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Forum Index > Precision long range hunting and shooting > Cold clean barrel point of impact

Cold clean barrel point of impact

15 Jan 2013
@ 04:35 am (GMT)

Dave Clouston

Hi Nathan
Just wanted to pick you brains on cold barrel point of impact, I understand the benifits of a fouling shot or two but it isn't always pratical to have fired a fouler in a one shot hunting situation.

EG many time when I go hunting it will be with a clean barrel and a fouling shot will either disturb area or the landowner.

From your experience how repeatable is the first shot from a cold clean barrel?

I remember a gun writer (might have been G Henry from Rod & Rifle) from back too many years ago when i first started hunting advocating sighting in for first cold barrel shot and it served me well with a .270 that would put first two shots reliabley into 3/4 inch then further shots would open group to just over inch.

Is it an option to record where first shot clean shot hits and use that as you zero and then also record P.O.I post fouling shot and adjust scope the few clicks if further shots required hunting or shooting sessions continues?

many thanks

Replies

15 Jan 2013
@ 05:30 pm (GMT)

Nathan Foster

Re: Cold clean barrel point of impact
Hi Dave, I really enjoyed reading Graeme Henry's work. He was a real nuts and bolts, no bullshit, down to earth, hard working person.

What I have found over the years, is that some rifles shoot dramatically different with the first shot, up to 1.5" away from other shots. So sometimes it is not feasible to sight in for the fouler if follow up shots are to be expected at longer ranges. To this end, it is important to ascertain how far away the fouling shot is from the main group and to what range the rifle is going to be used out to.

Henry had to cater to readers from various disciplines as I have to also. I think in this regard, Henry was talking about the needs of the deer stalker who only gets to go away every so often, intends to take just one shot, then spends the rest of the weekend trying to haul out meat. This method of sighting in may or may not suit cullers depending on how far they shoot, it does not suit the long range hunter at all.

Henry never put forwards an idea that he could not himself utilize so lets look at his kit. He had a .270 Finnbear most of the time, it went through a few barrels. Pet load was always the 150gr Hotcor at 2950fps. Rifle was sighted in 3" high at 100 yards and 'around' 3" low at 300 yards. Zero around 270 yards. All figures that were easy to meemorize. Henry shot out to a range of around 400 yards. he liked accuracte rifles but suggested that 40mm was practical for hunting puropses. Henry usually worked towards a load that would shoot .75" (so did I before the long range game and all of its challenges and stresses came along).

So we take the figure of 40mm at 100 yards (1.575"), then we take Henry's average group which was .75" or 19mm, then add a fouler and now we can see the full picture of where Graeme Henry was at, what he was thinking. 40mm x 4 = 160mm or 6.3" at 400 yards. Henry's main game animal was Red deer, followed by Sika and Fallow.

There is one caveat here though. You had to be able to do this over a back pack (many folk now use a bipod). Henry's 40mm group was relative to field positions, after finishing bench work.

I am in absolute agreement that a 6" group indicates the maximum range a rifle can be used to on most medium game (apart from the larger species). I have seen human error ruin things if 7-8" is considered an acceptable group size. So in other words, if a .308 LR rifle shoots 1" at 100 yards (or 1MOA) over a back pack, it should be considered a 600 yard rifle. After 650 yards, you begin to see brisket shots, dorsal vertebrae shots and gut shots.

Sorry for the long winded explanation but I think it is best to really get into why and how Henry came to his conclusions.

I had an email this morning which I will also cut and paste below:

Hi Nathan, congrats on your new book. If u have a moment if like to ask you about a problem I have. My first shot on a clean bore seems to be 1.5" high and half " left, then the rifle groups very consistently at my preferred zero. Can this phenomenon be minimized by changing my cleaning regime or am I doomed to having to "foul" the barrel before hunts?

Currently I swab out/soak the barrel with bore tech eliminator until no copper residue, then dry swab , then a couple of passes with hoppes before storing with a light residue of hoppes. I always run 2-3 dry patches befor heading to range . It is a stainless barrel.
Any suggestions?

Hi ...., its a tough call, some of my rifles do the same and I use exactly the same cleaning methods as you. You can if you want to, refrain from using copper remover between hunts until the rifle has had a total of say 30 shots through it, then go through the full cleaning process. In this instance, it is best to use CRC/WD40 or CRC long life (best) for cleaning and storage. Dry pull prior to hunting otherwise the zero will be the same as a fouling shot.

It really depends on how you are using the rifle. If you are shooting 30 shots in a day, its best to defoul and go on as you have been doing. But if you are only firing 5 shots or so, you may be able to get away with no defouling for weeks or for some folk- months.

The final method is to use moly coated bullets (or some form of coating- there are new ones now). This will minimize the copper fouling so that the fouler is the same as the rest of the shots. if you use moly, keep the bore well lubed with a rust preventative between hunts and lube bore if on an overnighter once you are in camp- your Hoppes system is probably best. If you do not use a lube, the bore (even stainless) will or may rust due to the hydroscopic nature of moly combined with the corrosive action of sulphur. I find that with hydroscopic products, even CRC is enough to give the product something to absorb. test rifle to see how it shoots first shot, when shooting over CRC/CRC long life. This will tell you whether the bore needs to be dry pulled before shooting, or whether it can handle a light lube (do not worry about hydraulic forces with very light coatings).

On blued guns, use Hoppes, then store with motor oil (I use chain bar oil). Obviously, a dry patch is necessary before shooting to prevent hydraulicing the bore.




10 Nov 2018
@ 12:23 pm (GMT)

bryan long

Re: Cold clean barrel point of impact
If CRC longlife not good enough to store a blued barrel with and shoot over?

Just got 3 cans today
11 Nov 2018
@ 08:57 am (GMT)

Nathan Foster

Re: Cold clean barrel point of impact
Hi Bryan, in Ireland, you may need to go one step heavier in viscosity for long term storage. It depends on how much shooting you are doing. If you think that you might not be using the rifle for the next month or so, utilize a heavier lanolin type base.

If you had been storing with a heavier lanolin (e.g fluid film) and intend to go hunting for a DAY OR EVENING: Dry pull and hunt on the mostly dry bore (there should be some fine residue left behind).

If you had been storing with a heavier lanolin (e.g fluid film) and intend to go hunting for a SEVERAL DAYS BACKPACKING: Dry pull the bore thoroughly, then re-apply a shoot over lube (or shoot off fouler / range check, then apply lube).

If you have been using a heavy wax / cosmoline type for storage: Use a solvent to break down the wax, dry, then choose one of the above methods.

If you have a suppressor and it is producing heavy carbon that needs to be removed, but you need copper in the bore in order to avoid a wide flier cold shot: Use KG1 (some people use Big Green) to remove excess carbon. Note that this does remove some copper so get it in, scrub it, then get it out. Use the muzzle as a visual guide but also pay close attention to the neck area of your chamber. After cleaning, neutralize with brake cleaner or meths and then apply your storage lube.

One thing to add to the above posts:

Given time, if you can get the bore into a state where there is no dramatic difference between the first and third shots (no gloopy copper) then the cold basrrel shot will be close to the final groups (inside an MOA). If the fouling is very low and you are not having to strip copper between shoots and only having to polish every 150 rounds or so, the cold barrel plus total group size may be well inside .4" (the shots taken on the 7mm Practical page / 180gr ELD-M were all cold barrel shots).

But on the other hand, if the rifle is producing a different POI due to barrel temper vs harmonics, well there is not a lot we can do about this. Lever actions versus forend assemblies are another good example of this in the extreme. In a lever, it is important to keep both the cold barrel POI and total group POI in mind, especially if the trajectory is steep. If a lever strings 3 MOA vertically then it will have a limited range of about 200 yards. If the trajectory is steep, then it will be too much math for most folk, taking both trajectory and stringing into account. Its no good relying on the first shot, shit happens. So in this situation, it is better to try and stalk closer to up your chances of both a good first shot and good follow up shots if needed.
 

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