cold bore question

[RichCoyle]

A cold bore is when one takes his cold rifle out of the case and fires a shot. Everything after that is NOT a cold bore shot. With that posted I will post some info and a question. The last two times I went to the range and fired a cold bore shot I did a follow up as though I wounded the animal and fired a second shot. This was at 300 yards. The first cold bore shot and follow up were 1" apart. A few days later I did this again. This time the two holes were 1 1/16" apart. But they overlapped the first two holes so the four holes made a "group" of 1 1/16".

Now for the question to you statisticians. How many thirty shot groups will I need to be confident the next cold bore shot will be within one inch of the aiming point?

 

[johnmyers]

That's great I would call it good

 

[Varmint Hunter]

A cold bore is when one takes his cold rifle out of the case and fires a shot. Everything after that is NOT a cold bore shot. With that posted I will post some info and a question. The last two times I went to the range and fired a cold bore shot I did a follow up as though I wounded the animal and fired a second shot. This was at 300 yards. The first cold bore shot and follow up were 1" apart. A few days later I did this again. This time the two holes were 1 1/16" apart. But they overlapped the first two holes so the four holes made a "group" of 1 1/16".

Now for the question to you statisticians. How many thirty shot groups will I need to be confident the next cold bore shot will be within one inch of the aiming point?

One 30 shot group should be sufficient. But ........ rather than take chances, run a 50 round group because that's what is in the MTM box anyway.

 

[Barrelnut]

I think your good. Next test would be 300 yards, cross canyon, 10 MPH crosswind, rifle on a rotten stump, looking into the sun, while setting on a yellowjacket nest. Seems that would give your maximum "cone of fire".

 

[Eagleman Long Range]

Mostly what I see called cold bore
Is a clean bore vs fouled bore

 

[Ol' Red]

Following

 

[MagnumManiac]

Let me say this; 1 30 shot group is not the same as 3 10 shot groups if each is started with your cold bore parameters…
Many things may influence the outcome.

30 30 shot groups is statistically seen as good data, 10 30 shot groups is a start…

Cheers.

 

[sea2summit]

I think there's two things. Cold bore and cold shooter. There's only once shot to do both of those things in a single day IMHO…but, you can do multiple cold bore shots. I like to do ten targets ten "cold" bore shots once in a while. Think it says a lot more than 5x5 or whatever that doesn't really matter when shooting at an animal.

 

[johnmyers]

For me I consider cold bore in hunting rifle when barrel is fouled and cold what 2 shots do as in hunting situation. I do this multiple times spread over a few days and if velocity and POI is consistent I call it good. First 2 shots hunting should be all you need. JMO

 

[Tiny Tim]

A lot of variables to deal with. Truest test would be the closest to same conditions on multiple days and with a cold bore and warm shooter (meaning firing a different rifle to get warmed up). 5-10 shots would give you an acceptable group (firing at the same target on multiple trips). then a follow-up shot at another bull on the same target sheet. this would entail 5-10 trips to the range and 10-20 shots total. This would hopefully give you the best guess as to your rifles capabilities.

A more realistic expectation factors in the shooter, meaning cold bore, cold shooter.

The process is a PITA and with my limited attempts, my typical results are that if there is a significant dispersion after 2-3 trips, the rifle has an issue (barrel is end of life/not broken in, bedding is inconsistent, sighting system issue, etc...). I do something like this occasionally in the winter months as that is when I shoot the most. It is tedious and I believe a person would go to this length because they already suspect something is wrong or purely out of curiosity. If the latter, they will likely only do so a few times. My $.02.

 

[Shane Lindsey]

Only you can answer your confidence question, but I would say do the same cold/dirty shot and a follow up three more times. If it repeats, it's not coincidence.

30 shot groups is crazy on a hunting rifle. Yeah, it may say something about load/rifle/shooter, but irrelevant in a hunting scenario.
You can bang 30 shots, all touching, and then go out a punt it on one animal.

 

[Quintus]

I think your good. Next test would be 300 yards, cross canyon, 10 MPH crosswind, rifle on a rotten stump, looking into the sun, while setting on a yellowjacket nest. Seems that would give your maximum "cone of fire".

Don't forget, you also need to run WOT over a 1200' elevation gain before building your shooting position and get both shots off in under 7 seconds to make sure you have an accurate simulation. I know my groups shift 1/2 MOA when my heartrate is 220 and I am entering cardiac arrest. That was a tough 30 cycle 60 shots over 30 days, but I need to make sure I had the gravitational pull of the full lunar cycle included in my data. If I had a nickel for all the 380 class bulls missed because a guy zeroed on a waning gibbous and had to take a shot on a waxing crescent, I'd be a rich man.

 

[Shane Lindsey]

Thermals, don't forget thermals

 

[Shane Lindsey]

Don't forget, you also need to run WOT over a 1200' elevation gain before building your shooting position and get both shots off in under 7 seconds to make sure you have an accurate simulation. I know my groups shift 1/2 MOA when my heartrate is 220 and I am entering cardiac arrest. That was a tough 30 cycle 60 shots over 30 days, but I need to make sure I had the gravitational pull of the full lunar cycle included in my data. If I had a nickel for all the 380 class bulls missed because a guy zeroed on a waning gibbous and had to take a shot on a waxing crescent, I'd be a rich man.

If only you were using a .22 bangemupcartridge of the week...