Jump to content

Factory M4 LEO Mag Spring - How Many Coils to Cut???


Blain

Recommended Posts

I have a few shotguns (M2 Tactical, Winchester 1300, 18" 590 w/ +1 extension, etc) that will consistently fit 7 star crimped 2 3/4" shells in the tube of any make.  Now, 3" or roll crimped 2 3/4" they will only fit 6, but anything 2 3/4" and star crimped is no problem.  Hell, the M2 will fit 7 of the longest Federal star crimped shells with a half inch to spare!

The Benelli M4 LEO is the exception.  Even with the spring retainer removed, only SHORT star crimped shells will be able to have 7 fit in the tube w/ factory mag spring.  Fiocchi, Fetter, Winchester, (Federal bulk birdshot) are some of the shorter star crimped shells that will JUST BARELY be able to fit 7 of in the LEO factory tube.  Federal's star crimped buckshot shells are a little bit longer, not enough to be a factor in the other earlier 7+1 guns I mentioned, but enough to be a factor for the M4!  I am a quarter or so inch away from being able to fit a 7th Federal star crimped buckshot shell in the gun.

I would like to be able to fit 7 federal shells without issues.  What does everyone here do modification wise to allow a little more space in the mag tube for your M4s?

Currently, I am keeping 7 Winchester shells in the tube to try to compress the spring a bit.  I did this trick for an 870 I put a wolff spring in that wasn't able to quite fit 6 shells in the tube.  Keeping 5 shells in there for some weeks, compressed the spring a bit and made it take enough of a set for me to be able to comfortably load 6.  So far, I have kept my M4 loaded with 7 Winchester shells for a few weeks, and it doesn't seem as if the spring has compressed at all.

I was thinking of putting a wolff spring in there to see if that would help, but I know wolff springs are even stiffer than factory so I don't see how that would make a difference.

I am also contemplating maybe cutting 2 or 3 coils.  I'd hate to do anything that would interfere with the reliability of the shotgun though, as strong mag tube springs are key.  How many coils cut would allow me to squeeze that extra ~1/4" for the 7 Federal shells in the factory tube WITHOUT hampering long term reliability?  Is there anyone who has done it?  What has your experience been?

Finally, I am just curious, is the one piece factory Marine M4 tube a hair longer than the LEO two piece?  Did those with the M4 in the service with the 1 piece tube have any issues fitting 7 shells in the tube?  I have to wonder if the one piece may in fact be a hair longer, which would make loading a 7th shell all the more easier.

Thank you!

 

Edited by Blain
Link to comment
Share on other sites

1 minute ago, Ceephus said:

Start with 1 coil and work your way down.

I can do that but was wondering what those who have tried it first hand have ended up doing coil wise?  Would like a bit of a frame of reference to start! 

Link to comment
Share on other sites

It's hard to say. When I got my M4 I ran and still run Federals because I had 6 cans of the stuff. My OEM spring wouldn't fit 5 rounds (I have a shortie with a 5rd tube) I clipped coils 1 by 1 until they fit, ended up clipping 3 I believe. Later I bought a CarrierComp spring and didn't have to clip it at all. I also put a flat faced follower in there versus the OEM which had a slight protrusion, and after all that, I can get 5 in there no problem. There is NO wiggle room, meaning when I get that last round in and it clicks, it's not moving forward any further. I also slightly pulled my spring retainer out a bit and let the mag cap push it back down so it would protrude as much as possible versus sitting flush. It all works through a couple thousand rounds now. Federals just run long, it's a common issue with M4s. RxArms makes a titanium mag cap that has a deeper well that gives you more room than the OEM cap as well too. Also about feeding reliability after cutting the coils, I ran 500+ rds through mine to test, it fed fine, no hiccups.

Edited by Ceephus
  • Like 2
Link to comment
Share on other sites

2 hours ago, SOCOMguy said:

Try with an original 5 RD spring, I understand that Benelli uses that spring in both the 5 and 7 RD tubes.  Also leave out the retaining clip. just remember to use care when removing the cap.

Joe B 

Hi Joe,

Did you read my OP?  I mentioned that I am NOT using the retaining cap...

Also, if the 5 round spring is the same length as the LEO 7 rd one, then what is the point of swapping the same spring in???

Link to comment
Share on other sites

my entry fits 5 rounds in the tube with a little room to spare, my brother could only do 4 and had to trim the spring.

 

does anyone know if the RX arms TI cap is a little longer? if it was a tad bit longer, it would sit more flush with the barrel

Link to comment
Share on other sites

4 hours ago, mr2jeff said:

my entry fits 5 rounds in the tube with a little room to spare, my brother could only do 4 and had to trim the spring.

 

does anyone know if the RX arms TI cap is a little longer? if it was a tad bit longer, it would sit more flush with the barrel

RxArms cap is externally the same length as OEM.

  • Upvote 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...