940 Pro Tactical
- Thread starter DL Knives
- Start date
Starman213
Copper BB
Yep, the barrel clamp is still made out of polymer.
AIRB0RNE6176
.410
Which sucks, as I've burned through two (2) of them in less than 2,500 shells. The first clamp had a flashlight, and the second clamp was bare. The plastic gets too hot and starts to warp. Tightening it down doesn't help as the plastic/polymer stretches and is the worst idea of material for a barrel clamp on a semi-auto shotgun. Hopefully, GG&G, Nordic, or Mesa Tactical will step up with a metal one...
WVDeere
.22LR
At first I had the issue of only loading 5 shells. Once I took the extension loose and adjusted it I can now load 7 low brass shells fine but slugs or buckshot which are a slight bit longer I am about 1/4-1/2 inch shy of getting the 7th one in. I feel like my spring is extremely long. I am going to leave it loaded with 6 for about a week or so then disassemble and try again. Seems like the follower needs trimmed or possibly the spring itself but I don’t want to hurt reliability. It ran everything I put through it the first day. But I want it to hold that one extra shell also. It has required a little more babying than I was expecting to get everything running smoothly.
One thing to be aware of is the differences in shell lengths from different manufactures. Common 2 3/4 and 3 inche shell actually come in a wide variety of lengths depending on the brand, whether they are low or high brass and the type of crimping. You can see 2 3/4 unfired shells that are around 2 1/4 to 2 5/16 in length and 3 inch unfired shells that vary around 2 1/2 to 2 5/8 inches.
You might want to measure the shells you are using and compare them to other brands. The capacity issue you're seeing might not be the gun but the ammo you are using.
Regards
WVDeere
.22LR
I appreciate it. And yes there are some variances in shells. But only 1 out of 4 brands I tried were able to fit 7 in the mag tube. And it’s close. The others are close to 1/2 inch short of going on. My spring is probably 24-30 inches longer than the tube. It’s a pain to get back in. Just seems extra long.
WVDeere
.22LR
Update on my issues. I reached out to Mossberg. They emailed me back saying that if the shells are over 2.5 inches long it will probably only hold 6. The forearm is designed to have play. I remedied the popping with a dremel. Still moves but atleast doesn’t make a loud crack. However now I have a new issue. The bolt does not seem to have enough spring to push the shell in. And only when the mag tube is full. Pull the bolt back and it stays fully back with a shell in the elevator. you have to either slam the bolt forward or slightly touch the elevator from the bottom to get it to chamber. Only on the first 2 shells out of the tube then runs fine. I can’t figure it. I’ve cleaned everything I can and tried working the bolt over and over. Hoping to shoot it some more this weekend and it is just a break in thing.
WVDeere.
Regarding your “new issue”. The number of rounds in the magazine tube or the magazine assembly (tube, spring, follower) should have nothing to do with the operation of the bolt. Something’s wrong.
With the gun clear (nothing in the tube, on the elevator and nothing in the chamber, nothing on the bench) does the bolt lock back normally? When you hit the bolt release does the bolt slam home normally? Do this half a dozen times. Is all ok?
Have you ever disassembled the back of the gun? I’m talking about removing the stock and bolt return spring assembly?
Regarding your “new issue”. The number of rounds in the magazine tube or the magazine assembly (tube, spring, follower) should have nothing to do with the operation of the bolt. Something’s wrong.
With the gun clear (nothing in the tube, on the elevator and nothing in the chamber, nothing on the bench) does the bolt lock back normally? When you hit the bolt release does the bolt slam home normally? Do this half a dozen times. Is all ok?
Have you ever disassembled the back of the gun? I’m talking about removing the stock and bolt return spring assembly?
WVDeere
.22LR
I have not disassembled the back of the gun. I noticed when I shot the gun yesterday. Fully loaded Fire one round the next hangs up. Barely touch the elevator from the bottom it goes home. Locks back fine empty. When hit release it goes home hard like it should. You can load 7 or 6 rounds in it and pull back the bolt and release and it stays open. Have to nudge the elevator from the bottom or hit the bolt to get it to close when loaded. Rounds 4-1 run fine.
WVDeere
.22LR
Update. Went to the range today to see if this thing just need broken in. I bought 100 shells of high brass 1350fps birdshot and had some random boxes of low brass some high velocity buckshot and slugs. They all ran the same. Terrible. After letting the gun sit basically in a CLP bath over night. Cleaned it up and removed the oil where it shouldn’t be and put some back where it should and the problem just keeps getting worse. Jams every 2-3 rounds. Failure to feed. Failure to eject. Bolt keeps getting stickier. I feel like it’s either the trigger group and elevator or the buffer spring in the stock. That I never messed with. I took it by 2 gun stores today. They both agreed something is wrong but didn’t know what. One of them has sold many many 940 pro shotguns and never had one returned. A call to mossberg got me an automated message to go online and fill out a form to ship it to them. Said lead times are 6-8 weeks. To top it off my red dot would randomly shut off. Have to hit the + button several times for it to come on again. Or maybe was changing to night settings on its own idk. Could be million good ones and I picked the rotton apple. So much for the excitement of a new shotgun. See ya in the spring. Here a few pics I snapped of the issues. 
jxring
.22LR
All,
I consider myself fortunate to have purchased/obtained a NIB 940 JM PRO (9+1) here in CA (yes we do purchase firearms here). I have a 590 and also a 500 SPX with the awesome LPA sights on the 500 SPX. I put Mossberg sights on the 590. I also have a heavy barrel that I bought separately (military thicker wall for the 590) that makes it a 590A1.
My 940 JM Pro came with only the Briley Modified choke tube (missing the others) and also missing the manual. One call to Mossberg was all it took and the manual was in USPS and the Briley chokes (IC & C) in a case were received also at no charge. Five Stars to Mossberg for awesome service! I may purchase a Full choke tube from Briley later. I contacted Briley and the choke tubes are also Win-Chokes. Again, these 940 JM PRO critters are kind of hard to get, especially after the first of the year. Now that I have the Cylinder choke tube--going to put some slugs down range and report. The 500 SPX was "super scary" accurate with my slug hand loads (1 oz.). Cannot wait to check out the 940 JM Pro! First gas shotgun I've ever had.
JX
I consider myself fortunate to have purchased/obtained a NIB 940 JM PRO (9+1) here in CA (yes we do purchase firearms here). I have a 590 and also a 500 SPX with the awesome LPA sights on the 500 SPX. I put Mossberg sights on the 590. I also have a heavy barrel that I bought separately (military thicker wall for the 590) that makes it a 590A1.
My 940 JM Pro came with only the Briley Modified choke tube (missing the others) and also missing the manual. One call to Mossberg was all it took and the manual was in USPS and the Briley chokes (IC & C) in a case were received also at no charge. Five Stars to Mossberg for awesome service! I may purchase a Full choke tube from Briley later. I contacted Briley and the choke tubes are also Win-Chokes. Again, these 940 JM PRO critters are kind of hard to get, especially after the first of the year. Now that I have the Cylinder choke tube--going to put some slugs down range and report. The 500 SPX was "super scary" accurate with my slug hand loads (1 oz.). Cannot wait to check out the 940 JM Pro! First gas shotgun I've ever had.
JX
jxring
.22LR
All,
Just pictures of the 1 ounce slug hand loads and some .69 ball (scary bad) hand loads from the Mossberg 500 SPX. Indoor range at 25 yards on standard and reduced sized targets. I do not assume any responsibility for loading data (you are on your own) . All of these were from Mossberg 500 SPX cylinder bore stock Mossberg. These were fired from a fixed rest, the "ball" rounds walked into the target (maintained same hold throughout).
Just pictures of the 1 ounce slug hand loads and some .69 ball (scary bad) hand loads from the Mossberg 500 SPX. Indoor range at 25 yards on standard and reduced sized targets. I do not assume any responsibility for loading data (you are on your own) . All of these were from Mossberg 500 SPX cylinder bore stock Mossberg. These were fired from a fixed rest, the "ball" rounds walked into the target (maintained same hold throughout).
Attachments
JeepsAndGuns
.410
Kinda looks like you are having a failure to extract and eject.
How does the extractor look? Does it grab the rim of the hull good? Is the spring good, have plenty of tension?
How about the chamber?
You might try taking a bore brush and a short section of cleaning rod, chuck it up in a drill and put some bore cleaner on it then run the dill working the brush through the chamber to clean and lightly polish it. Then clean it out and try again.
I for one am really interested in how this turns out, as should Mossberg - future sales hang in the balance. 
I looked at a Beretta A300, but any semi-auto decision is on hold for now. I only own the one Mossberg - the Mav '88 - but joining this forum has instilled a sense of brand/family loyalty - kind of like how I am with side arms. [S&W] Thanks for the updates. 
I looked at a Beretta A300, but any semi-auto decision is on hold for now. I only own the one Mossberg - the Mav '88 - but joining this forum has instilled a sense of brand/family loyalty - kind of like how I am with side arms. [S&W] Thanks for the updates.