Cold weather grouping problems updated with pics post #25

volks_r_us

volks_r_us

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Hello guys

My AR-15 is giving me headaches. The Damn thing doesn't want to group anymore.
I used to put 5 rounds in a Quarter all summer long. Now since the cold weather is here It just spray bullet in a 4 inch area at 200m.
I am pretty sure it's weather related, but I already tried different loads with no success :(

I went .3 grains lower (min load), .5 grains higher while increasing .1 grain at a time. I also tried different seating depth. Still cant group.

Anybody ever experienced the same problem ?

Is it the Bullet, the powder or the gun the problem ?
I am not sure what to do. Start all over and develop a winter/bullet combination?
Does that means the Bullets and powders that never work well last summer could turn my rifle into a lazer in winter ?

This could be Easier. makes me want to buy a Chrony
 
Last edited:
Chrony

A chrony is not very expensive!

volks_r_us said:
Hello guys

My AR-15 is giving me headaches. The Damn thing doesn't want to group anymore.
I used to put 5 rounds in a Quarter all summer long. Now since the cold weather is here It just spray bullet in a 4 inch area at 200m.
I am pretty sure it's weather related, but I already tried different loads with no success :(

I went .3 grains lower (min load), .5 grains higher while increasing .1 grain at a time. I also tried different seating depth. Still cant group.

Anybody ever experienced the same problem ?

Is it the Bullet, the powder or the gun the problem ?
I am not sure what to do. Start all over and develop a winter/bullet combination?
Does that means the Bullets and powders that never work well last summer could turn my rifle into a lazer in winter ?

This could be Easier. makes me want to buy a Chrony
Click to expand...
 
im new to the trying to be super accurate thing but and even knewer to ARs but...

simple metallurgy says that metal will shrink in cold weather (barrel, action etc) have you tried just firring to get your barrel warm and keeping it warm? i know with my tika when the temps drop my first 2-3 shots off a cold barrel (cold not fouling) are never as accurate as when i keep the barrel warm

and it may be the bullet / powder combo, iv seen lots of guys who come up with winter loads
 
Try working up a load using magnum primers. They burn a bit hotter for a bit longer and give more reliable ignition in cold weather. Some powders don't like the cold either.
If you're using grease as the rifle's lube, you may want to clean it out and shot bone dry or use powdered graphite too. That's not an accuracy thing though.
"...Bullets and powders that never work well last summer..." Not likely. What powder are you using?
 
Have you given it a really good cleaning? have your scope/sight mounts shrunk in the cold to the point of being loose?

Magnum primers are a very good suggestion, and using a non-temperature sensitive powder will help too, such as Varget.

I use Varget in a variety of cartridges, such as my 6BR's and I see almost do difference in precision between +35 and -15 using the same load.
 
Obtunded said:
Have you given it a really good cleaning? have your scope/sight mounts shrunk in the cold to the point of being loose?

Magnum primers are a very good suggestion, and using a non-temperature sensitive powder will help too, such as Varget.

I use Varget in a variety of cartridges, such as my 6BR's and I see almost do difference in precision between +35 and -15 using the same load.
Click to expand...

What he said.......+ 20 or -20 with powders like Varget I use the same load all year long. The only difference I find in the winter is a slight loss of velocity, however accuracy is not affected.

Jan10shootII.jpg
 
I have the exact same issues using my AR. Inconsistency with group. I can shoot less than half all the way up to 2" during the cold.

I have put it on the back burner until the temperatures return to summer like conditions. I was so fed up I was debating selling it.

Good luck!

Greg
 
Two thoughts. One as others have suggested try a Hodgdon Extreme powder like Varget or H4895. The other is bullet stability. What bullet are you shooting? Type and weight? and your barrel twist? If you are close to being unstable, then a lower ambient temperature can push it over the edge.
 
Ron AKA said:
Two thoughts. One as others have suggested try a Hodgdon Extreme powder like Varget or H4895. The other is bullet stability. What bullet are you shooting? Type and weight? and your barrel twist? If you are close to being unstable, then a lower ambient temperature can push it over the edge.
Click to expand...

hummm ...
I think you may have the Answer.
I am firing 69.gr HPBT out of my 1:9 barrel.
My barrel is very sensitive to bullet length I tried many different bullets and everything longer than the Sierra HPBT 69gr will no stabilize ever if it weight less than 69gr
This could be border line
as for the powder I use IMR 4895. I did Try varget in the past with no real good result in that rifle. I will give H4895 a try.

'
I am gonna go buy a Chrony Today this should help Sorting things out
 
I have found with IMR powders I need 3 loads for my rifle..... Here is a particular example;

.243 win, 95gr Nosler BT IMR 7828 Win LRP Win Brass

-20 46.6gr 3130 fps (avg)

0 45.0gr 3080 fps (avg)

+20 43.4gr 3035 fps (avg)

This is my experiance with this powder in this case. The tightest groups were at -20 & the largest at 0.

I have never thought about playing with the OAL for the different loads, but that may solve that little problem in my example........

Cheers!
 
I’d chronograph in summer and in winter to see if there is a difference. I don’t rely on “non temp sensitive” powders because in my experience they don’t work. My match .308 Varget loads chroney differently in summer and winter; comparable to other rifle powders I have used. It could be projectiles. I buy bulk 55 grainers and sometimes they shoot well within MOA and other lots will not stay inside 2 MOA.

You might have to add a grain (or 2) of powder to your loads to increase the velocity to summer standards. Again a chroney will be the only way to tell for sure.
 
Honestly, a Chrony is a waste of time. Judge by the results, not the speed. Try increasing the loads until you see pressure signs and back down until you get accuracy. This will be tricky in a semi, so watch primers for excessive flattening or cratering, and of course for any stoppages.

A 9" twist is loose but 69 grain bullets should work fine.
 
I haven't chronied not because of a waste of time but that they are so finnicky. Worse than a women so days.

1 in 9 should work for 69 grain. All barrels will like different stuff, again like a women.

For me there were too many variables during the winter time to try to determine what was going on. I have no issues shooting a bolt gun but with this being my first semi-precision gun I seem to been having a hard time mastering it.

Greg
 
I think I'm more temperature sensitive than anything else. Tried to shoot a group in -10 with a wind chill of -17C today and with a gun known to shoot sub 1/2 MOA I shot a 2MOA group. It was harder to focus with my eyes watering up, cold fingers and face. After one group packed it up. Try in warmer weather.

Of course all the metal, wood and plastic will change molecular structure slightly due to cold, but I cannot see that it would cause the group to open that much.
 
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