances vary and change from part to part. 

 

In the end, there is no "Secret Sauce" or special recipe for these guns. The user has to be realistic in what they're looking for out of their gun as far as trigger pull weight and what ammo/primer combo they'll be running. You just cant have a super light trigger pull (Sub 5lb DA) ammo and set off ridiculously hard primers seated at an inconsistent depth. It sucks but we're just going to have to live with the fact that some guns hit much harder than others with the same setup of parts and components. Like i mentioned above i truly believe its a mix between the cast parts, factory machining tolerances, and overall quality control. Not knocking these guns one bit as we truly believe these are the most accurate factory guns you can get your hands on, unfortunately we cant have our cake and eat it too. 

[MissionaryMike]

Also, as John has mentioned previously, he has achieved lighter and lighter, and more and more reliable results after multiple polishings, inspections, and problem solving, as have I.  Previously, I've expressed my frustration in trying to achieve the same light trigger pull as some of you here.  That frustration motivated me to keep at it.  After almost 2 months of tweaking and tuning, I think that my end result is fantastic – very good reliability, as well as a pretty light DA with my preferred #12 PDO Spring, around #4, 10oz, which is light enough for me.  I figured out that the "stacking" feel that I felt w/ the PDO springs was actually a result of the trigger rubbing along the cut out in the frame for the trigger as I pulled back.  The cut out looked like a trapezoid, not a rectangle.  Weird.  So I had to file that part out considerably.  I mean, who doesn't properly cut out that part of the frame?  Answer: Tanfoglio.  There were 2 or 3 other areas in the frame right where the trigger bar glides that were causing a lot of friction as well.  The mirror polish on my trigger bar would get all scuffed up after just one range trip.  I'm pleased with my gun now, but I tell ya, it took a lot of time to figure things out.  Now I'm wanting to put an optimized Stock 3 together.

 

Edited February 13, 2017 by MissionaryMike

[MissionaryMike]

32 minutes ago, PatriotDefense said:

I can tell you everyone has their own way of tuning, tweaking parts in the gun, and of course their own set of problems that arise when guys push the envelope of what the gun can reliably run set up a certain way. We're starting to see that there are just to many variables in play to have a constant baseline of what works in a "tuned gun". Ammo and primers of course are a huge variable as everyone has seen lately in threads saying "you have to seat deep!!!". The cast parts that are inside of these guns certainly do not help out as well as tolerances vary and change from part to part. 

 

In the end, there is no "Secret Sauce" or special recipe for these guns. The user has to be realistic in what they're looking for out of their gun as far as trigger pull weight and what ammo/primer combo they'll be running. You just cant have a super light trigger pull (Sub 5lb DA) ammo and set off ridiculously hard primers seated at an inconsistent depth. It sucks but we're just going to have to live with the fact that some guns hit much harder than others with the same setup of parts and components. Like i mentioned above i truly believe its a mix between the cast parts, factory machining tolerances, and overall quality control. Not knocking these guns one bit as we truly believe these are the most accurate factory guns you can get your hands on, unfortunately we cant have our cake and eat it too. 

You're absolutely right.  I originally had unfair expectations with my Stock 2.  I've come to accept that I've pushed it as far as it can go, and even though it doesn't look like what I had hoped, it's still an excellent result.

[IronArcher]

I'll be doing a few more curtain rod tests with the spring that should be here Wednesday.
I KNOW 1 of the reasons I have issues is that I am using the "wrong" hammer.
I know at least one of parts I installed wasn't made for my hammer, and I suspect another part as well isn't as compatible with my stock hammer.

Can you guess which stage I took the gun apart, and threw in some preload spacers (and a sight adjustment)?




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[taxil343]

On 2/13/2017 at 9:24 AM, MissionaryMike said:

Also, as John has mentioned previously, he has achieved lighter and lighter, and more and more reliable results after multiple polishings, inspections, and problem solving, as have I.  Previously, I've expressed my frustration in trying to achieve the same light trigger pull as some of you here.  That frustration motivated me to keep at it.  After almost 2 months of tweaking and tuning, I think that my end result is fantastic – very good reliability, as well as a pretty light DA with my preferred #12 PDO Spring, around #4, 10oz, which is light enough for me.  I figured out that the "stacking" feel that I felt w/ the PDO springs was actually a result of the trigger rubbing along the cut out in the frame for the trigger as I pulled back.  The cut out looked like a trapezoid, not a rectangle.  Weird.  So I had to file that part out considerably.  I mean, who doesn't properly cut out that part of the frame?  Answer: Tanfoglio.  There were 2 or 3 other areas in the frame right where the trigger bar glides that were causing a lot of friction as well.  The mirror polish on my trigger bar would get all scuffed up after just one range trip.  I'm pleased with my gun now, but I tell ya, it took a lot of time to figure things out.  Now I'm wanting to put an optimized Stock 3 together.

 

My results are similar. After initially doing as good a job as humanly possible, or so I thought, of polishing, my gun was about 95% with Winchester SPPs and 80% with CCI SPPs running a 12lb PDO hammer spring. At the advice of John I put the heaviest spring I have in the gun and shot a match. After the match I cleaned the gun and did another round of polishing. I have repeated this 3 times now and the gun runs 100% now with Winchester SPPs and a 12lb PDO hammer spring.

[johnbu]

Glad to hear about someone that tried it and found it actually worked.

 

 

[taxil343]

20 minutes ago, johnbu said:

Glad to hear about someone that tried it and found it actually worked.

 

 

Thanks again for the advice. 

[johnbu]

You're welcome!

 

I suck so bad at scooting and shooting there is no reason not to share the tips and tricks discovered. Lol.

 

My current preferred procedure is to detail strip, clean, polish "pretty good" and assemble / test / tweak and tune each part as it's assembled. It's a PITA doing multiple teardown / assembly but it isolates each element.  Had MissionaryMike tested the trigger with bar only (no plunger, sear, hammer) he probably would have found that bind sooner.  same with the hammer (no spring) to see if it swings free, etc etc.

 

And then running heavy springs to better show friction spots.