Understanding Cold Barrel Shots

[Marcel Matusik]

I live on a farm in the Western Cape of South Africa. It is very mountainous, with various flat sections, divided by gorges and valleys. We farm apples and pears. We have a variety of wild life, which we thoroughly enjoy having. However, one of our frequent visitors and borders, are baboons. In summer these baboons can cause considerable damage to fruit trees, as well as decimate crops.
Our only significantly effective management is to shoot selected baboons in the visiting troops, to ensure that they understand the "No go Zones" clearly. It is very effective, and since we have a dedicated professional hunter employed to manage the troops during this time, we experience great success.
Obviously, this form of management is frowned upon by various groups, but we can honestly say that their alternate management styles, fail dismally, with some having short term effect, if very little at all. These range from monitors, electric fences, trenches etc.
However, I also often shoot specimens out of season, when they start using my apple trees as a jungle gym, and youngster training grounds. With obvious damage occurring. So, I remind them of the boundaries set in summer.
I shoot a Remington 700 Varmint SF, with a CHOATE "John Plaster" ultimate sniper Stock, and a MTC Taipan 6 x 24 x 56 Scope. (I know! Not a fantastic scope, but all I can afford, while saving for a NFX zero stop). I have a rifle level fitted, and load my own 168gr Sierra Match King in Lapua Brass, with match primers, at almost full power load. I do Ogive measures and recently started Molly Coating the heads. I have an exbal balistic shooting chart, which I have tested and adjusted up to 800 yrds.
I have some trouble with grouping at 100 Yrds, with the first shot (Cold Barrel) being about 1/2" high , consistently. This is without Molly coated heads. I am hoping that the Molly will help reduce the variance in placing of the first shot. I can now adjust for this reasonably well, but it still an "Unknown Variable" which reduces my confidence on a first shot. Especially, when many shots are beyond 300 Yrds, and often up to 700, and on a reasonably small target.
I am trying to find some good reading on this "Cold Barrel" shots, and how to overcome it, if it is at all possible, or is it just my rifle? I have a friend highly experienced and trained in long range shooting, who shoots without having this problem.
I would greatly appreciate any advise, or directions to good reads, on this topic.
Thanks to you all who put valuable information on this site. I have learnt much from all your pains and successes, which I know often come hard by. I appreciate it very much.
Regards from the RSA!

 

[royinidaho]

Very well written post!

Given that your cold bore shot is consistently 0.5 MOA high you should have confidence I it? Or do I not understand something?

I'm assuming that the cold bore shot you mention is not a "clean bore" cold bore shot?

How many shots at one time are usually taken. I wouldn't think those critters would not hang around very long after that first shot?

Rather than upgrade the rifle for one that puts the first shot with the of the group I would simply hold 0.5 MOA low on subsequent shots.

With an MOA reticle this should be straight forward.

There may be other ways to compensate but holding off on subsequent shots seems an easy way to go.

It would also be good to know how long between shots it takes to attain cold bore status.

Hope this helps.

 

[mtnwrunner]

Very well written post!

Given that your cold bore shot is consistently 0.5 MOA high you should have confidence I it? Or do I not understand something?

I'm assuming that the cold bore shot you mention is not a "clean bore" cold bore shot?

How many shots at one time are usually taken. I wouldn't think those critters would not hang around very long after that first shot?

Rather than upgrade the rifle for one that puts the first shot with the of the group I would simply hold 0.5 MOA low on subsequent shots.

With an MOA reticle this should be straight forward.

There may be other ways to compensate but holding off on subsequent shots seems an easy way to go.

It would also be good to know how long between shots it takes to attain cold bore status.

Hope this helps.

Yeah, what he said. As long as you know where the cold bore shot is going, you are in the money. And I don't think you have an issue as long as it stays consistent.

Randy

 

[WyoElk2Hunt]

I learned from a shooting class that for hunting you need to set up a cold bore zero. Most of the time you only get one shot or maybe two before the game is dead or gone. Shooting a fouled barrel you only take two shots and make that your cold bore zero. You can use a different rifle if you want to shoot more but only two shots from each rifle and set your cold bore zero. Check the rifle the next morning and when you get your cold bore zero you are ready to go hunting. If you are target shooting then this will not apply.

 

[Marcel Matusik]

Hi Guys, wow what a great response from you all. Thanks!
Yes, the 1/2 inch is reasonably consistent, on warm days. On really cold mornings, it gets closure to the bull, below 10 deg Centigrade, in the centre.
I forgot to mention that the rifle has only shot about 150 rounds, and that every cold shot, was with a perfectly clean barrel. In speaking to a very experienced shooter this afternoon, I may have come slightly closer to understanding the problem.
He recons that firstly, i could have bore cleaning residue, as I only put a single jag through before shooting, after the barrel was cleaned. this could be a contributor, as not all the solvent was necessarily cleared. Thus a faster higher shot. Secondly, and I think more pertinently, the barrel may not be completely broken in yet. Seeing, that I am cleaning the bore after every shooting session, properly, I may be cleaning most of the copper out of the tiny machining pits in the barrel.
He suggest I try and do a lessor clean, and definitely not polish out the barrel, and then do some groupings.
This may allow the machining holes to stay filed, and slow the first shot as per the 2nd and 3rd etc.
As a test I'm going to shoot 3 shots, and then simply, nylon brush the bore 3 times, and put a dry jag through. Then do a 5 shot group the next day, with a cold shot included, and see how they group.
To answer the questions you posted. I shoot a 5 round grouping with a couple of minutes between shots. No fast firing.
I'll post the results with the trials above.
Thanks again !!
now off to gun)

 

[Marcel Matusik]

Oh, Roy, I hardly ever shoot more than two at a time. Correctly stated, the troop usually scatter for the hills, after the first shot. However, we do get the odd "new" troop, that are gun dumb! They usually do not really know what to do, and run in all directions, or just sit and look at each other, well that is until the next two shoots follow, and then they figure out a hiding place may be on the cards, and fast! Most I've shot at once is three. Them critters are slippery at full pace, and they scale rock faces like lizards!

 

[MontanaRifleman]

Marcel, Welcome to LRH?

Most rifles will have a POI shift from clean to fouled bores. To minimize that, I try not to clean until needed... i.e. bore gets dirty or accuracy starts falling off. After cleaning, if I intend to use the rifle in the field for hunting or what ever, I will foul the bore and check zero. At that point there should be no shift in cold bore shots. If there is, there may be a problem with action bedding or scope mounts, etc.

In the last year or so, I have come to the same way of thinking as your friend who recommends not cleaning the bore completely free of copper and carbon... unless I plan to put it up for a long period of time.

Cheers

 

[royinidaho]

Marcel.

You're getting some great info.

I'm one of the lucky one, 3 of my main rifles put the first clean bore first shot in the group.

Nevertheless, I have been told by the fella that made 2 of them to never, never, take an unfouled barrel hunting. I have come to trust Kirby Allen totally and he said this. Also he built two of my shooters.

Also I clean after about 20 rounds. Why? Cause Kirby said.

You are quite a shooter. There aren't many shooters that know their rifle as well as you know yours.

I'd hate to be bro baboon in your neck of the woods.

 

[MontanaRifleman]

Marcel, Welcome to LRH?

Typo...

Should be...

Marcel, Welcome to LRH!

 

[RMulhern]

Temp changes have MUCH TO DO with a change in zero....considering cold bore shots.

 

[Marcel Matusik]

Thanks, Mark.
The more I have discussions and read up, the more I am in agreement with you and my friend.
I'm going to do some test this afternoon, once staff are off the farm. I excited to see what the outcome is going to be!
I am extremely confident in the scope and mounts. I have a NF piccatini rail, and 30mm NF rings, well secured. The scope has past my own box test four times, at various intervals. The stock is really good, and I have had no sighting problems, or required any adjustments, after removing and refitting the stock.
I think the biggest problematic variable with my rifle, is me the operator!!
I'll post results soon.

 

[Marcel Matusik]

Yip, Temp is definitely a factor, and one that is not that easy to calculate. Practice, practice, practice, and then ask, and then practice.....
What a great sport this is...... Thanks!

 

[Bullet bumper]

After reading all the posts I have a few observations.
First off when trying to fix an accuracy problem do not introduce more potential variables.
So forget molly coating until the cold shot issue is resolved or improved.
If temperature is a factor then I would start with checking the stocks bedding and tightness of action screws.
It is possible that the bedding needs some modifications.
Also I don't think the answer is to clean less so much. I think after you have cleaned , the bore needs a fouling shot or two to condition it .
So before you shoot at a target on a clean barrel . Patch out any oil from the barrel AND CHAMBER and if possible fire a shot or two into the ground inside the shed or barn where the noise will not travel and then go shooting baboons . If thats not practical due to time of day then do it the day before after you have cleaned and lightly oil the barrel. Clean out the oil just before setting off to hunt .
If you hold a gun hard against your shoulder it will print higher than if you shy away from the recoil .
So make sure your shooting style is the same each time.
From a clean barrel Moly coating takes many more shots to settle down the group than uncoated bullets so that is only going to complicate it more . Later it can be a big help but not know . I have been doing my own Moly coating for many years .
It could just be something you are doing at the first shot and then you settle into a better pattern . A movie of you shooting would be a great analysis tool as it will pick up little things that we do wrong that we don't think we are doing . I once helped a guy from Germany and after about 6 months he sent me a video of him shooting at his range . BINGO ! I spotted 7 basic mistakes he was making and it sorted his style right out , groups dramatically shrunk after that . Did similar for a guy in El Paso Texas from still photos .
Just cover your face with a hat and sunglasses for privacy .

 

[Marcel Matusik]

Hi all. Thanks for the very helpful info. I agree that I should sort the problem out before introducing new variables like molly coating.
I have been back on the range!!! gun)
I have great news! The fouled barrel solved the problem. I shot two rounds through the rifle on Friday.
On Saturday morning, I shot 5 rounds out approximately 1 minute apart. the first two shots were within 1/2" group, making a figure 8 shape, as they overlapped. Unfortunately, I pulled the third shot to the left by 3/4". The forth and fifth were in the first 1/2" group. I waited an hour and just did a pull through with my snake. (No oils/abrasives at all - new snake) , and then shot 5 rounds again. Again, first three shots spot on around the bull. All overlapped. My forth I again pulled left, but 5th spot o again.! I then went hunting some KOLGAANSE (Large Geese) with a a neighbor. We took shots ranging between 100 to 900 yards. My friend shoots a 300 Win Mag. Savage. I had minimal success on the 812 yard shots, but they were only off slightly (3 to 4 Inches left or right) due to my poor wind estimates. We never had a wind meter, and it was quite breezy. At 350 yards, spot on. The various shots were taken long breaks, whilst driving around looking for the geese. So always a cold shot, and I was very happy with the height placement, according to my chart. Height was mostly 100%, but just my windage adjustments that were not the best.
So, it seems my problem was a clean perhaps oily barrel. Now I am very confident that the problem is solved.

Thanks again to all the contributed.