Cold and accuracy

[nhenry]

I developed my 280 Ackley load in 60° weather a month or so ago.

1/2 MOA with 120gr TTSX over IMR 4350 going 3368 fps is what I built. I’ve shot it multiple times and it’s been consistent with the group sizes, except for this most recent time.

Over the weekend, I took it to the range in 25° weather and the first shot from the cold bore was right on the money, but subsequent shots spread out to 2” or more.

What in tarnation is up with that?

Can the cold mess up groups that much?

Don’t know if I should be worried or if I should build up a different load with H4350 in the coming weeks. My hunt’s right at the beginning of December.

I asked a buddy about this and he said to use CCI 200 instead of the Remington 9 1/2 I was using. Maybe it’s inconsistent ignition. It could also be shooter error.

 

[cloverleaf]

I have a load for my 250 Savage that goes the other way.... colder it gets the better it seems to shoot. However, in your case, cold is hard on everything, might change tension on screws, scope adjustments or fit of the bedding. Personally, the cold just messes with my body. Operator error is more likely at 25 degrees in my case. next time you go to the range, throw your shells up on the defroster, and tuck them in your coat. See if it changes. CL

 

[hunter24605]

Hard to say what’s happening, is the rifle bedded? Maybe the cold effects the stock? But it certainly drives home the need to test your setup in the conditions you expect to be hunting in.

 

[nhenry]

Hard to say what’s happening, is the rifle bedded? Maybe the cold effects the stock? But it certainly drives home the need to test your setup in the conditions you expect to be hunting in.

Rifle’s bedded, stock’s a McMillan carbon fiber stock. Although there is an uneven spot where the bedding went under the shank of the barrel. That hasn’t caused issues before, but I’ll take it out just in case.

 

[nhenry]

I have a load for my 250 Savage that goes the other way.... colder it gets the better it seems to shoot. However, in your case, cold is hard on everything, might change tension on screws, scope adjustments or fit of the bedding. Personally, the cold just messes with my body. Operator error is more likely at 25 degrees in my case. next time you go to the range, throw your shells up on the defroster, and tuck them in your coat. See if it changes. CL

To add on your screw tension point… I retorqued it when I got home. It might have came a bit loose. Hopefully it’s just that.

I’ll try the warmth thing as well. I’m really open to any suggestions

 

[ShadeTree]

60 degrees down to 25 should have little to no affect on IMR4350. At least in my experience. If going down to WAY cold, then probably more likely. But there could always be firsts I suppose with an unusual batch of powder.

Heat and cold can really affect plastics and synthetic plastic derivatives. Can't imagine it would have the same affect on carbon fiber though. But it is possible that the stock was allowing that uneven spot you're talking about to be more forgiving and flexible in warmer weather and now that it's cold that stock is as stiff as a board. I'd quicker think that the cold affected torque tensions that were on the edge before, so see if what you did works. If that doesn't I'd take out that uneven spot you talked about.

 

[nhenry]

60 degrees down to 25 should have little to no affect on IMR4350. At least in my experience. If going down to WAY cold, then probably more likely. But there could always be firsts I suppose with an unusual batch of powder.

Heat and cold can really affect plastics and synthetic plastic derivatives. Can't imagine it would have the same affect on carbon fiber though. But it is possible that the stock was allowing that uneven spot you're talking about to be more forgiving and flexible in warmer weather and now that it's cold that stock is as stiff as a board. I'd quicker think that the cold affected torque tensions that were on the edge before, so see if what you did works. If that doesn't I'd take out that uneven spot you talked about.

I went ahead and just took out the uneven spot, just in case. It's all torqued down to 55 in-lbs per screw (typically what I use with pillared stocks). I wouldn't think the carbon fiber would be the issue, either.

 

[300WSM]

It's not the temperature it's the barometer.
IMO...
Some things it isn't...
Bedding...
You aren't free flowing and then suddenly not via a 35 degree drop.
That's nothing really.
We've 95 degree days here in the summer and 10 degrees in whitetail season and everything in between.
If you're using quality rings and bases that's not your issue either.

That said I'll give you some things to think about...
How many rounds since your last cleaning?
I had a rifle one time 17 rounds was it. Sub 1" all day long. Round 18 the group turns into 2"
It was 17 rounds all the tine every time.

Now what are you dealing with? A change in your group which means sonething changed.
Stock and bbl are not expanded or contacting that much in any kind of pressure you can survive in.
Think about it...how many hundreds of degrees are you talking to start making that steel alter it's normal configuration? A lot more or less than you're dealing with.
Same with the stock.

What it in fact much more sensitive is chemicals. Two things at work there to make go bang. Primer and powder.
Powder in particular can definitely be impacted by the atmospheric pressure. How much I can't say. I've seen it first hand but...I'd also say it wasn't a sub 1" to 2" or more.

If you've grouped a half inch before you're talking a 400 percent change between the two groups.
That seems too extreme to me to just be pressure related which is why I asked about your cleanings.

Lastly I just went through this but a brand new expensive scope right out the box was walking around. Yours has some time on it and maybe the weather is coincidence and your scope internals are now moving just enough to expand your group.

No matter how much you want to don't dismiss the simple things.

Good luck

 

[nhenry]

It's not the temperature it's the barometer.
IMO...
Some things it isn't...
Bedding...
You aren't free flowing and then suddenly not via a 35 degree drop.
That's nothing really.
We've 95 degree days here in the summer and 10 degrees in whitetail season and everything in between.
If you're using quality rings and bases that's not your issue either.

That said I'll give you some things to think about...
How many rounds since your last cleaning?
I had a rifle one time 17 rounds was it. Sub 1" all day long. Round 18 the group turns into 2"
It was 17 rounds all the tine every time.

Now what are you dealing with? A change in your group which means sonething changed.
Stock and bbl are not expanded or contacting that much in any kind of pressure you can survive in.
Think about it...how many hundreds of degrees are you talking to start making that steel alter it's normal configuration? A lot more or less than you're dealing with.
Same with the stock.

What it in fact much more sensitive is chemicals. Two things at work there to make go bang. Primer and powder.
Powder in particular can definitely be impacted by the atmospheric pressure. How much I can't say. I've seen it first hand but...I'd also say it wasn't a sub 1" to 2" or more.

If you've grouped a half inch before you're talking a 400 percent change between the two groups.
That seems too extreme to me to just be pressure related which is why I asked about your cleanings.

Lastly I just went through this but a brand new expensive scope right out the box was walking around. Yours has some time on it and maybe the weather is coincidence and your scope internals are now moving just enough to expand your group.

No matter how much you want to don't dismiss the simple things.

Good luck

First, thanks for the long explanation. I appreciate your time.

It could have been cleaning as well, or rather different copper being introduced. I fireformed some factory Rem brass loaded with Core Lokts... I didn't clean in between. Maybe that was it. Before that I only used Barnes and Hammers in it. I'll clean it.

I've had two scopes on it. The first was a VX3-HD 4.5-14x40 and this current one is a VX-3i 3.5-10x40. I've used Leupold Backcountry rings the whole time. Neither scope moved around POI between firings. That's not to say it's not the scope, but I doubt it.

The rifle, for reference:

 

[300WSM]

First, thanks for the long explanation. I appreciate your time.

It could have been cleaning as well, or rather different copper being introduced. I fireformed some factory Rem brass loaded with Core Lokts... I didn't clean in between. Maybe that was it. Before that I only used Barnes and Hammers in it. I'll clean it.

I've had two scopes on it. The first was a VX3-HD 4.5-14x40 and this current one is a VX-3i 3.5-10x40. I've used Leupold Backcountry rings the whole time. Neither scope moved around POI between firings. That's not to say it's not the scope, but I doubt it.

The rifle, for reference:

View attachment 18237

I'd clean it real good...

And shoot again.

My method of cleaning leaves nothing in the bbl

Shooters choice
Dip brush
Brush vigorously
Patch wrapped around brush
Dip in shooters choice
Push out of barrel
Unscrew brush
Remove nasty patch
Bring rod back through
new Patch around brush
Dip
Push through
Remove brush and nasty patch
Dip...
Rinse and repeat
I do that until no more fouling appears on Patch

The i do the same with a dry brush wrapped with dry Patch
Do that same procedure of removing before bring rod back through
Repeat with dry brush and patch
A few more times

It looks kike a mirror when I'm done.


You have your own routine and probably as good but that's how I do it

Keep me posted

 

[nhenry]

I'd clean it real good...

And shoot again.

My method of cleaning leaves nothing in the bbl

Shooters choice
Dip brush
Brush vigorously
Patch wrapped around brush
Dip in shooters choice
Push out of barrel
Unscrew brush
Remove nasty patch
Bring rod back through
new Patch around brush
Dip
Push through
Remove brush and nasty patch
Dip...
Rinse and repeat
I do that until no more fouling appears on Patch

The i do the same with a dry brush wrapped with dry Patch
Do that same procedure of removing before bring rod back through
Repeat with dry brush and patch
A few more times

It looks kike a mirror when I'm done.


You have your own routine and probably as good but that's how I do it

Keep me posted

I'll keep this updated with what I find. I hope it was just me the entire time.

 

[cloverleaf]

Its the "variables" that kill ya. Ive swapped more than one scope only to discover it was a change in primer I forgot about etc,etc etc...... Good Luck! CL

PS- your post made me think of somthing I wrote here many years ago re: shooting in the cold. Got a kick out of reading it again and thought I would share again. A youger more able self.... Not ot high jack your thread..... Some of the photos are held hostage by photo bucket, but there is one left towards the bottom of the load I referenced. That cold day it shot the group pictured. At 70 degrees, seems like its an inch plus shooter, but again, lots of variables....

well- it was warm in town.......

Well, call it cabin fever. But it was a beautiful day here in the great white north and last week it had been 40 degrees or better a couple days last week..... As I sat on the driveway on the east side of the house in the afternon sun I couldnt resist the idea. Any way the fellas had a...

forum.nosler.com

 

[nhenry]

Not quite the conclusion to this that I wanted, but it’s at least on a happy note.

I could not figure out why my rifle all of a sudden stopped shooting the load I worked up. I even brought 2 extra rifles to the range to shoot in between single shots from the 280 to make sure that it was cooling down. Nope, it hates the load it loved before. That’s weird.

I was smart, though. I built a load using 143gr Hammer Hunters and H4831 and ended up with this:


Even got the hammer trails. Made people at the range lose their minds.

 

[300WSM]

Not quite the conclusion to this that I wanted, but it’s at least on a happy note.

I could not figure out why my rifle all of a sudden stopped shooting the load I worked up. I even brought 2 extra rifles to the range to shoot in between single shots from the 280 to make sure that it was cooling down. Nope, it hates the load it loved before. That’s weird.

I was smart, though. I built a load using 143gr Hammer Hunters and H4831 and ended up with this:
View attachment 18284

Even got the hammer trails. Made people at the range lose their minds.

I'm not sure if you've shot more and updating or just elaborating more to your original story.

Also, Please enlighten me on the "hammer trails" statement

Thx

 

[AFG270]

Check this out! | Hammer Time

https://rumble.com/vqu31c-101gr-hammer-hunter-7-08-deer-hunt-hammer-trail.html This is a stunning video sent by a customer. We decided that we needed to name the vapor trail that is associated

hammerbullets.boards.net

Good job! And you even got a Hammer Trail.

 

[nhenry]

I'm not sure if you've shot more and updating or just elaborating more to your original story.

Also, Please enlighten me on the "hammer trails" statement

Thx

I shot more and am updating.

Cutting oil gets left in the tip from manufacturing the Hammers and they leave a wicked smoke trail

 

[DrMike]

Not quite the conclusion to this that I wanted, but it’s at least on a happy note.

I could not figure out why my rifle all of a sudden stopped shooting the load I worked up. I even brought 2 extra rifles to the range to shoot in between single shots from the 280 to make sure that it was cooling down. Nope, it hates the load it loved before. That’s weird.

I was smart, though. I built a load using 143gr Hammer Hunters and H4831 and ended up with this:
View attachment 18284

Even got the hammer trails. Made people at the range lose their minds.

Well, that load does give you some fine end results. That should work. And the hammer trails are just an extra to let you know that a pill actually exited the barrel.

 

[nhenry]

Well, that load does give you some fine end results. That should work. And the hammer trails are just an extra to let you know that a pill actually exited the barrel.

I was getting stressed because my deer hunt is next week. Glad I was able to come up with something