My 527 7.62 X 39 will not fire in cold weather.

[Explosive]

 I have a great warm weather CZ 527 in 7.62 X 39, but now the weather has got colder and it's useless.

I have been shooting Chinese surplus all summer without any issues, but started having fail to fire with multiple rounds a few days ago.   I was not sure if it was the ammo or the rifle, so I left a couple of rounds outside overnight ( -15 C ) and shot them this morning without a problem.    I then left the rifle on the bench for 30 mins and it would not fire any ammo after that, not even commercial Barnaul soft point.  I was getting light primer strikes every time.   

Are stronger striker springs available, if so can anyone tell me where to get one ?   Has anyone else had this problem ?

Thanks

[crosstimbers]

Sounds a bit like you may have some gunk that gets thick in the cold and is preventing the firing pin from delivering a full strike. Have you tried taking the bolt apart and cleaning it?

[Explosive]

Sounds a bit like you may have some gunk that gets thick in the cold and is preventing the firing pin from delivering a full strike. Have you tried taking the bolt apart and cleaning it?

That was the first thing I did, it made no difference unfortunately.

[crosstimbers]

Then I don't know. I can't think of another part of the firearm that should be susceptible to temperature change, causing light primer strikes. I dont think the spring, but maybe someone with more knowledge will chime in 

[Explosive]

Then I don't know. I can't think of another part of the firearm that should be susceptible to temperature change, causing light primer strikes. I dont think the spring, but maybe someone with more knowledge will chime in 

What annoys me about this, is that CZ rave on about how useful this carbine is for shooting cheap military surplus. I have an SKS that will shoot the same ammo in any temperature.
I know winchester commercial primers are very soft, so I pulled the bullets and powder to re-use in new brass cases with winchester primers.     The temperature has risen a bit so I will wait till tonight when it drops again to see if they work as well as I hope they will.

[alp3367]

Then I don't know. I can't think of another part of the firearm that should be susceptible to temperature change, causing light primer strikes. I dont think the spring, but maybe someone with more knowledge will chime in 

 Yeah, you're first guess was mine as well. I can't really think of anything that a temp change would affect like that. If it wasn't for the temperature part I'd look at pin and spring, but...that's a puzzler. Also curious to see if anybody else has an idea or what it takes to resolve it.

[david s]

There have been in the past reports of the 7.62 Carbines that didn't have quite the striker power needed to properly ignite some surplus ammo. Some people have replaced the firing pin spring. JP PRODUCTS makes a heavier spring for the 527's. Being it seems to be only happening in cold weather I would start by reexamining the bolt assembly to see if somethings not right or over lubed as suggested by crosstimbers. You don't want grease as a lube on the strike assembly when the rifle is really cold.

[Explosive]

There have been in the past reports of the 7.62 Carbines that didn't have quite the striker power needed to properly ignite some surplus ammo. Some people have replaced the firing pin spring. JP PRODUCTS makes a heavier spring for the 527's. Being it seems to be only happening in cold weather I would start by reexamining the bolt assembly to see if somethings not right or over lubed as suggested by crosstimbers. You don't want grease as a lube on the strike assembly when the rifle is really cold.

The only lube in the striker assembly is WD 40.   I tried it again just now at -12 with the ammo I loaded with the (what I thought were softer)winchester primers, all three failed to fire but two unmodified Chinese surplus did.  The opposite from what I thought would happen. 

JP Products will not ship internationally, I live in Canada.

[crosstimbers]

Then I don't know. I can't think of another part of the firearm that should be susceptible to temperature change, causing light primer strikes. I dont think the spring, but maybe someone with more knowledge will chime in 

What annoys me about this, is that CZ rave on about how useful this carbine is for shooting cheap military surplus. I have an SKS that will shoot the same ammo in any temperature.
I know winchester commercial primers are very soft, so I pulled the bullets and powder to re-use in new brass cases with winchester primers.     The temperature has risen a bit so I will wait till tonight when it drops again to see if they work as well as I hope they will.

As with anything else, sometimes you get a bad one. But I dare say that you'll eventually get this fixed. My 527 in 7.62x39 is absolutely reliable, and it does as CZ says, digest anything I have ran through it. So I wouldn't give up on it, replace the firing pn spring and see what that does 

[Explosive]

Then I don't know. I can't think of another part of the firearm that should be susceptible to temperature change, causing light primer strikes. I dont think the spring, but maybe someone with more knowledge will chime in 

What annoys me about this, is that CZ rave on about how useful this carbine is for shooting cheap military surplus. I have an SKS that will shoot the same ammo in any temperature.
I know winchester commercial primers are very soft, so I pulled the bullets and powder to re-use in new brass cases with winchester primers.     The temperature has risen a bit so I will wait till tonight when it drops again to see if they work as well as I hope they will.

As with anything else, sometimes you get a bad one. But I dare say that you'll eventually get this fixed. My 527 in 7.62x39 is absolutely reliable, and it does as CZ says, digest anything I have ran through it. So I wouldn't give up on it, replace the firing pn spring and see what that does 

My 527 7.62 x 39 is always absolutely reliable when it's not freezing.    Where do you live ?

[crosstimbers]

Yes, I'm down south. But for the record freezing temps affect ammunition more than metal gun parts. Like you said before, the ammo you were expecting to not fire did, and vice versa. Try a new firing pin spring, if it doesn't work, sell the rifle.

[crosstimbers]

To all-

I just thought of something, after reading back through this thread. The Op says he uses WD 40 as a lube in the bolt. While WD 40 is not supposed to freeze until something like -50 degrees, I have read that it should not be used on firearms because it can solidify into shellac-like layers and affect function under certain circumstances.

Is it possible that something like that could affect firing pin travel, perhaps more so when its really cold, and perhaps not be cleared out by a routine cleaning of the bolt?

[david s]

I have both the of the 527 Carbines (223 & 7.62) as well as quite a few other 527 rifles. None have given me any primer ignition problems. Some of these get used during Montana's winter as coyote rifles. They see cold weather. The striker/firing pin assemblies also get run dry, no lube. There lubed on the cocking cams and that's it. When I began hunting in northern Wisconsin the Remington 740/760 pump and semi autos were pretty popular. The hunters who used these rifles ran them dry if they wanted the rifle to be reliable. As something of a general rule WD-40 isn't considered a good firearms lubricant. It has one use and that's water displacement from metal hence the WD formula 40 name.

[crosstimbers]

I have both the of the 527 Carbines (223 & 7.62) as well as quite a few other 527 rifles. None have given me any primer ignition problems. Some of these get used during Montana's winter as coyote rifles. They see cold weather. The striker/firing pin assemblies also get run dry, no lube. There lubed on the cocking cams and that's it. When I began hunting in northern Wisconsin the Remington 740/760 pump and semi autos were pretty popular. The hunters who used these rifles ran them dry if they wanted the rifle to be reliable. As something of a general rule WD-40 isn't considered a good firearms lubricant. It has one use and that's water displacement from metal hence the WD formula 40 name.

Agreed...
 
If I understand it, this is the problem. OP's rifle works fine in temps above sub-zero. Below that it shows light primer strikes and rounds that do not fire.

If I am wrong about that please correct me.

Then, when temps fall below that, the rifle has on again, off again, ignition of both milsurp and civilian ammo, with neither one being more prevalent than the other.

So, something is causing the rifle to not ignite the primer of the ammo after temps get really low.

There are TWO possible explanations. One- the rifle has something gumming up the works and causing light strikes at low temps, and Two- the low temps are causing the chemical components of the primers not to ignite as intended.

If the rifle is getting light strikes in warmer weather, then the second possibility is the likely culprit.

Given that the rifle works fine in weather above sub-zero temps, it is highly unlikely that the problem is with the rifle itself. It's either with the affect of sub-zero temps and the ammunition, or something that is gumming the works up in such cold.

So, the only firearm related answer that I see as a possibility, would be a weak firing pin spring. In which case a specialty spring wouldn't necessarily be the answer, just a different spring.

Thats just my two cents. FWIW

[Explosive]

crosstimbers

You are right about the rifle working properly in above sub-zero temperatures.

When the temperature is below about  -15 no ammo works, neither commercial or military.

I have left ammo out all night in below - 15 temperatures , and frozen other ammo in the freezer, and it all works fine in the rifle when it's brought directly from the house.

If I leave the rifle and bolt outside for 30 minutes it will not hit the primers hard enough to detonate them.

The internals of the bolt have been cleaned of all oil and it makes no difference.

I don't just want a new firing pin spring, I want a new heavy duty firing pin spring.