Shooting a dirty rifle

[Gmac]

Savage Trophy Hunter 308, stock sport barrel, nothing special, Boyd’s thumbhole stock, pillar bedded, Vortex 6-24 tactical on top.
Relatively new to long range but shooting MOA at 500-600 yds as long as I can guess the windage correctly. Why do my groups tighten up with a dirty barrel? I read that this happens and experience it myself routinely, but WHY? Thnx for the help.

 

[Conaso]

The barrel become somewhat consistently fouled with powder residue. Also temperature of the barrel will be a factor. Several shooters at our range have a little temperature strip adhered to their barrel for temperature consistentcy.

 

[Sogan]

There are imperfections in a barrel. When a round is shot the copper and carbon fill these tiny imperfections and will usually result in better accuracy. Most here do not clean until accuracy begins to fall off. This varies with each rifle and caliber but I do not clean my .308 until 600-800 rounds.

 

[Kimber.204]

There are imperfections in a barrel. When a round is shot the copper and carbon fill these tiny imperfections and will usually result in better accuracy. Most here do not clean until accuracy begins to fall off. This varies with each rifle and caliber but I do not clean my .308 until 600-800 rounds.

Think about it this way, when the barrel is completely clean, then you shoot it, you leave some deposits in some places, but other places are still relatively "clean". Then the next shot you get more deposits other places and so on.

So, until the barrel is "seasoned" or "fouled" you are effectively shooting a different barrel each time. Now, by that logic, it is in fact a different barrel with every shot, but lets assume that after a given number of fouling shots the change in the barrel is relatively minimal, compared to the change caused the first or second shot.

Eventually the carbon and the copper build up enough that it is deforming the bullet excessively, or it is increasing the pressure. Different powders burn differently in different cartridges. In my 6mm Competition Match using RL26, accuracy falls off a cliff well before 150 rounds, shots way off call, random flyers, etc. But when using H1000 or Ramshot Magnum, I could easily go 250 rounds. I never tried more than that. That worked out to cleaning every 2 weeks this past summer and it was very convenient.

Regards,
Ross

 

[brianf]

if your really shooting consistent 1 moa at 5-600 with a factory barrel dont touch it. lol
but most factory barrels do not have the same finish on the inside especially at the throat as custom barrels do.
your probably filling in voids and grooves that were left over from the initial machining process, and the bullet jacket is being distorted less.

 

[Eric1977]

On the subject.... when people say that they do not clean every ### of rounds, say 500 or more..... how long does it take you to rack up that round count?

I don't get to shoot as often as I like, so I might shoot that many rounds in a year. The thought of not cleaning my barrel for a whole year doesn't sound good to me personally. I guess I have the old days etched in my brain and am afraid of corrosion.

 

[brianf]

if your barrel is stainless dont worry, if its not stainless the burnt powder will absorb moisture and you may get pitting if there is enough humidity.

 

[Kimber.204]

On the subject.... when people say that they do not clean every ### of rounds, say 500 or more..... how long does it take you to rack up that round count?

I don't get to shoot as often as I like, so I might shoot that many rounds in a year. The thought of not cleaning my barrel for a whole year doesn't sound good to me personally. I guess I have the old days etched in my brain and am afraid of corrosion.

That's a great point. I clean my deer rifle after I shoot it, weather at a deer or at the range, it gets cleaned that night. When I said earlier that I don't clean until needed (from an accuracy standpoint) I'm referring to my match rifle that will go through a barrel every two years or so.

Also, regarding stainless steel barrels, please note that they are still STEEL, and they will rust.....it just takes longer.

 

[OLD308]

Spend the time and find you and your systems true shooting potential. (300 yard 5 shot 5 groups average groups) After each range session pull a dry bore snake through it and leave it alone. Every time you think about cleaning it, check your grouping against the above referenced. You will be shocked at how long a 308 will go with out fouling issues. It’s not a barrel burner, so don’t clean it like one. Let science tell you when it’s needed not tradition.