I recently had my gunsmith put a new Lilja barrel on my Winchester model 70 chambered for 300wsm. He asked me if I would be using factory ammo or reloading my own, I told him I'd be reloading my own. He said that I would get better accuracy if he reamed it so that it was tight chambered. After he reamed the barrel he then used his lathe to take a bit off of the diameter of the neck of my brass so that I could chamber my round.

My question is this, I may have the terminolagy wrong, but has anyone heard of this procedure before, and does it really improve the accuracy?

Charliebuck,
A minimum chamber is one of the many things that can contribute to good accuracy. The other thing he did was to neck turn your brass on a mandrel that is sized for the caliber. He most likely didn't do it on his lathe but on either a hand tool or an electric one that is sold by reloading companies. (I peddled mine a month ago.) It eliminates the uneven thicknesses in brass in the neck. It is always done on bench rest rifles, and rarely on hunting firearms. It can help but the improvements are minor and in my thinking is of little importance in the field.

[ 10-03-2002, 05:00: Message edited by: Customstox ]

This sounds like a tight neck rather than a tight chamber. This is one of the things the benchrest guys do to wring that last .001 inch of accuracy out of the BR rifles. This by itself will only marginally improve your accuracy. There are many ohter thing that need to be done to the rifle and losts of nit picky thing to do when reloading, like segregating your brass by weight, deburring the flash holes from the inside, just to name a few. The problem with this in a hunting rifle is that you may not be able shoot fractory ammo in a pinch if the made the neck diameter in the chamber too small. You either won't be able to even chamber a factory round or if you can, there may not be enough clearance around the case neck to allow it to expand and release the bullet, thus causing high chamber pressures. Tight neck chambering should be reserved for only dedicated benchrest or target rifles.

You really need to kwow the "neck diameter" of your chamber. If it is below .296 you may not be able to SAFELY use factory ammo or unturned brass. I have rifles with and reamers that make "tight neck" chambers. All of them require that I turn the brass to about .012 wall thickness. This is part of having longrange accurate BR rifles but only if you want to go all the way. You should have a long discussion with your gunsmith on this rifle and chamber. If it is a "tight neck" the neck dia. should be engraved or stamped on the barrel with the caliber.

Among cobbling together various bore sizes of hunting rifles I sometimes digress and flail away at benchrest, tactical and 1000 yarder rifles. My reamer collection probably has 30 or so tight neck/tight base reamers with special throats for those long spears the accuracy crowd sticks in their cases.

So, what I am trying to say is I understand tight chambers and tight necks very well. A tight neck chamber has absolutley no business in a hunting rifle. And a gunsmith has no business putting together a rifle that requires neck turned brass that will be used by one inexperienced in the art of preparing and neck turning brass.

John Ricks,

You are spot on the mark......

I agree with John 100%.

www.duanesguns.com

I am currently having a rifle put together where I specified a slightly tighter than SAAMI minimum chamber but with a neck that would allow the use of factory ammunition. The factory specs left quite a bit of room to tighten up the neck and particularly the throat area.

Just to check I measured a bunch of factory loaded cartridges for neck diameter. I do plan however on turning all of the necks, not because I have to but because I want to. Get the neck dimension from your smith and make sure that is what you will be satisfied with.

Hey Charliebuck, Years ago when I messed with Wildcats and such stuff, the majority of those rifles were done by an old Gunsmith in KY. The very first one I got from him had the following stamped on the barrel above the caliber:

MAX NECK OD 0.33x"
______308Win______

I don't remember what the final number was, but it doesn't matter. That was many years ago and it is interesting to me that no one has mentioned it in this thread. In fact, it is difficult to understand "WHY" any Gunsmith would chamber a rifle with a Tight Necked Chamber and "NOT" stamp the MAX NECK OD on the barrel. I do not see this as a "minor" issue.

I do agree that since your post indicates you don't fully understand about "Tight Necked Chambers" that your Gunsmith should not have finished your rifle like this. Depanding on the finished Diameter, it could be dangerous to fire Factory Ammo in it.

I'd encourage you to go back and have him recut it to the SAAMI Standard. Then once you wear out a barrel or two, a Tight Necked Chamber "might" be of benefit for you. At first they aren't any benefit at all, then after a barrel or two they can be and finally if you live long enough, once again they aren't a big help to your overall Hunting accuracy.

Good point, I do the same thing, that is I engrave the neck diameter on the barrel just after the caliber designation if it is a tight neck. Same for a non freebored Weatherby, I engrave "No Freebore".

Build the hunting rifle correctly, using quality parts, and it will make small groups with standard necks.

Thanks for the input guys, you've been very helpful. He's turned the necks of the brass that I'll be using in this gun, and I indicated to him before he started to work on it that I would strickly be reloading for this gun, So I guess I'll try it like it is. I had never heard of this procedure before, and knew you guys would know what I was talking about. Thanks again.

John Ricks is completely right. If you've never fooled with tight neck cartridges, it was absolutely irresponsible for him to chamber your rifle that way. Besides that it is very doubtful that you will see any benefit accuracy wise from this with a sporter weight barrel. Also, it is federal law that a barrel be engaved with the correct chambering and if he did not engrave the altered neck diameter on the rifle he violated the law and common sense. I have a .257 Weatherby reamer that I had made with a short throat. Every time I chamber a rifle with it I engrave .257 Weatherby Short Throat on the barrel so that some possible future owner of it will know it isn't standard.

I don't understand why everybody is condemning this gunsmith for makeing a tight necked chamber when Charliebuck didn't specify what size it is. If he made a diameter that will accept factory ammo and you use a bushing die that will minimally work the brass what has he done besides do you a favor in extending your brass life?