I have had a Sako action rebarreld by a local smith. I have had very poor accuracy, with most groups, with any load going around 1.5". Occasionally, a group might go under 1" but there always seems to be a flyer or 2, and not always in one direction. While reloading this morning my son mentioned just neck size, and see what happens. As I was neck sizing, I felt the cases were being resized. After micking, I found the area just below the junction of the shoulder to be .460 before resizing. The SAAMI Spec for the chamber at this point,is .455, and .454 for the cartridge. Sized cases are coming out of my sizing die are about .452, which means my cases are expanding .008 each firing. Think this might affect accuracy?

Regards

Jerry

I would look at other potential trouble spots like bedding, crown etc, before worrying too much about the neck diameter.

quote:

I found the area just below the junction of the shoulder to be .460 before resizing. The SAAMI Spec for the chamber at this point,is .455, and .454 for the cartridge.

Westpac: I appreciate your getting back to me, but neck diameter has nothing to do with my post. See above, and oh yeah the smith charged me lots of money to bed, float and according to him the crown was fine, after all he did the barrel job, and didn't pay attention to the facts as presented either. What I really need is help solving this problem, that has been going on with the this rifle for 260 rounds.

Thanks

Jerry

Jerry,I normally dont have much to say,,BUT. after your first sentance you talk only about neck diameter.and then reply "neck diameter has nothing to do with my post".. It dont really matter how much the smith CHARGED you. There are a lot of people willing to help BUT from your second post your not willing to look at other options and wont accept help even if given!!So why did you even ask ? just my opinion.

Ty Falcon, thanks for caring enough to reply. Again, I am not mentioning neck diameter, merely mentioned I am going to try to neck size in the hopes that my oversized chamber problem may be mitigated by that effort. My question (and hope) is that the help offered here would be experience of a similar sort by owners of rifles chamebered poorly and oversized. As I see it, I am afraid the barrel is ruined, I am hoping not, hence my question to this forum.

Oversize chamber won't effect accuracy that much, just brass life. Neck sizing won't help that much either. What make barrel did you have installed? Did you have any action work done when you had the barrel installed?

Most likley if you smith was a competent one, the work is as it should be. I don't know what you have already tried, but I would look for things like action screw torque, make sure there is no debris between the action and bedding. Is the area beneth the recoil lug cleared out so the lug dose not hit at the bottom potentially making a pivot point? Is the bullet matched for the twist rate. Is it a load that previously shot good? If so, after the barrel has been set back, and rechambered it may not be the load it likes now. A friend of mine faught with one for months, until we changed scopes. The scope he had was a proven one for many years, but they do wear out! So many things it could be just have to tinker till you find it. I know this may not be much help, you probably already tried all that, good luck let us know if you get it figured out. I've got Ruger I'm fighting with right now myself. Could be somthing simular.

Are you using a Neck Sizing die to neck size, or just not seating a full-length die all the way?

Yeah, weighing in at a whopping .460, that wasn't the neck.

Even though you are wanting to neck size only, it sounds like you are experiencing what anyone who "full length" sizes encounters, a loose chamber. Not a big deal unless you are shooting for a record or money.

Have a new die made, or, have the existing one altered so it doesn't size the shoulder. That .008 won't do anything provided you have a neck die that clear a .460 "girth". And like I said earlier, albeit, I didn't read your original post correctly, I think you have more going on with that rifle than the .008.

Thanks guys, your comments are greatly appreciated. The Barrel is supposed to be a Shilen. I have not been neck sizing, and after 260+ rounds, I found the difference in the case diameter by accident in a conversation with my son. I will now use a neck sizer, that will give me the body clearence as Westpac suggested. The scope is a relativley new Nikon Monarch 3X9. The bedding and all the action points were again supposed to be taken care of while the rifle was at the gunsmith.I did most of the stock work, so I know the float is good. My frustration has been a lack of any consistancy from group to group. Oh, it will shoot a .700 group today, and with the same ammo, it will be 1.25 tomorrow. Hope the neck sizing works.

Jerry

Too Many Tools:

Do you have a suggestion as to the sizer? I have both.

Jerry

If I only wanted to neck size I would use only a neck sizer. As to FL dies I set mine up to just touch the shoulder with a shim under the lock ring of the die. Then if I need to bump the shoulder I remove the shim.

Jerry

I don't think you mentioned, but what Sako, what cartridge, how heavy is the barrel etc. The fact is tht 1.5" accuracy is not "very poor" in a lot of hunting guns. Is it a very light gun? If so, a floated barrel may not be best. (Even for some heavy ones for that matter. I have stocked a lot of rifles over the years and have had the best results with a solid bed out past the chamber and then floated to the foreend tip. If the stock is very trim through the action, my experience is that the rifle will be very critical as to tang fit and screw tension.

I agree that the diameter difference will not matter to accuracy at that level. I have seen rifles with much looser chambers shoot very well. If the front ring/recoil lug is properly bedded, I would try really clamping it down and loosening the rear screw until it is barely tight. See what this does. Also, side pressure anywhere along the action is generally bad.

The Action is an L579, chambered in 243 Winchester. The barrel is a medium sporter 24". Stock is a Richards, I inletted and fit the action too, then the smith bedded it etc. Not a light barrel or a flimsy stock???

I have necked sized some cartridges I fired this morning, without changing the size of the case body. We'll see what it'll do.

Jerry