Chambers with tight necks?


July 6, 2006, 11:33 PM
Do chambers with tight necks accelerate throat erosion?

If you enjoyed reading about "Chambers with tight necks?" here in archive, you'll LOVE our community. Come join today for the full version!
July 6, 2006, 11:42 PM
If anything, I would expect it to lessen throat erosion, as the case neck would not be allowed to expand as much, thus better channeling the hot gases behind the bullet rather than into the base of the bore.

I would think that, more realistically, it is acedemic at best. High pressures and fast/hot powders are the known culprits of accelerated throat erosion.

July 7, 2006, 06:39 AM
Mach IV,
Roger that. And since you brought up the subject of propellants, I have to ask: Do you have any experience with Vihta Vouri's N500-series propellants? I have used N550 in a .300 WSM and N560 in a .338 Lapua Magnum quite liberally in the past. And though I obtained truly remarkable performance in each instance, barrel life was tragically short. See my thread herein on 'short barrel life'. Some have said that these propellants are atrociously hot. But we (my smith and I) just couldn't find the evidence for their having flame-cut the ***** out of the subject barrel throats upon examination with a bore-scope!

BTW, do you purchase your own reamers so that you can get the same chamber with the same dimensions (e.g. custom neck diameter) barrel after barrel? It has been suggested to me that I do this by people I consider real authorities on the subject (e.g. Dave Brown @ Sierra Bullets).

July 7, 2006, 08:33 AM
Buying your own reamer guarantees consistency.

Expansion doesn't mean squat for throat erosion - you're worried about what's in front the case, not what's behind it.

Improper cleaning screws up more barrels than hot loads. Also, shooting the thing while HOT is a bad idea... Warm okay, but too hot, and that accelerates barrel wear.

How many rounds did the barrel last?

July 7, 2006, 10:18 AM
everybody is right here, the most important things: clean smart, dont fire hot, try to use a bullet or propellant that burns up while still in the cart neck, and not into the bbl. the old 6mm remmy bullet for example , was fantastic for this, very long neck, nice shoulders. think Audrey hepburn.

Ol` Joe
July 7, 2006, 12:14 PM
Heat and pressure erodes throats. Any cartridge that produces lots of hot high pressure gas for a extended period of barrel time will erode throats fast -think 220 Swift. Neck/case geometry or caliber,has no real effect. A cartridge that burns lots of powder at very high pressure acts as a cutting torch on your bore throat. The Lapua mag is a noted overbore cartridge that fits disription to a tee. You wont get long barrel life with it or others of its ilk. The best one can do is take your time when shooting and let the barrel fully cool between shots. Expect to have to replace barrels at a quicker rate then you would with a 338 Win, it`s part of the cost of shooting these big guns.

July 7, 2006, 12:50 PM
What Ol' Joe said. The biggest determinate of accelerated bore wear is cartridge case capacity to bore size.


If you enjoyed reading about "Chambers with tight necks?" here in archive, you'll LOVE our community. Come join today for the full version!