Home Forums Reloading Big Game Rifles Sighting in questions....

I'll be using TSX, all copper bullets in my .06 and .270.

I read that I should "foul" the barrel after cleaning. Is it the powder that fouls the barrel, or the bullet? Can I foul it with some FMJs?

Sighting in: 3 shots? 5??? How much time between shots?

I know the barrel needs to cool... How much? Just to be able to handle, or more cool?

Thanks! Ken

It is essentially to get any cleaning residue or oils out of the gun that might cause the first shot to shoot to a different point of impact. It is usually pretty insignificant at reasonable hunting distances. A patch with alcohol on it might do the same thing to remove any oils. But, if your barrel isn't stainless, you run the risk of corrosion on bare metal.

Plenty of animals are killed with the first shot out of a clean barrel.

A barrel with oil it in can throw shot off as much a 4" at 100 yards. I typically check my zero a few weeks before the hunting season an then let the barrel dirty until after the season. Of course a cold barrel may or may not shoot the same POI as a warm barrel, but a barrel with oil in it from cleaning or storage will most often not shoot same POI.

Each barrel that has had several if not many rounds thru it may foul different amounts depending on how smooth the barrel is.

That fouling may be of both powder and copper fouling,(lead if cast bullets are being used) but accuracy usually drops off if that is the case.

Then too,there are barrels that are a tad over sized and they don't shoot very accurately until they have considerable fouling in them.


There is no one answer to fit all.

2 shots to foul a clean barrel.

2 shot groups, max. This presumes you've worked up a load you want to use for hunting. Pay close attention to where the first shot lands

FMJ ahead of TSX for foulding? I've always fouled with TSX/TTSX if that's what I'm going to sight in for. Gilding metal is 95% copper, so it probably doesn't make a diff (only to a loony)

I foul the barrel with the same bullet and powder I will be using on the hunt.
If the rifle has been sighted in previously I will shoot 1 or 2 to verify POA = POI.
If I'm sighting in, I will shoot 1 then adjust until I am very close to my required POI , then shoot 3 and use center of group for final adjustments.

+1 NVhntr. always Full metal jacket bullets not a good idea,

I'm with the previous two posts. It used to be(with the old Barnes bullets) that they "NOT" be shot behind a cup and core bullet,as accuracy would suffer greatly. It was said,in the Barnes X early days,to treat them much the same as shooting cast bullets. memtb

Wow!... I'm not really understanding what fouls the barrel... If it's mostly burning the oil out,, or if FMJ copper is different that TSX/TTSX copper is any different?.... Sorry, I'm dense.

Jacket material on most, but not all, lead cored bullets is not copper, it's gilding metal. Barnes TSX/TTSX are copper.

Different bullets will foul the barrel differently due to varying metal properties. Cup and core bullet jackets are an alloy of copper and tin. Monocore bullets, like the Barnes, are all copper.
Also different powders will leave different residue properties. That's why it is advised to clean the barrel when switching from one powder to another during load development.

Best practice all around would be to foul with what you will be shooting.
How much difference it makes for hunting accuracy I can't really say, that's just how I do it.

I have been hunting with rifles that have not had their barrel cleaned after sighting.

Where the rifles first shot hits from a cold fouled barrel is my current system.

Here is how a new to me custom on a pre-64 did with a cold barrel at 200 yds.

I've found that my Howa will settle in after about 3 or 4 rounds from a clean bore.

As far as barrel heating the rule of thumb is if you can't hold onto the barrel with your bare hand it is too hot.
That may only be 3 shots from a fast round through a featherweight barrel or several more with a standard weight barrel and a slower cartridge. Haven't burned up any yet, YMMV.

A little off topic, but an observation of mine. Also, someone brighter or with more experience,feel free to chime in. From my limited experience, medium to big bore rifles seem to be closer to final group location than do small bore rifles. My wife's rifle (.338 WM), and my .375AI,barely open up the group during fouling shots. Whereas,with our .223,a 5 shot group with fouling rounds would be around 4". memtb

kms, since your gun was sighted in w/a fouled barrel...just make sure you put 2-3 rounds down the barrel to make sure it's fouled before taking it hunting. Here's one place that reloading comes in handy since you will usually have a few crooked rounds after reloading 20 or so. powdr

powdr,

I don't find that fouling shots are needed for a rifle to stay sighted in.

Thanks for all the explanations and great advice!