Coldbore shots

[436]

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

There are many ways to skin this cat. For many years on and off the job, I had one way for a true cold shot zero. First, my rifles were always set up for a "clean cold bore shot" so, my range regiment was; I'd zero the rifle waiting for 3 to 5 minutes between shots, depending on the weather temperature. After I obtained my zero and recorded my 5 shot groups the grouping size and POI being were I wanted, usually dead centered an under MOA at 100 yards depending on the rifle and application. I'd clean the rifle (hot, not red hot ) wait about an hour to let the rifle cool, and allowing me to settle down. I would then fire a cold bore shot, making any adjustment I thought the rifle needed to get to the center of the target I'd then clean the rifle again, get back on the rifle fire another adjust if needed and clean again... repeating this until the cold bore shot was right where I wanted it. Most of the time the cold bore shot was within the 5 shot fouled barrel group, sometimes it wasn't, but, you can note adjustments needed to bring the 5 shot group POI back on the cold bore after the cold bore shot in the field. I kept all my work and game rifles clean stored and cold bore zero. As I said there are many ways to go about the cold bore shot zero this was mine and it worked for me. I sure you know, that you have to stay with one stable repeatable load to have a true cold bore zero.

 

[Indian7953]

There are many ways to skin this cat. For many years on and off the job, I had one way for a true cold shot zero. First, my rifles were always set up for a "clean cold bore shot" so, my range regiment was; I'd zero the rifle waiting for 3 to 5 minutes between shots, depending on the weather temperature. After I obtained my zero and recorded my 5 shot groups the grouping size and POI being were I wanted, usually dead centered an under MOA at 100 yards depending on the rifle and application. I'd clean the rifle (hot, not red hot ) wait about an hour to let the rifle cool, and allowing me to settle down. I would then fire a cold bore shot, making any adjustment I thought the rifle needed to get to the center of the target I'd then clean the rifle again, get back on the rifle fire another adjust if needed and clean again... repeating this until the cold bore shot was right where I wanted it. Most of the time the cold bore shot was within the 5 shot fouled barrel group, sometimes it wasn't, but, you can note adjustments needed to bring the 5 shot group POI back on the cold bore after the cold bore shot in the field. I kept all my work and game rifles clean stored and cold bore zero. As I said there are many ways to go about the cold bore shot zero this was mine and it worked for me. I sure you know, that you have to stay with one stable repeatable load to have a true cold bore zero.

I used to have a 7 mm rum with the lightweight pencil Burrell that would string shots right to left as it warmed up, also when it was clean it would shoot about 3 inches to the right at 100 yards second fowling shot would bring it back to you about an inch to the right and the third fowling shot would put it just slightly left so I sighted this gun in three shots fouled and cold bore. I took it out every day early in the morning when it was cool and calm and fired one shot into the target and it would be within a half an inch at 200 yards every morning that's where I cited it in at and it worked consistently like that, second shot would be within a half an inch, Then they would string left as a barrel warmed up.

 

[.25MOA]

I use the method of a timer on my phone, shooting a shot every 3 minutes to keep temp consistent here's a 10 shot group at 100m

 

[del2les]

An old sniper from AMU instructed us to fire one shot each day and at different times of the day. As he put it, you never knew when you would see your game, what that day's weather might be, how long your rifle/ammo was exposed to that temp, etc. We placed our rifle/ammo outside first thing in the morning so as to cold/heat soak and then during different times each day, took to the range and fired one shot at varied distance.

It was a very eye opening exercise and forced us to use all our knowledge of distance shooting in a hunting situation. Remember, if you sight and train during nice fall weather and hunt in high altitude and colder weather, be sure to train in those.

 

[Velvet]

[QUOTE=" I sure you know, that you have to stay with one stable repeatable load to have a true cold bore zero.[/QUOTE]
Yes, I have prepared 40 rounds for this specific task, and it is the same load used to shoot regularly.
I use the OCW method to get my loads, and the one obtained gives sub-moa precision consistently in this rifle, for this combination of bullet, powder and primer.
I want to find that Zero that is not going to fail, so the concern of performing a test as accurate as possible, to detect if there is remarkable variation between the coldbore shot and the following. That's why I asked how long to wait between shots, to simulate a real coldbore shot. I adhere to the opinions that say that coldbore is unique per session or day. The current load will not be modified in the near future.

 

[Velvet]

An old sniper from AMU instructed us to fire one shot each day and at different times of the day. As he put it, you never knew when you would see your game, what that day's weather might be, how long your rifle/ammo was exposed to that temp, etc. We placed our rifle/ammo outside first thing in the morning so as to cold/heat soak and then during different times each day, took to the range and fired one shot at varied distance.

It was a very eye opening exercise and forced us to use all our knowledge of distance shooting in a hunting situation. Remember, if you sight and train during nice fall weather and hunt in high altitude and colder weather, be sure to train in those.

I agree with this. Each hunting situation is different in many ways. No two shots are the same.
What I intend is, first to reduce the number of variables to identify if there is a very notable variation in the POI. Then, do what you say, practice in the field or all possible scenarios to corroborate the results obtained.

 

[David Lindler]

Since cold bore is what you have hunting we play a game at deer camp the day prior to opening day. We each slap down 20 bucks set up a target at 200 yards.
Everyone gets 1 shot from the rifle he's going to hunt with any way you want
offhand... kneeling..your choice.Closest scoops up the cash AND gets his choice of stands opening day! Some hot competition!

Cold bore shots have a lot of variables to consider when moving geographically such temp, altitude, barometric pressure, humidity ect. The key is to know your rifle and ammo. Your cold bore shot is often the only one you get on game. Test if possible when there are altitude and temp changes. This is a cold bore shot with my 338 Lapua at 1006 yards. 23 mph cross wind. Doped the wind . Forgot to factor in spin drift. Won the bet.

 

[KyCarl]

I'm lucky a rifle that shoots dead on in Kentucky shoots the same at camp in West Virginia. I'm ready when I get there! Wind Rain Snow those are the same for everyone any given day?

 

[Velvet]

Cold bore shots have a lot of variables to consider when moving geographically such temp, altitude, barometric pressure, humidity ect. The key is to know your rifle and ammo. Your cold bore shot is often the only one you get on game. Test if possible when there are altitude and temp changes. This is a cold bore shot with my 338 Lapua at 1006 yards. 23 mph cross wind. Doped the wind . Forgot to factor in spin drift. Won the bet.

Congrats for that shot David!!!!
I agree that the coldbore in hunting is the only one we have.
If we always hunt in a similar place / weather conditions, we must know how much the POI varies for that environment, if it really varies noticeably.
If we are going to hunt in a completely different area (air pressure, temp, etc.), we must set a new zero for the new place. It would be the most prudent, it seems to me.

 

[Zymurgist]

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

It depends. A carbon fiber wrapped barrel will heat up hotter and faster than an all steel barrel. CF also takes longer to cool do to the poor thermal conductance compared to a steel barrel. Which do you have?

 

[Velvet]

It depends. A carbon fiber wrapped barrel will heat up hotter and faster than an all steel barrel. CF also takes longer to cool do to the poor thermal conductance compared to a steel barrel. Which do you have?

Proof Sendero

 

[David Lindler]

It depends. A carbon fiber wrapped barrel will heat up hotter and faster than an all steel barrel. CF also takes longer to cool do to the poor thermal conductance compared to a steel barrel. Which do you have?

I have both and like the steel better for shot to shot consistency. My 338 Lapua with ss bartlien barrel can hand 10-12 shots and not get too hot. My proof research 338 edge about 5 and POI starts to change

 

[Velvet]

I have both and like the steel better for shot to shot consistency. My 338 Lapua with ss bartlien barrel can hand 10-12 shots and not get too hot. My proof research 338 edge about 5 and POI starts to change

Watch this Proof video.
While I didn't count all the shots they made, they are more than 5 sure, and practically the POI doesn't change.
We do not know if the first shot at the target is coldbore, or a next one

 

[DLR24]

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

Take this with a grain of salt man. We would wait 10 minutes in the army between shots to simulate cold bore. It made for some very long days at range. I don't pay too much attention to temp of my barrel (heavy barrel) but I do make sure that if I clean I foul my barrel with 2 to 3 rounds before competitions. If you have a very thin profile barrel then temp will definatly make a huge difference. Hope this helps.