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Cold bore consistency?

T.Mihm

T.Mihm

Sergeant
Full Member
Minuteman
Apr 5, 2010
126
0
33
Houghton MI
#1
Have already read the topics about cold bore shots and whether or not it's the firearm or the shooter, so with that said...

I have noticed on the last three or four range days, I have gone to the range just to do a 10 shot dot drill with the .308, do some work with the .22, and go home. Consistently, the cold bore shots with my .308 whether or not I shoot it first or after practice with the .22 are ~2.75MOA high. At 100, 200, and 340 yards, the distance from the cold bore shot to the center of the rest of the group, or the pattern of the dot drills at 100 and 200, always tend to vary between 2.75 and 3 MOA high.

I'm not going to say whether its the platform or the shooter. All I'm wondering is that if it's the platform, can I count on a cold bore shot being 2.75MOA high at longer ranges? And if it's the shooter, is there any general direction I can take to bring the cold bore shot down?

Thanks for any input, and have a good one!

-Travis
 
#3
Re: Cold bore consistency?

agreed on the cleaning/oiling etc. Barring cold shooter, that is a good possibility.


The rifle should not just put that first shot high, barring suppressor or something being added to change it. Have you done dry fire a bit before taking the first shot? That always helps me not muck up the cold bore. Maybe warm up with the 22 and see if it happens still? You could always get someone who you know can shoot fairly well to try a cold bore or two and see if they can replicate the shot going high.
 
#5
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Travis Mihm</div><div class="ubbcode-body">Can I count on a cold bore shot being 2.75MOA high at longer ranges?</div></div>Any consistent deviation will be consistent: Meaning, add 2.75 MOA to your first shot at all ranges. That said, I am not yet sure that what you describe is a consistent deviation.
 
#6
Re: Cold bore consistency?

I'm far from an expert, but 2.75 MOA seems like a fair amount. If it's a cleaning issue, let that sucker foul and then do it 3-4 times and see if that makes a difference. I used to clean, clean, clean, and now I shoot, shoot, shoot, etc... Clean it when it needs it and not before. Just my opinion, I'm wrong alot.
 
#8
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Travis Mihm</div><div class="ubbcode-body">Have already read the topics about cold bore shots and whether or not it's the firearm or the shooter, so with that said...

I ... always tend to vary between 2.75 and 3 MOA high.

I'm not going to say whether its the platform or the shooter. All I'm wondering is that if it's the platform, can I count on a cold bore shot being 2.75MOA high at longer ranges? And if it's the shooter, is there any general direction I can take to bring the cold bore shot down?

Thanks for any input, and have a good one!

-Travis</div></div>

Hey Travis - the topic has been discussed extensively (thanks for the repost Graham); IMHO 99% of the time its the shooter/shooter not adjusting for change in conditions, 1% or less is the rifle. The cold bore shot not infrequently separates competitors and the goodies at the prize table, even at the highest level...having said that 2.75 MOA is not acceptable. On your best day, what MOA can your rifle shoot?

How do you know its not the rifle? Can you borrow a rifle from a "no-miss" cold-bore rifle of a friend/colleague, and have them shoot yours? I think it wouldn't be hard to figure out which component is accounting for your deviation from there. Any guys here around Travis able to help him out?

And on that last question - if you are serious, and have the funds, definitely consider signing up for the online training. If that's not feasible, see if there are some NRA/precision rifle instructors in your area. Answers about cleaning rifles etc. can all be found with the use of your searches here.
 
#10
Re: Cold bore consistency?

Buy a good barrel= less movement on cold bore
dont clean rifle as often if u are going to have to shoot cold bore shot = less movement on cold bore
control breathing slow heart rate down practice dry firing a 200 times a week learn your trigger and most of all shoot a lot off lead down range until the rifle becomes second nature to u
and on a 308 1-10 twist barrel i have found a hart m40 contour has had the least cold bore issues FOR ME.. I am not starting a barrel war just one guys test on one guys guns
 
#11
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">Some one I trust told me its cold shooter not cold bore that causes the shift </div></div>Most of the time that's true, but one gun in ten does have a cold bore shift: Lindy's AE did. My AE does. My other rifles don't. The trick is knowing whether it's you or the gun.
wink.gif
 
#12
Re: Cold bore consistency?

This thread was starting to worry me when it went to “it’s the shooter that causes the cold bore shot” From my experience which is somewhere in the middle of the group I’d guess I have found that the newer the gun/barrel I have had the more possibility of cold bore shot being out of the normal group. I have a Savage 10 fcp in 308 1 in 10 with less than 1k rnds on it and it constantly shoots 2moa @12:00 on a cold bore whether it’s a clean barrel or not. In fact I was at the range today, temps were in the 40’s and cold bore was 2.25 and next 5 grouped at just over 1moa spot on @ 100yds. After 3 more 5 shot groups left the Savage and set up with a Rem 22-250 shot several groups then went back to the Savage (30 min. or so latter) and started a tracking drill and the first shot was 2moa @12;00 with the next four shots of a 6” box drill not being more than ¾ moa off the dots. Someone please tell me I’m not the only one that has experienced this cause I can almost plan on this deviation on my cold bore shot since I realized it happens. If this was shooter err why would it happen when I picked the gun up for a second time 30 min. latter in the same range session? The Savage set on the ground with bolt open and had plenty of time for the barrel to cool from the fist shoot.
Travis what I can’t understand is that fact you said your cold bore shots at 100,200 and 300 are all showing an approx 2.75moa. deviation from your groups. That doesn’t make sense to me for the fact that if you 2.75 moa at 100 then a true cold bore effect of that moa deviation at 200 should really be double that and 3 times that at 300 if I understand simple trajectory. Somebody help me here if I’m going crazy and by all means correct me.
 
#13
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bushmaster55</div><div class="ubbcode-body">This thread was starting to worry me when it went to “it’s the shooter that causes the cold bore shot” From my experience which is somewhere in the middle of the group I’d guess I have found that the newer the gun/barrel I have had the more possibility of cold bore shot being out of the normal group. I have a Savage 10 fcp in 308 1 in 10 with less than 1k rnds on it and it constantly shoots 2moa @12:00 on a cold bore whether it’s a clean barrel or not. In fact I was at the range today, temps were in the 40’s and cold bore was 2.25 and next 5 grouped at just over 1moa spot on @ 100yds. After 3 more 5 shot groups left the Savage and set up with a Rem 22-250 shot several groups then went back to the Savage (30 min. or so latter) and started a tracking drill and the first shot was 2moa @12;00 with the next four shots of a 6” box drill not being more than ¾ moa off the dots. Someone please tell me I’m not the only one that has experienced this cause I can almost plan on this deviation on my cold bore shot since I realized it happens. If this was shooter err why would it happen when I picked the gun up for a second time 30 min. latter in the same range session? The Savage set on the ground with bolt open and had plenty of time for the barrel to cool from the fist shoot.
Travis what I can’t understand is that fact you said your cold bore shots at 100,200 and 300 are all showing an approx 2.75moa. deviation from your groups. That doesn’t make sense to me for the fact that if you 2.75 moa at 100 then a true cold bore effect of that moa deviation at 200 should really be double that and 3 times that at 300 if I understand simple trajectory. Somebody help me here if I’m going crazy and by all means correct me.
</div></div>
I'm not sure if anyone can tell you if its the rifle or you without actually testing it themselves. But in case your wondering if its all savages since they are 'lower quality', it is not. My savage FCP-K never hasa cold bore deviation. My first shot always in a reasonable distance from center, where it can be considered just the spread of an average group.(.5-.75 MOA)
 
#14
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Travis Mihm</div><div class="ubbcode-body"> Consistently, the cold bore shots with my .308 whether or not I shoot it first or after practice with the .22 are ~2.75MOA high. At 100, 200, and 340 yards, the distance from the cold bore shot to the center of the rest of the group, or the pattern of the dot drills at 100 and 200, always tend to vary between 2.75 and 3 MOA high.</div></div>

You answered your own question. Making a cold bore shot has little to do with why it happens so much as it does to know that it does happen. If you dope your specific rifle correctly, you'll know (as in your case) where your cold bore hits and you can correct for it. You're getting a consistent deviation with a cold bore which is actually best case scenario and minimizes the chances that it's you that's causing it. There simply is no hard/fast rule when it comes to the cold bore. Can it be the shooter? Yes. Can it tbe the rifle? Absolutely. The trick is finding out which is true in your specific case and adjusting for it. If you're a decent shot with good fundamentals trust more of what you see, and less of what you read.

Next time out using your known good dope that produces the shift, correct for it using a hold and see you you make the shot. If you make it, use that hold for the next few cold bores and see if you hit it consistently. If you do its likely something with the rifle/ammo combo when the bore is cold. If you gradually start to see the POA line up with POI its a fair assumption that it's you and you're starting to change the habit that's causing it. Again, trust what you see. There is a lot of good information in front of you after a shot...all you have to do is see and register it. Too many shooters chase their tails trying to figure out the "why".

See it. Acknowledge it. Correct for it. And the "why" will come to you.
 
#15
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bushmaster55</div><div class="ubbcode-body">
Travis what I can’t understand is that fact you said your cold bore shots at 100,200 and 300 are all showing an approx 2.75moa. deviation from your groups. That doesn’t make sense to me for the fact that if you 2.75 moa at 100 then a true cold bore effect of that moa deviation at 200 should really be double that and 3 times that at 300 if I understand simple trajectory. Somebody help me here if I’m going crazy and by all means correct me.
</div></div>
It's my understanding that a MOA at 100 is a MOA at 200,300 etc. Yes the measure in inches will double approximately but the MOA does not. Someone correct me if wrong, but it's like the Boss says a Mil(or MOA in this case) is a Mil.
Eric
 
#17
Re: Cold bore consistency?

I hear people tell me that they have a cold bore shift but its always different. In that case what they are seeing is the shooter, only option. I would have to guess that this is what most shooters see.

When the cold bore is consistent it is the barrel. A non match/ hand lapped barrel will have all sorts of pits and inconsistencies inside the barrel. These pits need to fill with copper fouling in order for the barrel to shoot consistent. So its not a Cold bore, its a clean bore. After shooting one, or sometimes many shots that fouling fills up those pits and grooves and smooths out the bore and should improve your accuracy. It kind of artificially hand laps the barrel.

At a certain point this copper build up becomes a problem however because copper will continue to build upon copper. So eventually you no longer have a smooth finish through your rifle but where the pits were now you have build ups or bumps of copper that will not allow your bullet to stabilize and cause your rifle to be less accurate and consistent. Now you have to clean out all that copper and start over.

So your best option is to have a custom hand lapped match grade barrel. You may still see some clean bore shift but it will be VERY minimal. You will have to clean far less and you should pretty much have quality accuracy through the life of the barrel.
 
#18
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MN sharpshooter</div><div class="ubbcode-body">At a certain point this copper build up becomes a problem however because copper will continue to build upon copper. So eventually you no longer have a smooth finish through your rifle but where the pits were now you have build ups or bumps of copper that will not allow your bullet to stabilize and cause your rifle to be less accurate and consistent. Now you have to clean out all that copper and start over.</div></div>I'm not so sure about that: My .308 won't become a 7mm; my bullet stability is not affected; and I don't have to clean-out all the copper.
 
#19
Re: Cold bore consistency?

I never said anything about your 308 becoming a 7mm, the fact is that the build up of copper within the bore eventually will protrude out into the boar even though your only talking about thousandths of an inch. This is why eventually on a factory barrel your accuracy eventually goes to shit due to copper fouling. Your bullet eventually rides over a bunch of microscopic speed bumps going down your barrel. Copper fouling is your friend on a factory barrel but only to a point.
 
#20
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MN sharpshooter</div><div class="ubbcode-body">the fact is that the build up of copper within the bore eventually will protrude out into the boar even though your only talking about thousandths of an inch. This is why eventually on a factory barrel your accuracy eventually goes to shit due to copper fouling. Your bullet eventually rides over a bunch of microscopic speed bumps going down your barrel.</div></div>How do I get even one thou of copper buildup in my barrel when the bullets keep going by? Wouldn't that escalate my presures and increase the velocity of the projectiles?
 
#21
Re: Cold bore consistency?

No your absolutely right, copper buildup in a barrel is a myth and being such a myth then there is no need for such things as copper solvents.
 
#22
Re: Cold bore consistency?

Where's Tripwire when someone needs him?

Any of you guys ever borescope your rifle after an extended shooting session?
Miles
 
#23
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MN sharpshooter</div><div class="ubbcode-body">No your absolutely right, copper buildup in a barrel is a myth and being such a myth then there is no need for such things as copper solvents.</div></div>I didn't say copper buildup was a myth. And I didn't say there is no need for copper solvents. You are attempting to change the subject, which tells me that you are on the defensive and unwilling to answer the question. There's no need to get defensive. I am not on the attack. You made a statement and I questioned it, that's all. I implied that using copper solvent doesn't make my bore bigger, and certainly not .001 bigger as you mentioned in your post. Were you repeating what you read somewhere? Because that's OK, just admit it and tell us where you got it from. Or would you be willing to explain how and/or why it is that you know what you claimed to know?

The question still stands: If what you say is true, then wouldn't that escalate my presures and increase the velocity of the projectiles?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: milo-2</div><div class="ubbcode-body">Where's Tripwire when someone needs him?</div></div>LOL!
Are you saying that 'someone' needs Tripwire to do something that 'someone' is not prepared to do himself?
grin.gif


And, no, I don't borescope after an extended shooting session. Do you do get a colonoscopy once a year?
laugh.gif
 
#24
Re: Cold bore consistency?


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: milo-2</div><div class="ubbcode-body">Where's Tripwire when someone needs him?</div></div>LOL!
Are you saying that 'someone' needs Tripwire to do something that 'someone' is not prepared to do himself?
grin.gif


And, no, I don't borescope after an extended shooting session. Do you do get a colonoscopy once a year?
laugh.gif
[/quote]

1. No, just lightening things up.
smirk.gif


2. Yes, I'm of age.
laugh.gif


I usually shoot at my gunsmith's range, and have scoped my barrels on occasion. Barrels all have their own characteristics as to copper fouling.
Don't mind me!
 
#25
Re: Cold bore consistency?

Graham and Tripwire need to go to neutral corners. If we have to referee it won't be good. Stop the bad blood guys.
 
#26
Re: Cold bore consistency?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">Graham and Tripwire need to go to neutral corners. If we have to referee it won't be good. Stop the bad blood guys. </div></div>

How come so many times when a person who's name is in green posts, the fun stops?
 
#27
Re: Cold bore consistency?

Recently attended a shooting class where we had 16 shooters and we were started the day off with a cold bore zero, and clean bore zero. No one really defined a cold boar shot nor was the cleaning method specified.
As all experienced shooters know there are a lot of variables that define a cold boar shot as well a clean boar shot. Ammor temperature, methods of cleaning and on and on.
I defined my cleaning techique on a bolt gun with a nylon brush with my favorite cleaning stuff followed by a few clean swabs.
I do not see any difference in a cold boar and clean boar shot. Some other shooters with undefined cleaning techniques experienced a 2 MOA change in point of impace. I guess it depends on the gun.
-Dan
 
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