Eliminate Cold Bore For Pennies... Its worth a try.
- Thread starter The ROC
- Start date
Very interesting, I hope it pans out with my go-to Anschutz.
My first thought was that a piece of painter's tape on the muzzle will work as well as a finger cot with less of a PITA fumbling factor, and might be effective at the chamber end as well. As to how the range safety folk will react to that, well, on the longer ranges I usually shoot alone at the club, it's more of a weekend place. And now to figure out how Canadian cold affects everything- ice crystals in the barrel instead of water droplets?
My first thought was that a piece of painter's tape on the muzzle will work as well as a finger cot with less of a PITA fumbling factor, and might be effective at the chamber end as well. As to how the range safety folk will react to that, well, on the longer ranges I usually shoot alone at the club, it's more of a weekend place. And now to figure out how Canadian cold affects everything- ice crystals in the barrel instead of water droplets?
This video has nothing to do about cooling the barrel down.
They are essentially adding a slight bit of moisture into the barrel on purpose as the theory is that there is a slight amount created by the first round going through a cold bore.
Exactly.
I wonder if there is an "alternative" method to the straw? Maybe a lightly wet patch with water through the barrel before the first shot? But when? Just before the match/ shooting session? Just before leaving the house for the trip to the match, push a wet patch through, piece of tape that the muzzle end, bolt closed and into the rifle case? This maybe a nice experiment to conduct during the winter months.
Time to visit the range and get some velocity readings from my rifle and ammo setup especially the first 5 - 10 rounds and see if the first shot is higher than the remaining shots that follow as per Josh's video.
I wouldt want to use a patch of water. I remember reading about shooters putting a patch of lockeeze through after cleaning.
It's correct that the video is unrelated to cooling down the barrel. No one should be worried about a .22LR rifle barrel becoming overheated, especially one used for target shooting where a cold bore flyer may be an issue.
A wet patch with water through the bore will not be helpful.
The reason for a cold bore flyer is related to the lack of fresh fouling in the bore. When a .22LR round is fired, the combustion of the propellant and primer causes the detritus of the detonation to accumulate moisture. This is why the debris in a freshly shot bore will be wet.
If a bore has been allowed to sit for a time that wet fouling will dry. Similarly, a freshly cleaned bore is dry. When the fouling is moist or wet it allows the rounds to travel through the bore at their expected MVs. A .22LR bore needs moist fouling for consistent shooting.
Plugging the bore at the muzzle and breech lengthens the time required for the fouling in the bore to dry by as much as half an hour as the video suggests. Similarly, breathing moist air into the bore is for the purpose of reintroducing moisture to the fouling. Pushing or pulling a water laden patch through the bore will only make it wet with H2O, not the required moist fouling.
Every cold bore shot in the video was very close too 1152 fps! Would it not just be easier to get data for the increase and know this is going to happen on the first shot? I personally won’t be blowing down a straw into any of my guns. Think it would be very hard to get consistent results with the temperature of all the variables being so different, air temp,barrel temp as well as your temp of exhaled breath coupled with the relative humidity outside. The video was very interesting and thanks for posting it.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
BPCR shooters have been blowing down bores for years... to try and keep the fouling soft. 22LR fouling is kind of similar... the intent is the same.
It is not something I am going to bother with as the odds of introducing MORE variables increases. I think shooters should spend more time shooting at paper vs looking at chronographs. Does your rifle have a cold bore shift? And how far if it does?
A few FPS may not mean a thing... or it could mean far more then you expect. There is an assumption speed is the tell all... anyone shooting for any length of time, will see that it is far from a reliable predictor of results so the best solution is to track where that first shot actually goes... on paper
Any consistent pattern can be adjusted for and then it is no longer an issue. Any pattern that is inconsistent, shoot enough and you will learn the extremes of the pattern ie.. how bad it is going to get.
Something shooters keep forgetting, the ammo we use is the largest variable of all. Does every first rd shot, hot or cold, end up in the center of the group downrange?
Jerry
It is not something I am going to bother with as the odds of introducing MORE variables increases. I think shooters should spend more time shooting at paper vs looking at chronographs. Does your rifle have a cold bore shift? And how far if it does?
A few FPS may not mean a thing... or it could mean far more then you expect. There is an assumption speed is the tell all... anyone shooting for any length of time, will see that it is far from a reliable predictor of results so the best solution is to track where that first shot actually goes... on paper
Any consistent pattern can be adjusted for and then it is no longer an issue. Any pattern that is inconsistent, shoot enough and you will learn the extremes of the pattern ie.. how bad it is going to get.
Something shooters keep forgetting, the ammo we use is the largest variable of all. Does every first rd shot, hot or cold, end up in the center of the group downrange?
Jerry
As a 3 position smallbore shooter I found this very interesting as well Jerry, Simply for the fact that it was never considered something to worry about even in our 100 yard any sight matches.
In the video the shooter said he missed the target with his first shot, leading me to wonder just how small a target he was shooting at.
a 100 yard smallbore NRA target for example has an X ring of 1" and a 10 ring of 2".
The aiming point is 8", but with a scope that is not applicable.
Cat
Last edited:
I brought a chrono out to the range for the first time last week, and the first shot of the day was definitely "hot" at ~50fps more than the rest, and shot almost 2" high. This was a freshly scrubbed bore with no carbon ring.
I'm curious to try this... I wonder what kind of looks I'll get at the range when I start "puffing" on my rifle with a bendy straw lol
I'm curious to try this... I wonder what kind of looks I'll get at the range when I start "puffing" on my rifle with a bendy straw lol
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Shooting from a clean bore is going to be different from a fouled bore no matter the conditions. I suspect, the barrel wouldn't 'settle' down for some 20 to 30rds.
Hopefully, you will be able to give this a test from a fouled bore... say 50 rds fired.
More typical of what might happen during a match day.
Good luck..
Jerry
The first round from a clean bore will typically be faster. While it may seem counterintuitive, the reason for this is friction. About eight years ago, Jerry Halcomb, a successful American BR shooter, explained why this occurs.
The first shot going high is likely caused by the increased surface friction of the clean barrel as evidenced by the a substantially higher velocity observed with a chronograph. Variation in the bore surface friction dramatically alters the pressure under the curve which drives the acceleration, velocity and ultimately the timing of the bullet exit with the pressure wave traveling back and forth on the barrel. This is particularly important in the first few inches of bullet acceleration. Depending on how dry and rough the barrel is, it can be as high as 50 FPS above average. Sometimes you can actually hear the supersonic crack even though the ammo is subsonic. The next round will not do this. If the bore is properly pre-lubed, this effect can be greatly reduced or even eliminated.
See post #6 here h ttps://www.rimfireaccuracy.com/Forum/index.php?threads/clean-bore-shot-location.26535/
When a first round goes through a bore in which the fouling has dried and hardened, it may experience something similar to what's described above.
The friction experienced by the first round means it doesn't accelerate the same way as subsequent rounds will. While the faster first round will usually strike higher than those that follow, it may also deviate from a predictable trajectory because of the change in acceleration and it's potential effect on barrel harmonics. When shooting through a fouled bore, rounds will accelerate similarly to their ultimate MV.
The takeaway from this?
First, season the bore with fouling shots before shooting for score. Shoot only for score with fresh, wet fouling. Second, anticipate drying and hardening fouling if shooting is suspended. If safe and permitted, shoot foulers intermittently to keep the fouling in the bore fresh and wet. Alternatively try one of the suggestions made in the video.
The first shot going high is likely caused by the increased surface friction of the clean barrel as evidenced by the a substantially higher velocity observed with a chronograph. Variation in the bore surface friction dramatically alters the pressure under the curve which drives the acceleration, velocity and ultimately the timing of the bullet exit with the pressure wave traveling back and forth on the barrel. This is particularly important in the first few inches of bullet acceleration. Depending on how dry and rough the barrel is, it can be as high as 50 FPS above average. Sometimes you can actually hear the supersonic crack even though the ammo is subsonic. The next round will not do this. If the bore is properly pre-lubed, this effect can be greatly reduced or even eliminated.
See post #6 here h ttps://www.rimfireaccuracy.com/Forum/index.php?threads/clean-bore-shot-location.26535/
When a first round goes through a bore in which the fouling has dried and hardened, it may experience something similar to what's described above.
The friction experienced by the first round means it doesn't accelerate the same way as subsequent rounds will. While the faster first round will usually strike higher than those that follow, it may also deviate from a predictable trajectory because of the change in acceleration and it's potential effect on barrel harmonics. When shooting through a fouled bore, rounds will accelerate similarly to their ultimate MV.
The takeaway from this?
First, season the bore with fouling shots before shooting for score. Shoot only for score with fresh, wet fouling. Second, anticipate drying and hardening fouling if shooting is suspended. If safe and permitted, shoot foulers intermittently to keep the fouling in the bore fresh and wet. Alternatively try one of the suggestions made in the video.
My cold bore fouled bore shot is almost always 20-30fps faster that the average of the rest of the shots. Today is much more humid than normal. Cold bore shot was not faster for the first time. I guess I will try the straw trick. Foulers during our matches are called misses. I dropped at least 1 point from what I think was cold bore shift in ‘23.
