First off, I want to give a big hello! I lurked here for a bit and looted the information y’all have shared when I built my AR pistol and I’m happy to say its completed! Before I get asked why a pistol, I built it to hunt deer with in Illinois. Yes, its legal to hunt with as long as the magazine is not inserted (I asked the IL DNR to confirm before I even built the gun and they said I was good to go). I’m very happy about my lil’ thumper and I have already taken it on a few hunts this weekend.
Now for my problem. I wasn’t sure if this was the correct location for this question as it is more ammo based, so please pardon me if I posted it in the wrong area. While sighting my gun in, I experienced a hang fire. I was doing the initial function test/sighting in and I pulled the trigger, I heard the hammer hit, and then the expected boom. I am using Hornady 250gr factory ammo and a gun that I built. At the time of that hang fire I didn’t think much about it and didn’t experience any more that day. Fast forward to yesterday and I am out hunting. I have a deer come in, I take my aim, pull the trigger, and once again I hear the hammer hit and then a boom. Luckily enough I missed the deer completely, but this misfire “trend” now has me concerned.
I have the problem narrowed down to a few areas that I think could cause it. First is the ammo, which is an obvious choice. I have emailed Hornady and I am waiting on their response. I really hope it’s the ammo, but I want to see if anyone else has had this problem. I reload but haven’t had time to develop a load for the 450 yet.
The second area that may be a problem is the trigger. I “modified” the trigger to have a cleaner break. This trigger is a crappy DPMS trigger that I wanted to mess around with. I heat treated and quenched the entire trigger and polished the sear to mirror finish. I was mainly concerned with the sear faces and paid no attention to the hammer, so I could have softened the hammer to the point where it is deforming when it strikes the firing pin, but I don’t know if that’s plausible or logical. I did shoot this lower, using a different upper, before the gun was complete just to ensure it all worked which it did.
The final problem area is the lube I used. I generally run my ARs on the dry side. I don’t run and gun or throw thousands of rounds down range a month and I’m lucky to shoot 500 rounds a year so a massive amount of lube is not needed when I shoot. I spray and wipe off the internals with RemOil, but for some reason this time I didn’t. At the range I got a free tube of lube. Being a sucker for free stuff I took it and properly lubed my bolt, firing pin, and BCG up. What I really think happened is the lube “gummed up” in the lower temperatures and slowed down the firing pin which caused a light strike on the primer. Either way my BCG and bolt are getting degreased tonight and lubed my normal way.
If you have any experience with this or have any insight please let me know! Also sorry for the long post.