According to RI State Law, Mags over 10 rd capacity must be removed from RI, destroyed, or surrendered to the police (with caveats about that).

Before proceeding, allow me to say that I am NOT a lawyer, and any further comments are made by a layman who has carefully read the law(s) and has consulted multiple Lawyers.

DO NOT proceed as though any comments here are "legal advice".  Links to pertinent State laws, and additional "Guidance" from RI Atty General are available in other posts above.  STRONGLY advise reading them and interpreting them as though the slightest deviance from them will result in serious legal problems.

Posted elsewhere:
"My good friend, having been forced to experiment with and modify followers (along with Magblocks) due to their State's magazine laws, has related the following to me:

Modifying plastic feed lips is seldom necessary, and if needed, is an art requiring specifically made tools and experience to do so. Modifying metal feed lips also requires a specific Feed Lip adjustment tool, and some experience.  Modifying feed lips on some magazines, whether OEM or aftermarket, may be necessary for best reliability.  With the increased demand for 10-rd mags, some mfrs might be offering "questionable" units --and lemons occur amongst even "GTG" mags.  If your mag is GTG before installing a Magblock, it will likely be GTG after installation--at least as far as the feed lips are concerned.

Substituting a DECENT follower, intended for that specific type of magazine (possibly slightly modified) in lieu of modifying OEM follower is vastly preferable to modifying OEM follower.  Retaining GTG "Original" follower allows the mag to be returned into GTG full capacity at a future point.   It's understood that substituting a suitable follower and perhaps modifying it may be a significant PITA.  Follower mods usually include trimming the vertical height, usually by shortening the "post" or "legs" on bottom of follower.  Sometimes the width/length of the follower must be slightly reduced.  Sometimes cuts must be made in the sides of the substitute follower to suit the particular recipient magazine.

Most often these follower issues are easily seen with a good light.  My friend reports that cheesy OEM followers can often be replaced with suitably modified followers which is often a significant reliability upgrade to some magazines.  "Green" GI followers are often easily adapted, since the "post/leg" on bottom of follower is long and can be trimmed to suit.  It may be possible to adapt/retrofit the well-regarded Magpul followers to some magazines for which they were not originally intended, but its' original configuration, with short "post" underneath the follower might be problematic in some instances.

Examples of Followers which are NOT usually interchangeable (at least as far as bolt-hole open feature goes) are the AR-type follower and the Ruger Mini-14/-30 type follower.  Owners of both types of firearms are advised to have a certain amount of suitable and GTG spare followers on-hand for experimental purposes.  Order more if needed--while you can.

According to my good friend, installing Magblocks is something of an art.  Not all Magblocks fit "properly" even into the magazines which the Magblocks are "supposed" to fit.

My friend says that FAL and M-14/M1A Magblocks fit fine.  Other Magblocks "may" fit fine, as long as user very carefully orders "correct" items.  Even so, some minor mods to the Magblocks "might" be necessary.  The folks at Magblock will work with the buyer, but they may ask for pix of both mag and the Magblocks in order to best do so.  When in doubt, contact Magblock folks before ordering.

A Dremel tool with a rotary file and a sanding drum, along with good light, sharp eyes, and a deft hand is strongly suggested.  "Fitting" Magblocks and "fitting" followers is not hard, but it takes a certain amount of precise work."

All of us have different ways to deal with recent RI Mag Ban Law.  My good friend has chosen to fully comply with their State's Law, at considerable expense, in order to RETAIN their magazines in lieu of exporting them, destroying them, or surrendering them.   Understood that opinions vary.

Also understood that some folks will disagree with my good friend's practice.  Their technical advice, based on personal experience, is very sound, I believe.

Some further comments: In the unfortunate event that a shooting occurs, your property may be searched for other firearms and related devices--such as "contraband' magazines.  Having an "illegal" magazine will add to your legal problems and may count against you in open Court.

Again, NO lawyer, and just guessing.

Your call.

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