Erratic 300 Win Mag

[groundskeeper31]

I recently purchased a Howa Game Pro-2 rifle, model 1500, in .300 Winchester Magnum. I found a load, Nosler Trophy Grade, 180 Accubond, that can shoot nice groups. 100 yards, 0.6". 200 yards, just over an inch. The issue is erratic shot placement. With a clean bore, first 6 shots at 200 yards were 4-5 inches high and about a 4" group. Then, next series of shots, shot one- 2 inches high. Shots two through 5, 5" high but a nice group of four shots at around an inch. Shot 6, touching shot one in the lower position.

I had a similar situation during a previous shooting session. After shooting about 15 rounds, the last four made a 0.6" group at 100 yards and 3" high, which is where I had zeroed.

I have tightened the actions screws to 50 inch pounds and checked the scope bases and rings for proper tightness.

Is my shooting technique the issue, or the rifle. I shoot from the range's wooden bench rests with a sandbag front rest and a rabbit ear rear rest under the stock. The barrel of the rifle is completely free-floated in the Hogue synthetic stock, with pillar bedding.

Ideas?

 

[cotntop]

I had a rifle that would shoot several in the same spot then move several inches with a tight group. I can't remember whether it was scope or rings or both.

 

[ebb]

I would shoot it some more and see if it gets better when you have 150 to 200 rds through it. can you look at the bore and see if its coppered up? When it gets some shoot through it, it may smooth up and get more consistent.

 

[K22]

I had a similar situation during a previous shooting session. After shooting about 15 rounds, the last four made a 0.6" group at 100 yards and 3" high, which is where I had zeroed.

This caught my attention - it could mean that this rifle needs some copper seasoning to shoot to a consistent zero. Some call this establishing "copper equilibrium".

Try experimenting with not cleaning it as frequently and / or just using a carbon remover solvent and see what happens.

I discovered that there is some merit to the assertion since several of my rifles would not shoot consistently if I used an aggressive copper solvent. I backed off and the clean barrel flyers disappeared, and I didn't have to shoot several rounds (season the bore) before I achieve point of aim consistency.

 

[Carl S]

I recently purchased a Howa Game Pro-2 rifle, model 1500, in .300 Winchester Magnum. I found a load, Nosler Trophy Grade, 180 Accubond, that can shoot nice groups. 100 yards, 0.6". 200 yards, just over an inch. The issue is erratic shot placement. With a clean bore, first 6 shots at 200 yards were 4-5 inches high and about a 4" group. Then, next series of shots, shot one- 2 inches high. Shots two through 5, 5" high but a nice group of four shots at around an inch. Shot 6, touching shot one in the lower position.

I had a similar situation during a previous shooting session. After shooting about 15 rounds, the last four made a 0.6" group at 100 yards and 3" high, which is where I had zeroed.

I have tightened the actions screws to 50 inch pounds and checked the scope bases and rings for proper tightness.

Is my shooting technique the issue, or the rifle. I shoot from the range's wooden bench rests with a sandbag front rest and a rabbit ear rear rest under the stock. The barrel of the rifle is completely free-floated in the Hogue synthetic stock, with pillar bedding.

Ideas?

I've seen Howas improve significantly when the hogue stock was replaced

 

[coldboreshot]

If this is happening after you clean out the bore, then it is taking you some rounds to lay down copper traces and re-foul the bore and the shots are settling in. Im not familiar with Hogue stocks but could be possible, but more likely, if you are hitting tight groups, back and forth between different POI's. I would also examine your placement behind the rifle. Inconsistencies will cause POI shifts. Also make sure your scopes parallax is set accordingly. As your eye moves in the eyebox, the reticle will follow. Adjust accordingly so that sure that does not occur. Make sure those wooden benches are secure. Any movement will throw shots.
That's my 2 Lincolns.

 

[groundskeeper31]

I would shoot it some more and see if it gets better when you have 150 to 200 rds through it. can you look at the bore and see if its coppered up? When it gets some shoot through it, it may smooth up and get more consistent.

Currently at 100 rounds. I did a break in with shoot one, clean; shoot one, clean to ten, then three shot, clean. Groups did get better as progressing. In cleaning, first used Hoppes to clean fouling, then copper cleaner. Cleaning time has gotten less as more shots fired through the barrel. Thanks. Will continue practice

I would shoot it some more and see if it gets better when you have 150 to 200 rds through it. can you look at the bore and see if its coppered up? When it gets some shoot through it, it may smooth up and get more consistent.

 

[groundskeeper31]

This caught my attention - it could mean that this rifle needs some copper seasoning to shoot to a consistent zero. Some call this establishing "copper equilibrium".

Try experimenting with not cleaning it as frequently and / or just using a carbon remover solvent and see what happens.

I discovered that there is some merit to the assertion since several of my rifles would not shoot consistently if I used an aggressive copper solvent. I backed off and the clean barrel flyers disappeared, and I didn't have to shoot several rounds (season the bore) before I achieve point of aim consistency.

Interesting. Both of the tight groups achieved with the current ammunition were after shooting a number of rounds and were the last group fired. I will definitely give this a try!

 

[groundskeeper31]

If this is happening after you clean out the bore, then it is taking you some rounds to lay down copper traces and re-foul the bore and the shots are settling in. Im not familiar with Hogue stocks but could be possible, but more likely, if you are hitting tight groups, back and forth between different POI's. I would also examine your placement behind the rifle. Inconsistencies will cause POI shifts. Also make sure your scopes parallax is set accordingly. As your eye moves in the eyebox, the reticle will follow. Adjust accordingly so that sure that does not occur. Make sure those wooden benches are secure. Any movement will throw shots.
That's my 2 Lincolns.

As this rifle has some significant recoil, I am sure the placement of the gun back onto the sand bag and my holding are not consistent. I will plan to place tape on the stock, and bench for consistent placement.

 

[K22]

Interesting. Both of the tight groups achieved with the current ammunition were after shooting a number of rounds and were the last group fired. I will definitely give this a try!

I was "brain washed" into conventional cleaning doctrines and believed it all to the letter. I'm only a varmint hunter but I do need and strive for precision. Typically, for me, if I'm in the 1/2 moa range I'm meeting my standards.

I was happy as a "pig in mud" until about 3 years ago when I had to change to an odorless solvent. For more years than I can remember I used Shooter's Choice and was completely satisfied. When I change to an odorless system, i.e., Bore Tech's system of C4 and Cu+2 the problems began. I experienced clean barrel flyers and my point of impact changed until I was able to put several rounds down the bore then performance returned to "normal". I was completely baffled. I was doing everything that expert cleaning doctrines specified regarding carbon and copper removal.

In addition, both C4 and Cu+2 did a vastly superior job of removing carbon and copper respectively over the solvent I had used in the past so this should have produced better results, right? Well, it didn't. I was puzzled.

After exhausted research I stumbled on some alternative viewpoints that basically promoted the idea of establishing copper equilibrium to achieve consistency in point of impact. I was very skeptical but tried it, nevertheless. The new approach involved just to use a carbon removal solvent that mildly affect copper. So, I used C4 with a bronze brush. I also extended the cleaning cycle from 30 to 60 rounds.

After testing for about 6 months, I discovered that this process yielded the same approximate results as Shooter's Choice, consistency was re-established. As most know, Shooter's Choice does not remove a lot of copper fouling. I was stunned since this approach goes against the leading expert doctrines on cleaning i.e., aggressive copper removal. Nevertheless, it worked for me and I'm back in the "mud with my happy pigs".

I'm not advocating this as a better method and I'm not disparaging top expert shooter's cleaning regimes - I'm only saying that for me, this approached solved my annoying problem of clean barrel flyers and the need to re-season the barrel. In this age of component shortages, the last thing I want, or need is to have to waste components on "re-seasoning" the barrel so its shoots where I want it to. I only care about one thing - performance. I should also add that I rarely shoot out of a hot barrel - even during range practice. I'm focused on cold barrel shots because this is the predominate shooting scenario I encounter in the field.

I can PM you the references if you'd like and you can use your own judgement.

 

[22BRGUY]

I have the exact same rifle in 7mm Rem Mag except mine was finished out by Smith and Wesson with a beautiful deep rich bluing job and gorgeous walnut stock
Those Big Boomers have a whopping recoil for sure. The tendency for me was to really GRIP and hold on to the rifle. The problem could be that the pistol grip hand or the shoulder placement or the cheek weld could all be reasons for inconsistencies. Before the bullet even leaves the barrel, unless all of those grip and hold positions and forces are IDENTICAL, they will cause different shot placement.
Best Wishes