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Mossberg 930 Autoloader Barrels

Re: Does the 935 Barrel fit a 930 Receiver?

I did a little more reading in the owners manual and it states that the barrels are NOT interchangeable...

Top of Page 17.
Barrels are not interchangeable between model numbers, gauge or capacity. 930TM and 935TM model barrels are interchangeable only with barrels of the same model, gauge and capacity.

But I was wondering if the difference was just the return spring. (Item # 12 in the parts list) But since I don't have the actual P/N's (just the parts list is included in the Owners Manual) I can't say for sure what is different. If that is all, heck you buy a 935 return spring and barrel assembly and you now have magnum capability for a whole lot less. That ultimate goose gun all of a sudden becomes real cheap.

Anybody have access to the actual P/N's of the various components of the two models?

Paul
 
Re: Does the 935 Barrel fit a 930 Receiver?

No, they are not interchangable. The 935's receiver and ejection port are longer to accomodate the 3 1/2" shell. The 935's barrel is overbored to 10 gauge dimensions as well for improved patterns. The barrel is correspondingly a bigger diameter. While they may look very similar the are dimensionally very different.

Mossberg 935 barrel. Note area of barrel that actually is inside receiver. It is longer than the 930 barrel.
Mossberg935barrel.gif


Mossberg 930 barrel. Note area of barrel that actually is inside receiver. It is shorter than the 935 barrel.
Mossberg930barrel.gif

I hope this helps. All information and pics is available on the Mossberg website.
 
Re: Does the 935 Barrel fit a 930 Receiver?

I have been digesting this. The one thing I know is that I still don't know. A picture doesn't really tell me anything. It would still be really nice to have hard data like the parts number list to be able to tell exactly which parts are different.

Stemming from the design of the formidable 935 Magnum, the 930 is the best value in 3" autoloaders
on the market today

But I also don't want to disrespect tcecil88 because he is probably right. But I'm still holding out for a parts list or someone who actually owns both models to be able to say what actually is different.

Respectfully
Paul
 
930 spx chamber/gas port/spring question

Just got a 930 SPX Blackwater edition – really like the shotgun but like many during my first time out with it the low power Federal shot shells would occasionally stove pipe/half eject. Then on round 75 or so one stuck tight in the chamber and the joy was over - I had to disassemble, manually release the extractor with a small screw driver and then use a cleaning rod to tap the spent case out of the chamber.

Looking at the chamber I noticed how rough it was, that definitely would cause issues with extracting “lower power rounds” – overcoming the extra friction. Had the same issue with my RRA 458 SOCOM scratching up the brass really bad and fixed that by polishing up the chamber with my dermel with felt polishing wheel and Flitz – the 458 now runs extremely well. So I broke out the equipment and polished up the first 3/4 of an inch of the 930’s chamber – it came out pretty nice (picture below). You can see the difference between the factory surfacing and polish. I think this must be why they want you to cycle a lot of high power rounds through it – smooth out those chamber ridges.

930spxpolishedchamber1.jpg


Back out to the range and 150 rounds later things worked pretty good overall. Now I could ONLY get the 930 to stovepipe or not eject the "low power" spent shells (about 80% of the time) by “limp-wristing” the shotgun while firing (letting it float). No more of the stuck case thing! I noted that the action would cycle back 1/2 to 3/4 of the way when letting it float. Very close to ejecting but not quite there…

So the next thing to inspect was the gas ports – picture below (there is a little loose debris in the right port). The right one measures 0.143” diameter and the left is 0.141” diameter. One solution would be to drilling them both out on the mill with a #27 drill (0.144”) which increases the total port area by ~3% - not very much. The next standard (easy) option would be a drill #26 (0.147”) which provides an increase of ~5% for one port and ~8% for both. I would of course debur the port when finished. My question – has anyone increase the gas ports on one of these 930’s? If so what sized did you go to and what were the results?

Also, I have read that there is a “Red” spring for the 930 gas system which supposedly can handle the lower power round more reliability – this might be the issue rather than the gas ports. Can anyone confirm this? I have the “Blue” spring as can be seen in the photo.

930spxgasports.jpg
 
Re: 930 spx chamber/gas port/spring question

Welcome to the Mossberg Owners Forum Starfury !!

Looks like you got the solution figured out...are you a gunsmith !?
 
Re: 930 spx chamber/gas port/spring question

Not a gunsmith, just a mechanical/aero engineer that works hands-on with a lot of hardware for my day job. I always enjoy working on the new firearms I pick up and try to remedy all the little nagging issues. I knew the 930 had some issues based on all the posts but I saw that as a challenge as well :)

Something else occurred to me after posting last night, I wonder if the barrel gas block would perform better (i.e. let the gas piston ride more freely with less wear) if I polished up the block inner surface extending from the gas ports to the edge – you can see by the picture above that the surface area that the piston moves across is rough as a cob as well. The additional benefit of smoother/polished surfaces is that they are much easier to clean, don’t pick up debris as easily and don’t rust/corrode as fast.

What got me thinking about polishing this area as well is that I noted the piston moves freely when install in the gas block and you pull it back and forth as a subassembly. However, when installing the barrel subassembly back onto the tube as a full assembly (minus the forearm) and pull on the piston, it moves but it is tight and sometimes sticking in the stroke, the return spring (at the base of that pusher assembly) isn’t enough to always push it home without a little coaxing. If you drop the bolt – it always shoves the piston all the way up to the home position (I guess that is Mossberg’s way of assuring the weapon always resets itself). I think some of this might have to do with the alignment issue in the gas block with the heavy spring and the little seal rings that float somewhat. I have noted some of the scratches on the tube others have talked about and that sometimes it is hard to slide the barrel subassembly over the tube. I made an aluminum insert (same diameter as the tube) which I can push into the gas block and slightly move the spring/seal around (somewhat by trial and error) until I find the position where the barrel subassembly drop easily onto the tube.

Thoughts? I might have to tool it up tonight and polish that gas block area up as well to see what results I get.
 
Re: 930 spx chamber/gas port/spring question

I went ahead and polished up the inner surface of the gas block and it came out good – piston slides smoothly but there is still a little resistance when it’s all assembled. With the gas spring seal aligned, the barrel slide right on - so the resistance is most likely due to the stack up of out of plane tolerances between the barrel and tube (heck it is only a $600 shotgun). Will have to give it try this coming weekend to see if anything improves on cycling the low power stuff – if not I think I will go after the gas ports.


930spxgasblockpolished.jpg
 
Re: 930 spx chamber/gas port/spring question

I bet your 930 SPX will run like butter with the low brass. My SPX has been 100% with the low brass value pack’s from Wal-Mart. I would also polish the chamber.
 
Re: 930 spx chamber/gas port/spring question

That is very nice work, I'm dying to find out the results because I want to do the same thing. I polished the mag tube down to the receiver and also polished the bottom of the bolt and the top of the carrier that the bolt rests on to see if this could make the gun cycle faster. I never had a problem shooting low brass, but I never used any thing lower than 1250fps either. I have the blue spring, but the problem I have is the barrel putting grooves on the mag tube not lining up properly when I uninstall and reinstall the barrel. I just want my 930 to cycle fast so I can "fire 12 rounds in 1.44 seconds" like a manufacture claims for that brand of shotgun. Update: Saturday I got up and tried polishing the chamber, and the inside of the barrel it worked out fine, just have to wait for better weather next week to test the work.
 
Re: 930 spx chamber/gas port/spring question

BenSamp – glad the polishing went well! I was having that grooving/binding issue as well on the tube and made the aluminum insert (dia =0.993”) shown in the picture to slide in the gas block (with the gas piston out). I would use it to slightly reposition the seal until I found the sweet spot. I saw another post on this forum where he (SoCal Choppas) used a deep well socket to slide in and work the alignment:

viewtopic.php?f=14&t=2202&hilit=craftsman&start=75

On mine, it seems like it wanted to be tweaked slightly towards the barrel and then the barrel subassembly would just pop right on and off the tube – no binding at all.

gassealadjuster.jpg


I made it out to shoot today - after polishing the gas block and cleaning up the gas ports. I put about 125 rounds through it using 5 types of ammo and was pleased overall with the results – almost there!
- Cheap Federal Value-pack multipurpose 2-3/4”, 8shot, 1-1/8oz, 1200fps (low aluminum base)
- Winchester Super Speed X game loads 2-3/4”, 6shot, 1oz, 1350fps (low aluminum base)
- Winchester AA super sport clays 2-3/4”, 8shot, 1-1/8oz, 1300fps (low brass base)
- Winchester Rifled Slug value pack 2-3/4”, 1oz, 1600fps (high brass)
- Winchester Magnum Buckshot value pack 3”, 15 pellets, 1210fps (high brass)

ammoused.jpg


I fired from the shoulder (or as close to the shoulder as possible) keeping the gun tight with the gun in 4 different positions (upright-normal, turned 90deg ejection port down, upside down, and 270deg with ejection port up). I then fired in the same orientations limp-wristing by really only holding the forearm and letting the entire gun pretty much float. I had NO stuck cases and those that didn’t eject would extract very easy with the charge handle (cycling the next round in). Here are the results:

Federal Value Pack - Light recoil as expected:
From the shoulder location fired reliably in all positions - no failures of any kind
When limp-wristing, it failed to eject cases about 90% of the time, insensitive to position.

Winchester Super Speed X game loads – Recoil about same maybe a little more than Federal:
From the shoulder location fired reliably in all positions - no failures of any kind
When limp-wristing, it failed to eject cases about 70% of the time, insensitive to position.

Winchester AA super sport clays – Recoil about 10-15% more than Federal:
From the shoulder location fired reliably in all positions - no failures of any kind
When limp-wristing, it failed to eject cases about 10% of the time, insensitive to position.

Winchester Rifled Slug value pack – Recoil about 50% more than Federal:
From the shoulder location fired reliably in all positions - no failures of any kind
When limp-wristing, it fired reliably in all positions - no failures of any kind.

Winchester Magnum Buckshot value pack – Recoil about 80% more than Federal:
From the shoulder location fired reliably in all positions - no failures of any kind
When limp-wristing, it fired reliably in all positions - no failures of any kind

Overall, I was very pleased with the results and I have pretty much figured out this shotgun. I still want to make sure that it is 100% reliable with all ammo while shooting from all types of holds (ie the limp-wrist condition) so my next step is to investigate replacing the Blue gas block spring with the Red spring – will call Mossberg and see if I can get them to send me one.

Something else I noted (an anticipated results) from my tests is that there is a big difference between the low brass and low steel base shotshells. The brass definitely extracts much better and I expect it is because when the cases deform plastically to the barrel contour when firing, the brass cases contract/release with about half the force as steel since brass has a lower modulus (Steel is much much stiffer and will want to stay ‘inflated” in the chamber).

So for now I am going to stick with the Winchester AA (it’s only about a $1 more a box at wal-mart) to assure the shotgun cycles in the most reliable fashion possible. To me it is much more important to have a firearm which can be discharge/cycle reliably without regard or thought of its position or type of hold! Has anyone tired their 930 SPX with both the Blue & Red springs and noted the differences?
 
Re: 930 spx chamber/gas port/spring question

First of all welcome to the forum, and this forum has a great addition in you with your engineering background, their are a GREAT bunch of guys and gals here whom I have received a wealth of knowlege from and enjoy reading their posts. Your first post gave me the inspiration to do the same thing to mine in search of making my 930 the gun it should be. 1 rep point given. Thanks Starfury.
 
Re: 930 spx chamber/gas port/spring question

Starfury said:
Has anyone tired their 930 SPX with both the Blue & Red springs and noted the differences?
Click to expand...

I've got the original SPX (black spring) and just added a 24' barrel with the blue spring. No change in cycling that I've seen, I've been lucky, my 930 runs without a hiccup and I run only Rem light target 1145 or low recoil 1100 for birdshot and Fiocchi / B&P low recoil slugs.
 
Re: 930 spx chamber/gas port/spring question

Welcome to the Mossberg Owners Forum Ride !!

Lots of great info here...
 
Re: 930 spx chamber/gas port/spring question

BenSamp – thanks! I am honored :) You are right about this forum and I have been reading through the posts – lots of excellent information and people here!

Ride – so you have both the 18” and a 24” barrel - this is fortunate! Next time you are out can you run a quick test for all of us? If so, with your low power (low steel base) shotshells and the short barrel fire a 3 or 4 rounds while limpwristing it (holding it by the forearm and let the shotgun pretty much completely float with the recoil when firing). However you choose to let it float please make sure you are safe – at least with the low power rounds I found it’s easy to control. See if it ejects the spent cases – the action really slows down and you can watch it move. I have noticed that when limpwristing the ejected cases travel only a foot or so from the gun (pretty much seem to just fall out). Then do the same thing with the 24” barrel.

I suspect that you might have some issues with the 18” barrel (will depend on how that black spring performs – it’s an independent variable here); however, with the longer barrel I expect it will be more tolerant on extracting the low power shells. This is primarily due to barrel pressure being maintained a little longer (~ 0.6 millisecond) while the wad/shot travels the extra 6” of barrel length past the gas ports; plus the small benefit of the extra barrel mass increasing the shotguns inertial mass.

Sure hope you can run a quick test next time you are out!
 
Re: 930 spx chamber/gas port/spring question

As a follow-up I fired a couple more boxes and then took some measurements for fun of the low brass/steel shotshells (after firing). The purpose was to see how much “swelling” the brass/steel head experience after firing/extracting and if there was any taper along it (rear being near the primer and front being near the wad). Found the following after measuring 4 cases of each type – these are average values.

On the Winchester AA super sport clays (low brass head)
• Original diameter =0.801”
• After firing swells to 0.808” diameter with no taper rear to front

On the Winchester Super Speed X game loads (low steel head)
• Original diameter =0.801”
• After firing swells to 0.812” diameter with no taper rear to front

On the Federal Value Pack (low steel head)
• Original diameter =0.802”
• After firing swells to 0.806” diameter at the rear and 0.814” at the front so there is a taper front rear to front. This means that the case is squeezing the chamber tighter up inside.

Also, on the Federal Value Pack I noted that the front portion of the low steel head was typically not symmetric - it would tend to bulge a little more on one side making it non-curricular and reaching a diameter as much as 0.817” on a few cases. I didn’t see a bulge on the other types of shotshells. I can imagine the asymmetry would also aggravate extraction of the low powered rounds since friction is increased as the shell is dragged out. I am assuming that the axis of the bulge/wider diameter lined up with the extractor but I couldn’t confirm.
 
Hey guys;
whats the part number for a 24" or 28" Barrel thats threaded for a choke but comes without the porting ??? I need one my 930spx barrel because my 930SPX barrel is ported ...
 
Hello everyone. Sorry I have been away for awhile. But I have been having so much fun.

RippSpeed here is the Mossberg Webpage for barrel info. http://www.mossberg.com/products/access ... ion=access

And the Slug barrels come ported.

Now an update on my 930 SPX w Pistol Grip which presently has the Slug Barrel (P/N-93030) w Integrated Scope Mount. I just ordered the 28" barrel for it (which is kind of why I'm here) and wanted to report that I'm shooting 2 3/4 Hornady SST slugs 200 yards accurately all day long with my Nikon 1.65-5X Scope and BDC reticle. The Remington 3" ACCUTips are very nice too and mushroom perfectly but kick like a mule.

BUT... while I'm sighting in, I take no more than two shots and then let the barrel cool. Otherwise the third shot dives and the forth shot dives more. And I mean falling off the paper diving. So, when sighting in, have fun but more importantly take your time. Otherwise you will be scratching your head wondering why your shot placement is all over the place. When your hunting, the only shot you are taking is when the barrel is cold and will hopefully be the first and only shot. Of course we know when hunting deer etc., it's really only the first shot that counts. Because if you did it right, you shouldn't need the second right?

Lastly, when you have the integrated scope mount, you have to remove the picattiny rail on the receiver which leaves the holes open. I didn't get new set screws to fill them and experienced no issues.

Now with the new 28" barrel on the way, I won't have a rear sight at all because the barrel is a vent rail with a fiber optic bead up front that is flush with the top of the receiver. The Turkey barrels come with a rear sight on the barrel. I thought about mounting a Red Dot Reflex but it would sit way too high and you couldn't use a rig like the Burris Speedbead because of the location of the safety. Other barrels by Remington come with a second bead sight about half way down the barrel. Anyone else with the 28" barrel noticed this being an issue? I would like to have something at the back to line up to but I have no clue yet how cheek weld on the tacticle stock is going to effect looking down the sight to begin with. Thanks. Have a great day everyone.

Paul
 
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