View Full Version : Light primer strike related to temperatures?
Went hunting this afternoon and had a nice 8 point in my sights. Pulled the trigger, and "click." Long story short, racked it a few more times with the same result - primer strike but no boom.
I got back inside and took a look at the bcg, and specifically the firing pin. Well lubed, a little dirty, but nothing bad. Wiped it off, put it all back together and went back outside. To my surprise, it fired.
Weapon is a .300 blk, Bcm lower, Bcm upper receiver, noveske 8.2" barrel, Daniel defense bcg, suppressed. Had it about two years with couple hundred rounds through it without issue. Usually lube with slip or clp.
Temps dropped to upper 30s this afternoon, and this was the first time I've fired it in what Alabama calls cold weather. After I was able to successfully get the weapon to fire again, I read about cold temps potentially causing this issue. So I left it outside for about an hour, only to come back and have the same ftf issue.
Where should I start with troubleshooting? Is the cold affecting something, or should I look elsewhere?
Excessive lube on firing pin?
Rifleman_04
12-10-16, 21:32
Unless it was freezing temps and the gun got water or condensation in the internals, either slip or clp shouldn't cause any issues with the cold.
I run slip and clp generously on my rifles here up north in sub zero temps with no issues.
Eta: bringing a cold gun inside to warm up causes condensation then bringing it outside to freezing temps may be the cause of your problems.
See point number 4 from this article:
http://www.activeresponsetraining.net/ar-15-maintenance-and-repair-five-tips-from-armorers-school
Ammo details? Trigger details?
See point number 4 from this article:
http://www.activeresponsetraining.net/ar-15-maintenance-and-repair-five-tips-from-armorers-school
Very low on my list.
556BlackRifle
12-10-16, 23:41
I'd be surprised to see upper 30's cause the lube to harden unless you're using some kind of paste. Do you have a light weight hammer spring installed?
Do you have a picture of the primer, just wondering how hard it actually hit.
The only thing i can think of is check your firing pin channel in the bolt, maybe with the cold it is just enough.
Another thing , was the BCG in full battery.. Every once in a while on my 300, the bolt will pick up a round and load it ,but the case doesn't get seated behind the extractor, leaving the BCG slightly out of battery.
Just some thoughts
I would second the trigger question as well. You need lube on the bolt--but you don't need it to be "dripping wet" It may be the combination of excessive lube and a weak hammer spring.
Barnes 110gr vor-tx, standard Bcm installed trigger
Yeah, I had read that too. I have always been generous with my lube, so I checked that first. I wiped it down and reapplied minimally, but got the same result.
See point number 4 from this article:
http://www.activeresponsetraining.net/ar-15-maintenance-and-repair-five-tips-from-armorers-school
The trigger is whatever Bcm used in their lowers a few years ago - not their newer trigger.
It would surprise me if it were the mild temps as well, because I know there are tons of guys that run their's in cooler weather.
I'd be surprised to see upper 30's cause the lube to harden unless you're using some kind of paste. Do you have a light weight hammer spring installed?
42824
Do you have a picture of the primer, just wondering how hard it actually hit.
The only thing i can think of is check your firing pin channel in the bolt, maybe with the cold it is just enough.
Another thing , was the BCG in full battery.. Every once in a while on my 300, the bolt will pick up a round and load it ,but the case doesn't get seated behind the extractor, leaving the BCG slightly out of battery.
Just some thoughts
42825
This is a fired round from this morning after being left inside overnight. Considerably deeper.
BangBang77
12-11-16, 11:28
The firing pin is failing to strike the primer due to 1 of the following:
- extractor is not making it over the case rim when the round is chambered. How are you chambering the round? Are you riding the charging handle home or dropping the bolt catch and allowing the buffer spring to drive it home?
- the firing pin isn't traveling far enough in the bolt due to clearances, debris, etc.
- the hammer is not contacting the pin with sufficient force to insure solid contact with primer.
Replace the hammer spring
Assuming that is the issue, should I worry about this happening again, or is it possible I just got a bad spring originally?
And are you chalking this up to a weak hammer spring exacerbated by the cooler weather affecting the spring tension?
Replace the hammer spring
Out of curiosity do you have a rubber o-ring on your extractor spring?
Assuming that is the issue, should I worry about this happening again, or is it possible I just got a bad spring originally?
And are you chalking this up to a weak hammer spring exacerbated by the cooler weather affecting the spring tension?
Springs are a wear item. They can grow weaker with use. While a weak spring may have enough energy that there are no ignition problems, variations from thickened lubricants, build up of fouling and primer hardness can bring on intermittent failures to fire. Cleaning a re-lubing can eliminate the problem but it's just a temporary fix. The spring is still weak. The shooter is also fooled into thinking that cleaning & lubing fixed the problem and the next time the malfunction happens, the shooter again cleans & lubes, repeating the cycle until the spring is replaced. Replace the spring now and save yourself the trouble. Don't use a reduced power hammer spring chasing a lighter trigger pull. Light hammer springs will only exacerbate the problem
Thanks. Just ordered. (nice having a Ranier Membership for things like this - free shipping on all items, even a $3 spring set).
Springs are a wear item. They can grow weaker with use. While a weak spring may have enough energy that there are no ignition problems, variations from thickened lubricants, build up of fouling and primer hardness can bring on intermittent failures to fire. Cleaning a re-lubing can eliminate the problem but it's just a temporary fix. The spring is still weak. The shooter is also fooled into thinking that cleaning & lubing fixed the problem and the next time the malfunction happens, the shooter again cleans & lubes, repeating the cycle until the spring is replaced. Replace the spring now and save yourself the trouble. Don't use a reduced power hammer spring chasing a lighter trigger pull. Light hammer springs will only exacerbate the problem
Not sure - never taken it down that far. DD bcg.
Out of curiosity do you have a rubber o-ring on your extractor spring?
bloodlord77
12-11-16, 21:04
Hmm. I've had short stroke malfunctions in freezing weather while using machine grease. Never a ftf though.
Have you tried different ammo?
Not since this happened (I didn't take another kind with me). This is the same round I've been using for a while now.
I have shot a variety of subsonic rounds through without issue.
Tonight, I disassembled the fcg and the springs were very gummy, covered in lube. This is my bedside rifle, and it sits upright behind my nightstand. I'm wondering if all the lube from North of the fcg has been dripping into the fcg? I'm sure that, coupled with a weak hammer spring led to the "Jesus deer" situation, as my brother called it.
I continue to picture the deer looking up at me in the stand, Gladiator style, taunting me with, "the frost, sometimes it makes the gun click."
Another thing , was the BCG in full battery.. Every once in a while on my 300, the bolt will pick up a round and load it ,but the case doesn't get seated behind the extractor, leaving the BCG slightly out of battery.
Out of curiosity do you have a rubber o-ring on your extractor spring?
How are you chambering the round?
Are you riding the charging handle home or dropping the bolt catch and allowing the buffer spring to drive it home?
OP,
What about the above items?
I don't ride the ch (pull back and release), and the bcg was in full battery as much as I could tell visually. I punched the forward assist for good measure.
I will try to take down the bolt when I get a chance this week. Anyone know if dd uses a rubber O ring? How do you expect that to affect performance (good or bad)?
Eurodriver
12-12-16, 07:25
Another thing , was the BCG in full battery.. Every once in a while on my 300, the bolt will pick up a round and load it ,but the case doesn't get seated behind the extractor, leaving the BCG slightly out of battery.
Just some thoughts
Do you reload your own 300blk? This can be from using brass that is too thick (certain imported ammo especially) in the neck.
Negative - Barnes 110gr vor-tx.
Do you reload your own 300blk? This can be from using brass that is too thick (certain imported ammo especially) in the neck.
I don't ride the ch (pull back and release), and the bcg was in full battery as much as I could tell visually. I punched the forward assist for good measure.
I will try to take down the bolt when I get a chance this week. Anyone know if dd uses a rubber O ring? How do you expect that to affect performance (good or bad)?
The biggest issue with hunting in cold weather is the o-ring hardens up and increases extractor force greatly.
If the bolt is closed slowly when initially loading (common to reduce noise while hunting), the bolt may be very difficult to close using the forward assist.
Just an update to add finality to the thread, I got a chance to break it all down and replace the springs, and it seems the issue was a combination of weak springs, excessive lube gunking up (consistency of a melted gummy bear), and cold temps exacerbating the two issues.
(ignore the trigger spring orientation)
42953
42952
And yes, dd does use a black rubber o-ring
556BlackRifle
12-21-16, 16:01
So it's shooting okay or is this just what you've seen so far? Light weight hammer springs are notorious for light primer strikes but it would be good to verify....
I'll be able to verify in the next couple of weeks and will update accordingly.
Thanks to everyone that contributed.
I recently experienced the exact same thing with my Colt HBAR during cold weather testing. Temps were in the mid-teens and ammo had Wolf small rifle magnum primers, which are on the hard side. First couple rounds had light strikes and no boom. Worked the action including dry fire a few times,tried with ammo - boom! No further problems. Trigger is a Jewell, set for 2.5lbs first stage, 2 lbs 2nd stage.
Figured it was congealed lube on the firing pin.
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