JM 930 light primer strikes

[JohnLTD]

In for solution.

I had 2 very unwelcome light strikes at a match this past weekend and it has always occurred with Federal Tactical LR slugs. I think I is just the ammo but my other shotguns touch it off no problem so I'd like to see if anyone can figure it out. FYI It has happened with the gun clean and also filthy so I don't think that is really playing a part.

[Nuke8401]

Dirty rings, not going into full battery. Dirt on inside of rings make piston tight in bore. Also firing pins peens over on the hammer end. Check it for mushrooming. Both rings should be connected to the piston, wider ring captures the other ring. Search and you will fimd dirty rings as the cause most of the time.

[Nuke8401]

Read "mossberg 930 is a bolt action now" thread

[mpom]

If not going into battery, then there should not be a firing pin indentation in primer, correct?

When I had my misfires I clearly had indents in primers.

I have to apologize for sending people on a wild goose chase, looking for a stronger hammer spring at local hardware stores. Yes, I did get some springs there but for a different project. Believe the stronger spring I use which eliminated the misfires came from my collection of various gun related springs. Looking the stash over, 1911 and Hi Power main springs are too large in diameter, but Ruger 1022 hammer spring is a perfect fit at .25" OD. According to my caliper the Mossberg spring wire diameter is .043" and my spare 1022 spring is .044", and a bit longer at 1.5" vs 1.3" for the Mossberg. Looked at aftermarket Extra Power Ruger 1022 hammer springs and Wolff makes one, SKU #166803, for around $7.50. A 10 pack goes for $30, so pretty reasonable if this works. Wolff is currently closed so could not ask their tech dept what wire dia. they use in the EP one.

Again, sorry for the misinformation and hope this new info is useful

[Nuke8401]

Can't find the post now, but "Benny" has commented on this sevveral times in the past. Wire wheel on a dremil is the easy way. Also lubrication of tube and rings; use whatever you want, I use Mobil one, most important thing is to wipe all lube off. Lube just makes the rings gum faster. With the forarm left off assemble the gun, you should be able to move he piston by hand and it should return forward by spring pressure. With the bolt not in full battery the firing pin basically has to reach across the gap betwen bolt face and shell or if you assume the shell is touchimg the bolt face the shell can move forward in the chamber thus not givimg a solid firig pin strike. While I have replaced my firing pin, I don't think slight mushrooming of the hammer end is a problem.

Edited July 3, 2013 by Nuke8401

[Triggerbender]

If not going into battery, then there should not be a firing pin indentation in primer, correct?

When I had my misfires I clearly had indents in primers.

I have to apologize for sending people on a wild goose chase, looking for a stronger hammer spring at local hardware stores. Yes, I did get some springs there but for a different project. Believe the stronger spring I use which eliminated the misfires came from my collection of various gun related springs. Looking the stash over, 1911 and Hi Power main springs are too large in diameter, but Ruger 1022 hammer spring is a perfect fit at .25" OD. According to my caliper the Mossberg spring wire diameter is .043" and my spare 1022 spring is .044", and a bit longer at 1.5" vs 1.3" for the Mossberg. Looked at aftermarket Extra Power Ruger 1022 hammer springs and Wolff makes one, SKU #166803, for around $7.50. A 10 pack goes for $30, so pretty reasonable if this works. Wolff is currently closed so could not ask their tech dept what wire dia. they use in the EP one.

Again, sorry for the misinformation and hope this new info is useful

I just pulled the spring out of a 10-22 and it measures .040

So I tried it just putting it in under the cap without cutting it and no cocking indicator and it is lighter/softer than the Mossberg spring.

Ruger Redhawk pistol springs are the same length and O.D. I found some reduced power ones laying around (12,13, 14lb.) but are too weak and according to Wolff's web site standard spring is 17lb..

The XP spring might do it, Beat them upabout a 930 XP spring while you are there.

Edited July 4, 2013 by Triggerbender

[LikesToShoot]

Can't find the post now, but "Benny" has commented on this sevveral times in the past. Wire wheel on a dremil is the easy way. Also lubrication of tube and rings; use whatever you want, I use Mobil one, most important thing is to wipe all lube off. Lube just makes the rings gum faster. With the forarm left off assemble the gun, you should be able to move he piston by hand and it should return forward by spring pressure. With the bolt not in full battery the firing pin basically has to reach across the gap betwen bolt face and shell or if you assume the shell is touchimg the bolt face the shell can move forward in the chamber thus not givimg a solid firig pin strike. While I have replaced my firing pin, I don't think slight mushrooming of the hammer end is a problem.

I picked up some different ammo tonight but didn't make it to the range. I went with Rob to Sparta to help Jeremy, Aaron and Kevin with building the stages for this weekends match.

The gun passes piston movement test so I'm feeling real good about mine just being an ammo problem, if not I'll be firing a bolt action 930 as mentioned above.

[Triggerbender]

This is where I am on this deal.

I own more than my share of shotguns, I have shot 300+ rounds a week since 1981. I am not new to shotgun many have come and gone over the years good and bad.

The Mossberg has the SLOWEST lock time out of all of them with the lightest strikes.

I reload and have Winchester, Cheddite, Federal and Wolf primers on hand.

Hands down Wolf shotgun primers are the hardest, when I use Wolf in the Mossberg it leaves the primer with the smallest dent after being fired. So small it is hard to believe it fired, I don't used them in this gun anymore.

All other fired brands look as normal in the Mossberg and the Wolf look normal after being fired in all the other curret stable of shotguns.

It ALMOST looks like a cleared unfired AR round after you drop the bolt on it and the unsprung FP taps the primer thats how light a strike it has.

It does this consistantly and no other gun I have does this.

In my mind a better hammer spring is in order. Would be nice to be confident it will go bang when you pull the trigger.

If you do a search for 930 light primer strikes it appears to have been an issue for years.

Look at the pic below at the center bottom row shell this is how mine look using Wolf primers.

This pic is from another thread where the same issue is with Remington factory shells.

I don't use Remington shotgun primers.

Edited July 4, 2013 by Triggerbender

[LikesToShoot]

Ok, made it to the range this morning and had 2 out of 100 light strikes. Thanks to Nuke8401, I pulled the forarm off and checked the piston movement, yup, it's sticking at times.

Now, out comes the Flitz and the buffing wheel.

Thanks Nuke!

[Triggerbender]

Ok, made it to the range this morning and had 2 out of 100 light strikes. Thanks to Nuke8401, I pulled the forarm off and checked the piston movement, yup, it's sticking at times.

Now, out comes the Flitz and the buffing wheel.

Thanks Nuke!

Make sure to take the rings off the piston and clean and polish up the contact surfaces.

Mine has piston been polished to a mirror finish inside where it runs on the mag tube, around the ring lands and inside the rings and around the sealing areas.

The piston and rings are a real crap magnet for sure.

[Nuke8401]

Yes inside the rings seems to be the key. Even with a wire wheel on a dreml it is easy to polish the dirt and not get down to metal, I use a scrib to check, some clean with a scrib. Also look in the cyl where the pistol goes, there may dbe a ring of dirt wheremthe rings normally stop going forward, as long as the piston goes fully forward this shouldn't matter but I clean it every few times I clean the piston. I would say a clean piston with minimal lube should be trouble free for 600-1000 rounds. I usually clean mine just befor a match and test fire. Of course it could be something else but this is kost likey the cause.

[LikesToShoot]

I guess I'm just spoiled by shooting an M&P pistol that requires very little attention and this JM just started being picky a few months ago. I thought I has cleaning it well enough but obviously I was wrong.

Is ther anything wrong with taking the rings off and throwing them and the piston in the tumbler for a good cleaning?

[Nuke8401]

I havent tumbled mine but should be ok, its at least as tough as brass. Again, I'm not claiming the is the exeact cause of your problem but history here says it is the most likely cause. Empty chamber starts/hamd cycling seems to be the other isue. Good luck.

[mpom]

No joy on getting info from Wolff on wire diameter of XP 1022 hammer spring, as they are closed today. Imagine that, a 4 day weekend!

Will try again monday. Found out Power Custom also makes an XP hammer spring for ruger 1022. Of course they are closed too.

[Nuke8401]

I would hesitate to use a heavier hammer spring as the firing pin already gets mushroomed from the oem spring. Might be worth loking at a weaker firing pins spring but that might lead to slamfire.

Edited July 5, 2013 by Nuke8401

[mpom]

heavier spring is what it took to get reliable ignition. will replace fp if/when needed, but had no choice, as unreliable shotgun with unmushroomed fp is a paperweight.also thought about a lighter fp spring but did not want to risk an ad. my new hammer spring is marginally stronger than oem, as trigger pull is not noticably heavier, yet cocking force is a bit heavier.

a light primer indent with a bolt in battery begs for a harder hit. its working so will have to accept possibility of shorter fp life, although dont really think this will happen if fp steel and heat treatment are decent.

[Triggerbender]

heavier spring is what it took to get reliable ignition. will replace fp if/when needed, but had no choice, as unreliable shotgun with unmushroomed fp is a paperweight.also thought about a lighter fp spring but did not want to risk an ad. my new hammer spring is marginally stronger than oem, as trigger pull is not noticably heavier, yet cocking force is a bit heavier.

a light primer indent with a bolt in battery begs for a harder hit. its working so will have to accept possibility of shorter fp life, although dont really think this will happen if fp steel and heat treatment are decent.

I'm with you on this deal, if I have to replace a firing pin I can live with that.

If Mossberg won't sell me one I'll make one, still can't make springs though.

[LikesToShoot]

heavier spring is what it took to get reliable ignition. will replace fp if/when needed, but had no choice, as unreliable shotgun with unmushroomed fp is a paperweight.also thought about a lighter fp spring but did not want to risk an ad. my new hammer spring is marginally stronger than oem, as trigger pull is not noticably heavier, yet cocking force is a bit heavier.

a light primer indent with a bolt in battery begs for a harder hit. its working so will have to accept possibility of shorter fp life, although dont really think this will happen if fp steel and heat treatment are decent.

I'm with you on this deal, if I have to replace a firing pin I can live with that.

If Mossberg won't sell me one I'll make one, still can't make springs though.

I was up late last night trying to get this thing cleaned up for the match today. EVERYTHING was scraped clean and polished but at times the piston wouldn't go into it's bore no matter how much I tried to make things smooth. I had to give up and get other things ready and hope for the best.

Well today before the match I ran into JM himself. I introduced myself and congratulated him on his most recent win. Then I asked if he could offer a suggestion on what I should look for regarding my light strikes. He said to pay attention to possible carbon ring in the bore by the gas ports and above where the top ring stops. I told them that all has been cleaned VERY well and asked about it possibly be a weak gas piston return spring. He said he replaces all the springs each year including the recoil and extractor spring. I thanked him for his time and wished him and enjoyable match.

Today I ran through 12 of 20 stages and had 1 light strike near the end of our day, There were two Benelli's on the squad that each had one light strike each, so I guess I can't complain.

If the opportunity arises tomorrow I may tell him how it went for me and ask if he has a suggestion on where we can get springs since Mossberg won't sell them to us.

[Triggerbender]

heavier spring is what it took to get reliable ignition. will replace fp if/when needed, but had no choice, as unreliable shotgun with unmushroomed fp is a paperweight.also thought about a lighter fp spring but did not want to risk an ad. my new hammer spring is marginally stronger than oem, as trigger pull is not noticably heavier, yet cocking force is a bit heavier.

a light primer indent with a bolt in battery begs for a harder hit. its working so will have to accept possibility of shorter fp life, although dont really think this will happen if fp steel and heat treatment are decent.

I'm with you on this deal, if I have to replace a firing pin I can live with that.

If Mossberg won't sell me one I'll make one, still can't make springs though.

I was up late last night trying to get this thing cleaned up for the match today. EVERYTHING was scraped clean and polished but at times the piston wouldn't go into it's bore no matter how much I tried to make things smooth. I had to give up and get other things ready and hope for the best.

Well today before the match I ran into JM himself. I introduced myself and congratulated him on his most recent win. Then I asked if he could offer a suggestion on what I should look for regarding my light strikes. He said to pay attention to possible carbon ring in the bore by the gas ports and above where the top ring stops. I told them that all has been cleaned VERY well and asked about it possibly be a weak gas piston return spring. He said he replaces all the springs each year including the recoil and extractor spring. I thanked him for his time and wished him and enjoyable match.

Today I ran through 12 of 20 stages and had 1 light strike near the end of our day, There were two Benelli's on the squad that each had one light strike each, so I guess I can't complain.

If the opportunity arises tomorrow I may tell him how it went for me and ask if he has a suggestion on where we can get springs since Mossberg won't sell them to us.

As fast as that guys finger is, the slow lock time seems like it would be a problem.

I would bet his trigger has been massaged a bit and since his name is on them and he is sponsored by them it would not be in his best interest to get in the middle of the of the design/quality issues with these things.

A little off the record tip would be nice though.

[mpom]

Got to talk to Wolff and their XP 1022 hammer spring is made from ,040 wire, so not much different than Mossberg stock, but is longer at 1.6" vs 1.3", so 23% longer, which should require more compression force at cocked hammer height.

Power Custom uses Wolff springs. SKU for Wolff single spring is 16801 for $7,50 or a 10 pack, SKU 16803 for $30. Hope this is a solution for some folks. Has worked for me. Wonder what hammer spring Mr JM runs, if not OEM.

Mark

Edited July 8, 2013 by mpom

[LikesToShoot]

I had one more "light strike" today and consider all the other guns having issues at the match I don't think that was too bad.

Now I don't really think it's a hammer spring issues but more likely due to it being out of battery. I'm going to try a new piston return spring and see what happens.

[mpom]

would think you should look at the spring pushing bolt carrier into battery, which lives inside the stock, if problem is bolt out of battery.

can test theory to see if out of battery hammer drop could give a shallow indent by priming a fired hull and dropping hammer on it while pulling back on bolt handle to unlock bolt a bit. suspect there will be np primer indent. would try it but dont have a 209 primer.

could it be linked to ammo choice? are all the light hits same ammo?

[Triggerbender]

Got to talk to Wolff and their XP 1022 hammer spring is made from ,040 wire, so not much different than Mossberg stock, but is longer at 1.6" vs 1.3", so 23% longer, which should require more compression force at cocked hammer height.

Power Custom uses Wolff springs. SKU for Wolff single spring is 16801 for $7,50 or a 10 pack, SKU 16803 for $30. Hope this is a solution for some folks. Has worked for me. Wonder what hammer spring Mr JM runs, if not OEM.

Mark

Did they say if they were looking into making a spring for the 930?

You would think with all their spring experience they could recommend a flipping spring for the thing.

[LikesToShoot]

would think you should look at the spring pushing bolt carrier into battery, which lives inside the stock, if problem is bolt out of battery.

can test theory to see if out of battery hammer drop could give a shallow indent by priming a fired hull and dropping hammer on it while pulling back on bolt handle to unlock bolt a bit. suspect there will be np primer indent. would try it but dont have a 209 primer.

could it be linked to ammo choice? are all the light hits same ammo?

Jerry said he eplaces all the springs once a year. When I call Mossberg I'll se what they'll sell me. I do plane to get the recoil spring too. I guess I'll replaced the recoil and the piston spring at the same time and be done with it.

The ammo brand didn't matter.

[mpom]

TB- the lady at wolff said they have no plan to make xp hammer springs for the 930, not much demand. dont know how high on the chain of command she is. the spring manufacturer i hot linked is a good option as they use 0.042 wire, thicker than even wolf's xp, and springs are 2" long. downside is $25 minimum order plus shipping, but that $25 gets you a boatload of springs! if someone takes the risk and orders, they could easily triple their original investment, selling the springs for $1 each!