Anyone have photos of throat and start of lands, maybe a bore scope picture?


Ive been examineing my 6,5 throat where the lands start trying to determine if I have carbon fouling at that point.

In My 9.3 I can see the lands start with a distinct step. But what I can see in the smaller 6.5 looks more like a where the edge of lands start is "chamfered" .

Do some reamers cut the throat to lands at 90 degrees and other reamers cut a 45 degree++ there abouts in the start of the lands?

The forward edge of the neck portion of most reamers is slightly beveled. Depending on the degree of the bevel, the throat may begin within the bevel, or, below it. Errosion will appear as a sand blasted surface and the edges will be obscure. If that is what you were looking for.

I think it might be throat errosion. It looks like a sand blasted appearance right where the lands start, and the edges of the lands look beveled not a distinct edge. This is a 6.5x55 winchester barrel, useing R22 powder

I thought it was a carbon ring deposit at the start of the lands. Examineing the bore down the muzzle , the blueing inside isnt even worn though to see any bare steel at all. Looks new. It has just under 400 rounds through it.

Engineers debate it and I still coem down on the side of stress corrosion, as opposed to erosion.

At any rate, they will all do it and it is nothing to worry about. Today bore scopes have caused more perfectly good barrels to be scrapped than anything else. The only time to do anything diferent is to seat bullets out longer when accuracy drops off. Soem people want to scrap a barrel as sson as they see pits or the stress corrosion areas.

Shoot it and be happy . With only 400 rounds through a 6.5x55 barrel, you should have a long barrel life ahead of you.

How you shoot it will affect how quickly stress corosion makes a serious impact on your barrel. Getting it hot is bad, shooting slow and never letting the barrel get too hot is good. There are other factors, but barrel temp is the one you have the most control over.

Thanks Mark, I remeasured my different bullets hitting the lands and looks like my COL to hit the lands has grown about .020 average. This m70 6.5 throat when new was .030 longer than a new sweded mauser barrel.

Think I beter slow down at the range and let my rifles stay cool.

What about double base powder like r22, dont they eat throats more than single base?

Isnt H4831 single base?

Abrasion is the process of wearing down or rubbing away by means of friction; corrosion is the act or process of destroying a metal or alloy gradually, especially by oxidation or chemical action; erosion is any of a group of natural processes, including weathering, dissolution, abrasion, corrosion, and transportation, by which material is worn away...

I will agree with Marc in that barrel temperature is a key contributor to an eroding throat.

Boy I just looked at 3 6.5x55 barrels and my old 308 barrel a 9.3 barrel 270 and a 3006 barrel.

These 6.5's with the 7.9 twist and smaller bore are just look different at the start of the lands. Now my m70 6.5 doesnt look so bad after compareing to a new sweded barrel and another 2nd swede barrel. The 7.9 twist rifleing/lands just angle sharper and cant see a distinct edge to them.

Fussy gussy!