Light strikes Part 10, subsection G, appendix ii

[konkapot]

STI Trubor. Runs factory ammo all day long. 

 

I had some infuriating light strike issues. 550 was set right, all rounds "passed" a visual and tactile test for high primers. Was getting 1-4 light strikes per 100. 

 

Switched to some oddball eastern european primers and the problem went away. 

 

Until it came back, which is now has. 

 

The only variable I haven't messed around with is brass. Most of my 9mm major brass gets tossed or used for practice and then tossed. 

 

Match brass is typically once fired 9 minor factory ammo. However, it is remotely possible that some 9major brass made it's way into the bucket. 

 

When I was shooting/loading 38sc, the brass was new or twice fired, and I never had problems with light strikes, and had great SD/AVGs at chrono. 

 

Help me please. 

[Rnlinebacker]

1 minute ago, konkapot said:

STI Trubor. Runs factory ammo all day long. 

 

I had some infuriating light strike issues. 550 was set right, all rounds "passed" a visual and tactile test for high primers. Was getting 1-4 light strikes per 100. 

 

Switched to some oddball eastern european primers and the problem went away. 

 

Until it came back, which is now has. 

 

The only variable I haven't messed around with is brass. Most of my 9mm major brass gets tossed or used for practice and then tossed. 

 

Match brass is typically once fired 9 minor factory ammo. However, it is remotely possible that some 9major brass made it's way into the bucket. 

 

When I was shooting/loading 38sc, the brass was new or twice fired, and I never had problems with light strikes, and had great SD/AVGs at chrono. 

 

Help me please. 

Keep the same logic you did with 38sc. Buy starline brass in 9 for matches and majors. I did it this year and ammo issues were zero

[AHI]

By any chance is the head stamp the same? (the ones that have light strikes)

[Lightj75]

Do the rounds fire if you drop the hammer on them again or will they not go off no matter how many times you try ?

[konkapot]

I don't generally recover them, as this is occurring at matches. 

 

Typically they are NOT the exact same headstamp. 

 

The few that I have recovered typically do NOT fire on the second strike. 

[MuayThaiJJ]

I would think bad primers, I get them 2/100

What weight mainspring? Mine is 15#

[konkapot]

To address this issue a few months ago I went to a 20lb mainspring. Also set aside the CCI primers, which were being slightly more problematic

[AHI]

Do you wet clean your brass? 

If so how do you dry the brass? Do you remove the spent primers  before you clean?

Do you lube your cases before you load?

If so with what? How long do you let them set before loading? How do you lube?

The brass you have recovered. 

Did they have crimped primers originally?

Have you removed your firing pin and examined it for damage? Chipped tip for example.

Debris in firing pin channel?

 

I had to modify my 550 priming system . to seat below flush. With all Head stamps of brass. 

Edited November 14, 2021 by AHI

[konkapot]

No wet clean. No case lubing. NO crimped primers; cull those out. 

 

Firing pin is brand new; problem was present with both the old AND new firing pin. FP channel is spotless. 

 

What did you have to do to your priming system?

[AHI]

2 hours ago, konkapot said:

What did you have to do to your priming system?

The primer cup is what limits seating depth. So what I did was grind/file about 20 thousands off the bottom.

By doing this the primer punch will go farther in to the case. Now the hole in the brass stops forward movement 

of the handel.After doing this all my lite strikes went away .  Now you have to develop a feel for when a primer is

seated vs crushed.

 

https://www.dillonprecision.com/rl-550-primer-system-parts_8_44_25373.html

 

Edited November 14, 2021 by AHI
Added schematic

[konkapot]

AHI I will take a look at that. 

 

An unexpected development. I was dryfiring and it didn't sound "right." The firing pin  seemed to be flush with the FPS. 

 

Removed FP and it was clean and unbroken. 

 

The FP spring seemed a little short. Replaced it with a new one which was much longer than the one in the gun. Cracked off a couple of primer-only cases and will livefire tomorrow. 

[Lightj75]

25 minutes ago, AHI said:

The primer cup is what limits seating depth. So what I did was grind/file about 20 thousands off the bottom.

By doing this the primer punch will go farther in to the case. Now the hole in the brass stops forward movement 

of the handel.After doing this all my lite strikes went away .  Now you have to develop a feel for when a primer is

seated vs crushed.

 

https://www.dillonprecision.com/rl-550-primer-system-parts_8_44_25373.html

 

I had a few light strikes when I first got my 750 about 2 months ago. I was going to do this exact same thing but before I did I realized that the index on my  my shell plate of my 750 was slightly off. Which made the primer punch sit slightly off center of the shell holder. Adjusting that and making sure the primer punch was adjusted as high as possible solved my issues so far. The punch on the 750 has a channel that the set screw sits in that holds it so it can only be adjusted so far up or down but if you get it as high as possible it allows you to seat the primers pretty deep. I was only seating to around .002 which doesn't work for me so after the adjustment if I really push I've had some federals go down to .014 but I usually seat them to .005-.009.

[konkapot]

FP spring fix was not a fix. Dramatic improvement, but still had 2 out of 200. 

 

Edited November 15, 2021 by konkapot