Cold Bore, what exactly does that mean?

[jtischauser]

I have heard this term a bunch from the long range sniper crowd. What exactly is the definition? I have noticed my groups shift POI from when I lay down a 5 round slow fire group when I first arrive at the range as compared to a slow fire group after a 30-50 round session if fast fire 50-100 yard drills when the barrel is warm to hot.

 

[pyplynr]

A cold bore shot is the first shot you take for the day with an uncleaned barrel. They will impact in a different spot than a warm barrel. And a clean cold bore will have a different point of impact than both. After the first shot from the CCB there is some fouling in the barrel that will change point of impact. My .308 cold bore shot is 1" high and 1" right @ 100 yards and clean cold bore shot is 1 1/2" high and 1" right.

 

[brandt9913]

What Adam said and bench and prone matches allow sighter shots prior to record shots so no one is having to shoot cold bore for record. Some matches will have a cold bore shot target. The 600 yd prone matches at the OKC Gun Club allow unlimited sighters and then 20 shots for record in the first match in 25 minutes. Then 2 sighters and 20 shots in 22 min for record in matches 2 and 3.

 

[jtischauser]

That's what I was wondering if it was first shot our after a bunch of shots. I don't think I could really figure my cold bore at 100 yards since my 1-2 MOA groups at 100 with only a 1-4X scope are probably too large to determine the cold bore shot from my other poor shots.

 

[dennishoddy]

People that hunt, almost always figure the cold bore shot is the one to use vs competition shooters that need a warm barrel.

 

[pyplynr]

People that hunt, almost always figure the cold bore shot is the one to use vs competition shooters that need a warm barrel.

Yup, I got a buddy that sets his deer rifle up for the cold bore shot only. 1 shot per day for 5 days is when he confirms zero. After his cold bore shot dead center on my 4" steel plate @ 100, every shot after that just barely misses all around the plate.

 

[dennishoddy]

When I went elk hunting in NM, I knew there would be sub zero temps, so I put my rifle in the freezer overnight before taking a shot. Second shot, warm barrel, it was only off a little over an inch, so that made me feel pretty good. Next issue was the 9000' altitude difference.

 

[0hm]

^^^ see above, the altitude problem can be SERIOUSLY confusing, as your dope card is completely worthless if you worked up your loads in oklahoma.