splitting the difference cold/warm barrel question..

[justinp61]

How much difference on target is there between the cold bore shot and the rest of the group at 500 and 700 yards? If you're hunting at these distances the cold bore shot is the most important.

Is one shot really enough to consider the barrel warm? It's not on my rifles. I had a hunting rifle with a pencil barrel that would make considerable moves as it heated up. I took one shot about three hours apart to zero it.

I'd probably zero it at 200 yards and let the 100 yard rounds fall where they fall. Then I'd shoot it out to the maximum range (700 yards) in 50 or 100 yard increments and record the clicks required or reticle subtension to hit the bull at each yardage.

This and $1.75 will buy you a cup of coffee in some places.

 

[Onehorse]

Kind of a long question but I feel the backstorry is important to understand it... My gun is zeroed at 100yrds. When my gun is cold bore/first shot it hits above the bullseye, and then all consecutive shots hit bullseye..(half inch difference from cold bore to warm bore) so I adjusted my zero to split the difference that way my cold bore shot hits top edge of bullseye and all consecutive/ warm bore shots hit bottom edge of bullseye, at 100yrd. This adjustment was 0.50 moa down. Whenever I'm shooting long range to confirm my dope I'm always shooting a "warm barrel" because I'll check my zero first, then I'll shoot 3 shot groups at different ranges (100-700yards). Never shooting a true cold bore at long range. Well my gun is primarily for hunting so the cold bore shot is what really counts.
That's why I think in theory bringing the zero down to split the bullseye would make sense that way at long range the the cold bore shot isn't too high but instead both cold bore and consecutive warm bore shots would be close to where you want to be hitting your target... The question is.. since I've never truly checked my dope with a cold barrel but only warm... by splitting the difference from cold bore and warm bore in theory my dope should stay the same? Bringing my cold bore long range shots just above to where my tested warm bore long range shots were? (yes I know the warm bore shots will now be a bit lower as well, but I'm trying to get best of both worlds in the event I need to take a follow up shot on an animal..)
Shooting a 147gr 6.5 creedmoor hornady eldm

I think you target shooters should quit hunting! (Just kidding.) I get that you are just trying to improve your accuracy, and that's commendable. It certainly beats not shooting all year and taking three shots with the old "ought six" the day before the opener. But sometimes you are just jumping down a rabbit hole that you dig for yourselves. If you are measuring in 1/2 MOA increments and the difference between the top of the bullseye and the bottom of the bullseye, you already have way more than enough accuracy than what you need for any hunting situation. Good luck and have fun.

 

[baldhunter]

First shot cold barrel,shot from a clean cold barrel or a dirty cold barrel?That can sometimes make a big difference too.Even though most of my rifles will shoot same point of impact clean or dirty on the first round cold barrel,some may require a couple of fouling shots after cleaning before the first round cold bore will stay in the group.I've had best luck with leaving the barrel dirty after a trip to the range.Next time first round cold bore is usually right where it's supposed to be.

 

[bultinkle]

I might be a little different in thinking. I have rifles set up for hunting and rifles set up for competition. My hunting rifles are set up for cold bore shot. You might only get one shot and that shot better be on the money. As far as my competition rifles, generally speaking, sometimes you get time to sight in and get get dope. But, by the time you are called for a particular stage, you may have a cold bore. that first shot hopefully is right on or it will be a long stage.

There is an assumption that the cold bore will group differently than the entire group. I'm not sure why but it's often considered almost a given.

I haven't seen it in real life. My assumption would be no difference without evidence there is. Hopefully this next year I can set up a fun mini experiment with 20-30 cold bores for my hunting rifle and really get an idea.

 

[69precision]

Go read the LONG thread over on Rokslide forum about cold bore vs hot bore shots and where they group.
Short answer:
Temp doesn't matter and you aren't shooting enough rounds per group (aka under 30 rounds per group) to actually get an idea of your rifles "probability shot come".

If you are basing your rifles' accuracy on 3, 5, or even 10 round groups then you are setting yourself up for problems when you start comparing groups.

Nah. 100 shot groups are the minimum needed.
Jokes and bad advice aside, for hunting the cold bore shot matters the most by far. Also clean vs dirty cold barrel can be different. I think the OP's logic is sound. The important thing will be to do the same test at his max hunting distance. Once he knows if he likes what is happening at say 500yards, then he can decide if splitting the difference is still what he wants to do.

 

[RockyRandy]

Kudo's to you for knowing that cold bore shoots are different, .50" at 700 yard is 3.5". On elk you are still 100% in the boiler room. What's the most import is that you have confirmed that your shot is .50" high by doing this 4 to 5 time. When I practice I also start by shooting a cold bore shot and confirming that it is real. That dot is smaller then a dime.

 

[Greyfox]

If your rifle is consistently delivering the precision you state, a mid-point zero on a .5MOA dispersion will be put you in good shape for med/large game hunting. But….Since you state that you haven't yet tested true "cold-bore" performance, I would do so….preferably at the maximum distance you plan to shoot game. IMO.

 

[sturner]

Guess I'm just lucky never seen the difference between the first one and the fifth one
i ain't even had to holler hold up i need a warm up shot

 

[Laelkhunter]

I would sight in so that cold bore shot will be where you want it to go. As others said, that is the most important one and you shouldn't need a second shot if the first is "on target". THEN, if you do need a second shot, a half MOA is going to be hard to correct for because the target animal will not be standing still like it was at the first shot, and YOU probably won't be too calm or still either. In which case, you cannot correct for the half MOA in the second or third shot scenario. Not sure that makes any sense, but I understand what I'm trying to say.

 

[BCC72]

I don't know where you hunt but When you're talking 'half minute of hunting'…. You're good.
I'm sure as a hunter you wouldn't plan on taking that 700 yd shot without a perfect rest and you've had time to look at your dope, set up etc. make a note on your dope chart, Zero for cold bore and call it good. Here in Montana, the temperature can steal 1-2fps per degree from a rifle alone. That can equal .5MOA (50 degree swings in a day are common), wind in your face could be .5MOA.
If you're racking a round in for a follow up shot, it should be fast and immediate and hopefully just an anchoring shot after a lethal first.

 

[69precision]

I'm definitely not shooting big enough groups, I have never heard of shooting 30 round groups. I reckon a man is never too old to learn

Depends what you're preparing to do. If you're planning to shoot competitions where you have to shoot 30+ rounds in a relatively short time then it might be helpful to know if your rifle has any tendencies at round 25 that are different from round 5.
People can do whatever they want or think works for them, but for hunting or shooting some steel it seems like shooting 30+ round groups would not be the best use of my time and money. If I can put 5 shots into .75 moa regularly, I consider it a .75 rifle. People are welcome to think it means nothing and I need to be shooting 30 round groups before I can claim that. Lucky for me I'm a good 30 years past worrying about pleasing other people, especially as it relates to a hobby.

 

[Lenny Foffa]

When I am at the bench ,I accept the second shot from my rifle as the Zero. ( Sometimes) The just cleaned rifle may require a fouling shot. Then I wait 45/60 seconds depending on air temp. and then fire a second shot. That is the shot, from a cold or cool barrel, becomes my starting point for the three shot group. Make adjustments if needed after the third shot. The thin barrel on my Ultralight heats up easily. This past summer I waited over 2min and 20 seconds, by the phone timer for the barrel to feel cool. I do not rush the second and third shots. Sometimes , as a TEST, I will take a second follow-up shot just to see where it shoots. I do this to try to simulate an actual hunting scenario. Often, it's very close to the first shot.

 

[Mike Matteson]

How much difference on target is there between the cold bore shot and the rest of the group at 500 and 700 yards? If you're hunting at these distances the cold bore shot is the most important.

Is one shot really enough to consider the barrel warm? It's not on my rifles. I had a hunting rifle with a pencil barrel that would make considerable moves as it heated up. I took one shot about three hours apart to zero it.

I'd probably zero it at 200 yards and let the 100 yard rounds fall where they fall. Then I'd shoot it out to the maximum range (700 yards) in 50 or 100 yard increments and record the clicks required or reticle subtension to hit the bull at each yardage.

This and $1.75 will buy you a cup of coffee in some places.

A little of the subject. It use to be a purple heart and $0.15 would get you a cup of coffee anywhere. That was back when coffee was $0.10.
Now back to the subject. I am a firm believer in cold bore shots when you are hunting. Follow up shots if needed too. I feel that you need to know how your rifle is going to react. Now my first 5 shot out the barrel to me are the most important.
What I hadn't given much thought on on cold bore shots in extreme cold weather. Now I never or didn't think that I had a problem with what I would call extreme cold bore shots. I have taken larger animal in -20 weather and in 100+ out to 500yds. So back to the boards and see what happens.
Going to the range and shooting your rifle cold bore, but how about in extreme weather with you packing your rifle around in the mountain on your side. It can't be room temp or out of the truck to the range rack to setup and shoot.
I can't answer that question, but now you have me wondering if there any different. Maybe somebody can answer that?
I find this very interesting, and will continue to read.

 

[HandgunHTR]

If you have a good barrel, there will be no statistical difference between the impact point of your first "cold bore" shot, and any of your warm or hot bore shots.

If there is, your barrel is junk or the shooter is the problem.