Ammo for JM Pro

[Jfarewell]

Gentlemen, I shot a match yesterday with some Winchester Supertarget which I picked up cause it was all they had in stock. This JM Pro is a new beast to me and I've only put around 300 rounds through it thus far and up till now it's been a little picky with the ammo. The supertarget was a complete flop. It wouldn't eject right, caused several double and even a triple feed (WTF moment), and completely screwed me on the first stage of the day. Later I swapped a squadmate for some federal and had much better luck.

Besides the obvious lesson which I should have never done in the first place (bringing untested ammo to a match), what ammo can you recommend for this SG? Looking for something that will run it effectively and not break the bank. Also, where is the best place to pick up SG ammo online? I'd rather put in a good bulk order than to trust Wally-World to have it in stock.

Any advice would be appreciated.

[usmc1094]

I've only ever run walmart winchester and federal in my JM. With that said it may not be the best sg ammo, but it does work. Around 300 rounds I had a disaster of a match with it. The sg wouldn't eject, didn't make it through a stag all day. I did some research after that match, and found that polishing the chamber may help. So I did it, wasn't hard, 10 mins with some metal polish on a cotton shotgun swab on a cleaning rod in a cordless drill. I took it out to the range at work and ran 100 rounds with no issues, then at my next match it ran with no problems. Hasn't had any problems since. (300 more rounds or so) hope that helps.

[rangerguy]

I run walmart federal and Remington gun club. Only two I will use.

[Jfarewell]

Thanks for the advice. I'll look into polishing it before I take it out again.

[LikesToShoot]

Gentlemen, I shot a match yesterday with some Winchester Supertarget which I picked up cause it was all they had in stock. This JM Pro is a new beast to me and I've only put around 300 rounds through it thus far and up till now it's been a little picky with the ammo. The supertarget was a complete flop. It wouldn't eject right, caused several double and even a triple feed (WTF moment), and completely screwed me on the first stage of the day. Later I swapped a squadmate for some federal and had much better luck.

Besides the obvious lesson which I should have never done in the first place (bringing untested ammo to a match), what ammo can you recommend for this SG? Looking for something that will run it effectively and not break the bank. Also, where is the best place to pick up SG ammo online? I'd rather put in a good bulk order than to trust Wally-World to have it in stock.

Any advice would be appreciated.

Once broken in, AND cleaned, it should run anything you feed it.

[legacy]

If you have an Academy near buy check out this

http://www.academy.com/shop/pdp/estate-cartridge-dove-load-12-gauge-shotshells/pid-577001

I run a lot of it through my Benelli, usually has good crimps and its 3+ dram.

[GunCat]

The Winchester bulk/promo load with the ribbed hull and silver (steel rims) have a bad reputation for quality (Soft plastic that grab the chamber; rims that expand, come loose, cock sideways and hang)

The Federal 100 packs at Wal~Mart generally run well, but may occasionally have a rough or bent rim that can hang up.

Most of the WallyWorlds will also have Winchester AA or Remington Nitro which is a much better ammo (both from feeding/cycling and patterning aspect)

Edited October 21, 2013 by GunCat

[Mberry]

I think you may be experiencing the joy of a dirty JM. I had one, and loved it, but every 3-500 rounds it needed to be fully cleaned. If you haven't already, take it all the way apart and clean it. By all the way apart I mean take the rings off the piston. There is a huge thread on the JM here that will probably be helpful to you and there are several videos on YouTube demonstrating how to clean it.

Winchester AA Supersport 7.5's at 1300 FPS ran great in mine and seemed to keep it running longer than the WW bulk pack stuff.

It's a great gun, its just required more time in cleaning that I was able to commit to it. I ran faster with it than my Benelli, but the malfunctions cost me too much time.

[Jfarewell]

The Federal that I shot later ran fine so I'll look into getting some of that. I've also been curious about the Estate loads. Any thoughts?

[jon49erfan]

I always used Winchester super target and never had problems. I used the 12m7.

[Nickoli]

I have only ran the Federal bulk packs through mine. Not one issue besides about 3 light strikes before I replaced the hammer spring. Over 1k through it and no ejection issues. But before I even shot it I went through the gun completely after reading up on it and polished everything that has been talked about in other threads.

[bigkyle72]

The Federal that I shot later ran fine so I'll look into getting some of that. I've also been curious about the Estate loads. Any thoughts?

Estate is g2g in my JM! I had the exact same problem with mine. Stay with the federal.

[bigkyle72]

I have only ran the Federal bulk packs through mine. Not one issue besides about 3 light strikes before I replaced the hammer spring. Over 1k through it and no ejection issues. But before I even shot it I went through the gun completely after reading up on it and polished everything that has been talked about in other threads.

Where did you get the new hammer spring?

[rangerguy]

Use an extra power hammer spring from a ruger 10/22

[Boxerglocker]

All I use in my JM Pro is Winchester Super Target #6 and 7.5 as mentioned above clean and keep the piston dry.

[Robbie]

I keep mine clean, and run Federal Target Loads 7.5 and 8's. No problems

[Jfarewell]

Thanks for the replies. This should solve my problems.

[Nickoli]

Where did you get the new hammer spring?

I just ordered mine from midway.

[rtp]

I've been a 'bad' JM owner, running the bulk Winchester through it that is generally among the most problematic, along with a mixture of just about anything/everything else as long as it's 1200FPS or higher.

I finally got a light strike in a match this weekend, round count ~800, so it's time to put in the 10/22 spring and be done with it (yeah, better to have done it before, but...)..

Total issues to date:

2x failure to feed, first was handing to a friend on his first shot, I'm marking off as not shouldering properly, as I subsequently went through the mag tube with no issues, shot another 100rds that day without issue. No known cause on the second other than running out of shotgun ammo at a match so barrel-scraping - it went in the tube if it was 12ga and not buck or slug.

1 light strike

I've done most but not all of the 'current hit list,' compiled from here, elsewhere, and experience to date with it..probably worth at least familiarizing yourself with each item, or doing additional research and considering what may or may not be worth doing.

1. De-grease the heck out of it from factory. This includes taking the rings off the piston. Green brake cleaner, gun scrubber, whatever.

2. Check for lip at mag tube/extension joint, bevel/file lightly if need be to avoid possible follower hangup.

3. Check if inner larger gas system spring wears on mag tube (do you see scratches on disassembly/barrel removal?), tweak with extension + 19-22mm socket inside the spring to center it, and/or dremel/buff sharp edges inside of spring. You do not generally want to remove the big spring from the outboard side of the barrel gas cylinder!

4. Minor buff on shell stop, polish chamber. You can polish the chamber by removing the barrel then polish w/dremel w/cratex or felt wheel + polish, or drill + steel wool wrapped around a cleaning rod/barb. Intent is to at minimum to smooth out any roughness in the chamber where the shell brass contacts, will help w/consistent ejection.

5. Check mag tube spring length and tension, especially on non JMs - seems a mixed random bag-o-springs was used for at least a while. Spring should be ~12-16" past end of extension tube for the SPX and JMs.

6. Disassemble rings from piston for cleaning, scrub/soak it + gas tube - clean every ~200 rounds for 930, possibly a bit longer for JM with the chromed/hard plated components.

7. Run the action on the wet side, while the piston/gas system should run as dry as possible while still supplying some lube. I'm currently trying some dry lube after some polishing, but the jury's still out on that one at the moment..

8. If your gas piston isn't sliding in and out of the gas cylinder fairly easily...you either need to clean it, or didn't clean it properly with rings off the piston. Can do some light polishing of the barrel's gas cylinder if desired.

9. Brownell's link for fix for feed issues, again amounting to light polishing: Brownell's 930 video

10. Polish extractor, extractor plunger, extractor groove in barrel.

11. Light primer strikers - seems hit and miss, but if you have this issue or simply want to be pre-emptive, replace the hammer spring with a Wolff Extra Power 10/22 hammer spring, left at full length (it will be slightly longer than the MB spring) or trimmed down slightly.

12. The barrel clamp if so equipped can impact POI. On the Nordics, you can tighten down the mag tube, then loosen the mag tube from the nut slightly(1/8-1/4 turn), then tighten up the clamp, no more POA/POI changes.

13. Polish the stock follower or replace it. The main point here IMO is to debur any minor imperfections, and allow it to easily make it over the joint where the tube + extension join together. I didn't have issues with the stock follower, but many have griped about it.

14. The screws for the rail may be 'lacking' in Loc-tite, with or without a rail. Check if they're snug (I had some loosen up), and if not or if you desire, unscrew, drip a small dab of Blue Loc-tite (or green, just not red unless you want to have to heat it to remove later!), and re-assemble. Be careful as a typical small flathead screwdriver is too big - use a gunsmith small screwdriver or jewelers screwdriver if possible.

15. 'slop' in trigger assembly. With the weapon cleared, wiggle the trigger assembly. You'll note some amount of side to side wiggle, but almost no front to rear. Loaded and in functionality, should be no impact - seems like they all pretty much have this minor 'slop' side to side. If truly concerned about it, look here: http://gunsumerreports.com/review_mossberg_930_tactical_p7.php

16. The hammer end of the firing pin may (likely) mushroom over time; may be something that stops and may or may not affect functionality. Just an item to 'be aware' of at this point.

17. Most barrel clamps w/out grooves in the mag tube can move under shooting conditions. You can put a piece of double sided carpet tape between the clamp and tube to eliminate this movement and finish wear.

[RJH]

Remington nitro or sps if you want absolute reliability.

[rtp]

@GunCat/Steve

I've never seen the extent of your pics, but certainly the start of it ('ripped' base from extraction). My assumption has been it was a combination of cheap shells, and hanging up slightly in the chamber (whether the base or the plastic hull). I did some very minor polishing of my chamber, but is there another cause/effect assumed to be the culprit there?

Haven't seen this at all lately to my recollection, but shooting different shells now..

[GunCat]

The rim on the shell pictured was ripped after the hull stuck in the chamber and the owner did the old buttstock to the ground method of extraction assistance with an 870. The action came open and the hull remained in the chamber.

Notice the burn on the top picture (yellow arrow) where gas was escaping from a fracture in the hull. A slick as glass chamber can help a poor quality shell extract a bit easier, but generally the low quality ammo is main cause of the problems.

[all4sho]

i just picked up a 24" model, and so far its eating anything i put in it, no complaints yet

[frankge]

just bought a 24" one today - having fits with my 1100 tac4. I've been reloading shotgun for years because I shot trap for so long. I wonder how reloads will do. I use Rem nitro, STS, and gun clubs. Switched to e3 powder a long time ago as I had an 1100 and needed it to stay cleaner longer. e3 is amazingly clean for a shotgun powder.