Another Issue With Accuracy


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ArtP
August 8, 2010, 03:16 AM
Perhaps this belongs in Rifle Country but I think reloaders are more knowledgable.

I have been reloading for about a year, but it's been a pretty intense year with a lot of work/study/experimentation. I have other rifles I've developed loads for that perform at a half MOA. For the sake of simplicity, can we eliminate the shooter or reloading methods as the culprit?

I have a Sako AV Hunter in .270 Win made in the late eighties. I bought this rifle used. The previous owner lightened the trigger and did a really lousy bedding job.

I made a variety of reloads using several different bullets (130's and 150's), several different powders, seating depths, different charges etc. I also tried two brand/weights of name brand factory ammo. In all I fired about 200 rounds with accuracy floating between 2 and 4 MOA. There seemed to be no rhyme or reason to the accuracy; i.e., I did not see it improve as I approached loads it liked - it didn't like anything and no pattern ever developed indicating I was even heading in the right direction.

I had a gun smith "fix" the bedding by removing all bedding one inch North of the recoil lug - that was his recomendation. I polished the bore with J-B Bore Bright and to this untrained eye the bore looks beautiful with strong rifling from throat to muzzle.

I took it out again today with 8, three round groups, 24 rounds in all, at 4 different charges spaced .8 grains apart, ending at book max load. Same flippin' results - 2 to 4 MOA. I had a friend shoot it too, he shot the worst group of the day.

I did notice something curious but need to go back to the range to prove it. It *seemed* like the fist shot from a reletively cool barrel landed closest to point of aim, with the second and third shots flying off badly. I would like to go back and shoot at three targets with identical load; target one containing all the first shots, target two containing all the second shots and target 3 containing all the third shots. Target one would contain all "cool" shots and two and three would contain hotter shots. Good idea / bad idea?

If the results are what I suspect, target one performing, by far, the best, is it time to chuck this Sako wood stock and get something better, thinking the stock is letting the action move around and/or the bedding is causing the problem? I don't know where to go from here with this rifle besides selling it. Any advice, direction?

The stock certainly is a beauty and I'd hate to get rid of it, but...

Thanks for your concideration.

If it matters I've used bullets from Sierra, Hornady and Remington and IMR 4350, 4831, RL19, H4350. I've used Wolf and Remington primers and Winchester and Federal brass. The last batch of handloads I also deburred the flash holes as well.

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PT1911
August 8, 2010, 03:29 AM
how long were you waiting between shots? In a taper-barrel gun, if you are testing accuracy, you have to be patient and allow the barrel to cool between shots..

I recommend removing the bolt between shots and standing the rifle on end to aid in cooling.


as to shooting different shots in different groups, I wouldnt... rather I would shoot with different set cooling times between shots...

first group, say 5 minutes between shots
second group, 2 minutes between shots
third group 1 minute between shots
fourth group, 30 seconds between shots.

just my advice... take it or leave it.

ArtP
August 8, 2010, 03:33 AM
I'm letting the barrel cool 10 to 15 minutes between groups, on a hot day. The three shots in the group are being taken within about 2 minutes.

I practice the same method out of my .243 where I get .4 to .75 groups.

PT1911
August 8, 2010, 03:39 AM
In an attempt to eliminate as many factors as possible, I would take longer between SHOTS. Give the barrel time to cool before sending another bullet down range.

Each rifle is different as is each load... save finding out the affect of heat on your barrel for another time.

I have a Weatherby VGX delux in 270 win that will shoot under an inch easily cold and clean... If, however, the barrel is allowed to get hot and the bore dirty the spread will open to 4 to 6 inches.

JimKirk
August 8, 2010, 08:21 AM
I use a 12V air mattress pump to cool my barrels when shooting long groups, if needed. Just connect it to the truck or ATV battery and either stick it in the open bolt chamber or hold it with my hand on the muzzle end. It only takes a short time to cool this way.

Jimmy K

Remo-99
August 8, 2010, 09:02 AM
I did notice something curious but need to go back to the range to prove it. It *seemed* like the fist shot from a reletively cool barrel landed closest to point of aim, with the second and third shots flying off badly.

This could still be an issue with the bedding, something that wasn't rectified with the rebedding.

Personally I like a nice even bedding on the action and nothing touching the barrel...et all.

JDGray
August 8, 2010, 09:49 AM
Did the smith you took it to check the crown for damage? Did he bore scope it for you? Maybe the barrel is shot out, unlikley but who knows. The previous owner botched the bedding job, maybe he botched the crown and throat too. I like working up loads in .5gr incriments, .8 is a pretty big gap, you may be missing your accuracy node, but I doubt that too. Are you using a scope? Maybe thats the problem:scrutiny:

Good luck with your issue:)

SlamFire1
August 8, 2010, 10:35 AM
Let see, the last guy bedded the action. SAKO's come with the factory with darn good wood to metal bedding. There would be no reason to bed a SAKO unless the rifle was inaccurate from the start.

My guess, you need a new barrel. For whatever reason, your barrel has always been a stinker.

375shooter
August 8, 2010, 11:17 AM
Let see, the last guy bedded the action. SAKO's come with the factory with darn good wood to metal bedding. There would be no reason to bed a SAKO unless the rifle was inaccurate from the start.

My guess, you need a new barrel. For whatever reason, your barrel has always been a stinker.
I agree, it probably is the barrel. :mad:I doubt the stock is at fault. I also have a Sako AV, that I bought new, made in the '90s. It consistently shot between 4 and 7 inch groups at 100 yards. No amount of fiddling with bedding or bullet/powder combination's had any positive effect whatsoever. I also tried different high quality scopes to rule that out. Oh, and also, the barrel was kept clean, so copper fouling build-up was not the culprit.

I took the rifle to the gunsmith and had him install a Shilen sporter weight barrel. Now the rifle consistently shoots less than 1.5 MOA with most loads. That was over 20 years ago. I've been very satisfied with the gun ever since.:D

Actually, a friend also bought the same rifle new, at the same time as me. His rifle also shot lousy. He never did rebarrel his. Instead he just took the loss and never really used it for anything. Shooting such poor groups, makes a rifle pretty much useless.:barf:

ArtP
August 8, 2010, 11:49 AM
. I like working up loads in .5gr incriments, .8 is a pretty big gap, you may be missing your accuracy node, but I doubt that too. Are you using a scope? Maybe thats the problem:scrutiny:

Good luck with your issue:)

I usually go 1 grain increments on a caliber that calls for about 50 grains of powder - just to get close. Once I get it in the ballpark, I further test at .2 grain increments. This rifle showed a very slight improvement at book max load. The max load happen to shoot the days best and worst group (worst group by my friend), so I don't know what to make of it either.

It has a Leupold VariX-III 3.5-10x40. I really doubt it's the scope but admit I have not tried another scope.

As for a reason the previous owner was dumping the rifle, I was told the guy picked up a "domestic" and was selling all his guns, as the shop owner pointed to several of them on the rack.

Someone here mentioned they rebarreled to achieve 1.5 MOA groups. I'd be okay with a factory barrel shooting those groups, but to me, that is unacceptable out of a custom barrel. Are my expectations out of line to expect, at worst 1-1.5 MOA out of factory and .5-.75 MOA out of something custom?

As it stands now, I'm getting about the same accuracy as I get with my 10/22 using bulk 22LR ammo shot at 100 yards.

NCsmitty
August 8, 2010, 12:34 PM
It's certainly aggravating when a so-called quality rifle won't live up to its name and shoot good groups.
You owe it to check the scope and mounts/bases, to be able to verify that they are not the problem.

I personally float all my barrels to eliminate varying harmonics that can disturb a lighter barrel, especially as it heats up.

If all the other "tricks of the trade" fail to correct the problem, you can use the option to rebarrel with a quality match type replacement. You have a high quality action to work with.




NCsmitty

rcmodel
August 8, 2010, 01:23 PM
The first thing I would suggest you do is get a bottle of copper solvent and clean the crap out of the barrel.

With a checkered history like that rifle has, I doubt anyone has ever cleaned the copper fouling out of it, ever.

I ran into pretty much the same thing on my dentists Browning BAR 7mm Mag.

He was getting 3"-4" groups and was ready to send the rifle in for a new barrel.

Turns out, it was so badly copper fouled you could barely see the rifling.
I actually got long strips of jacket metal out of it at first.

After two days of copper solvent treatments and then a good lapping with JB Bore Paste it was shooting sub MOA with three different factory loads.

rc

ArtP
August 8, 2010, 02:01 PM
The first thing I would suggest you do is get a bottle of copper solvent and clean the crap out of the barrel.



rc

I thought the same. Which is why I scrubed the snot out of it with JB, as I mentioned in the openeing post. Isn't a regular cleaning, followed by 60 full strokes with JB (two patches, two applications of JB), then another light cleaning to remove any JB, good enough? After I was done, it looked mirror perfect.

If anything, I'm more disappointed the barrel cleaning failed than the "once over" and improved bedding by the gun smith.

PT1911
August 8, 2010, 02:05 PM
copper solvent is the only effective way to remove copper fouling.

rcmodel
August 8, 2010, 02:05 PM
Oh! :o
I missed that part when I read your first post.

Have you tried shimming the forend to put more pressure on the barrel?

That should be a good way to test out the "poor bedding" theory.

Shimming the forend will either make it better, or worse.

rc

ArtP
August 8, 2010, 02:09 PM
It's certainly aggravating when a so-called quality rifle won't live up to its name and shoot good groups.



NCsmitty

I have to say that is exactly what is causing all the frustration. If I were using a short-range caliber or mediocre rifle I would expect this sort of accuracy and be happy about it. I consider .270 to be long range and Sako to be in the upper two-thirds of brands noted for accuracy. I suppose I feel my expectations are in-line.

I have a Marlin 44 mag carbine and if it shot 4 MOA, I'd call that par for the course and sleep very well.

918v
August 8, 2010, 02:11 PM
Did you try a different scope? Are the rings on tight? Have you tried placing a rubber wedge between the forend tip and the bottom of the barrel? That sometimes works with skinny barrels.

JDGray
August 8, 2010, 07:43 PM
Someone here mentioned they rebarreled to achieve 1.5 MOA groups. I'd be okay with a factory barrel shooting those groups, but to me, that is unacceptable out of a custom barrel. Are my expectations out of line to expect, at worst 1-1.5 MOA out of factory and .5-.75 MOA out of something custom?



I've never had problems getting .75 moa out of a factory barrel, the customs will do lots better than .5-.75 moa if your up to it. So no, your not expecting to much:)

MEHavey
August 8, 2010, 11:15 PM
I see "hints," but no definite statement:

Is the barrel floated or not?

Can you wrap a dollar bill half-way around the barrel and slide it between barrel
and stock channel all the way from muzzle to just forward of the chamber?

ArtP
August 8, 2010, 11:56 PM
I see "hints," but no definite statement:

Is the barrel floated or not?

Can you wrap a dollar bill half-way around the barrel and slide it between barrel
and stock channel all the way from muzzle to just forward of the chamber?

Previous to the gunsmith visit the forend was bedded, tight with the barrel, four-five inches past the recoil lug. I took the gunsmiths advice and left the bedding in and let him remove all the bedding forward of the recoil lug except for one inch.

What I have left is bedding material, firmly up against the barrel, one inch past the recoil lug. I can slip a dollar bill all the way down to where the bedding ends, one inch past the recoil lug.

jim243
August 9, 2010, 12:18 AM
If the previous owner messed up the bedding, he might have messed up the recoil lug area as well. You didn't mention if you checked the crown?

What types of groups are you getting? Vertical stringing, horizontal hits (right or left of center POA) or all over the target.

As to trigger, how many lbs pull, short or long takeup, does it break clean and how do you feel it performs?

Jim

ArtP
August 9, 2010, 12:50 AM
The gun smith said the bedding around the recoil lug was okay. I don't fully trust this smith as he didn't have a bore scope (***?). I checked the crown myself with magnifying glass and Q-tip (catch snags). I didn't specifical;ly ask the smith, maybe a mistake to assume he checked the crown too, I know he checked the barrel.

The groupings are more vertical than horizontal.

The trigger is the one bright spot of this rifle, besides its looks. It's had work done to it and breaks clean at one pound.

jim243
August 9, 2010, 01:47 AM
Well we are back to the stock and the bedding, from what you have said, I don't understand what the barrel is pushing against when it heats up. Are you absolutly sure the barrel is not rubbing the fore end when it fires?

Hopefully some others can give a better idea what to do.

Good luck
Jim

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