A friend has a Tikka Whitetail Hunter in .300 Win mag that has a peculiar problem. Every few rounds, shooting nothing but factory ammo, the bolt lift is extremely hard and extraction difficult, as if the round generated too much pressure. However, rounds from the same box of ammo, fired immediately before and after the problem round, eject normally.

My first thought was that his rifle had a very short throat, and that bullets were running up into the lands. However, if that were the case, should it happen with only one in five or ten cartridges, or with everything in the box?

A local gunsmith took a quick look, and suggested that the problem might be with the loads he was using--a premium Winchester load featuring nickle-plated cases that, according to the smith, tended to cling to the chamber walls after firing--and recommended that he try a box of the cheaper Winchester ammo with brass cases. I could be wrong, but that answer didn't sound very likely, and I suggested that he find another smith (and, by the way, a couple of the brass-cased rounds also caused problems).

The hard-extracting rounds don't seem to show any other obvious pressure signs. The primers might be a little flatter when compared to other rounds, but that also might be a case of seeing what I expect to see--at any rate, any additional flattening in minimal, at best.

The problem does not appear to be a dirty chamber, as the rifle is, for all practical purposes, new, and the chamber has been cleaned.

I told my friend to stop shooting the rifle until a competent gunsmith takes a look at it, but at the same time, I'm interested to hear if anyone has any ideas about what the problem might be.

Thanks.

could be a high spot in the chamber. Are there any scratches on the fired cases that are present on all the cases or on the ones that extracted hard?

Iwould try polishing the chamber. A tight fitting bore mop and some Flitz or such just spin it a bit in a cordless drill at not too high of rpm's. I have had experience with several Kimbers where the exact thing you described was occuring, and the polishing thing did the trick, 3 of them were 300 WSM's and two of them were 300 Win Mag. (a couple of other calibers also).

Good Luck--Don

Actually the nickel cased ammo could be the problem!! Contrary to what the gunsmith said, it's because the nickel is too hard and doesn't grip the chamber, resulting in too much bolt thrust and higher pressure. This is a documented fact. I would definitely try some brass cased stuff before proceeding further.

Whiteeagle,

Cleaning or polishing the chamber is sure worth a try. The chamber does not have to be rough, just be gunked up with residue from something like dried WD-40. I have seen the same difficulty in extracton in shotguns, cleaning the chamber with solvent and an oversized brass bore brush usually puts things right.

Thanks for the input. I'll let my friend know--we'll be hunting in Newfoundland next week, and have plenty of time to discuss it.

If anyone else has any suggestions, please pass them along. Thanks again.