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AI Mrk III firing pin not striking the primer hard enough.

C

Catfish_Hunter

Private
Full Member
Minuteman
Oct 24, 2013
29
0
Fl
I’m running a AI Mrk III with Black Hills , 180 grn bonded ammo. Out of 150 rounds I’ve had 30 misfires. The rounds appear to have a light primer strike on them. I shot 200 rounds of Hornady without incident. As soon as I switched back to Black Hills I had 4 misfires out of 20 rounds. I’m mandated to use Black Hills, 180 grn bonded ammo.

Has anyone else encountered this problem? If so what was the solution? Or does anyone have any ideas what is going wrong? I have lost all confidence in Black Hills at this point.

Thanks in advance
 
Yes they look pressed in far enough that you would think the primer would have ignited. All primers were flush with the casing, with the exception of where the firing pin struck them. I’m racking my brain because we had to use 165 Hornady for a school and it worked great.
 
I will be trying some Black Hills Gold 175 out in mine soon. I know LoneWolf USMC pretty much uses Black Hills exclusively. I wonder if it could be harder primers in the Bonded ammo. Are you mandated by your dept?

Random: Are you using the 180 in the factory 1-12 Barrel?
 
Let me know how it works out for you. Yes I’m mandated. Yes in factory 1-10 barrel. I never thought about harder primers. I’m wondering if it maybe a combination of both harder primers and maybe the firing pin being a millimeter or two off, thus, not allowing that fraction of length to fully engulf the primer. IDK though.
 
I know as far as Mil-Spec ammo the primers are harder. May be the same with the bond/tactical type ammo. If you are mandated by dept, I think you should raise concern. I think the round firing in a stressful situation, is more important than the bonded/tactical ammunition. If you present your results to whomever mandated the ammo, I'm sure they would make the needed accommodation. Even if you are mandated to a certain brand, there are other options by the manufacture, that I'm sure would accomplish the task.

PS: I have alway heard of the AI's having heavy strikes, so its still possible it may be an issue with the rifle.
 
AI Mrk III firing pin not striking the primer hard enough.

I don't think the primers are so hard that they are sending back the firing pin. Think, people.
 
I appreciate it brother. The strange thing is, the rest of the team doesn’t have an issue with the rounds and no one has had a misfire except me. Furthermore you are completely correct about the round not firing. I can’t compromise my team, I’ve expressed my concern and the fact I can’t be online until my confidence is restored. Most likely we are going to send the rifle back since its brand new. But I wanted to reach out to the fellas on here, so I had a general idea of what I’m talking about. Also you never know if one of you guys have come across the same issue.
 
AI Mrk III firing pin not striking the primer hard enough.

308Shooter1911 said:
With AR-15's there are certain triggers that will not reliably ignite mil-spec ammo. I am simply offering a suggestion.
Click to expand...
In which case the cause is not the trigger. It might be the hammer spring, but it won't be the trigger.
 
Graham what if the fire pin assembly is a millimeter or two off, combine that with a harder primer and it could be possible. Do you agree? Or no? (Just asking)
 
Graham said:
In which case the cause is not the trigger. It might be the hammer spring, but it won't be the trigger.
Click to expand...

In AR-15's the trigger assembly includes the hammer springs…But since you want to split hairs…

[MENTION=3257]Catfish[/MENTION]…Just for you, I will try some 180's in my AE. It'll be next week, and only 20, but I will let you know my results. Is the rest of your team using AE's as well? If so, you already have the answer…It's the gun.
 
AI Mrk III firing pin not striking the primer hard enough.

If it's an AI the first thing I would do is check the firing pin protrusion and make sure the bolt is set up correctly.
 
[MENTION=47858]308Shooter1911[/MENTION] thank you. [MENTION=13650]Graham[/MENTION] yes its an AI MRK III can you explain a little more indepth about checking the firing pin protrusion and setting the bolt correctly? Furthermore will the weapon sometimes fire if the bolt is improperly set?
 
Without being able to take some measurements, it's impossible to diagnose. Have you stripped the bolt and cleaned the FP tunnel? Maybe something's making the FP drag. That's the first thing I'd check.
 
Pulled the bolt and checked the FP channel no issues. I think the best course of action would be to send the rifle back. Mainly because if 9 other rifles are all functioning properly on the same lot of ammo, than it’s probably mechanical.

Thanks again for the help. Ill post the outcome once I know it.
 
This may be way off but I had a similar issue with a Tikka years back. Turns out the guy at the gun store put the action screws in back to front hence the front screw was long enough just to creat enough of a problem that it would affect the firing pin strike. The bolt still closed but it caused constant misfires.
 
Again thanks for the advice. I have elected to refuse to carry the rifle until it can be checked out by the manufacture. I will be sending it back on Monday with a box of misfired black hills and another box of live rounds with the same lot number. I’m going to guess the FP is off by a millimeter or two, just enough to where you have inconstant primer strikes on mil spec ammo.

I will post the results on here when I find them out.
 
Catfish_Hunter said:
Again thanks for the advice. I have elected to refuse to carry the rifle until it can be checked out by the manufacture. I will be sending it back on Monday with a box of misfired black hills and another box of live rounds with the same lot number. I’m going to guess the FP is off by a millimeter or two, just enough to where you have inconstant primer strikes on mil spec ammo.

I will post the results on here when I find them out.
Click to expand...

Best of Luck. The folks at AI will take good care of you, they are GREAT people who do not take these issues lightly. I would also send back a box or two of ammo from the same lot number that has not been chambered or fired. You may want to include a photo copy from your data book to include temperatures. For the record, am extremely jealous you guys get the AI's for your sniper team. We are relegated to the 700, but I own my own personal AI AE MkIII. :cool:
 
[MENTION=87790]remington patriot[/MENTION] That’s a good point about the log brother. I’m in FL like you. I’m sending a box of misfires and a box that hasn’t been chambered or fired from the same lot number. For what we do the Black Hills bonded 308 180 grn is awesome. I can punch through glass up to 10 feet without the round being compromised. We did a whole study on it.

However right now I don’t have confidence in the weapon or round, due to the misfires. What round are you guys running? And how big is your sniper team if you don’t mind me asking.
 
Catfish_Hunter said:
[MENTION=87790]remington patriot[/MENTION] That’s a good point about the log brother. I’m in FL like you. I’m sending a box of misfires and a box that hasn’t been chambered or fired from the same lot number. For what we do the Black Hills bonded 308 180 grn is awesome. I can punch through glass up to 10 feet without the round being compromised. We did a whole study on it.

However right now I don’t have confidence in the weapon or round, due to the misfires. What round are you guys running? And how big is your sniper team if you don’t mind me asking.
Click to expand...

Right now we still use the Fed 168g FGMM for everything. We are trying to go to a "tactical" round instead of an open air round for obvious reasons but it has been slow going. We have been trying to Speer Gold dot bonded round and some Hornaday variations.
 
That's a very strange problem on an AI. Were all of the rounds that didn't fire out of the same lot? Were your teammates running ammo from the same lot as you? By any chance did you try running any of the misfired rounds through a teammate's rifle? Hopefully AI gets it sorted out quickly. Keep us posted, man!
 
[MENTION=52724]tylerw02[/MENTION] the rounds were from different lot numbers. During our last shoot I had several misfires so I tried one of the misfires in a different rifle, round didn’t fire. So I gave that lot number to a team mate and switched him boxes (pita for logging purposes) no issues from their rifle where I had issues with their lot numbers.

The rifle is on its way back to AI with the misfires and a box of ammo with the same lot number. I will advise on the outcome. Since it’s a brand new gun I think I’ll name her bitchey, since she doesn’t like anything I give her. lol
 
If the round that misfired in your rifle also misfired in another rifle, it makes me wonder if ammunition may have been the problem and no the rifle. Hope it gets sorted out quickly!


Sent from my iPhone using Tapatalk
 
Graham said:
If it's an AI the first thing I would do is check the firing pin protrusion and make sure the bolt is set up correctly.
Click to expand...

This was my first thought as well - make sure the firing pin protrudes within spec, and have your armorer generally go through it to make sure it's not a weak spring, worn firing pin, etc.

John
 
I could not find any Black Hills Bonded ammo, so I picked up some Black Hills 175 Match. It fired fine, but I went to reload the cases, and noticed the primers were crimped and difficult to remove, like military brass. This does not mean that they are military primers, but I thinks its a good indication that the primers used are harder than standard. Your rifle should still ignite them reliably though...
 
Ok so my AI came back a few weeks ago. AI said there was nothing wrong with the rifle. Note I've been on a new AI same ammo and lot number as the previous one with no issues. They have put the rifle I was having trouble with in the armory as a spare. Problem is and I'm going to convey this, that rifle needs to be tested by another sniper ASAP before going into the field. While I don't have issues with my new AI I have lost all confidence in my old one.
 
This is strange as going by evidence it has to be the rifle.. Did you ask AI for a log of what exactly they tested ?
 
No but that's a great question I'll ask the amorer and post a reply. We have 7 others shooting the same lot and ammo. Mine was the only rifle that had issues. Which leads me to believe it's the rifle. Also to note I've been on a new AI since then and haven't had any issues.
 
After speaking with our armor he advised AI "adjusted" the fire pin but that wasn't the issue according to them. The rifle seems to be firing fine now. I won't use it, so it's listed as a spare. Thanks for everyone's help.
 
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