Cold bore shots more accurate?

[The Lone Haranguer]

It is true that rifle barrels, when heated up, will sometimes send the bullets to different points of impact than the first shot from a cold bore. This happens more often with light thin barrels than the heavy barrel of your police rifle. To measure group size of only the "cold bore" shots, you would have to let the barrel completely cool between each shot, which could take hours. I think I would run out of patience first.

 

[JohnBT]

"I'm curious as to how many of the responders to this thread have done controlled tests on multiple guns"

I've read the results. Should we repeat the tests?

Me, I've been shooting more than 50 years, was an undergrad physics major and stayed at a Holiday Inn once or twice. Want me to call my 78-year-old uncle and ask his opinion? He used to do trades back in the '50s and '60s where he'd give 6 rifles to get 5 or 3 for 2 to get one he wanted. Then he'd trade some of those to get others and so on. I got to shoot a fair cross section of long guns during my childhood. The technology hasn't changed much.

That hexagonal boron nitride mentioned earlier is well thought of my some varmint and high power shooters, but you do lose 50 or 100 fps in velocity because the pressure doesn't build the same way behind a really slippery bullet.

My uncle and my father got me hooked on this stuff. And my other uncle and my grandfathers. And then there were all of the cousins. If I called my dad he'd tell me the same old thing - stick with the Model 12 and the Python.

John

 

[JohnBT]

"To measure group size of only the "cold bore" shots, you would have to let the barrel completely cool between each shot, which could take hours. I think I would run out of patience first."

Ah, you need a fine .22 rimfire to pass the time. Get a really nice one and you can just admire it when you're tired of shooting little groups. A Cooper Custom Classic.

 

[MCMXI]

No I do not. . Accuracy by the multitudes is usually measured by group size. Precision is placing your shot to the POA no matter the condition clean, dirty, cold, hot, and etcetera.

The definitions of accuracy and precision are the same in the shooting sports as they are in numerous other fields.


Definition of accuracy and precision

In the fields of science, engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to its actual (true) value.[/U] The precision of a measurement system, also called reproducibility or repeatability, is the degree to which repeated measurements under unchanged conditions show the same results.[1] Although the two words can be synonymous in colloquial use, they are deliberately contrasted in the context of the scientific method.

 

[Monkeyleg]

I did anecdotal testing in the 90's with different rifles, and did find that barrel temperature as well as chamber temperature seemed to make a difference in my groups. Maybe I'm superstitious, but I've found I get tighter groups if I let my rifle barrel cool for 5-15 minutes between shots, depending upon the ambient temperature.

I really put a lot of oil in the bore after cleaning, so I shoot three fouling shots before going for the "real" shots.

Just for background, I've shot .20" groups at 100 yards, .610" groups at 200 yards and 1" groups at 300 yards with the .308 in the video. I finally found a range nearby where I can shoot to 500 yards. The results will be interesting. I'll also try shooting from a warm barrel to see what happens.

 

[blackops]

All of this is simply a case by case scenario. What rifle you are shooting, barrel, ammunition, atmospheric conditions, the shooter, etc. all are factors in the equation of how each individual rifle’s “fouling” or “cold bore” shot is going to register.

 

[Art Eatman]

I've never particularly worried about the technicalities in all this rifle stuff. I started messing with centerfires, and handloading, a bunch of years ago. I did gunshow tables for around thirty years, and messed with a lot of the trade-ins.

Leaving out dead time, call it forty years of messing. Figure an average of only one shooting session a week, which is reasonably close. So when I post about what I've learned, there's a fair amount of benchrest and field experience behind it...

 

[sansone]

I think it's just clean & oily 1st shot vs dry & dirty repeat shots. Seems the brrl would need to heat up more than just 6-8 shots to change POI

 

[AK103K]

Isnt where the first shot goes the whole point?

Knowing where the rest will go afterwards isnt a bad thing either, but the first is the critical one.

Realistically, the difference isnt usually worth the worry, unless youre doing all this for points or bragging rights over group size.

 

[sansone]

for hunting yes, 1st shot is usually all you get. But paper-punchers are looking for group size

 

[AK103K]

Soooo, were back to that age old argument, eh? Tastes great, less filling.

 

[Offfhand]

Quote from above post;

"I did anecdotal testing in the 90's with different rifles, and did find that barrel temperature as well as chamber temperature seemed to make a difference in my groups. Maybe I'm superstitious, but I've found I get tighter groups if I let my rifle barrel cool for 5-15 minutes between shots, depending upon the ambient temperature."

Check out a real bench rest tournament (Not guys plinking from a bench at local range) and watch how fast the real accuracy experts fire. This summer at the IBS Championships I watched one of the top dogs in the game shoot back to back 5-shot groups at 200 yards that measured LESS THAN TWO TENTHS"! I timed him on the second group and he fired five shots in under 20 seconds!

 

[Monkeyleg]

Seems like a knocked over a hornets' nest here.

Check out a real bench rest tournament (Not guys plinking from a bench at local range) and watch how fast the real accuracy experts fire. This summer at the IBS Championships I watched one of the top dogs in the game shoot back to back 5-shot groups at 200 yards that measured LESS THAN TWO TENTHS"! I timed him on the second group and he fired five shots in under 20 seconds!

I'll do that.

Art, not many people can match your experience, if only because few people are as old as you.

 

[flashhole]

So what is the definition of a clean barrel?

 

[Freedom_fighter_in_IL]

Check out a real bench rest tournament (Not guys plinking from a bench at local range) and watch how fast the real accuracy experts fire. This summer at the IBS Championships I watched one of the top dogs in the game shoot back to back 5-shot groups at 200 yards that measured LESS THAN TWO TENTHS"! I timed him on the second group and he fired five shots in under 20 seconds!

And just what kind of barrel did that bench rest weapon have on it? More than likely a $8,000.00 dollar precision Keplar or something along those lines. Barrel quality, rigidity, rifling quality and many other things make a HUGE difference in those things. Our average hunting profile barrel will almost ALWAYS have some "walk" to it after a heatup. Some rifles, after having been shot a lot, require some fouling to tighten up the bore for good contact between bullet and rifling. Comparing a high end bench rest rifles grouping to your typical or even high end hunting profile barrel is like trying to compare a Ferrari to a Ford Taurus. Just not a fair comparison whatsoever.

 

[Offfhand]

Quote from post above:

"And just what kind of barrel did that bench rest weapon have on it? More than likely a $8,000.00 dollar precision Keplar or something along those lines."

Weapon? It was a SPORTING RIFLE, not a weapon. In fact, it was a simple varmint class rifle within weight requirements. But it may have been a precision Keplar, as suggested, have no idea. But what is a precision Keplar? Is Keplar a gun maker? Never heard of it so please describe. Do they really cost $8,000? Wow! Is there website for Keplar? Would like to learn more about Keplar.

 

[Freedom_fighter_in_IL]

German barrels. Not sure of the website. Made by Keplar GunWorks (Not sure on that german translation) And didn't know it was a sporting rifle. You did say "bench rest tournament" And ANY rifle, be it sporting, bench rest comp, or 10/22 is a WEAPON period. Calling it anything else is just PC for the anti's.

If memory serves you have "Light guns" which is 17 pounds or less and then "Unlimited" class in IBS. I would not consider a 17 pound rifle a "typical" varmint rifle. My point was this though, most, if not all, of those rifles are tweeked out, top of the line, no hold barred firearms and can't really be compared to your typical hunting profile type firearm.

 

[Offfhand]

Quote from above post:

"If memory serves you have "Light guns" which is 17 pounds or less and then "Unlimited" class in IBS. I would not consider a 17 pound rifle a "typical" varmint rifle. My point was this though, most, if not all, of those rifles are tweeked out, top of the line, no hold barred firearms and can't really be compared to your typical hunting profile type firearm."

Sorry to have to keep correcting you, I think you are trying to be helpful, only confused and somewhat misguided. Do this: check out IBS rules for varmint class rifles. Light varmint max is 10.5 pounds, scope included, heavy varmint class max weight is 13.5 pounds. Apparently you are confused about rules for long range bench rifles. Also check out rules for dimensions, which specify that the varmint class rifles be similiar to standard hunting or varmint rifles. As for prices, I called a gunsmith who specializes in bench rifles and checked his prices. Best of everything: action, trigger, barrel and stock, plus work, runs $1,800-$2,400. With biggest difference in prices being stocks, with wood becoming more popular and also costing more than synthetics. Add the cost of scopes, which run from about $400, to $2,000, and prices top out about $4,000 for best of everything, with median being in $2,300-$2,600 range. He also advised that good used rigs can be had for about $1,500 or less but usually need a barrel job. He had never heard of a "Keplar" barrel. I did a search and it turns out that Keplar barrels
have something to do with wine barrels. Hope you find this information helpful and will get you started of for a better informed 2011. Happy New Year

 

[Art Eatman]

flashhole, I'd go with the notion that it's the condition after one is done with a cleaning effort. Commonly, there would be a very light film of oil in the barrel.

The question for many is whether this film makes a difference in the point of impact of the first shot, compared to the following shots.

Sometimes, yes. Sometimes, no. Seems to me the deal is to do the minor amount of testing on a particular rifle. Compare first with the film of oil. Then, before firing a first shot from a clean barrel, run a dry patch through and shoot a group.

Last, fire a fouling shot before then beginning with a fully-cooled barrel.

As long as I'm nattering and doing vignettes: My father built up an 03, back some sixty years ago. The first shot from a cold barrel was invariably two inches higher than the next however-many. Clean, dirty, didn't matter. The deal was "cold barrel". He re-bedded it. No joy. He rebarrelled it. No joy. He just said, "The hell with it," and held two inches low for any first shot. He still managed to bust many a white spot on Bambi...

 

[flashhole]

Art - that's exactly why I asked the question. No matter how much I clean my gun (bore patches or bore snake) after a chemical scrub (copper and lead solvents) that first shot or two always blows stuff out the barrel that was caught in the rifleing. And ... it affects the first shot accuracy.

A dry scrub after a few fouling shots is what I consider a clean barrel. So, consecutive shots after repetitive use of a bore snake between each shot, letting the barrel cool, gives me one ragged hole shot-to-shot repeatability with my handloads.

 

[MCMXI]

No matter how much I clean my gun (bore patches or bore snake) after a chemical scrub (copper and lead solvents) that first shot or two always blows stuff out the barrel that was caught in the rifleing. And ... it affects the first shot accuracy.

That's not my experience with my Krieger barreled .308 Win. Some friends that I shoot with have high-end custom rifles with non-Krieger barrels and their first shot is to POA as well. Again, I'm not talking 100 yards but 200 or 300 yards where issues will show up readily. I run a dry patch through the barrel but as Art stated, there's still a very thin film of oil in there. However, it doesn't affect accuracy at all, well, not at 300 yards anyway.

 

[BrocLuno]

Huh ...

Is this exercise about paper punching or hunting? If hunting, it's the cold bore first shot that counts All others are follow-up shots :banghead: