500 magnum light primer strike

Smokinciv · #1 10-29-2017, 04:23 PM

Hi guys I'm new to your sight. When my wifes gram passed she left my wife and I some money. I told her on the lasts days of her life I will buy something I will keep forever and pass on to my son. So I bought two 500s ,one 83/8 and one 4 inch barrel . love them both,I might not shoot much 700 grain Underwood's anymore but the fusions are a blast. So anyway the long barrel 500 has developed light primer strikes in da . single action goes bang every time!! I checked the tension screw under grip ,it was tight!! Any ideas? Have about 250 rounds through each!

gwpercle · #2 10-29-2017, 06:25 PM

1. Factory trigger and springs ?

2. Factory ammo , remanufactured or your/your buddies handloads?

The more information the easier it will be to diagnose the problem.

Smokinciv · #3 10-29-2017, 07:00 PM

Factory trigger and springs . reman from cheaper then dirt . they fire everytime in the 4 inch 500. The 83\8 fires everytime in sa . won't fire at all in da. Tryed some fusion ammo
same result.

sturtyboy · #4 10-29-2017, 09:45 PM

More information would help too. Is the problem .500 a used gun?

Check your strain screw (main spring screw) under the grip. This should be tight and not shortened or loosened. SA has a longer hammer travel than DA. If the main spring has been changed or the screw tapered with, this is usually the result.

Sometimes they back out on their own or the owner backs the screw out or shortens the screw to lighten the DA.

I you have a used .500, you really wouldn't have the history of the gun and could have any one of these scenarios cause the light strike.

Pizza Bob · #5 10-29-2017, 10:05 PM

Are there FP marks on the rounds that don't fire? Do they go off with a second strike?

If no, or off center marks, the cylinder is overrunning the stop. If light marks and good ignition on second try - high primers.

Adios,

Pizza Bob

rct269 · #6 10-29-2017, 11:24 PM

You said factory springs. You didn't (or haven't yet) responded to the question as to the gun's status------bought used?.

If it was bought used, I'll suggest you don't KNOW if the springs are factory or not (also may not KNOW if the strain screw is original length). All this perhaps unwarranted skepticism on my part arises from my knee-jerk reaction as to the cause of your problem---which is "spring kit". That in turn arises from my recent experiences with spring kits---which have been an eye opener---both good and not so good---although I must admit the not so good experience arose from my vast experience with these guns (S&W revolvers in general---not "THESE" guns)---which renders spring kit instructions entirely unnecessary----or maybe not. My very first effort resulted in the gun locked up tight. The next time around (WITH the instructions) worked out great!!

So----bought new---as in "unfooledaroundwith"---or used?

Now, having run my mouth in that direction, let's go back to square one. You said the long barrel "has developed"---which is to say it was fine, and then it wasn't. So what's the end of the firing pin look like-----same as the short gun---or boogered? And you must forgive me for not knowing the first thing about these guns (and having no desire to learn), but given that the firing pins are frame mounted (??), do both of them protrude from the frame the same amount? AND measure that amount---a stack of feeler gauges will work fine if you don't want to whack off a piece of your machinist ruler. (I know I wouldn't!)

Bottom Line: These guns (any revolver---besides some Colts maybe) require no knowledge of rocket science. Whatever's amiss is simple. Consider the possibilities, and eliminate them---one by one. There aren't that many.

Ralph Tremaine

Next question: Why in the world would you fire one of these cannons double action?!!

Smokinciv · #7 10-30-2017, 10:52 AM

I bought both 500s brand new. Zero parts changed on either. I checked screw under grip it is tight.

Smokinciv · #8 10-30-2017, 11:04 AM

Ralph , I just recently started shooting them both in da ,after I took a ccw course and have been practicing out of holster .. I took course with my SIG 9mm sa/da . so I got a holster for my 4 inch barrel and have been trying out of holster with that.. I do not plan n carrying 500 but we can here in Pennsylvania.. So that is how I found out long barrel doesn't fire in da. When it first started it did not happen all the time. Now it is always

Smokinciv · #9 10-30-2017, 11:10 AM

Pizza bob yes there are FP marks . right in the center of primer.if I try same round again in da it will not fire,try the same round in sa and bang she fires .the da hit on primer is pretty stout looks like it should fire ,I guess the sa is hitting it a tad more.

Smokinciv · #10 10-30-2017, 11:12 AM

Thanks guys I'm trying to get all details out. Been a while asking for diag help online

rct269 · #11 10-30-2017, 01:59 PM

Okay---given bought new, springs/spring tension would seem to be out of the question. Give that firing pin a HARD look!!

The DA strike is less, softer if you will, simply because the hammer falls a lesser distance--has less momentum---and whatever the formula is for determining force will demonstrate the effect. Similarly, the mainspring is being released (in DA) at a point of less tension/compression/strength/whatever than is the case in SA. All that gobbledygook aside, the force of the DA strike is clearly adequate to ignite a primer------if---if the firing pin is long enough to mash the priming compound against the anvil. Without knowing the first thing of real value about all this, I'll suggest the power/strength of the strike is more than enough to disperse the compound such that another strike (even SA) will fail to ignite the primer.

Is the firing pin the answer? I don't know, but it makes sense---to me.

Ralph Tremaine

Smokinciv · #12 10-30-2017, 07:45 PM

I took it to range right before dark . I fired it 5 times. 4 went bang da. 1 would not fire da . it did fire in sa.

sturtyboy · #13 10-30-2017, 07:46 PM

Ralph is on the scent...

Check the travel distance of the FP. Compare the two .500's. If they are both the same distance, I'd assume the spring needs to be addressed. Things happen to new purchases...that's why the warranty. Call S&W and send it back to them. You might use the opportunity to ask them to smooth the action on it at the same time.
Sounds like you like the .500 Mag punishment and can afford the ammo. I would at least make it smoother.

I enjoy my .500 Mag too. I reload full house loads. I can't see the purpose to have a "horses leg" of a gun like a .500, just to spit out a soft load. There're much cheaper options out there.

It's the overall experience. The ball of fire, the dirt rising off the ground, the shear amazement that you've survived the concussion and the smile on everyone's face.

Just be sure to keep your grip behind the cylinder gap as you would on every revolver. This .500 will remind you why it's a good idea to keep your pinky's back.

I'm 6'8" and 270. I have big hands and shoot mine DA inside a 8" plate@ 7 yds. rapid fire with full house loads. Never more than a box after I switch hands. And never at the beginning of the range shoot. It will screw you up for the rest of the day.
My hands on my carry... You can see why my support hand could get in the way. Believe me, I've learned a long time ago.
big mitts.JPG

It's fun to reach out 100 plus yards too. But you get tired quickly. It has a punishing recoil for sure.

Protocall_Design · #14 10-30-2017, 07:58 PM

Sometimes the factory firing pin is a bit too short. The longest and best factory ones are .495. You can get longer ones from Apex or Brownell's. I have seen factory ones as short as .480, .485 is common and too short.

JDinAZ · #15 10-30-2017, 08:09 PM

You may need to use a loupe when you check out the tips of the firing pins. A feller I know out here had a flat spot develop on the pin in his 986. He suspected it at the range. Tore down and checked with loupe. Yup sure as all git out a flat spot starting on the tip of the firing pin. Well that the gist anyway his rendition would be a bunch of **** you couldn't read it

Smokinciv · #16 11-04-2017, 07:10 PM

I will def look at firing pin tomorrow. I just got back from range. I loaded up 5 325 grain armscor rounds. 4 fired da Again one I had to sa it.

500 gun hunter · #17 11-04-2017, 07:32 PM

I had the same proublem with mine but it was a used when I got it took the grip and cover off pulled out the retaining pin for the firing pin and pulled it out there is a spring in front of the pin I took it out and took a magnifying glass and looked in the hole found a tiny burr just inside the hole I tool a rat taled file and put it in the hole every little pressure and turned the file the burr came right out reassembled no proublems any more have shot 100 rounds

cmj8591 · #18 11-04-2017, 07:35 PM

I'm betting on the reman ammo. I bet they used large pistol primers instead of large rifle primers. Most 500 brass has deeper primers pockets designed for the large rifle primer. If the gun only misses with that ammo, then that would be my guess.

Smokinciv · #19 11-05-2017, 12:44 PM

Cmj8591 ,I believe you are correct. I took my 4 inch 500 this morn . I brought 5 rounds , 3 went da the other 2 had to be hit sa. I examined the 2 that would not go da and can clearly see the primers are not sitting even in the pocket. . well at least I only have 300 rounds left of the problem ammo....thanks for all your help and input guys...