Cold bore shot question.

[Southernfryedyankee]

As you are sighting in, your barrel will start to warm up usually gaining a more consistent POI. After you have your rifle sighted in and your barrel cools your POI will likely change correct? My question is when you go hunting and do not have a chance to warm up the barrel, what is the "likely" POI change I will notice from a cold bore to a warmed up barrel. I like to make quick, clean and effective 1 shot kills but dont want to have to worry about being inches off from my cold bore if I am shooting at an animal. Any help would be great.

 

[ICANHITHIMMAN]

As you are sighting in, your barrel will start to warm up usually gaining a more consistent POI. After you have your rifle sighted in and your barrel cools your POI will likely change correct? My question is when you go hunting and do not have a chance to warm up the barrel, what is the "likely" POI change I will notice from a cold bore to a warmed up barrel. I like to make quick, clean and effective 1 shot kills but dont want to have to worry about being inches off from my cold bore if I am shooting at an animal. Any help would be great.

YOUR DOING IT WRONG

The first shot is the only one that matters! I see guys at the range fighting with there rifles all the time on this. I here alot of"it was zeroed last week" then I watch as they fire 30 to 40 rounds in a half hour from thin factory barrels. Chasing there zero around the paper and then blame the rifle.


After yoiu have your load worked up you zero your rifle. This takes me alot of time. I fire one round every 10 min. Once I have 5 shots at 200 yards on paper in the same hole with a 10 min brake in between all 5 shots I consider my rifle zeroed. It will not shift in a hunting situation where I have done my part. I can fire 3 rounds in rapid succession before I have to worry about shift.

 

[fj40mojo]

As a rule I try to site my rifle in for the cold bore shot and generally my 3 follow up shots will be fairly close. Ultimately though I want to know that that first shot is going to hit the mark. I don't pack rifles that have ultra rigid 1" diameter barrels, but that is one thing that will minimize POI change.

There is no such thing as a "likely" POI change. Stresses are imparted to the barrel during the various machining processes. As the barrel warms the stress will cause things to move. Hopefully they will move in a predictable manner. Unless you machine your own barrel you have no control over any of the aspects that impart stress like tool edge, tool pressure, feed rate, coolant, cutting oil, etc, etc. A few years back folks were cryo treating there barrels in an attempt to relive stress and to some degree I heard it worked, never tried myself but the process can be done with a half gallon of liquid nitrogen, a long insulated container and a chest type freezer. you submerge the barreled action in liquid nitrogen inside the insulated container and put it in the chest type freezer until the liquid nitrogen evaporates.

 

[Varmint Hunter]

I'm wondering if you are confusing a "cold bore" shot with a "clean bore" shot. In my experience a clean bore rarely shoots to the same POI as does a fouled bore. Fouled bores are much more consistent IMO and the velocity remains fairly constant as well, unlike a clean bore. When a barrel is cold, clean & oiled it will normally walk its first few shots around the target before settling in. You need to get past this point to determine what the accuracy potential of any given load may be.

Once my bore has been fouled (normally after about 3 rounds) I normally don't see a shift in POI. I do not shoot my rifles when they are HOT. If the barrel get beyond warm-to-the-touch then I let them cool.

I've seen guys at the range literally yank their hand away from the barrel after touching it to see how hot it was. This kind of heat is not particularly conducive to accuracy and greatly accelerates throat erosion.

If you want to keep the barrel cool at the range just bring 2-3 rifles and alternate between them after each group.

 

[FEENIX]

I'm wondering if you are confusing a "cold bore" shot with a "clean bore" shot. In my experience a clean bore rarely shoots to the same POI as does a fouled bore. Fouled bores are much more consistent IMO and the velocity remains fairly constant as well, unlike a clean bore. When a barrel is cold, clean & oiled it will normally walk its first few shots around the target before settling in. You need to get past this point to determine what the accuracy potential of any given load may be.

Once my bore has been fouled (normally after about 3 rounds) I normally don't see a shift in POI. I do not shoot my rifles when they are HOT. If the barrel get beyond warm-to-the-touch then I let them cool.

I've seen guys at the range literally yank their hand away from the barrel after touching it to see how hot it was. This kind of heat is not particularly conducive to accuracy and greatly accelerates throat erosion.

If you want to keep the barrel cool at the range just bring 2-3 rifles and alternate between them after each group.

+1! ... and once sighted to where I want it, I don't clean the barrel until after the hunting season, unless it's absolutely necessary (water, snow, dirt, etc ...). I always have at least 2 of my hunting rifles sighted in for the season.

Good luck!

Ed

 

[royinidaho]

The clean bore vs cold bore posts are good info.

My experience is that with "most" but not nearly all of the factory rifles I have experience with the cold and or cold and clean bore shots are off a bit from subsequent promptly shot shots. How much off depends on the rifle.

When tuned/set up/bedded with the best loads the tendency for the first shot to be 'off' a bit is greatly reduced.

On the only "custom" rifle I have, cold, clean, cold and clean it makes no difference on point of impact. When saying clean, I mean no oil residue which is removed by patch of alcohol followed by a dry patch.

However I never go after fur or game with a clean bore. Always two fouling shots.