CZ455 - Vertical Stringing in Cold Wx

[chrisward3]

Currently using a CZ455 with a Lilja Match Barrel that shot lights out with CenterX during the summer/warmer months (up in Canada). The stock is a Boyd's Pro Varmint that has been pillared and bedded for the action.

Since the temperature dropped up here, im noticing vertical stringing during the first 7-10 shots on a cold barrel/gun, which continues to occur if the gun sits outside (ie..during a match) longer than 15mins. Temperatures are anything below 0*C. I have moved to SK Biathlon to try and mitigate this, and while the stringing is less pronounced, it still occurs (~2" low at 50yds, gradually climbing back to my point of aim around cartridge #7). The stock is still free-floated when left in the cold, and I have pulled the entire gun apart in the cold, and re-torqued all pieces, and it exhibited the same stringing pattern. The SK Biathlon does not string out of a Custom 10/22 in a Victor Company stock shot under the same conditions. With ammo ruled out, any other thoughts on what could cause this?

My first thoughts (and feel free to refute!):

- the bedding job included the first 1" of the barrel (maybe some shift in the stock/bedding?)
- the lube im using on the bolt/firing pin sleeve may be thickening in the cold, warming up during the stage, and then re-cooling?)
- other ideas?

Thanks in advance
Chris

 

[PAYDIRT]

My stock barrel 455 is worthless, and I mean absolutely worthless when it's cold. Sad to hear your Lilja barrel is temp sensitive, because I was thinking that could be my fix. Last match I kept it on the dash of my truck parked facing the sun, and my ammo in my pocket with a Jonny warmer. Good luck finding your problem.

 

[Hellbender]

Can't rule out ammo lube thickening in the cold, both in the bbl. and the ammo itself.

 

[PAYDIRT]

Can't rule out ammo lube thickening in the cold, both in the bbl. and the ammo itself.

That's what I'm thinking too.

 

[Snuby642]

It's the ammo. Imho
Guess at your extreams even a biathlon acts up.

 

[justin amateur]

Cold affects the burn rate of powder/primer in the cartridges.
I had to prove that for myself recently. Brought to my attention in another thread.
Creates variations in mv's that will cause the stringing you see.
Store y'er ammo in a heated container until needed.
Hot water bottle tightly capped in a small insulated container to avoid frosty cartridges.

 

[chrisward3]

Why wouldn't I get the same effect out of the Custom 10/22 then? (Green Mountain Barrel)

 

[Snuby642]

Why wouldn't I get the same effect out of the Custom 10/22 then? (Green Mountain Barrel)

That's interesting, my 10/22 shaw does the cold weather stringing as it warms and cools.
Fyi I live in Texas and do not shoot your class of cold.

 

[Broncolou]

That's interesting, my 10/22 shaw does the cold weather stringing as it warms and cools.
Fyi I live in Texas and do not shoot your class of cold.

 

[Broncolou]

I usually have the first 3 shots with Eley Force start 1” low at 50yrds and work their way back to zero over 3-4 shots as the lube in the barrel warms up. Then it repeats each time I stop shooting for more than 5-10 min under 30*

 

[Rover31]

Here is what I know from Biathlon experience.
The barrels are treated and tested for accuracy in the cold. There used to be issues many many years ago with some barrels losing accuracy in “cold” conditions. What is cold to Biathlon? Typically that would be single digits in F. Some rifles would show issues though as they got to the teens.

So Anschutz has engineered that issue away with barrel treatment and testing. I have not seen this issue arise with any currently used Anschutz rifle. I do see it with some of the Izhmash rifles. Some of them do not like the cold.

Now for ammo, in competition most serious Biathletes use a Biathlon specific ammo. Training or “warmer” above 20f other ammo is used.

So long story, but it’s not the ammo, it’s your barrel.