Cold Bore Zeroing

[soundwaves]

l have allways zeroed my rifle when the bore was hot ( shoot adjust shoot again )
l only use my rifle for hunting so only shots l take are cold bore shots. l havent seemed to have trouble hitting game with the cold bore shot, yes l miss a shot here and there but never crossed my mind it could be the cold bore thing. how do you guys go about zeroing your rifles for that cold shots in the field.? will be sighting in my rifle again for some 175 grain federal power-shoks this week so any advice will be usefull and interesting.

 

[Rick Richard]

Zero by shooting three shot group. Once Zeroed, put it away until next time to the range. Next time to the range fire ONE shot at the target and then take target down until next time to the range. Subsequent trip fire another single shoot and remove target again. Repeat this sequence until you are fairly confident with the POI with a cold bore.

Just my way of doing it.

 

[soundwaves]

next day ? cant it be done in a day at the mountains while haveing ibex on the BBQ ? take a shot every 20 minutes, wait for the barrel to cool down while eating ibex and shoot again.... ?

 

[engineer40]

How much POI shifts are you seeing between shot number 1 and shot number 3? Usually there shouldn't be much. And if you're using a scope that has matching reticle and turrets, you should be able to zero your scope in under 3 shots for sure.

I haven't done as much testing as I'm sure many on this forum have. But in my experience, I have more POI shifts because of a clean barrel rather than a cold barrel. I never go hunting with a clean barrel.

 

[Engineering101]

I do similar to Rick. After zeroing with a 3 shot group I come back and fire ONE shot dirty cold bore whenever I get back to the range (I go a lot). All my hunting rigs are zeroed at 200 yards so that is the distance I check zero and I always use a chrono. I check the velocity consistency and I check the distance the bullet lands away from dead perfect. I use a new target each time and keep all targets. I repeat this periodically throughout the year. If the rifle keeps all shots within 1.5" from dead perfect, it is good to use. Recently (just before hunting season) I had my current favorite deer rifle throw one 3" inches low and right. I fired two more and had a 1 inch 3-shot group that was low right. I rezeroed and it was back to good. Might have been the change to the rainy season that caused the POI shift but it was still shooting dead nuts after the season. I'll keep throwing a cold bore shot downrange every now and then and if it shifts back to where it was when Summer arrives I'll know it is somewhat weather sensitive.

 

[gohring3006]

You want to really challenge your self.
Next time you go to the range, take your rifle out of your vehicle and dial and shoot the longest shot your range has with your first shot. I do it at 580 yards at a steel plate at my local range. I have a few rifles that will hit almost every time. It's very gratifying!!!

It sharpens my wind and trigger skills, because I don't have time to "warm up"..

But yea, I zero with a fouled bore.

 

[toddc]

I shoot 4 or 5 cold bore a day while hunting. I hunt LR exclusively. Most of my shots are over 500. Like 99%. I shoot rocks at varying ranges throughout the day and since our rifle season is well after quail season starts I don't worry about freaking game out. I have watched deer remain bedded when people were shooting within 50 yds so I don't sweat it.
This way I know that all is well, my weather data is accurate AND my gun is on. We hunt 100% from trucks and rifles and scopes take a lot of bumps in rough pasture.
I usually pull up and glass for a while and then pick a rock and bang one. I wait a while before leaving for my next glass spot. Keeps me sharp, my data sharp and my wind calls sharp.

 

[Schnyd112]

You want to really challenge your self.
Next time you go to the range, take your rifle out of your vehicle and dial and shoot the longest shot your range has with your first shot. I do it at 580 yards at a steel plate at my local range. I have a few rifles that will hit almost every time. It's very gratifying!!!

It sharpens my wind and trigger skills, because I don't have time to "warm up"..

But yea, I zero with a fouled bore.

Our long range varmint match opens the master class with a 850 yard steel coyote for the first shot of the day. Lower classes get sighters before the match and shoot different targets as they class up, masters are the only to shoot the 850 target.

Its part of my practice regimen now. Get targets set, get into a shooting position and shoot the long target. Like you say it keeps me sharp. There isn't time to get A feel for how the winds and updrafts are that day, settle into a position or get used to being behind the gun.

 

[Greyfox]

The significant difference between my LRH rifles and my competition/target shooters is that after being subjected to a defined number of fouling shots from a cleaned barrel, my LRH rigs must shoot to the same POI cold or warm. Of equal importance, the zero must remain constant. Load work to achieve this is tedious, and not all barrels will deliver this performance in which case they will not be used for LRH. Reloading component lots are standardized for the expected life of the barrel, which is never overheated during shooting. Unless subjected to excessive rain, snow, moisture, I will not clean the barrel for the season. These rifles are typically fired less then 75 shots in a season, fouling shots, zero check, long range test shots; the rest at game.....

 

[Zen Archery]

Depending on your caliber, hunting terrain and distance this won't be too much of an issue. Most hunting scenarios are not going to be beyond the distance where 1-2" is going to make that much of a difference. But it's good to know cold bore if extended ranges is your real world application.

 

[Bravo 4]

Cold bore mapping a rifle is a good idea. Especially for a hunting or precision rifle where first round hits are desired and may be the only one fired. If the first round out of a cold (fouled) bore does not hit same poi as consecutive rounds, folks call it a first round flier. I do not, since that is the one that matters I say the rest are fliers. If I get sighter shots to bring everything in for the next several then call it the opposite. I've had issued rifles that had this going on, nothing I can do about that except learn to deal with it. To check it I would do as stated, keep track of where the first round hits. If it's consistent then it's easy to deal with. If not there may be other underlying issues.
A good idea has been mentioned, keep a target and fire your first rounds on it for a series of range sessions. Or keep your groups fired on targets in a binder/shooting logbook and mark each shot as 1-2-3 (4-5 or whatever). I do this for a fouled and clean cold bore (this helps me determine how many fouling shots each barrel needs to calm down and shoot right). Sometimes you have to clean and just don't have the luxury of shooting fouler shots.

 

[alcesgigas]

I began using hBN two years ago after reading all the info available on this and another site. The selling point for me was--and is-- the elimination of that cold bore "flyer" that we're talking about here. At first I used denatured alcohol which diminished the distance from center consistently, but that flyer remained. Upon learning that 99% Isopro. alcohol is the way, the flyer flew... However, I still need to be aware that the first three shots after re-treating the barrels with hBN will be unpredictable. After those "foulers" I experience no cold bore irregularities. But, this is in two rifles only; a M70 Classic Stainless 270 and my LRKM 338 Terminator. I haven't used hBN in any other firearm. Therefore not a whole lot can be determined from my limited experience with hBN, but others have had similar results.

 

[WildRose]

l have allways zeroed my rifle when the bore was hot ( shoot adjust shoot again )
l only use my rifle for hunting so only shots l take are cold bore shots. l havent seemed to have trouble hitting game with the cold bore shot, yes l miss a shot here and there but never crossed my mind it could be the cold bore thing. how do you guys go about zeroing your rifles for that cold shots in the field.? will be sighting in my rifle again for some 175 grain federal power-shoks this week so any advice will be usefull and interesting.

I do it one shot at a time giving ample time between shots for the barrel to cool down.

 

[engineer40]

I do it one shot at a time giving ample time between shots for the barrel to cool down.

Sometimes when I know I'm going to want the rifle barrel to cool all the way down, I'll bring up to 4 rifles to the range and put up 4 separate targets. Otherwise it feels like I'm wasting too much time for the barrels to cool off.

Unfortunately I have to admit more than once, I have shot the wrong rifle at the wrong target... or at the very least, shot the wrong load at the wrong target. lol...