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6/4/2023 5:56:33 PM EDT
[Last Edit: FloridaMan][Edited]
Went to shoot my Scar 17 today for the second time since I've owned it. The first time I shot probably 100rds through it and it functioned flawlessly. The rifle is stock except for a Geiselle SSA trigger. Went to shoot it today and after a couple of rounds I went to pull the trigger and it wouldn't pull. Racked a live round out and it had a light primer strike. Odd, but I removed the round, chambered a new one and it shot fine. After a couple more rounds it did the same thing. Removed the round and it also had a light primer strike. Chambered a new round. Another couple rounds fired fine and then it happened a 3rd time. This time I rechambered the round with the light primer strike. When I pulled the trigger the rifle fired twice in rapid succession. Went through this same procedure and it happened again. Only double fired after rechambering the light primer strike.

Any ideas?
6/4/2023 6:05:01 PM EDT
[#1]
Ammo issue?  My 17 has been rock solid both before and after the SSE trigger.
6/4/2023 6:20:17 PM EDT
[#2]
Quote History
Originally Posted By Arty8:
Ammo issue?  My 17 has been rock solid both before and after the SSE trigger.
View Quote

Don't think so. Same ammo I shot the first time I took it out. A lot of weird things going on.

1. Light primer strike when it chambers a round
2. Trigger doesn't reset
3. Doubles fires only when shooting the round with the light striker
6/4/2023 6:47:33 PM EDT
[#3]
Other than cleaning the gas system......I clean mine every couple hundred rounds....it sounds like a trigger problem.  Is the gas port set to the right setting?
6/4/2023 6:54:32 PM EDT
[#4]
Quote History
Originally Posted By Arty8:
Other than cleaning the gas system......I clean mine every couple hundred rounds....it sounds like a trigger problem.  Is the gas port set to the right setting?
View Quote

Yes sir, gas system clean and set to the 12 o'clock pos
6/4/2023 7:18:21 PM EDT
[Last Edit: Arty8][Edited] [#5]
Mine has been so boringly reliable, it's a joke.  Check out this thread.  https://www.fnforum.net/threads/scar-17s-leaving-light-primer-strikes-on-some-ammo-causing-misfire.68443/

I have over 1K rds thru mine, I shoot PPU.  Could be ammo related. Try some different brands?

Changing triggers in mine only aided in accuracy...that's it.
6/4/2023 7:18:27 PM EDT
[#6]
Did you have the SSAE in for the first outing ?(when it was running well)

Is it possible you may have installed incorrectly?
6/4/2023 7:27:28 PM EDT
[#7]
Quote History
Originally Posted By Rubicon777:
Did you have the SSAE in for the first outing ?(when it was running well)

Is it possible you may have installed incorrectly?
View Quote

I did. It's actually an SSA. Little typo there
6/4/2023 7:32:16 PM EDT
[#8]
The odd thing is that the primer is getting tapped when the round chambers. It's not a light strike when I pull the trigger. Then when I rechamber and shoot that light strike round, the bolt slams home on the next round and sets it off.
6/5/2023 11:36:11 AM EDT
[Last Edit: Ruin][Edited] [#9]
If you’re 100% sure the ammo isn’t the issue and 100% sure the trigger is installed correctly/not the issue I’d begin by field stripping the gun and cleaning it thoroughly. That means the gas system too, pull the plug, clean the gas chamber/front sight area really well and patch it dry. Get the piston looking like new.

Next, inspect the remainder of the rifle for anything broken, missing or worn. Pay close attention to bolt sled assembly as well as bolt itself and firing pin. Peep into the polymer lower assembly as well, look at the trigger assembly and inspect for BMW as well as spring tension and/or irregular wear.

My buddy’s 17S had a similar issue, he didn’t realize the gas block area or piston required occasional cleaning.
You see that head come apart?
6/5/2023 6:41:14 PM EDT
[Last Edit: willi3d][Edited] [#10]
Are you using the Geissele super scar trigger, made specifically for the scar, or a standard SSA trigger for an AR-15?  The hammer, as well as the hammer spring setup, on the scar is different than on an AR.  If you’re using a standard AR trigger, that would be my first suspect.  Also, Geissele makes a heavier scar hammer spring for use with hard military primers.
6/5/2023 8:09:22 PM EDT
[#11]
Quote History
Originally Posted By willi3d:
Are you using the Geissele super scar trigger, made specifically for the scar, or a standard SSA trigger for an AR-15?  The hammer, as well as the hammer spring setup, on the scar is different than on an AR.  If you're using a standard AR trigger, that would be my first suspect.  Also, Geissele makes a heavier scar hammer spring for use with hard military primers.
View Quote

Scar trigger. I'm going to throw the stock trigger back in this weekend and see if it happens
6/5/2023 11:54:37 PM EDT
[#12]
It sounds like an ammunition issue with high and low primer heights. Ammunition loaded for modern semi-autos must be in correct spec (primer depth, resized, bullet seat, etc..) to work correctly in the weapon. Was there any case bulging at the rear of the casings when double fired or pancaked primers on fired cases? I load for my SCARS and my ammo has to be in spec for them to run 100%. Is the ammo factory new or reloaded or from a questionable manufacturer?
6/6/2023 6:11:20 AM EDT
[#13]
Quote History
Originally Posted By pancho66:
It sounds like an ammunition issue with high and low primer heights. Ammunition loaded for modern semi-autos must be in correct spec (primer depth, resized, bullet seat, etc..) to work correctly in the weapon. Was there any case bulging at the rear of the casings when double fired or pancaked primers on fired cases? I load for my SCARS and my ammo has to be in spec for them to run 100%. Is the ammo factory new or reloaded or from a questionable manufacturer?
View Quote
Ammo is IMI 150gr ball. Should be fine, but I'm going to pick up something different this week to try as well. I was hoping this would be a known problem with an easy answer, but doesn't look like that's the case. I'm going to have to use process of elimination to try and figure it out. If I don't get anywhere with it this weekend then it's going back to FN.
6/6/2023 6:20:09 AM EDT
[#14]
Look for a blown primer cup laying in the trigger housing.

6/6/2023 8:32:47 PM EDT
[#15]
Pulled the trigger assembly out and reassembled. Everything looks and feels as it should.
6/6/2023 8:55:49 PM EDT
[#16]
Also check the firing pin channel and make sure that it is clean and dry.
6/7/2023 4:04:36 AM EDT
[#17]
Grip screw flush with the housing? Geissele instructions claim if it extends in it can interfere with trigger function.
6/7/2023 11:15:44 AM EDT
[#18]
I pulled the whole gun apart last night and checked everything. It all looks good. I posted in the Geissele industry forum asking about potential trigger issues, but nobody has responded. Coincidentally I installed an SSA in an Ar lower last night and it's having issues. You have to pull the trigger twice before the disconnector releases the hammer. I've got SSAs in 4 or 5 of my lowers and never had any issues. Now I've got 2 projects to troubleshoot this weekend
6/27/2023 6:25:49 PM EDT
[#19]
Good luck, keep up posted with your test results.
7/7/2023 7:32:26 AM EDT
[#20]
Are you sure you are installing the triggers correctly?

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