Looking for opinions and experience on testing various .22lr ammo for accuracy. Do you clean the barrel between different brands and does the bore need seasoned with say 10 rounds of the next brand before testing for accuracy?
Thanks
What you should do can depend on what you're going to be testing. Many shooters recommend "cleaning" between varieties of ammo, and that can be a good idea. It is probably not necessary to clean with a bronze brush between different ammos. It is probably enough to run a patch on a jag with cleaning fluid down the bore after one kind of ammo is tested, followed by a dry patch or two. This is not really needed if you are testing different ammo made by the same manufacturer, say, for example SK/Lapua, because they will use the same lubrication on their bullets. It's more important when you switch between SK/Lapua, for example, and Eley, or RWS.
To summarize, if your testing SK/Lapua ammos, it shouldn't be necessary to clean between different varieties offered by that manufacturer. So shoot all your SK/Lapua and then clean before switching to ammo made by another ammo maker. A couple of patches should do the trick to give the new ammo a fair chance to go down a relatively clean tube.
Shoot brand X, clean, send a mag of brand Y down range, let "cool" start accuracy shooting with brand Y.
10-20 rounds for fouling
You could benefit by shooting some fouling rounds, but the advice to let a .22LR "cool" before shooting for accuracy is silly because this ammo does not cause any barrel heating that will affect your results. It's not .17HMR or .22WMR, let alone centerfire ammo, all of which can heat barrels.
First point is this is not worth considering if the rifle in question cannot hold 1 MOA at 100 yards on a calm day.
22LR rifles do not do well with frequent cleaning.
An aggressive cleaning strategy for 22LR might be every 500 to 1000 rounds.
Cleaning more often than that will typically do more harm than good.
Don't think you are going to shoot best groups with a clean barrel. The bullets are coated with a lubricant and you need that lubricant to build up in the barrel to be effective.
So to cut to the chase, don't bother to clean, just shoot 4 to 6 five rounds groups accurately on target and you can gage the change as the barrel settles into the new ammo.
22 barrels don't get very hot, so unless you are into 22LR bench rest, I wouldn't put too much thought into that.
Indeed, don't worry about heating up your .22LR bolt action rifle's barrel. Benchrest shooting doesn't heat up a .22LR barrel either. While an inaccurate rifle doesn't lend itself to ammo testing, you'll never know if your rifle can hold 1 MOA at 100 yards if you don't test. In fact a lot of shooters with experience can and do find shooting MOA consistently a challenge even with a good rifle. In any case, you need accurate ammo to find out if you and your rifle can hold MOA at 100 yards. The idea that cleaning more often than 500 to 1000 rounds does more harm than good is just plain wrong. Cleaning with a bore guide, a good quality one piece cleaning rod, and proper-sized patches cannot hurt a rifle. Some shooters disagree about how often to brush with a bronze brush, but few completely eschew its use. If in doubt, use a nylon brush.
In any case, if you are testing bulk ammo only, ignore all the advice above and just load your rifle and give it a go.