I have a friend that has an unusual problem. He has a contender with a 7-30 Waters barrel that will only fire Federal primers consistantly. Winchester primers will show a very good looking firing pin impression but will not fire. Just looking for some opinions.

Contenders have "special" problems.

The original contender was set up to fire either centerfire or rimfire. As a result, the amount of firing pin protrusion was a compromise between centerfire and rimfire -- and less than ideal for centerfire. It works if everything is just right, but when combined with excess headspace it can lead to misfires.

In theory, the 7-30 should headspace on the rim. In practice, it is better to set it up to headspace on the shoulder so that the case is a snug fit in the chamber.

My guess is that your friend is seeing the result of a combination of sloppy headspace and the TC's minimal firing pin protrusion. Try addressing the headspace first. Partial size the cases just enough to allow them to chamber reliably.

quote:

The original contender was set up to fire either centerfire or rimfire. As a result, the amount of firing pin protrusion was a compromise between centerfire and rimfire -- and less than ideal for centerfire. It works if everything is just right, but when combined with excess headspace it can lead to misfires.

Actually all Contenders are setup fire either CF or RF. The firing pin protusion for one is totally unrelated to the other as they are independent of one another. They would be no less ideal to fire CF as RF and correctly headspaced ammo with good primers have never failed to fired any one of dozens I have owned or worked with.

normally federals are the softest primer and guns with weak springs or not enough protrusion will fire federals when nothing else works. Thus loot at the spring and firing pin.

OK, I had read that bit about the TC firing pin protrusion somewhere but never actually measured it myself. My older model TC CF pin protrudes 0.060" compared to 0.050" on a Remington M700. Nothing out-of-the ordinary there.

Be that as it may, misfires with TCs are quite common, usually due to sloppy headspace, so the advice about headspace still applies, just that it seems unlikely on a rimmed cartridge.

Another thing that can go wrong is the hammer block mechanism. There is a piece that slides up to block the hammer. When the barrel locks up correctly, the blocking piece is supposed to fall down as the hammer is pulled back. If the barrel fails to lock up 100%, the blocking piece is not supposed to fall. If you watch it, you should be able to see the blocking piece fall as you pull back the hammer.

The blocking piece can jam if ice or pine needles get in that space, which has happened to me while hunting, which is why I don't hunt with TC's anymore. It's been a while since I had a TC torn apart, but as I recall, the blocking piece is propelled by a rather small spring, and it doesn't take much to jam it up.

Now if the blocking piece does not fall down, then the hammer will stop short of the firing pin, and there should be no indentation on the primer. That does not sound like the problem you are having with Winchester primers.

However, I had one frame with a "sticky" blocking piece that would sometimes fall only part way. The hammer would then graze the blocking piece, softening the blow enough to cause misfires even though the primer was indented. If I removed the blocking piece (not recommended), or if I switched to another TC frame, the problem went away.

If you can borrow another TC frame and try it with the Winchester primers, that would be an easy way to narrow down the problem.

I think there are some extra-strength hammer springs available for the TC, but IMHO the factory spring is more than adequate. Usually TC misfires are caused either by headspace or by problems with the hammer blocking piece.