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New JM PRO Owner "Disappointment"

NoImpactNoIdea

NoImpactNoIdea

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Hello everyone, I'm a new member w/a new 22" JM Pro. I have read a few threads, posts and the owner's manual about the JM Pro after my purchase trying to become knowledgeable. Of course my shotgun has a problem too. When fully loaded with an empty chamber I cannot load a shell by pulling the bolt to the rear and pushing the bolt release. Apparently this is a very well known problem. You guys know it, JM knows it, Brownell's knows it and has a WebBench article on the fix , and Mossberg knows it.

http://www.brownells.com/.aspx/lid=...ing-A-Mossberg-930-Feed-From-The-Tube-Problem

I followed Brownell's instructions but it did not fix my problem.

I followed Jerry's instructions on maintenance and lubrication. I even used the Hornady One Shot to clean it and Wilson Combat Universal oil to lube it.

If "everyone" knows about this problem why has Mossberg let this "Disappointment" continue to plague us.
 
I just ordered a SkyTac Modified Shell Stop/Bolt release for Mossberg 930 and a SkyTac Modified replacement lifter for Mossberg 930 (Polished). I am hopefull this will solve my issues.
 
NoImpactNoIdea said:
Hello everyone, I'm a new member w/a new 22" JM Pro. I have read a few threads, posts and the owner's manual about the JM Pro after my purchase trying to become knowledgeable. Of course my shotgun has a problem too. When fully loaded with an empty chamber I cannot load a shell by pulling the bolt to the rear and pushing the bolt release. Apparently this is a very well known problem. You guys know it, JM knows it, Brownell's knows it and has a WebBench article on the fix , and Mossberg knows it.
http://www.brownells.com/.aspx/lid=...ing-A-Mossberg-930-Feed-From-The-Tube-Problem
I followed Brownell's instructions but it did not fix my problem.
I followed Jerry's instructions on maintenance and lubrication. I even used the Hornady One Shot to clean it and Wilson Combat Universal oil to lube it.
If "everyone" knows about this problem why has Mossberg let this "Disappointment" continue to plague us.
Click to expand...

Aloha and welcome to the forum from NY.

Sorry to hear you are having problems with your new 930.

I don't own a 930 but I'm sure one of the 930 owners will chime in here and be able to help you.
 
Your problem more than likely is a magazine spring length issue. Sounds like your spring it too long causing too much force on the follower. When there is this much force the shell stop can't release a shell easily into the loading ramp.

If you load one or two less shells and it works this is your issue.

You need to cut a coil off at a time and find the sweet spot as in length. Too long and you have the issue your experiencing. To short and the last round or two won't have enough spring force to be thrown into the loading ramp.

There are several posts about magazine spring tuning on this forum. Search and you can read them all.
 
awiner said:
Your problem more than likely is a magazine spring length issue. Sounds like your spring it too long causing too much force on the follower. When there is this much force the shell stop can't release a shell easily into the loading ramp.

If you load one or two less shells and it works this is your issue.

You need to cut a coil off at a time and find the sweet spot as in length. Too long and you have the issue your experiencing. To short and the last round or two won't have enough spring force to be thrown into the loading ramp.

There are several posts about magazine spring tuning on this forum. Search and you can read them all.
Click to expand...

^ This has cured the issue for more than a few of our members.

Factory mag springs are almost always too long. When you pull the charging handle back, how much force do you use? The mechanism is designed to operate under explosive force, so treating it gingerly while manually operating can produce a few chambering issues.

...and welcome aboard...
 
I just tried it with 5 shells, same issue. When I got the first shell out I lost all force behind the rest of the shells. Spring got hung up on something. Pushed shells up with thumb and spring force came back. ??
 
If you are losing force the follower is getting stuck in the mag tube. This is common around the mag extension to mag tube joint.

Again there has been a lot of discussion about this in the past on the forum.
 
I had to tune my spring to the gun. I cut a few coils off after polishing the carrier latch and it started running really well. Another solution is to get a Nordic XXL end cap for your tube. It adds 1 1/2 inches to the tube and gives you just enough space for the spring to not have to much tension. On my 24" gun it also gave me an extra round in the tube.

https://nordiccomp.com/product/nc-shotgun-extension-tube-end-cap-xl/
 
I just worked on a brand new JM Pro a few weeks ago. It still had the old style Nordic tube. It did have a different follower, but the new follower still sucked.
 
No More Disappointment.
I'm HAPPY now. I've taken a chill pill, some advice and put forth a plan. I trimmed 1" off the mag. spring between funtion checks and ended up with a 36" spring that functions in my 22" JM PRO. I kinda went on an online shopping spree for my 930 before I got her up and running though. I purchased:
2- Wolff 40" mag. springs
Nordic low-drag follower
Nordic QDA plate
Grovtec QDA push button swivel
SkyTac shell stop/bolt release
SkyTac modified & polished lifter
OR3GUN Marine spacer tube(gray)
OR3GUN anodized forearm retainer
Now I'm just waiting for delivery on everything.
Happy endings are great.
 
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