I have a 300 win. mag that was built on a Sako AV action, Shilen magnum sporter match grade barrel, and a Brown Precision stock. I have about 500 rounds through it. It should shoot pretty decent but no matter what I vary in the load, I can't get it to shoot any better than 1.5 moa. I've changed numerous powders, primers, bullets, brass, and seating depth. The action has been trued. I was wondering if it is possible that the gunsmith who built the rifle bored the chamber too deep which would prevent the seating depth from being at it's optimum. I'm not a gunsmith and really don't even know if that's possible. I would like to get the grouping under an inch.

There could be a hundred things causing your problem starting with the barrel install to bedding the action. Compound that with a bolt handle contacting the stock, etc, etc, etc. One big problem could be a fouled barrel, are you sure you have cleaned it, correctly and thoroughly?

I own several other rifles and have never had this problem. My 6.5 swede shoots .5 moa all of time. I have another .300 win in Ruger No. 1 that shoots better. I don't think its cleaning because I don't seem to have this problem with any other rifle. I have a suspicion that its the barrel. My original question was about the chamber as to whether or not it could have been bored too deep leaving too much free bore to the lands. I tried checking the O.A.L. of the cartridge by inserting a bullet lightly in a case and chambering it. It left a bullet too long to fit in the magazine. I realize that its tough to diagnose a problem without seeing the rifle but it was worth a shot.

Hmmm; I have built 300WMs on Shilen Super match grades and they shot .5 moa. However, I have found their regular grade barrels to not be what I wanted; let's just say that without saying anything bad about them. I sent two back to be lapped (standard ones are not lapped but that should not matter) and stress relieved. They shot much better. Do you get one round by itself, then others in another group about an inch away. Oh, very unlikely (as in impossible) for your chamber to be too deep in the throat unless your smith uses a separate throater.
My machinist friend said to smack the barrel with a brass hammer to relieve stress for another friend with a shilen; he did and it started shooting pretty well. Remove it from the stock first. He said it would relieve stress; I don't know but it did something. I am not bad mouthing Shilen by any means so don't go there. Just reporting.

Thank you for answering my question about the chamber. I've never heard of smacking the barrel with a hammer to relieve stress, but I'll take your word for it. I'm not bad-mouthing Shilen either, but I have had better luck with a different brand. Oh well, back to the gunsmith, I guess. Thanks again.

I didn't answer your question about spread of shots. Yeah, there is almost always a flier, or worse. Its really infuriating to have a good group going, then have one 1-2" away. I thought the reason for buying custom barrels was you don't have to deal with the problems found in inferior products. What's the advantage of spending the extra money if you have the same problems?

They lap their select match barrels; they must have a reason.

What contour is the barrel? Is it a super light weight or a normal sporter contour? Also, is it free floated or does it have a pressure point at the fore end?

While it should shoot well free floated, you might try cutting some business cards up and shimming the for end to see if a pressure point helps accuracy.

I've found 300 WM throats to be pretty long. I guess they are set to be able to take a 200 or 220 grain bullet - which is much heavier than most of us shoot. I would prefer a throat set for 180 grain bullets at magazine length. If I wanted to load a 200 grain bullet, I would just sacrifice powder volume.

Sounds as if you may have a 300 Wby mag chamber. Are you sure it is a WM (win Mag) and not a WM (weatherby mag)?

I believe the barrel is called a Magnum Sporter and it is free-floated. Actually, when the rifle was built it was full-length bedded. Because of the accuracy issue I removed the bedding material and free-floated it. What you said about the extra chamber length to accommodate bigger bullets makes sense. As far a it maybe being chambered for 300 Weatheby, I don't have the case demensions, but is it even possible to shoot a 300 WM in that chamber?

I really don't know if the bbl is match grade or select match grade. I told the gunsmith I wanted a Shilen bbl but I'm not sure what I ended up with. I didn't know much about the options available at the time.

I am sure that you got a standard shilen barrel; not that there is anything wrong with them; I am not knocking them. I do not use them any more, however. Back to my friend's story; same as yours until he hit it with the brass hammer. I would not have believed it. Shilen select match are twice the price of a regular one.

Sounds as if you may have a 300 Wby mag chamber. Are you sure it is a WM (win Mag) and not a WM (weatherby mag)? "quote"

Wouldn't you be able to tell from the fired brass?

dpcd: I think you have solved it. I guess the next step is to get a new barrel...or a brass hammer. Hey..its worth a try. Don't think I'll go with Shilen, though. I have had good luck with Bartlien. Which company would you suggest?

dpcd: by the way, thank you for your service.

You are welcome.
I just had the guy who has that shilen that he smacked with the hammer, bring me a Bartlein blank in 6.5mm today; he, too, has had it with the other brand and wants to try this one. I am sure it will be fine. I use mostly Douglas for hunting rifles and some sort of cut rifled barrel for target shooters. Just fitted a Rock in 308. Cut rifles are very expensive though so for hunters, I don't use them unless customer wants one.

A 300WM cant go 500rds and have any kind of accuracy left.Your throat is probably eroded way and that is allowing you to seat however deep you want.I have a few 300WM`s and if I want one to shoot out to 300yds plus the bore has to have no more than 50 rds-believe it or not.On a 300WM you see rifling dissappear with each round.

My guestimation would be that it's poorly bedded.

The shape of your groups should help diagnose bedding problems.

When the flyer occurs is of interest to the process.

If you shot a .300 win mag case in a .300 Wby mag chamber you'd hardly have a neck on the fired case. As both headspace on the belt it "technically" could happen. Though nobody could recommend the practice.

With 500 rounds in it you'd have cartridge identification sorted out by now.

Inspect the crown, scope mounts, scope, clean the barrel. Go through bedding checks. Remember a "wedged" action is a bad thing. The action has to be able to vibrate and return to it's original position shot after shot. Anything that interferes with this is a bedding problem.

From what you said about seating depth/mag length it sounds like it's long throated.

Did you try seating the projectiles deeper ??

My .300 Wby shot a "half choke pattern" at 100 metres before I seated the projectiles progressively deeper.

I'll try seating them deeper. At this point I have nothing to lose. I'm quite certain that its not chambered for a Wby. The cases are not that deformed are easy to resize. I find it hard to believe that you should only get 50 rounds out of a barrel, though.

Roaddog,,no one pays attention to shitaway,,,he's totally clueless and full of shit on every subject.

dpcd: After reading what you said about the different grades of Shilen barrels, I called them today to if I could send it back to have it lapped. The lady said they hand lap all of their stainless barrels, but the tolerances are a bit tighter on the Select barrels. I may endup sending it in to be checked anyway.

Ah, ok; the ones I am talking about are CM. I did fit one about 20 years ago in 300 WM, and it was a Select Match, SS. It shot around .5 moa.

I find out, that the 300 WM shoot much better with a 12" twist.
Don`t know why but with a 12" twist the accuracy of my two rifles is much better then most 300 WSM.

Have you checked your scope and scope mounting system?

quote:

Originally posted by ElCaballero:
Have you checked your scope and scope mounting system?

I believe the scope and mounts are fine. I used the factory Sako mounts and I don't believe there is any problem with them. I used the same scope on another rifle with no problems.

What are the shape of your groups? Do they change as the rifle warms up?

Is the rifle pretty light? I have found that with some light weight rifles I needed to put my non trigger hand on top of the scope and hold the rifle down to get better accuracy.

quote:

Originally posted by Snowwolfe:
What are the shape of your groups? Do they change as the rifle warms up?

Is the rifle pretty light? I have found that with some light weight rifles I needed to put my non trigger hand on top of the scope and hold the rifle down to get better accuracy.

The rifle is medium weight, I guess around 9.5 lbs. Comfortable to carry in the field.

As to the shape of the groups, I really don't remember any consistency in them except that they were inconsistent.

It's been a while since I fired the rifle. It frustrated me so much that I pretty much gave up on it, but I love the Sako action. I have decided to fix whatever's wrong and that's why I decided to look to the Forum for some answers. I have a good starting point, I think. I'm down in AZ until April and the rifle is home, standing the the corner. When I get home I'll get started on it. I'll probably have some more questions so don't go away. Thanks again for all of the input. We'll git 'er done!

I went to the Southwest Nationals last weekend and saw some damn good shooting!

quote:

Originally posted by Roaddog:
I didn't answer your question about spread of shots. Yeah, there is almost always a flier, or worse. Its really infuriating to have a good group going, then have one 1-2" away. I thought the reason for buying custom barrels was you don't have to deal with the problems found in inferior products. What's the advantage of spending the extra money if you have the same problems?

Am not sure quite what you mean by "have a good group going" but will assume you mean that after three, or even four shots, you have a nice small group, and begin to take care not to make it any larger. And it's after you have first noticed how good the group is going that the flier occurs.

If so, my first guess is that it isn't the rifle at all, but the shooter. Any tiny change in the grip you have on the rifle or change in the way you pull the trigger, or position the rifle will often yield a flier. If your shots after the flier are back in the group, that's typical... once the pressure to complete a good group is off, the shooter relaxes and goes back to shooting using his muscle memory instead of trying to "think" the shots in there with his conscious mind.

And after several ruined groups over time, it gets even worse...the shooter has lost faith in his rifle. And then good groups become almost impossible with it.

Having said all that, I have three Shilen barrels in three different rifles. Though none of them throws "fliers", not one of them shoots as well as I had expected. So I use two other brands now...one brand for competition guns, and still a different brand for sporting rifles.

Ultimately, I doubt Shilen is the villain here though...

If it were my rifle I would first check to see if loosening and tightening either of the action screws caused the action to move or flex. Following this I would free float the barrel the entire way to the recoil lug.
Other than that I can't be much help because I would be content with 1.5 inch groups day in day out.

Alberta Canuck:

Like I said, it's been a while since I shot the rifle, but that was how I remember the groups turning out. I own several other rifles including another .300 WM and I don't seem to have a problem shooting acceptable groups with them.

May I ask you what brand of barrels do you prefer over the Shilen? I switched to Bartlein when I built a 6.5x55 SE and have had excellent results with it. I did use a heavier barrel on it. When I get back home I intend to start all over with it and maybe I can figure it out. I don't discount that the problem may be me, but we'll see. Thanks for the input.

I notice you live in Cave Creek. Did you make it to Ben Avery range for the SW Nationals?

You really need a Hornady bullet seating depth tool to figure out max OAL where hitting the lands.

I have yet to meet a 300 winny that won't shoot 3 in 1" or less .... even my R1 will.

Don't be hitting the barrel with a hammer !

First stop is a box of factory premium Barnes ammo with 180s. They are always seated deeper as Barnes like to be +- 50 thou off the lands.

Check all your rifle and scope screws, I'd swap to a known good scope.

Then see how she does. If still bad, the bedding is next. Make sure the barrel is really free floated and that the recoil lug is touching the stock nowhere except on it's rear (butt) surface.

If still bad, it's back to Shilen. Years ago I has a varmint weight premium from them in 22-250 that would not shoot ANYTHING under 1" (5 shots).
They screwed w/it for a month, relapping, different stocks. loads and so on. They finally found ONE load that would shoot bugholes. They sent it back with a new free premium blank in the same contour. I sold it all to a guy who knew the whole story and was perfectly happy to shoot Sierra Benchrest bullets to demolish woodchucks.

As one poster observed, you can kill anything you would hunt with a 300 winny shooting 1.5 MOA.

You might not want to sit at the bench next to me when I'm shooting my 721AC 300 H&H (1952) with a 6X Kollmorgan (1951) that will drop 5 168TSXs in under 1" @3150 fps stoked with 4831. Old gun w/wood stock, no fancy bedding, barrel has big lump on it (rear sight boss) and the scope must be a POS as it doesn't have "clicks" or 5 layers of the latest mouse milk lens coating.

Interesting how much "progress" we have really made.....

quote:

Originally posted by Roaddog:
Alberta Canuck:

Like I said, it's been a while since I shot the rifle, but that was how I remember the groups turning out. I own several other rifles including another .300 WM and I don't seem to have a problem shooting acceptable groups with them.

May I ask you what brand of barrels do you prefer over the Shilen? I switched to Bartlein when I built a 6.5x55 SE and have had excellent results with it. I did use a heavier barrel on it. When I get back home I intend to start all over with it and maybe I can figure it out. I don't discount that the problem may be me, but we'll see. Thanks for the input.

I notice you live in Cave Creek. Did you make it to Ben Avery range for the SW Nationals?

Ah, yes, but you have faith in the other rifles you shoot well with. So you shoot them with no particular undo amount of stressing yourself. Sometimes we just pressure ourselves more than anyone else could.

So my suggestion would be that you just shoot the rifle for fun, not for groups. After you've done that a while, over the months you may find it start to shoot with uncanny accuracy compared to what went before. Killing rocks at 300-400 yards together (or old golf balls at 100-200 yards) can do a lot to make you and the rifle good friends.

I'll PM you with my thoughts on barrels.

I went to Ben Avery immediately after moving back here (was gone 21 years) and was so disappointed in the situation I found there that I have never gone back for any reason.

There is now the very nice (and likely very expensive to have built) AZ Game & Fish headquarters at the range, but none of the casual "guys' day out" atmosphere I used to love. Felt more like I had walked into national headquarters for GM, or Radio Shack.

I know what you mean about the range. A lot of bozos. I like going out to the desert to shoot rocks, but usually alone. Thanks for the input. I'll give the gun a chance.

To "support" Shootaway, I'm posting pics of my 2 .300 Mag. with respective "inaccurate" 5-shots groups shot at 100 meters.



Blaser R93 at 465 shots



Remington Sendero at 513 shots

I wonder if both bbls. are gone and should be replaced by 2 new "accurate" ones...

Having a good gunsmith install a good cut-rifled barrel (Bartlein, Rock Creek, Obermeyer, Krieger, or Brux come readily to mind) and cut the chamber with a good reamer in excellent shape will get you in a happy mood again.

Sako actions tend to be pretty square and true, but have your smith check that anyway.

Andre,

Did you have any work done to your Sendero? It shoots remarkably straight. It is not easy to maintain your form through five rounds of .300 Win Mag.

No, apart from some trigger tuning, my Sendero is in "out of the box" condition (it's fed match prepped handloads, though, even the hunting loads). The funny thing is that the rifle shoots hunting bullets (Sierra 180 Pro-Hunter)even better than Sierra MatchKings. Here are some other groups with different loads/bullets.

Change the scope for one of known quality. If you have a rifle that shoots "lights out", put that one on it & shoot a couple of groups.

It may not be the scope, but you'll never know until you try a another one. Trouble shooting is eliminating the variables.