Originally Posted by
CFJunkie
J.Baker,
I'm not sure that you found a 'dirty barrel sweet spot' or just experienced delay in getting your concentration back after a 45 minute layoff.
At my age, I expect concentration lapses even when I haven't been interrupted.
Last week, I shot 100 rounds through one rifle with 4 closely related loads of 25 rounds each in 5 shot groups. That rifle is well broken in with over 4,000 rounds down the tube.
I measured all of the groups and found little difference, within an expected standard deviation, in the average group size except for about 4 groups that I managed to screw up with one shot when I didn't stick to my routine - probably due to lapses in concentration.
It was pretty cold so I didn't have severe barrel heating problems but I did notice that by the last groups of each load, the POI was slightly lower then it was on the first group. This particular rifle drops the POI by about 1/4 inch when the barrel temperature gets above 113 degrees and toward 122 degrees on the temperature strip that I have on the barrel.
The group average group size on the first and 3rd loads were slightly better than the 2nd and 4th loads, but they were well within the statistical range of the overall average for the day and the standard deviation of the 20 groups.
I would say that would probably mean that there wasn't a 'dirty barrel sweet spot' for that session.
Just for the record, I would describe 'fouling a barrel' as clearing out the residue from cleaning and providing a light coating of powder residue.
I am a firm believer that a hunting rifle should be 'fouled' before going hunting.
I just won't take a hunting rifle into the field just after cleaning because I have not experienced that it will provide a predictable POI with a newly cleaned barrel.
It may just be me and how I was trained.
But I set up a fouled barrel so that the POI is at the POA from a very cold barrel because that is how I expect to shoot when hunting.
I wouldn't call shooting 60 or 100 rounds fouling. That is far past fouling - it results in a dirty barrel and I would expect to clean the barrel when I was finished with the session.
But I don't expect that the accuracy of a rifle should be effected by that kind of use.
If it was, I would be disappointed.
In fact, I regularly shoot those kind of sessions with just about all my rifles and don't notice any drop off in accuracy during the session or on the last groups shot.
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