Glock 20 feed issues

[matt85]

so ive been getting the occasional FTF with my new G20SF and while its not common it still bothers me. its only happening when shooting full power 10mm loads and doesn't happen when using lighter loads or 40 S&W in the gun. out of around 500 rounds of full power loads its happened three or four times where the slide seems to jump the cartridge rim. my first thought is that its my increased power 22lb recoil spring pushing the slide closed faster then the magazine can keep up. but then I remember that I have 0 issues with lighter ammunition. my next thought is that the recoil impulse might be too much and its causing issues with the magazine. I run this gun on mostly full power loads (200gr at 1200-1250 and 180gr at 1250-1300) with some 40 S&W thrown in the mix here and there for my inexperienced recoil sensitive friends. I have had these feed issues with Underwood 200gr XTP, Sig Sauer 180gr FMJ, and my hand loads using 180gr coated bullet at around 1270fps.

ive got a 24lb recoil spring showing up on Monday and I may also order some +10% magazine springs from Wolff. I think I might try a 20lb recoil spring as well to see if my first theory has any merit.

thoughts?

thank you
-Matt

[tommac919]

Does it happen with multiple mags ?

[The_Shadow]

Matt, are the lighter 10mm & 40's feeding reliably with the 22lb spring?
Does the issue happen with one magazine of all magazines? 

I would start by checking to see if the magazine when loaded has any ammo rattling around when loaded.  (on occasions I have seen some ammo not align correctly in the stack)  Tapping the magazine so that all ammo is positioned to the rear is a good thing.

Taking the magazine apart and inspecting the spring to insure it is in correctly and the inside of the tube is clean and free of any foreign objects is a good place to start.  Check the follower for unimpeded movement as it travels in the entire tube.  It is possible you may need an extra power mag spring.  Usually factory springs will work.

Make sure you have a firm grip and not limp wristing.

[matt85]

Does it happen with multiple mags ?

I thought about this after the fact but did not keep track of which of my five mags was in use. ill mark my magazines and see if perhaps one of them is bad.

The_Shadow, the gun has fed 40 S&W perfectly with the 22lb spring. I haven't noticed any of the mags making noise. I'm pretty sure I'm not limp wristing any of my shots.

-matt

[Duck of Death]

Stretch the mag springs.  Solved a lot of G29 slide problems.  If that helps get Wolff +10% mag springs.

https://www.gunsprings.com/GLOCK%20%C2%AE/All%20Models/cID1/mID5/dID116#109

My full power load (Storm Lake barrel) is 14.5gr #9/180 Zero & it works OK since I stretched the mag spring.  Also works OK w/40SW 4gr Clays/180 Zero.  I use a 21 lb uncaptured Wolff recoil spring.

Might get rid of the tabs on the mags so they will come apart easily.

[matt85]

so I just swapped out my Glockstore 22lb captured recoil spring for a Wolff 24lb uncaptured spring and the difference is night and day (I just took the screw out of the capture rod). in fact the difference feels heavier then it should be... its hard to say without some method of truly testing the springs but I would say either the 22lb spring was actually lighter then 22lb or the 24lb spring is actually heavier then 24lb. I am a bit concerned that it sounds like the Wolff spring is dragging inside the gun during cycling but I don't think its too bad.

I will try out the pistol with the new recoil spring at the range this weekend.

-matt

[The_Shadow]

Let us know how things work out!  the Wolff 22 lbs is usually all mine needs for even the heavy impulse ammo.

[matt85]

Let us know how things work out!  the Wolff 22 lbs is usually all mine needs for even the heavy impulse ammo.

well its supposed to rain this weekend (cant use chronograph) and I don't have a load developed yet for the bulk Rainier 200gr plated bullets ive got. so ive decided to shamelessly steal your load of 10gr of blue dot from another thread. you were getting 1200fps from 208gr cast bullets so I should get results in the same ball park with 200gr plated bullets. I'm not concerned as much about accuracy or speed as I am function with full power or near full power loads.

-matt

[tommac919]

so ive decided to shamelessly steal your load of 10gr of blue dot from another thread. you were getting 1200fps from 208gr cast bullets so I should get results in the same ball park with 200gr plated bullets. I'm not concerned as much about accuracy or speed as I am function with full power or near full power loads

That will get you full power loads or very close... I load the 200 xtp to 10.2 and it's a very good combo

[sqlbullet]

--Mod hat on--
Keep in mind that 8.9 grains of the Alliant max for 200 grain Blue Dot loads.  Anyone who see's this should carefully consult reloading manuals, start low and work up carefully
--Mod hat off--

Also, if 10.2 grains gave 1200 fps with a 208 grain cast bullet, then I would expect a 200 grain plated bullet in the same gun to be slower.  There are two big reason.  More initial volume means less initial pressure, and a 200 grain plated bullet will not seal the bore as well as the cast bullet will, also resulting in lower pressure.

[4949shooter]

The 22 pound spring (captured) from Glockstore or Glockmeister should help. The spring mentioned by Shadow is good as well.

The above springs solved the issue with my Gen 3 and full power ammo.

Good luck!

[matt85]

--Mod hat on--
Keep in mind that 8.9 grains of the Alliant max for 200 grain Blue Dot loads.  Anyone who see's this should carefully consult reloading manuals, start low and work up carefully
--Mod hat off--

Also, if 10.2 grains gave 1200 fps with a 208 grain cast bullet, then I would expect a 200 grain plated bullet in the same gun to be slower.  There are two big reason.  More initial volume means less initial pressure, and a 200 grain plated bullet will not seal the bore as well as the cast bullet will, also resulting in lower pressure.

funny, Hornady claims max load is 9.4gr of Blue Dot under their 200gr bullet and Nosler claims 9.3gr of Blue Dot under their 200gr bullet. Alliant must have stricter lawyers Hornady and Nosler.

-matt

[tommac919]

I worked mine up to 10.2   BTW, in my case your pretty close to the edge.  10.5 was to much for me as I didn't like the way the cases looked.
( in truth, mine fall between 10 and 10.2 and I have seen no issues tho I don't shoot them on a reg basis )

And yes... ( for Mod Hat )  YMMV what works for me , may not work for you so move slowly and keep your fingers

[matt85]

the 24lb spring just made the issue worse, tons of failures to feed with the warm 10mm loads. funny, there was no issue feeding Winchester factory 40 S&W though.

think I'm going to buy a 20lb Wolff spring and see if this fixes the issue.

note: 10gr of blue dot under the 200gr Rainier plated bullets gave very bad accuracy. however the cartridges served their purpose of testing reliability.

-matt

[sqlbullet]

I would guess the heavier spring is reducing the time the slide spends at full cycle.  This reduces the amount of time for the magazine spring to do it's job.  With the 40 S&W ammo the top round of the shorter ammo rides forward in the magazine, effectively increasing this window of time.  The 20lb spring should help correct this issue for you.

funny, Hornady claims max load is 9.4gr of Blue Dot under their 200gr bullet and Nosler claims 9.3gr of Blue Dot under their 200gr bullet. Alliant must have stricter lawyers Hornady and Nosler.

-matt

This difference is almost certainly due to other factors, like chamber or bore size, condition or reloading components.  These factors aligned so that Alliant reached pressure earlier than Nosler or Hornady.  Alliant even published the MAP as 33,800 PSI. 

There are a number of reasons why they may have stopped at 8.9 grains
    That is heaviest charge of powder they had loaded for test
    9.0 grains exceeded the MAP specs for 10mm (37,500 PSI Transducer)
    9.0 grains exceeded the MLPM (38,700 PSI Transducer)
    9.0 grains exceeded the MPSM (40,500 PSI Transducer)
    9.0 grains had rounds that exceeded the MEV (45,000 PSI Transducer)

This is exactly the point of start low and work up.  You don't know what will happen in your gun.  Alliant, Hornady and Nosler all got different results using lab grade test barrels.

I would also note that reducing any of the published max loads by 10% would give you a starting load a half grain below the lowest published max load.  Reducing tommac919's load by 10% is still .3 grains above the Alliant max.

While I am pretty sure the reloaders here know what they are about and would know to cross reference and work up, this site is publicly visible to non-members who may find this thread by web search.   Those people likely will not see or read the Load Data-Warning thread that is a sticky in the 10mm Reloading area.  For this reason that sticky specifically asks members to document when they have exceeded published load data and site the source data from which they started.  This thread lacked that warning, so I added it using data from Alliant since that data is available online.

I have no issue with sharing over-book data.  I wanna know what people are loading.  At the same time, I wanna make sure everyone that may read the posts knows when they see over-book data.  What works fine for one reloader may be catastrophic for another.