How much headspace is to much?

[Gateway Kid SASS# 70038 Life]

I typically use my 357 uberti '73 main match gun for bigger matches and my backup for local matches.

Broke the tab on the backups bolt and had it repaired by a well recommended smith.

good looking work but started having an occasional failure to fire after reinstalling my parts.

Decided now would be a good time to double check the headspace (gun is about 4 years old, perhaps 50 or 60 K rounds)

On my main match using slips of paper between a federal cartridge empty and the bolt, hammer down I can insert 2 slips which read about .006 - .007.

On my backup using same technique I can get 3 slips of paper which reads about .009 - .010 (this is the one I am having issues with).

On my long range version (which has never had any issues) I can get 4 slips easily which reads about .012 - .013.

 

So the question is:

are my symptoms a sign of excessive headspace? or to little?

I know I can get slightly longer links, will that possibly correct the issue?

Why would it change?

my loads are 147 gr 38's at about 800fps typically in federal cases but sometimes use mixed brass

any constructive input would be greatly appreciated

 

Regards

 

 

Gateway Kid

[Garrison Joe, SASS #60708]

Your symptoms? You haven't given us much in the way of symptoms except one of your guns is not firing sometimes. Do you get a weak looking dent or no dent in the primer when that happens? Is it at high speed, or does it fail to fire sometimes when cycling slow? Do you have good firing pin protrusion on the gun that has a FTFire? Have you cleaned the firing pin bore and spring? Could bolt have warped slightly during repair and now the FP is binding in the bore through the bolt? And checked mainspring that it has not gone weak on you?

 

Measuring headspace correctly and getting a bad number is usually enough to establish that the gun has too much headspace. Measuring it wrong can lead to unnecessary work. Did you remove the extractor when measuring head space?

 

Usual recommendation is to refit the links when headspace is over 0.010 to 0.015". Excessive headspace can give you weak or no firing pin impact, especially if the extractor hook is not snapping snuggly over the rim by the time you fire, because the cartridge is free to bounce forward the amount of headspace that you have and absorb some of the FP's energy.

 

Longer links are the easy way to fix excess head space in a 73. If you have a short stroke kit installed, work with that same maker to see what they can do to give you longer link length.

 

Why does headspace change? It could never have been set right after a short stroke exercise or repair effort. Loads could be warm enough to bend links slightly or wear the pivot pins on which the links hang. The links you have in the gun may not have been fit tightly to the frame and bolt, allowing slop in the lockup and peening the pivot holes or bending the support pins for the links. An out-of-battery-discharge that bent the lever or carrier arm might be keeping the bolt from going all the way forward (this one is something I have run into).

 

Kinda sounds like it ought to go back to the smith who repaired the bolt tab and let them know what problems the gun has now.

 

Good luck, GJ

[Ace_of_Hearts]

Your symptoms could be anything from a worn/dirty firing pin, worn links, weak hammer spring, bent lever, OR bad head spacing.

It could even be that the repairs are holding the bolt back from closing all the way.

 

Look at all the options before taking on repairs on the most expensive one.

[Gateway Kid SASS# 70038 Life]

Thanks Garrison and Ace

As far as symptoms

gun simply will not fire perhaps every 15 or 20 rounds

recocking and pulling trigger sometimes several times will not fire the round but levering in the next round will fire as normal, set rounds aside and tried them in my main match gun and went bang as usual

pulled the bolt and recleaned the bore, made sure the spring was retracting the firing pin into the bolt easily, primer indent appears lighter than normal but still a decent looking strike, (not really sure how to measure the depth of the strike), removed the firing pin spring and the pin slides back and forth easily in the bolt, compared the lever to a new spare and cannot physically see any differences (don't recall having an OOB but anything is possible)

When the tab broke it was on a reload over the top that I botched and caught the round in a bind in front of the bolt. I did not consider the extractor could be an issue as empties are/were still tossed perhaps 3 feet up but have a spare and can replace it to check. As far as measuring the headspace I placed my empty in the carrier and levered as normal, with lever fully closed and case in the chamber I slipped pieces of printer paper between the bolt and rim of the empty until they would not slide in anymore then removed them and measured the thickness. did not remove the extractor but can certainly do that easily enough.

My firing pin sticks out the front of the bolt roughly even with the bottom lip of the extractor when the hammer is fully down and the bolt is in battery, I will get a measurement tonight. I have a spare lifter arm and mainspring and can fit them to this gun to be sure my current ones are not bent or weak.

 

Again thank you for the leads now I just need to get busy and follow up on your advice and spend some alone time with my rifle! (a worthwhile endeavor on its own )

 

Regards

 

 

Gateway Kid

[The Original Lumpy Gritz]

Try a stronger/new hammer spring. Make sure your firing pin is of correct length.

Don't use paper for a gauge. Use steel feeler gauge stock for that.

Deep clean the entire gun---

Make sure you are FULLY seating the primers in your cases.

OLG

[Marauder SASS #13056]

I prefer to keep the head space less than 10 thousands (beyond the shell). Of course, the official head space includes the head of the shell, so the specification is .060 to .070.

 

Usually, it is much more accurate to remove the extractor to measure.