Coldbore shots

[Equalizer]

Some rifles shift poi some don't. Two weekends ago I was shooting my Sako 75 V 223 (bull barrel) My first 5 shots went into one tiny ragged hole. I did take my time, aprox 1-2 minutes between shots but as pointed out earlier only the first shot was "cold bore".

 

[Equalizer]

Here is a great article on getting cold bore data...


http://americanshootingjournal.com/carlos-hathcock-method-of-sighting-in-a-rifle/

 

[robert l]

Hi guys.
How long between shots should I wait to simulate a coldbore shot? That is, after a sequence of shots, I would like to leave the weapon at rest until it returns to its original state. I have seen that both the POI and the speed between the coldbore and the second shot vary. My idea is to place a target and shoot several coldbores, to see variation of group and speed in relation to the second shot.
I thought about measuring the temperature of the barrel before doing the coldbore, and after each run, wait for it to cool down to that temperature. But maybe we have to wait longer, hence the doubt.
Any advice, much appreciated.
Best regards.
V

I just saw a bore fan i think on this site that really speed of the cooling in the bore. And it was not reall pricey.

 

[Slim13]

The only cold bore surprises I've had are the first shot after I've cleaned the barrel. Now, I only clean the bore for carbon until after hunting season, then I'll remove the copper. Come spring, 10-15 rounds will season the barrel right about where it likes to be.

 

[Velvet]

Here is a great article on getting cold bore data...


http://americanshootingjournal.com/carlos-hathcock-method-of-sighting-in-a-rifle/

It is hard work, which consumes a lot of time and dedication, but surely gives good results.
It is valid for a certain air density, but if you shoot that rifle several thousand feet higher, your zero will change radically.

 

[crkckr]

Velvet, you are absolutely right about the altitude changing your POI. Which is why you should always take a couple of sighter shots when you get to where you're going to hunt. Even better, if possible, is to get up that high before the season starts and learn what your rifle and load is going to do. You'll still need to take at least one sighter to confirm your scope & settings, just to make sure things weren't bashed out of kilter on the trip up your hunting area.

Equalizer, I enjoyed reading the article on Hathcock, especially since that's pretty much exactly what I do. I too keep detailed notes on conditions for each cold bore shot and on groups. After a while it paints a picture of what your rifle is going to do when you pull the trigger. It's a good feeling to really *know* this information!
Cheers,
crkckr

 

[Velvet]

Velvet, you are absolutely right about the altitude changing your POI. Which is why you should always take a couple of sighter shots when you get to where you're going to hunt. Even better, if possible, is to get up that high before the season starts and learn what your rifle and load is going to do. You'll still need to take at least one sighter to confirm your scope & settings, just to make sure things weren't bashed out of kilter on the trip up your hunting area.

Equalizer, I enjoyed reading the article on Hathcock, especially since that's pretty much exactly what I do. I too keep detailed notes on conditions for each cold bore shot and on groups. After a while it paints a picture of what your rifle is going to do when you pull the trigger. It's a good feeling to really *know* this information!
Cheers,
crkckr

Hi Crkckr
What you raise is correct. I always do a couple of test shots when I change height so drastically. Surprises can be great if you don't.
If time permits, there are options to this procedure:
- use ballistic software in which current atmospheric conditions are loaded, other than that of sight in (kestrel with ballistics, Leica HDB binos, and others), and make the appropriate corrections in the turrets riflescope to make the shot.
- Buy a Swarovsky DS that detects these changes automatically, and its internal ballistic calculator, shows correction in the reticle. Very expensive solution, economically and by weight.
- Approach as much as possible to the animal, to minimize these differences, and place accurate shoot .
A pleasure to chat with you gentlemen
V