cold wet bore/high first round?

[bamaranger]

More than any other rifle I own, a Savage Hog .308 is landing its first round about 2.5" high from a cold/wet bore. Following rounds fall correctly at my established zero. I've read about this tendency, but this particular rifle manifests the problem more dramatically than any other I own. The end result is +5" high at 100 as opposed to 2.5". Pretty significant. I'm not talking about a sopping, oil soaked bore either, just one that has been protectively lubed with a patch or boresnake by couple of passes.

The rifle is otherwise fine, with 3 rds sub MOA and 5 consistently at MOA.

I am not keen on the idea of having a field/hunting rifle, which sees use in rain and wet conditions over a period of 2-1/2 months, needing a bore that is unlubed/unprotected, to shoot its best. What to do? Is there a lube/protectant that may reduce this tendency? Presently, I use a boresnake with CLP for day to day cleanup/lube. If the rifle is shot a bit, I use rod & brushes, and Hoppes Copper. Usually followed by the 'snake with CLP.

 

[bacardisteve]

Some rifles shoot best with a dirty bore. You don't need to clean your bore after every trip in fact that can cause more harm than good. I don't clean my bores until accuracy starts to drop off. After cleaning some take several shots to foul the bore before they settle back into shooting their best groups.

 

[Mobuck]

If this is consistent and you KNOW it's there, simply compensate. The effect is aggravating but not irreconcilable.
As mentioned, it's not necessary to clean after every use unless you get the rifle wet. I compromise by pulling a well used BoreSnake with only residual lube through the bore a couple of times. Very little lube is deposited and the cleaning action is limited by the fact that the device is pretty well worn out. Particles of powder and other debris are removed and a very slight amount of lube remains which doesn't seem to affect first shot zero as much as a thorough cleaning.

 

[kraigwy]

That's why God gave us fouling shots.

 

[AllenJ]

While it is not uncommon for an oiled bore to shoot a different point of impact versus a dry bore, 2.5" is the biggest deviation I've ever heard about. If you insists on keeping the bore protected between every shooting your only choices to help the issue are to dry the bore prior to shooting or as stated above, compensate. Currently I have a Savage Precision Carbine that's first shot of the day is 1.25" high, regardless of clean or dirty bore. I have learned to compensate for it.

 

[Bart B.]

I've chronographed very lightly oiled and squeaky clean center fire barrels. Both shot the first 2 or 3 bullets out about 10 to 20 fps slower than the next few dozen averaged. There's more resistance with a fouled barrel so pressure if higher as is velocity. Ballistically, there's 1/20th inch drop difference at 100 yards with a 25 fps difference in muzzle velocity for a 308.

A 1 MOA shift in bullet impact 100 yards downrange is not caused by a couple dozen fps change in velocity. Something about the rifle's parts fit or shooter's position isn't repeatable until they've settled down. One common thing I've observed is people put the rifle butt lower in their shoulder for the first 1 or 2 shots, then move it higher up. That'll let the muzzle axis rise more (the recoil axis is often 2 inches above the heel of the stock) while the bullet goes down the barrel which puts the muzzle axis up at a greater angle as the butt slips down against the shoulder.

 

[Erno86]

If you can't make it to the range so you can fire a few shots too dirty the bore before a hunt, swab out the lubed bore with cloth patches of soaked brake cleaner degreaser. I'm not saying that the first shot will be on zero {though it might,] but the degreaser will help --- though you'd probably be in a better state of self-confidence if you just took it to the range for a pre-hunt dirty bore session.

 

[Bart B.]

Good idea, Erno. That's why I clean the corrosion preventing oil out of the bore with naptha on cleaning patches. So prepped, bullets shoot to virtually the same point of aim for 30 to 40 shots fired in half as many minutes.

 

[hartcreek]

How about you do what GIs have done for deckades...tie a condom over your barrel end when in the field? Clean your rifle when it needs it and shoot it. I put a few hundred rounds therough my 721 is it dirty no it has been sitting so before I shoot it again I will run a bore snake through it to get the dustbunnines and then get to shooting as I need to finish sighting it in at 200meters.

 

[rickyrick]

I stopped cleaning bores very often... Sometimes once a year on certain rifles.. I do push a soppin wet oil patch down the bore during storage.

Pull a bore snake through before going out to shoot...

Rifles used for hunting are zeroed for a cold shot

 

[Salmoneye]

That's why God gave us fouling shots.

And finger cots...

 

[cw308]

Sorry Guy's, I'm one of those that cleans after every outing. After cleaning I run a patch with Kroil oil down the barrel, Then run a dry patch down the barrel before I shoot. From the 1st to the 20th round all in the same group. If not, it's me and not the rifle.

 

[AK103K]

I always zero for the cold shot. By cold, I mean the gun is cold, and not warmed up.

This is how my old Remington 700V used to shoot at 100 yards, prone off a bipod or ruck, pretty much every time, from cold. You can see where the first shot went, and then how things usually changed with subsequent shots. Cleaning didnt seem to be the issue, as if the gun was left to sit, and then shot again, you got the same result.

Shot the same way, this is how my new(er) Remington 700 SPS Tactical normally shoots from cold, and continues to shoot when warm, to a point. It opens up some when "hot"......

Same load in both guns, and both were/are cleaned after every outing. No fouling shots taken.

 

[Snyper]

I've chronographed very lightly oiled and squeaky clean center fire barrels. Both shot the first 2 or 3 bullets out about 10 to 20 fps slower than the next few dozed averaged.

Does that apply to rimfires also"?

 

[Bart B.]

Rimfire barrels are the opposite. They put the first shot 1 to 2 moa high then subsequent ones lower to zero. Their slick bore has little resistance to the bullet so it gets pushed out faster.

First heard about this from a multiple time National and International smallbore champion decades ago; Lones Wigger. Then I started shooting rimfire matches with him. I correct my first shot from a clean barrel to 1.5 moa high; the next two or three move down to call. Then I shoot record shots.

First shot from a center fire barrel at ranges over 600 yards is corrected to about 1/3 moa low; goes up to call in the next one or two shots.

 

[30Cal]

I would compensate the first shot (if it's far enough that 1-2 minutes would matter).

My match rifle shoots about a 1-1.5 minutes high on the first shot. At 200yds, that's still in the 10-ring.

 

[Bart B.]

Not on high power 600-yd. MR52 reduced targets at 200 yards.

At short range, the difference is much less. A 20 fps difference with a .308 is only .04"; .20" for 100 fps. About 15% more at 200.

 

[cw308]

Guy's I guess I'm just lucky. I bought a CZ 452 Varmint 22LR 4 years ago to give me some trigger time in the cold months shooting indoors. The CZ 22 is close to my Rem 700 308 21" barrel 308 that I shoot outdoors in the warmer months. The 22 likes Wolf Match target Exter 40 gr. lead. I clean with #9 Hoppe's, cut a piece of lead away patch followed by #9 then dry patch & last Kroil oil patch after every range trip average 50 rounds. Never had a problem with flyers from a clean bore.Shooting with a fouled barrel would be a tuff sale for me. Sorry but I think there is something else going on if it can't shoot from a clean barrel.

 

[30Cal]

Sorry but I think there is something else going on if it can't shoot from a clean barrel.

Nothing's wrong with it. There is a reason why people who get paid to shoot plot every shot and diligently keep track of what's known as "the cold bore zero."

 

[Boncrayon]

Reload this Page cold wet bore/high first round?

If you are in a humid environment, moisture will condensate on the interior of the bore particularly in cold weather. I suggest, if this is the case, to lubricate with a lubricant/cleaner that emulsifies with the moisture when running a patch or snake through the bore. I use Ballistol because it emulsifies water and lubricates. It also cleans lead, and other soft metals at the same time (don't get it on your gold inlays as it is aggressive on all soft metals I heard!).

I shoot only after running the snake through the bore. It removes trash in the grooves and dust on the lands. After an outdoor hunt, use the same with the snake and again lube that will be cleaned out before the next hunt/range.