Jump to content
Rimfire World Community
Visit Brownells Visit AR15 Builder Visit Visit Site Visit Ballistic Advantage Visit Aero Precision Visit Cabelas

Better mag problems

Recommended Posts

hi I am having a few issues with my new dedicated cmmg mk4 the first time shooting it with the smith and wesson mags and better mag adapter it fired the first 6 rounds of blaser without any issues then the bolt started to lock back on a full mag simply pressing the bolt release chambered a fresh round and allowed me to fire another round but this keeps happening I can't get through a full mag with out this happening about 3-5 times also I'm getting some very light primer strikes that fail to fire. when you manually cycle the gun with the charging handle it feeds and ejects fine it seems to only be happening when firing. I am positive I have inserted the adaptor correctly as when it's working I can sometimes get off six or more shots back to back without any problems.I haven't had a chance to shoot without the adapter using the cmmg mags yet unfortunately.

If anyone has any ideas that might help I'd be very glad to hear it.


thanks guys

Link to comment
Share on other sites

I have a CMMG conversion in my Delton, but have always used CMMG magazines which require no adapter. I'd look at the following things to see if I could figure out what is the problem.

Is the adapter staying securely in place? Any shifting would cause problems

Have the magazines been proven to work fine in a different rifle and are the broken in well?

Is there any evidences of the bolt dragging on the adapter or top of the magazines? If it is dragging it could cause some of the problem.

The light strike FTF shouldn't go with a magazine adapter problem unless the bolt is dragging on the adapter.

I'm just thinking out loud as to what I'd look for in the trouble shooting.

Link to comment
Share on other sites

All excellent suggestions. I have used the adapter in my rifle for over 5000 rounds. Only time issues popped up is when the adapter got gummed up in the bolt hold open area. A quick dis-assembly and cleaning would get it back in working order.

Sometimes the issue maybe that same part having a burr on it causing it to bind.


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.

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...