Powder Change = Barrel Clean?


Gunny Sergeant
Full Member
May 5, 2009
Eastern Ohio
I have heard this before on AR-platform forums that every time you switch to different load you have to clean your barrel or it takes 5-10 shots for the barrel to set to the powder. Has anyone heard of this?

<span style="font-weight: bold">Example</span>:
Im shooting (.300WM) 220gr. SMK's with H-1000 then I switch to 208gr. A-MAX's with Retumbo. Will there be a deviation in accuracy until the barrel "sets in" to the powder?

I have never really handloaded for a precision rifle until now. I always just handloaded for AR-Platforms from .223Rem, 6.8SPC,6.5 Grendel, 45ACP and 50AE pistols. I always did a quick swipe with a cleaning rod when I changed loads. I never NOT did this so I dont know if I would of had a deviation.


Gunny Sergeant
Full Member
  • Jan 16, 2010
    Lewiston, ME
    Re: Powder Change = Barrel Clean?

    The answer is no. Where this may have started is with rimfire "match" ammo and then it isnt about the powder change its the wax used on the bullets. I was shooting today with BM11 and watched him go from 118LR to Federal GMM and hold under 1/2 MOA for each. I also was shooting 118LR (44g RL15) and my handloads 43.8g Varget and had no accuracy change going from one to another. Now if you do decide ot clean between you may have to shoot a few before the barrel settles back in and shoots well agan, but that depends on the barrel.


    Stupid can be fixed
    Full Member
    Apr 3, 2009
    Re: Powder Change = Barrel Clean?

    Going from stick powder to stick powder not usually a problem.

    Ball to stick or stick to ball I usually run a bore snake between.

    I don't know that it makes a difference, but when I'm doing load development that's the only time I really care about it. Just getting rid of the variables.


    Full Member
    Feb 17, 2011
    Little town now east of Bismarck
    Re: Powder Change = Barrel Clean?

    The simple truth is it can. Some barrels it will affect it and others it will not. Just to make sure I would not do load development from one powder to a different without cleaning first.

    My AR-10T is picky very picky in what I put in it. I shot up close to 500 shots trying to get a load for it. This tube is the pain in my rear barrel you only hear about. It needs like 10 to 15 fowling shots before it settles. Then it only holds for about 50 shots plus or minus.

    My pain was I tried different powders and it would create fliers until it blew out the old and got with the new or what ever it did. I read the article from sierra about reloading for gas guns and I tried to clean and that also did not help. So what I did was loaded up 50 shots of one load with 168gr smk and just shot it on a clean barrel shooting 5 shot groups until the 50 shots were gone. What I found was they started out bad then got better then held then got bad toward the end.

    My new bolt 30-06 is about the same it takes three shots to settle then you are ready to rock. I tried my standard M1 load in it and then tried a different powder and it went from bad to worse. I cleaned and tried it again and Varget was the trick.

    Each barrel is different and it will tell you what it likes. It just sucks when it is very picky in what it likes.

    Greg Langelius *

    Resident Elder Fart
    Full Member
    Aug 10, 2001
    Re: Powder Change = Barrel Clean?

    The important thing about powders and cleaning is the relative differences in carbon fouling. It's the kernel coatings like graphite, etc., whice remain behind after combusion that make up the fouling differences. They alter bore friction values, and impose bore transit time variations that may or may not be genuinely consistent with basic load performance.

    Cleaning can allow the change to a new page, but it needs to be pretty thorough, and then requires the bore to become newly seasoned with the accumulations that are only relative to the new load.

    To my mind these variations can be big or they can be small; and too little about kernel coatings and their consequences on accuracy performance is out in the public view to be able to decisively predict such matters.

    Unless you are dealing with accuracy imperatives like those present in BR shooting, these variations may become insignificant, or even indistinguishable. The only way to know is to try things both with and without such cleaning. Personally, I'm undecided on the true value of this.