We had a discussion recently about cleaning the bore of a .22 rimfire rifle. One poster said, "It will ruin the barrel. Never clean a rimfire rifle barrel!"

I got to wondering.

I have never believed the old wife's tale about never cleaning a .22 rifle barrel, but I guess there is only one way to know for sure.

There isn't much debate about cleaning a high power centerfire rifle barrel. Centerfire rifle cartridges are usually copper jacketed bullets that are pushed at high velocity, pressure, and resulting heat. This causes copper fouling to be deposited on the rifling and it must be cleaned periodically or it will result in deteriorating accuracy.

But a .22 rimfire is different. We are shooting lead, lubricated bullets at relatively low velocity and pressure. The result is that there is very little lead deposited on the rifling (if any), and the fouling is mostly the lubricant (usually wax or grease) and powder fouling.

This means that .22 rimfire barrels do not get badly fouled. But they do get dirty. And I tend to like my weapons to be clean.

The question today is: Will cleaning a .22 rimfire barrel "ruin" accuracy? Will it have any effect at all?

I went and got some .22 ammo and two different rifles. The rifles are my Remington 510 Target Master single shot (covered in this post The Remington 510 TargetMaster and Vern's Ruger 10-22. Both are very accurate "hunting" type rifles. They are not Olympic Quality .22 rimfire rifles, but are representative of what most people will be shooting.


The ammo is here:

First is some CCI MiniMag .22 Long Rifle Hollow Point, a good hunting ammo.

Next is some CCI Sub Sonic .22 LR Hollow Point that I saw and thought it would be good to test. Sometimes sub sonic ammo will shoot more accurately.

Lastly was some Remington Target Rifle ELEY Limited. This is supposed to be very accurate ammo, and the price tag bears that out.

I will first shoot a 5 shot group with each ammo and each rifle at 50 yards as a baseline.


First with my Remington 510 Target Master.


Then with Vern's Ruger 10-22.


Then I cleaned them up.

I removed the bolt from the Remington and pulled the trigger to get the release out of the way of the cleaning rod.


I first ran a solvent soaked .22 bore brush down the bore.


Then I ran a solvent soaked patch through the bore.


Then I ran a patch soaked with WD-40 down the bore to wash it out.


Then a couple of dry patches to remove any oil that was left.


Let's try the groups again.


And, here are the results for the Remington 510.

The first groups are on the left, with the "clean bore" group on the right. The arrow shows the first shot from the clean bore.

As you can see, the first shot was high, out of the group, but the rifle settled down quickly. (The POI is different because I adjusted the scope.)

After each "clean bore" group, I cleaned the bore with a wet and then dry patches until it was dry. It is surprising how much powder fouling is deposited by only 5 shots.


Then the sub sonic ammo.

Neither group is as tight as I had hoped, but the clean bore shot was right in the group.e130-12

Lastly, the Eley.

The first shot was high, but the whole group was disappointing. So, I shot another group below, which was much better.

(Just as a side note, this shows one of the problems of shooting groups for an experiment and post such as this one. Everybody shoots a "poor group" now and then. Mine just get published. )


Then we cleaned the Ruger 10-22 and tried it all again.

First the CCI Mini Mags.

Vern's rifle just doesn't "like" this ammo, in either a dirty or clean barrel.


Then the sub sonic ammo.

It really likes this ammo and the clean bore group was better.


Lastly the Eley.

There was one flier in the clean bore group, but it was not the first round. And his rifle likes this expensive ammo too.

Lessons Learned:

1. As we all know, different .22 rifles "like" different ammo. You never know what it will like till you try it.

2. In some cases, the first shot from the cleaned barrel was slightly out of the group. But this is not a big deal, as one fouling shot seemed to be all that was needed to settle it right down.

3. It did not "ruin" the barrels to clean them. Now maybe if I ran a brush down the bore 2,000 times each cleaning session, it might ruin it. But sensible cleaning does no harm to the barrel at all.

4. It did not hurt the groups to clean the barrels. In fact, in some cases, it seemed to help the groups.

5. Maybe in Olympic quality rifles, you might be able to see a loss of accuracy after cleaning, but a shot or two will get it to settle down quickly.

6. Go right ahead and clean those .22 rifles. It won't hurt them.