JM 930 light primer strikes

[LikesToShoot]

It's had maybe 3 K thru and I noticed about a month ago getting a click, no bang and a light primer strike. Maybe 1 out a 100. Cleaned the gun made sure chamber was CLEAN and shells fully seating and just thought it was a bad match of Federal Ultra ammo. Problem occurred a few more time with a different flat of Federal Ultra and guessed it doesn't like Fed. Ultra. Well tonight while sighting in B&P slugs it happened twice out of 15.

1st: Dropped a round into loading port, hit slide release, round chambered and then I loaded 4 in the tube, I pointed gun at target, pulled trigger and click, racked bolt ejected round with dimpled primer. Next round chambered and installed "bad" round in tube. Fired all five shots without a problem.

2nd: Dropped round into port, hit slide release, round chambered, and loaded 4 into tube. Aimed at target, pulled trigger, BANG, hull didn't eject. Racked bolt, ejected hull, chambered round, pulled trigger and click. Racked and eject round with light strike, chambered round, put "bad" round into tube and next four all fired OK.

The last five slugs fired w/o a problem loading one into port and other 4 into tube.

Good news is I can hit the A zone at 25, 50 and 75 yards and center of mass at 100 yards.

Bad news is I can't count on gun to go BANG.

Thoughts?

I'm going to clean the bolt, and firing pin channel tonight. I might try to stretch the hammer spring, seemed like a stout spring. No parts available from Brownell's, Mossberg apparently don't trust us to install parts in the 930.

Plenty of parts for Benelli available. Will a Benelli hammer spring fit/ work in the 930?

[Triggerbender]

I have had the same issue.

I have called Wolff and am trying to get an extra power hammer spring.

Being first and formost a shotgun guy, I noticed right out of the box the light, mushy trigger and slow lock time.

The cocking indicator may limit the coil I.D.. but I don't see eliminating that a big issue, the o.d.of the spring will need to stay .250in though.

Conact Wolff if they hear from enough 930 owners they will probably make one.

My next call will be to Mossberg but with my previous dealings not feeling much hope unless already in the pipeline from others.

Anyone know where to get a spring or know what other brand shotgun hammer spring would work?

I bet Jerry doesn't have that whimpass spring in his guns.

Edited June 29, 2013 by Triggerbender

[Triggerbender]

After thinking about it and reading a little more, the so called "trigger job" sometimes mentioned on these may consist of a lighter hammer spring?

Think a standard hammer spring would sort this out if this is the case?

Possible for a 500 pump spring to work?

Any sources known for replacements, I would give them a shot?

Benny Hill developed these he might know about spring availability.

Thanks for any help.

Edited June 29, 2013 by Triggerbender

[LikesToShoot]

When this problem first occurred I called Mossberg and explained how I used the gun and that I really needed a few spare parts. The rep. was understanding and asked for the serial # but mentioned that some parts were restricted. I kindly asked if I could purchase a fiiring pin and spring. After a short hold he said it was OK so I asked to order two of each and he agreed, ( i should have asked for more of other parts too).

The parts showed up about two weeks later, $47.ish and have been sitting on the work bench since.

Today I pulled the gun apart and started with the firing pin. There's really no channel to get clogged up so that's not the problem. The original pin measured 2.940" and the new one was 2.944" (on my caliper, YMMV) , of course the original spring was shorter. So I installed the new pin and spring and hope to run a hundred trouble free rounds thru it tomorrow.

[Triggerbender]

Was coil diameter and coil count the same as the original?

We are talking hammer spring not firing pin spring right?

Edited June 29, 2013 by Triggerbender

[LikesToShoot]

Was coil diameter and coil count the same as the original?

We are talking hammer spring not firing pin spring right?

I didn't think to get a hammer spring during that call to Mossberg. It was early morning, on my way to work, and I was surprised I got an answer. I ordered two firing pins and their springs, I wish I had tought to order a hammer spring. I didn't get a break down on parts cost or shipping. The total was around $47.00 and I gave then my C/C info at the first stop light I came to.

This new pin is .004" longer than what I had and I'm thinking it may be all that I need to light things up.

[mpom]

Had issue similar to OP; replaced hammer spring with one I found at Ace Hardware, trimmed to max length and no failure to ignite since, at least 300 rounds. Would be nice if Wolff made a stronger spring, but the Ace spring is going strong so far. Believe wire diameter is a bit larger. A shame Mossberg did not get this right, but an easy fix.

[Triggerbender]

Had issue similar to OP; replaced hammer spring with one I found at Ace Hardware, trimmed to max length and no failure to ignite since, at least 300 rounds. Would be nice if Wolff made a stronger spring, but the Ace spring is going strong so far. Believe wire diameter is a bit larger. A shame Mossberg did not get this right, but an easy fix.

How did you determine max length without coil bind?

Off to the hardware I go.

[mpom]

Before I changed out the spring I tried "preloading" the existing spring with a couple of small washers. I could only stuff one, as 2 would cause spring bind. Measured the spring plus one washer, about a 1/16 thick and trimmed new spring.

Can always just trim longer, say 1/8" or more and modify as needed till you can cock hammer, cut off a bit more for insurance and call it good. Went with new spring because adding spring compression with washer did not solve problem of misfires.

Nice thing is trigger pull did not change significantly with new spring; still about 4.5 lbs.

[LikesToShoot]

I had 2 light strikes out of 100 today with the Fed. Ultra. Looks like I'm stopping my ACE tomorrow and looking thru their spring collection.

[Triggerbender]

The nly

I had 2 light strikes out of 100 today with the Fed. Ultra. Looks like I'm stopping my ACE tomorrow and looking thru their spring collection.

The only hope you had was the longer firing pin.

A fresh firing pin return spring would work against you.

Edited July 1, 2013 by Triggerbender

[Triggerbender]

Before I changed out the spring I tried "preloading" the existing spring with a couple of small washers. I could only stuff one, as 2 would cause spring bind. Measured the spring plus one washer, about a 1/16 thick and trimmed new spring.

Can always just trim longer, say 1/8" or more and modify as needed till you can cock hammer, cut off a bit more for insurance and call it good. Went with new spring because adding spring compression with washer did not solve problem of misfires.

Nice thing is trigger pull did not change significantly with new spring; still about 4.5 lbs.

I tried the washer thing and saw no change either.

Do you have a size or part number for the spring you got?

Did you retain the cocking indicator?

I knowthe O.D. needs to be .250 to fit in the cap, so if you found a larger coil diameter did you get the cocking indicator thru the center of it?

Thanks

[LikesToShoot]

After work while driving to a local ACE hardware I made a few phone calls.

First I called Brownells and talked to one of their techs. He suggested I try to stretch the spring and he then tried to find info. for a spring that might work. Nope. I asked if he could provide any details of wire size and diameters of the springs in their spring pack. No luck there either. He then suggested I call Mossberg and get several hammer springs from them. I'll give him credit he was trying to help but didn't have any parts available.

Then I called Mossberg and explained to the lady what I was looking for. After about a 5 min. hold she told me it was a resricted item and part of the trigger group. She said I'd have to get it from Brownell's or Numrich. I laughed and told her that Brownells doesn't have anything listed for the 930. This is as I was walking into ACE.

Looking thru the drawers at ACE I only found one that would fit into the cap so I bought it. The wire size is .032" (factory is .039" on my scale) and it wasn't too much longer than what I already had. For $ 0.69 I figured I give it a try.

NOPE. It just doesn't feel like the hammer has enough force when dry firing into my thumb while holding the trigger group..I won't even waste my time taking this one to the range. Maybe if it was longer it might have worked.

EDIT TO ADD. I couldn't find anything on Numrich either.

Edited July 2, 2013 by LikesToShoot

[mpom]

Unfortunately I do not have the part # of the spring I picked up at a local hardware store. Yes, the cocking indicator fits inside the spring.

I would bring the old spring with you when looking for a replacement, and would look check out other HW stores, maybe True Value?

If necessary, can order something from internet, such as http://www.springsfast.com/part_detail_compression.php?part=4039&PHPSESSID=70e45b383b04db2540d5b00ae420637b

Yes, you have to buy a minimum of 6, but at $.42 each, your can spread the love!

Edited July 2, 2013 by mpom

[Triggerbender]

Unfortunately I do not have the part # of the spring I picked up at a local hardware store. Yes, the cocking indicator fits inside the spring.

I would bring the old spring with you when looking for a replacement, and would look check out other HW stores, maybe True Value?

If necessary, can order something from internet, such as http://www.springsfast.com/part_detail_compression.php?part=4039&PHPSESSID=70e45b383b04db2540d5b00ae420637b

Yes, you have to buy a minimum of 6, but at $.42 each, your can spread the love!

The custom springs from your link might be a way to go, don't know how much money or trouble this would be.

This seems to be an issue with this gun and if enough people contacted Wolff they might make some extra power springs.

I have contacted them once and they requested my spring measurements which I got right back to them and have since sent one follow up e mail and am still waiting on a responce.

[Triggerbender]

http://www.centuryspring.com/Store/search_compression.php

I found this place looking at the sizes they should have one to work.

How many lb. spring does a shotgun typically use?????????

I used the numbers off my original spring for a search and the one it came up with was 39lbs??.

looks like you have to buy $40 worth to order if I did it right.

[LikesToShoot]

http://www.centuryspring.com/Store/search_compression.php

I found this place looking at the sizes they should have one to work.

How many lb. spring does a shotgun typically use?????????

I used the numbers off my original spring for a search and the one it came up with was 39lbs??.

looks like you have to buy $40 worth to order if I did it right.

I went to another ACE and found a spring I think will work, for $0.95 @ I bought two.

Range test tonight , real test this weekend. 400 round match.

If it works I'll let you know and you can PM and I'll pick some up for you.

[mpom]

400 round match?

Where do you get your ammo from, as I would like to score some!

Hope a bit longer spring does the trick.

Would make sure the firing pin is clean and moves freely.

[Triggerbender]

http://www.centuryspring.com/Store/search_compression.php

I found this place looking at the sizes they should have one to work.

How many lb. spring does a shotgun typically use?????????

I used the numbers off my original spring for a search and the one it came up with was 39lbs??.

looks like you have to buy $40 worth to order if I did it right.

I went to another ACE and found a spring I think will work, for $0.95 @ I bought two.

Range test tonight , real test this weekend. 400 round match.

If it works I'll let you know and you can PM and I'll pick some up for you.

Take some measurements on it and see what you have.

I have been looking at the charts and am totally confused by all the different materials and formulas tofigure out the right spring.

My guess is the spring is under 23lb. comparing it to some 1911 mainsprings I have it is weaker.

Benny Hill or Kurt M might have some insight on this as they were in on developing this gun??????

[LikesToShoot]

http://www.centuryspring.com/Store/search_compression.php

I found this place looking at the sizes they should have one to work.

How many lb. spring does a shotgun typically use?????????

I used the numbers off my original spring for a search and the one it came up with was 39lbs??.

looks like you have to buy $40 worth to order if I did it right.

I went to another ACE and found a spring I think will work, for $0.95 @ I bought two.

Range test tonight , real test this weekend. 400 round match.

If it works I'll let you know and you can PM and I'll pick some up for you.

Take some measurements on it and see what you have.

I have been looking at the charts and am totally confused by all the different materials and formulas tofigure out the right spring.

My guess is the spring is under 23lb. comparing it to some 1911 mainsprings I have it is weaker.

Benny Hill or Kurt M might have some insight on this as they were in on developing this gun??????

Shot shells have never been in short supply around here. Lately it's around $65 for a float OTD at the LGS.

I think Benny and Kurt have jumped off the JM 930 ship but maybe they'll chime in.

My latest spring is .032" wire, .250" OS diam., 2 1/2" long with 19 coils. It was too long to get into the trigger group so I cut off 3 coils and used a screwdriver to compress the spring until the hammer could take over and lock it in.

My trigger pull is still at 4 1/4 lbs.

[LikesToShoot]

Bad news, Good news.

I shot some Fed. Ultras tonight (about 40) and had 3 light strikes. Man, I was bumming at this point.

Then I went to the rifle range to check my POI, since I knocked off the front sight and had to re-attach it. The sights were off and I correct them but I'm happy to say it fired 25 of the B&P slugs without a problem.

I'm going to double check the bolt, piston and everything else that moves to make sure nothing can keep this from closing up correctly. I'm also going to chamber check these Fed. Ultra's to see if there might be a problem here.

[mpom]

LTS, sounds like the replacement spring @ .032" is not as strong as the factory, and may not supply sufficient force to hammer, even if longer.

[LikesToShoot]

LTS, sounds like the replacement spring @ .032" is not as strong as the factory, and may not supply sufficient force to hammer, even if longer.

It's possible but the new spring feels like it has as much force and more follow thru than the original spring. I pulled it apart tonight and all is good. I gave it another good cleaning paying close attention to the piston and it's bore in the barrel.

With all the B&P firing fine I really think this is now just an ammo issue.

Remember Big Daddy's review until he found out he had ammo problems.

[Griz]

Have you ever pulled the rings off the piston and cleaned it?

[LikesToShoot]

Have you ever pulled the rings off the piston and cleaned it?

Yes, they're spotless. as is the tube and after last night the bore on the barrel that it goes into.

Speaking of piston and rings, when I bought the gun and took it apart there was one ring on the piston and a second ring on the tube sitting loose by it's self with the taper facing up. A friend of mine has a JM 930 and his was the a same way when we first took it apart. I shot it like this for the past year and haven't had any problems until a couple months ago. Recently I seen a You Tube video were the both rings are on the piston, that make more sense so I connected them the night before last.

During last nights cleaning I deep cleaned inside the bore were the piston goes.

Tonight I'll be back at the range with different ammo.