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New JM Pro 22", Initial Test Drive

Discussion in 'Mossberg 930 Autoloader' started by Sarge, Oct 10, 2019.

  1. Sarge

    Sarge .22LR

    Messages:
    12
    I picked up a new 22" JM Pro today. Mag extension nut was loose, recoil pad was loose, barrel clamp was loose. Action was sluggish returning to battery, compared to our 930 Field/Security Combo.

    So I fixed the loose stuff on the JM and hoped the sluggishness might iron itself out. It's been raining non stop today but I went out to shoot anyhow. Think i had some rain on the camera iens when I took this.

    [​IMG]

    I took an assortment of Univeral #8, Remington and Winchester 0 and 00 buck and some Remington 1 oz slugs. All shells were 2 3/4. It ran the first mag of Universals OK and choked once on the second. High brass buck loads started hanging up just short of being chambered. Slugs required the charging handle be manipulated every shot. The gun shot great with the IC tube installed and made well centered patterns and kept essentially all buckshot pellets on a 12" plate at 25 yards, where it was also easy to put a slug on an old spray paint can. I centered the 12" plate easily from 50 yards and nailed the diamond plate (both shown left of the shotgun) twice from 100 yards, all with slugs.

    I tore the gun down and discovered burred recoil spring ends and a good burr on the recoil spring plunger. I deburred both and turned a 1/16" bevel on the leading and trailing edges of the plunger. Then I polished the plunger with 1000 grit wet or dry, blew the grit off and gave everything a dousing with CLP. I also put a good dab of automotive anti-seize on the plunger end of the spring before reassembling the recoil system. This took all the sluggishness out of action cycling.

    The chamber had sharp edges around its circumference so I removed those and polished the chamber itself to 1000 finish. I cleaned the barrel well, reassembled the gun and headed back to the range with a box of Universal and 30 round each of Remington & Winchester 00 Buck & Slugs. 100% function and I ran the gun so hard the rain was steaming off the barrel.

    This JM is a great shotgun now, but it required way more correction than any new gun should. If a guy who couldn't work on guns bought this, he be shipping it back for Mossberg to correct a bunch of stuff they should have gotten right in the first place. Nobody wants a high dollar 80% kit with a serial number.
    Elbert Garrett likes this.
  2. Rob72

    Rob72 .410

    Messages:
    67
    And THAT'S why you pay about 1/2 the price of a Benelli M2, and about 1/3 the price of a 3 gun ready Benelli.:gift:

    Mossberg and Ruger are definitely "entry level" guns, and generally both need serious "break in"(which really is a term describing, "We don't have gunsmiths on-staff, and we expect you to grind things into operational position..."). I don't recommend either to people who aren't comfortable with some basic smithing.

    That being said, I suspect you'll be very happy with your Pro, now!:thumbsup:
    Sarge likes this.
  3. Sarge

    Sarge .22LR

    Messages:
    12
    I'm not a competitive shooter don't want to be one. Long-tube auto shotguns are a hoot to shoot, whether you’re a three-gunner or not. Actually I selected the 22” JM Pro with the intention of removing the magazine extension and restoring it to field length, during hunting seasons. I had a Remington 870 Special Purpose for awhile and I find these 21-22 inch guns about perfect, in actual use.

    I burned a box and a half of Federal All-Purpose 7 1/2s through it today, chasing clays blasting out of my old DoAll Whitewing. With a crossing tailwind of 20 mph, they were moving about Warp 2 and diving like fighter planes when the wind overcame them. I missed four while figuring where to hold. This shotgun is a natural pointer for me. and I broke 21 straight thereafter. I put five more birds in the rack, five more shells in the 930 and lowered it to field carry position, with the safety ON. Stepped on the pedal and broke five in a row.

    Ran a dozen more buck and slugs through it for S&G. No malfs today of any kinds. And yes Rob, I am very happy with it.
  4. Elbert Garrett

    Elbert Garrett .30-06 Supporter

    Messages:
    1,089
    Good review of a fine looking lead slinger! :thumbsup: Kudos in the rain!
    Sarge likes this.
  5. Sarge

    Sarge .22LR

    Messages:
    12
    Thanks for the kind comments.

    I picked a can of PB Blaster Dry Lube W/Teflon, scrubbed the magazine tubes of both our 930s and coated them with the stuff. It dries in seconds and leaves the surface looking sorta like a white powdered donut. I am new to this 'dry lube' thing; we'll see how it works.

    Having both guns disassembled revealed that the spacer tube on Old Reliable is a noticeably looser fit, than the JM's spacer tube.
    Elbert Garrett likes this.

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