My old-style Contender has started "snapping". I'm shooting reloads, but when I first started out with them a few months back they functioned fine. I've noticed that when a snap occours that the indention in the primer isn't quite as deep. Primer seating seems uniform throughout the batch. Could be a few bad primers, but I was wondering if the hammer spring could have weakened. How involved is replacing the spring?

the first thing i would check would be the size die adjustment. you may need to adjust it down a couple more thousandths er so to bump the shoulder back some. a few thousandths can mean a lot in headspace adjustment. a common cause of misfires.
be sure n lube inside case necks to minimize pulling the shoulder back out also.

only after verifying this would i suspect the hammer spring. always a possibility, but headspace adjustment is more frequent and likely.

The gun closes easly on the loaded round right? In other words you don't have to "snap" it shut to cock the hammer.

So "snapping" means a light primer strike with no ignition. I'm going to say just the opposite of Kyode, it sounds like maybe the cases is full length sized a little too much and it is down in the chamber a little too much and the firing pin is not getting a full strike. You need to take the barrel off the frame and see where a resized case sits in the chamber. It should be flush or a few thousands above the barrel. If it's down inside a few thousands back the full length size die out of the press a little and try another case.

Bellm sells a headspace gauge that is very handy and he has a good explanation on his web-site.
Bellm head space gauge

good point tigger. it could be either situation....or even a bullet seated too long. regardless....check "headspace" and adjust your dies accordingly.

Shortly after I purchased my contender { many years ago} Thompson issued an upgrade to the hammer springs because of missfires. You might give thompson a call and see if this upgrade needs to be done.

YUP, Kyode once a guy understands "headspace" in the break-open system it's a "snap" to reload for them... PUN intended...

Thanks to all for the input. Deer season's over tomorrow, so my project for the dead time between deer and turkey season will be to examine headspace issues.

Just looked at the primers that snappedand some that went off. The ones that snapped are barely dented, while the others are very definite. Headspace looks the same as factory loads. Really confused right now.

you can't reliably depend on "looks"....unless you are very experienced....and then you might get lucky and get close, or close enough. a couple thousandths one way or another can mean misfire....or not.

study up at the link tigger posted. the loaded rounds need to fit the chamber properly. die adjustment is a big part of that. remove the barrel and see how the round fits. adjust dies accordingly and take into account the barrel to frame gap. only after this is verified one way or another would i suspect the hammer spring.

instructions in some die sets may say to adjust the size die to touch the shellholder, which is completely and totally incorrect, especially for a break action gun. you gotta make the case fit the chamber correctly for best accuracy and reliability.

Kyode is 100% on!! He is also VERY experienced in this matter!!

well....let's just say i'm "sympathetic" towards it.

i had difficulty in understanding it myself, and had similar troubles as well.
some get lucky....or at least have a brain, n get it right the first time. i did not. i came up the hard way.

You state that the some primers are dented well and had good ignition. So that kind of rules out a weak spring for the moment.

The factory ammo must be close to proper haedspace for your barrel as you had no ignition problems. I have seen factory ammo that did not have proper headspace for some barrels and it gave eratic ingnition. Bellm tells of the 35 Whelen barrels from TC that had the same problem.

I have a barrel that has .009" space between the breach and barrel face. I set my sizing die up to push the shoulder back so the case is "sticking" out of the barrel by .006"-.007". This cured light primer strikes.

As stated before start with the headspace. Bellm has great instructions and sells the tools if you don't already have access to them. Do you have other barrels and if so do they give ignition problems too? As stated before break open guns need cases sized to the barrel and you will need to FL resize to barrel dimensions. You are not trying to neck size brass are you, if so try FL resizing as the guys have stated before.

I also have a .222 Rem. barrel and have never had a problem. No, I only full-length size the brass.

D.J.,

KYODE is "right on the money"! T/C had major "headspace" issues in the past, primarily with rimless cartridges, although the problem can occur with rimmed cases too. A notorious case was the 35 Rem. Years ago, I missed a 6x6 bull elk with the 35 Rem misfire. I was using Rem factory ammo and had 6 light strikes, and no discharge before the elk got bored and ran off. That incident started my quest to figure out the problem. It is the headspace issue, mentioned previously, more often than a weak hammer spring. Mike Bellm does sell heavier hammer springs too.

Doc

Anyone that owns a break barrel firearem needs to go to the Mike Bellm web and absorb what he has to say about reloading for them. I set up my reloading dies and sizing operation with a feeler gauge. Back off your sizing die to a point where it is just missing the shoulder. I will then measure the distance between the shell holder and the bottom of the die with a feeler gauge. Size a cartridge, place it in the chamber and insert a .002 feeler gauge between the base of the case and the action and close the action. If it is tight, won't pull out adjust the die down a couple of thousands (check it with the feeler gauge between the die and shell holder) resize the case and again check the clearance between the base of the cartridge and the frame. (you are making two measurements in this procedure, die to shell holder and base of case to frame) Adjust until you have .0015 to .002 clearance. Then check the clearance between the die and shell houder with the feeler gauge and record that in your reloading manual so you can always go back to that measurement. My setup is .019 between the die and shell holder. Doing this will virtually eliminate two of the problems that Contenders have that cause misfires.

Good Shooting!

KYODE mentioned lube in the dies.I f this isn't cleaned out from time to time the lube will push the shoulder of the cartridge back,I've experienced this with the 7mm T.C.U. After cleaning my dies the problem stopped.