Does a dirty fouled bore contribute to higher Standard deviation?

Clean or dirty? Which is best for optimum accuracy? Is there a “sweet” spot for the shooting BE specific applications, lightly shot but not fouled out bore? Rimfire, centerfire 45, is there a difference? Lead and jacketed, any diff? Caliber specific?

After year of shooting competitive hp rifle, slightly fouled seems best, however clean from the start is always ok too. With competitive shotgun, unless you are shooting a repeater, it really doesn’t seem to matter, with clean grease for the action being the most important.

For BE pistol, clean seems best, but I am not sure. Your thoughts?

I prefer dirty.
I know shooting Eley Bullseye over Aguila Pistol Will group like Thunderbolts!

So, clean and season barrel.

Standard deviation is not that highly correlated to group size for pistol loads. 
Pistol matches are generally 90 to 270 rounds.  
You should have a reliable gun, and decent grouping ammo / loads that can sustain at least that many rounds without issues. 
While I will wipe down, brush breechface, etc., and brush / patch a .45 barrel or use a pull though patch on a .22 barrel before or after a match.  I rarely do a full breakdown and clean, may 2 or 3 times a year.
Do fire the gun after a full cleaning before the next match just to make sure you put it back together right, etc. 

For pistol shooting I have said in the past that I allocate my time like this. 

Loading more than you clean, 
Shooting more than you load,
Training more than you shoot, 
Thinking more than you train.

So for me that means only clean when I need to and load on a progressive.  That gives me more time to shoot with a purpose, train with a plan and think about the important stuff (the shooter needs more work than the loads or equipment).  

CR

Fouled with the same ammo you're going to be shooting the match with.

Lube is your friend.

I always followed Larry Carter's advice and never cleaned the bore (only the chamber) of my Hammerli 208s. I always used quality ammo. When I was at my peak, I often would shoot an X on my first target of the .22 match. When I was actively competing, during the CF and .45 matches, I would shoot JHP for the long line and swaged lead bullets for the short line. I never cleaned the bore during a match. I always shot Kart barrels. My long line scores didn't ever seem to suffer. CR10X has it right. With pistols, you don't need to sweat the small stuff, like in rifle. In pistol shooting, you will lose many, many more points due to poor fundamentals, than due to equipment limitations. One thing though, start out with reliable and accurate guns.

A clean bore does not shoot to the same POI as a seasoned barrel. Olympic shooters very seldom, if every, clean the barrel of their .22 guns.
It has taken me up to 25 shots to get a stable and small group after thoroughly cleaning a barrel.
Try it yourself.
PS: Std. Dev. has almost NOTHING to do with accuracy until you get out beyond about 250 yards...

noylj wrote:A clean bore does not shoot to the same POI as a seasoned barrel. Olympic shooters very seldom, if every, clean the barrel of their .22 guns.
It has taken me up to 25 shots to get a stable and small group after thoroughly cleaning a barrel.
Try it yourself.
PS: Std. Dev. has almost NOTHING to do with accuracy until you get out beyond about 250 yards...

Would not a measure of a "stable and small group" be the standard deviation of distance from bullseye for each shot in a group? Stable and small both seem to be measures of precision if not accuracy, if I remember my statistics course correctly.

"People, people, people! What am I going to do with you? You buy these great guns, often for more than what two month's beer money comes to and then when they stop working after only 4-5,000 rounds of $100/case ammo, you get all whiny! Sometimes you send them in and I have to get the crud out of them - which most of the time is all they really wanted - just a little TLC. I decided, while trying to get the black stuff out of the creases of my hands this weekend, having just removed 15 paper towels and 20 patches worth of stuff from one of these poor pistols, that it was time for another note. So, first let us dispel one of the more persistant misconceptions floating around: A dirty gun is NOT a more accurate or a more reliable gun! It is NOT the best idea to "shoot 'em until they jam!" Just as you brush your teeth (hopefully for all around you) and bathe and change the oil in your Miata, you need to clean your gun!"


- Don Nygord

http://www.cincinnatirevolverclub.net/nygordsnotes/cleaning.htm




At $2500 for a Pardini, and $1/beer, over 60 days, that's 41 beers a day!   
Accuracy/precision don't mean squat if your gun won't function.

Fire to malfunction

sbtzc wrote:Accuracy/precision don't mean squat if your gun won't function.

There is a difference between cleaning the gun and cleaning the barrel bore.

I regularly clean and lube guns, but seldom clean the bore bore, as it seems to remain mirror shiny when using only lead or coated projectiles.

For most reloading discussions, standard deviation is generally used with respect to the velocity, group size is the general measurement for accuracy potential. While deviation of shot displacement from the center of a group can provide some information, we just generally refer the the worst one(s) as "flyers".

CR10X wrote:For most reloading discussions, standard deviation is generally used with respect to the velocity, group size is the general measurement for accuracy potential. While deviation of shot displacement from the center of a group can provide some information, we just generally refer the the worst one(s) as "flyers".

I have so many “flyers” I’m beginning to think I have an Air Force.

Unless you CALL the flyer, it isn't a flyer.
You say std. dev. and all I think about are chronographs and velocity. I don't think I have read or heard of ANYONE referencing std. dev. of group size before, other than the average and std. dev. of groups of five or more targets while testing the same load--and that is very rare.
The main 1911 (and other guns but to a lesser extent) issue with CLEANING is the over lubrication of the guns and firing simply making mud/concrete from the hot oils and soot. I have twice fired a fellow shootists gun and been sprayed with oil all over my glasses.
I have fired a single 1911 in competition for over two years (bullseye, PPC, IPSC) back in the late '70s without any cleaning other than wiping off the feed ramp if I felt like it and never had a failure.
Clean as much as you like, but accuracy will be effected by barrel cleaning. That is why for several hundred years there have been fouling shots before competitions.

I  haven't been able to "call the flyer" when using a Ransom rest yet.  

CR