My SAM-5S had a series of failures to fire XM193 catridges at about 600 rounds in.   I blasted the bolt group with gunscrubber, thinking the firing pin channel might be gunked up, and the problem went away for a hundred and twenty rounds.  It then returned in my last range session.  Three cartridges would not go off no matter how many times I dropped the hammer on them.  Put them in my AR (wondering if this batch of XM193 had super hard primers or something)  and they  cheerfully went bang.  Firing pin imprints did seem lighter, although they were definitely there.

Anybody have any idea of how to fix  this?  Is their a guide to disassembling a SAM-5 spring loaded firing pin bolt group to see if it is clean?  Is the spring loaded firing pin especially subject to light primer strikes?  Is this something common to AKs firing .223?

I really like the rifle, but this is annoying.  I'd like to get it fixed.

Definitely keep us posted -- I just picked up my new M-5S today! Arsenal are you listening?

OK, I'll call them.  Phone number on the website, I'm assuming.  The rifle is accurate, has zero cycling problems, is fun to shoot, and has those cool clear mags, so I hope they can figure out what is going on.

Are you sure you aren't shooting a Ruger Mini-30??

I finally talked to Arsenal last Friday.  The employee I ended up talking to was friendly enough and told me I should ship it in to them for inspection.  He speculated it might have something to do with the firing pin.  I shipped the rifle to them Saturday.

Friday night before I shipped the rifle I compared the bolt with two other spring loaded Arsenal bolts I have.  The firing pin in the SAM-5 bolt would only project slightly past the bolt face (when pushing against the force of the spring at the rear of the bolt with a tool)  The other firing pins projected much further.  So I wouldn't be surprised if I have a short or broken firing pin.  Hopefully it will be a simple fix.

I'd agree. in my experience they will take care of this.  

They replaced the bolt head assembly and shipped it back to me.  Should be here next week.  I'll run a bunch of rounds through it as a function check.  Anybody know exactly what the bolt head assembly refers to?  Not the complete bolt group, I'm guessing?  If it works, I will be pretty happy, so far a good experience with customer service.

DrewH,

Were you shooting at the NRA range a short while ago when this happened? I was the guy to the left of you, when you pointed out the dimpled primers. Hopefully all is fixed by Arsenal.  Too nice of a rifle to have it out of service...

Cheers,

lansker

Yep,

Sure sounds like my range session.  I remember I was telling you how much I liked it when I started having failures to fire.  And I really hope it is fixed.  I am pleased with Arsenal's repsonse so far. Planning to get it back this week and will no doubt be back at NRA over the long weekend trying it out.

Arsenal returned my rifle with a new, head spaced, bolt assemby.  Fired 180 rounds yesterday with no problems.  I plan to fire another 540 or so to check it out but looks good so far.  It does give out a major flash with XM193.

Well, I had a "click" while shooting another 120 rounds through my SAM-5 last weekend.  After a couple of more tries with the cartridge (which had a very light firing pin dimple in the primer), it went off and I had no further problems.  So, one in three hundred rounds, not bad, but not perfect, either.

First off,  I found Arsenal's customer service to be first rate.  I would have to shoot it some more to see if it really had a problem, but if continued to have one I'm sure they would fix it.  But, frankly, I am considering selling it.  I was already inclined to sell off one of my AKs and I may consolidate my calibres by selling off this one.

That said, the new Arsenal stamped 5.56 would take the same Bulgarian waffle magazines as the milled, right?   I may keep most of my magazines just in case  Wouldn't be the first time I had lots of magazines for a gun I don't own.