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Cold bore shot


Rangefinder

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A theory I subscribe to is one aired by Ryan Cleckner (shooting instructor). He thinks that it can be directly attributed to the shooter not being warmed up, rather than the condition of the barrel. He recommends 'warming up' by properly testing and adjusting position, dry firing and calling your shots (gauging your dry fire let offs). This makes a lot of sense to me - it's common to see people go straight from waiting around to straight on the rifle and firing. You wouldn't do this if you were golfing, as an example, would you? No, you would at least take some warm up swings rather than the first swing being the warm up (and a rubbish hit).

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David Tubb claims a major benefit of HBN is first shot accuracy.  I don't think that supports the warm-up theory (but it is still a good idea to warm up for the reasons suggested).

In general I would think oil residue would be a factor - I dry patch my centre fire rifles before shooting as, after cleaning, I finish with an oil patch and a dry patch to take the excess away but it still leaves a fine film of oil (Army SOP).

Many target shooters fire 'fouling shots' before coming onto target so they expect wayward shots from the first of the day.

I shoot .22 bench rest.  I can guarantee my first shot from a stone cold barrel will go high and left  - every time. I had been advised (years ago) that it was a lack of warm-up, but I'm satisfied that's just not the case, it's something about the rifle having stood for a week (not cleaned).  Baffles me what could be the issue because if I leave the rifle after shooting for an hour and then shoot again I don't have the problem.

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It's all to do with the state of the bore- I've seen it a 1000 times fullbore shooting. The first (clean bore) sighter almost invariably goes low and the true elevation is apparent by the third shot though the second is usually near enough.

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Rangefinder

INHO do not think you can eliminate this just know your rifles performance from cold clean bore, cold dirty bore etc. 

Not sure I’d go with the ‘clean shooter’ theory? Might be true with the first rifle used but I see this ‘effect’ in all rifles used one after another - so by the 3rd rifle I’m well ‘warmed up’. 😁

If I was a betting man it is as PbG states - the condition of the clean barrel, is there a bit of lube/cleaning fluid still in there, did you clean it exactly the same way a previous etc. - ‘no’.

This is why I do not clean between different loads during development (as I’ve seen stated in some folks load development process) , can you guarantee to clean the same way and also I do not want a load that only performs about of a freshly clean barrel - but I digress.

Concur on the 22rf peculiarities also, first rounds down my rifle go low and left but after this all go straight (but I still fire a couple of warmers). Could be to do with the ‘wax’ coatings on 22rf setting while left in the cabinet?

Brgds T

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What do you class as a cold bore shot?

Cold bore, cold shooter and clean bore?

Cold bore, fouled bore, cold shooter?

Cold bore, fouled bore, warm shooter?

I’ve found very little difference in my cold bore shots, but a significant difference with a clean bore. 
 

Most people confuse the two, but both often go hand in hand. Ie the shooter will clean their rifle and put in back in the cabinet. So next time they use it, it will have both clean and cold bore. I believe the first clean bore shot will be off due to the cleaning residue, oil being left in the bore. Causing a POI change. Also cleaning the barrel will remove copper fouling which help to fill the imperfections in the lands and grooves. As the bore gets dirty shots will fall to a more consistent to POI. Obviously when fouling reaches a certain level accuracy will drop back off again. 

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1 hour ago, SchmidtP3 said:

Avoid the damage of oil in the bore by cleaning out with a methylated spirit patch followed by a dry patch. Clean, dry bore. 

"Damage of oil"  ?  Please explain.

Cleaning out with meths (denatured ethanol) is not necessary or desirable as ethanol is hygroscopic so any absorbed water may remain in the bore.

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Using Wipeout tactical patch out or similar eliminates the need for any oil in the bore as it conditions and protects the barrel.  You can also use sheath cleaner which is a corrosion inhibitor following cleaning followed by a dry patch or M-Pro 7 followed by a dry patch.  I never oil the barrels these days as applying it, dry patch or no, invariably results in residue seeping into the chamber and although I used to dry patch, any oil residues to some extent affect obturation allowing the cartridge to slam back into the bolt (I noticed this especially with my .308).  Cold bore shots imho have a different POI due to powder or copper residues affecting barrel pressures on subsequent shots.  That and perhaps a warming barrel/chamber.  I can't see any other reason why a cold bore shot would differ (but they do!).  

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1 hour ago, Popsbengo said:

"Damage of oil"  ?  Please explain.

Cleaning out with meths (denatured ethanol) is not necessary or desirable as ethanol is hygroscopic so any absorbed water may remain in the bore.

Oil does not compress well, so oil in the bore is not a great idea with a high speed high pressure round screaming down the barrel. In extreme cases (a greater amount of oil) a bulge or pressure ring could be created. Plus, oil in a barrel creates a nasty signature puff of smoke (at least with the first round). To wit, I do leave my carbon steel barrel with a light coating of Ballistol, but prior to shooting it is given a patch with a meths patch followed by a dry patch or two. I don't run it through with a meths or alcohol patch and then leave it for days, usually as close to shooting as possible.

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37 minutes ago, VarmLR said:

 Cold bore shots imho have a different POI due to powder or copper residues affecting barrel pressures on subsequent shots.  That and perhaps a warming barrel/chamber.  I can't see any other reason why a cold bore shot would differ (but they do!).  

If the warming of the chamber and barrel was a factor, would a string of shots therefore not all result in different POI's? Until you reach a critical temperature and it stabilises?

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So you meant, over oiling may cause damage - yes fully agree for the reasons you stated.  A light patched-out oil residue is neither here nor there in my experience and it's standard practice (when I was a lad) in the forces.

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38 minutes ago, Popsbengo said:

So you meant, over oiling may cause damage - yes fully agree for the reasons you stated.  A light patched-out oil residue is neither here nor there in my experience and it's standard practice (when I was a lad) in the forces.

Sure, and probably ok with a very lightly oiled barrel. I have decided to keep it as uniform and routine as possible, so patch out with alcohol, then dry before shooting. That way I know it is clear, and will minimise as much variation as possible (maybe one instance there was more oil than usual, maybe one time it evaporated more than others, maybe a piece of grit gets stuck in some tacky oil etc etc). 

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For me, when just cleaning the carbon I will run a patch of CorrosionX through the bore when the rifle goes into storage. CorrosionX is an excellent proven rust inhibitor.

Pulling out of storage, I dry patch the bore to remove the CorrosionX, then use a HbN & 99% Isopropyl alcohol soaked patch to swan the bore and leave to evaporate 30mins-1hr before my shoot.

With the above, my first shots are always in the same place as the next as long as I do my part. I do definitely agree with the point about being warmed up ahead of shooting.

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4 hours ago, Popsbengo said:

Obturation not obliteration - that's what double loads do 😳

 

Yes, typo!  Actually it wasn't so much a typo as the settings on my machine changing the damned word that I originally typed!  I have since changed the settings (autofill is infuriating).

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3 hours ago, SchmidtP3 said:

If the warming of the chamber and barrel was a factor, would a string of shots therefore not all result in different POI's? Until you reach a critical temperature and it stabilises?

It can do just that with a slim barrel profile, but tbh I don't consider that a single round would, or could, warm the barrel or chak,ber enough to make such a difference in POI from cold.  One of my rifles (heavy barrel) has the same POI cold or not....it doesn't seem, to matter but my other two shoot left and slightly low first shot.  The left may well be me not getting correct cheek weld but as this tends to be consistent, it's more likely connected with fouling effects on subsequent firings.

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10 hours ago, Rangefinder said:

Hi can anyone advise on what causes a different POI with cold bore shot, can this be eliminated? 
 

thanks Jimmy 

My thoughts are some barrels simply require some fouling to maintain zero, others do not. As for shooter warm up the 2 min prep time we had in the USMC was sufficient to adjust the body and establish the natural point of aim. Having shot NRA junior small bore in my youth I soon learned a clean bore required several sighters to re establish zero. Breath and trigger control are always important and dry fire practice is a very good tool. Calling and plotting shots will teach volumes recording sighting changes and conditions as well. Will heat change the poi?, possibly I think only if the assembly isn't square (thread mating) I haven't seen changes in impact while hot or at least enough to matter. As other have said consistency in cheek weld is important, follow through after the shot and not disturbing your shooting position between shots for any reason. Best wishes for good shooting.

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1 hour ago, KABOOM said:

My thoughts are some barrels simply require some fouling to maintain zero, others do not. As for shooter warm up the 2 min prep time we had in the USMC was sufficient to adjust the body and establish the natural point of aim. Having shot NRA junior small bore in my youth I soon learned a clean bore required several sighters to re establish zero. Breath and trigger control are always important and dry fire practice is a very good tool. Calling and plotting shots will teach volumes recording sighting changes and conditions as well. Will heat change the poi?, possibly I think only if the assembly isn't square (thread mating) I haven't seen changes in impact while hot or at least enough to matter. As other have said consistency in cheek weld is important, follow through after the shot and not disturbing your shooting position between shots for any reason. Best wishes for good shooting.

Agreed.

Someone relatively new to reloading once asked me what the best way to tighten his groups up.  I responded that dry firing to get consistency of trigger break without gripping the stock or pistol grip tightly, cheek weld consistency and breathing control would half his groups.  He didn't believe me.  His 1.3inch 5 shot groups weren't too shabby for the load he had.  Next meeting, after he'd practised dry firing at home, his group sizes more than halved.  Once I have a 5 shot group of about half an inch from load development, it doesn't take much to tighten those into the 0.3's using disciplined technique.  We all fall foul of slip-ups and none of us I'm sure concentrate 100% on technique 100% of the time.

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On 6/20/2020 at 1:05 PM, SchmidtP3 said:

I have decided to keep it as uniform and routine as possible, so patch out with alcohol, then dry before shooting. 

I would think you'd get the most un-uniform barrel conditions, shot to shot, for the first few shots. Unless you clean and allow to cool between each shot.

True the starting conditions should be the same but the first shot will lay some residue down the barrel, the next will remove some and lay some more, and so on. It'll take a few shots before the last bullet fired removes the same amount of residue as it leaves behind giving you the most uniform conditions, shot to shot.It may be predictable but it does alter the POA/POI.

It's what fouling shots are for.

 

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1 hour ago, Mattnall said:

I would think you'd get the most un-uniform barrel conditions, shot to shot, for the first few shots. Unless you clean and allow to cool between each shot.

True the starting conditions should be the same but the first shot will lay some residue down the barrel, the next will remove some and lay some more, and so on. It'll take a few shots before the last bullet fired removes the same amount of residue as it leaves behind giving you the most uniform conditions, shot to shot.It may be predictable but it does alter the POA/POI.

It's what fouling shots are for.

 

I agree with that in a targetry context. I should have clarified that this, for me, is mostly in a hunting context, where the first shot should be the only shot (unless there is a second animal to shoot later). So when I zero at 100m, I would want my cold bore shot to be the same as my first shot in the field.

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39 minutes ago, SchmidtP3 said:

I agree with that in a targetry context. I should have clarified that this, for me, is mostly in a hunting context, where the first shot should be the only shot (unless there is a second animal to shoot later). So when I zero at 100m, I would want my cold bore shot to be the same as my first shot in the field.

The first shot shouldn't be that far off even given fouling etc. and anyway can't you develop a cold-shot zero position by testing? 

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I had a rifle that would would always place the first shot 1 inch low on the target. 

All other shots would be fine. 

If I let the rifle sit for 10 minutes and shot it again it would place the first shot low again. 

I have since had it rebarreled and it's fine now. 

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9 hours ago, Popsbengo said:

The first shot shouldn't be that far off even given fouling etc. and anyway can't you develop a cold-shot zero position by testing? 

Concur, your rifle should do the same thing for each ‘condition’ it is in as you take the 1st shot, you just need to know ‘what’

T

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