Flaw in Briley Mag Tube rail

[M4-Desert Camo]

I have the following Briley mag tube rail mount system on my stock M4.

http://www.briley.com/magazineextensionbarrelclamp-1.aspx

 

I was a the range yesterday and when tried to take things apart today to clean the M4 I discovered a flaw in their design and had a problem. When I unscrewed the Briley to take the barrel out the spring retainer cap came out (as well as the spring).

 

The oem dummy tube extension has a stop in it to hold the Spring Retainer Cap from working it's way out (see below)

[ATTACH=CONFIG]1952[/ATTACH]

 

The Briley unit does not have any kind of stop, it's unobstructed all the way to the end (see below)

[ATTACH=CONFIG]1953[/ATTACH]

 

I was able to put retainer cap back in. For the experts, does it look right? Am I missing anything? (see below)

[ATTACH=CONFIG]1954[/ATTACH]

 

Here is the Briley unit showing where the mag ends and how the rest is an unobstructed void.

[ATTACH=CONFIG]1955[/ATTACH]

 

I like the Briley unit but not if the Retainer Cap works its way out under use. Any ideas from the creative thinkers here to remedy? I was thinking about a piece of aluminum tubing cut to the right length to put inside the Briley acting as a stop. Hard part will be getting the exact length so it can be tight enough but not have the aluminum tube rattle inside.

[alexcapone]

I'm not sure about your specific problem but I've worked with the production manager at Briley and he is super helpful. PM me if you need his email...I don't think its on their website.

[12508]

Does it still add two extra rounds?

 

If the mag spring retainter is falling out of the tube, take some snap ring pliers and stretch it

so it is a snug fit.

 

Edit: Sorry, I just saw that it is NOT an extention.

Edited February 18, 2013 by 12508

[M4-Desert Camo]

Does it still add two extra rounds?

 

If the mag spring retainer is falling out of the tube, take some snap ring plier clamps and stretch it

so it is a snug fit.

 

It's not a tube extension (aka adding 2 more rounds), it just replaces the "false" OEM extension but adds two picatinny rails. I was at the range and put 85 rounds through the gun (first time since the Briley was installed). I used ring pliers to put it back, it's pretty darn tight. I just think the force of the firing process can work it out, this is why Benelli put a "stop" in place on the OEM tube so it has nowhere to go.

[paladinjme]

...so just stick a plug in the extension that butts up against the spring retainer.

[12508]

Try running it without the retainer and see what

happens. I ran a Nova that way with no issues.

[M4-Desert Camo]

...so just stick a plug in the extension that butts up against the spring retainer.

 

That's what I was thinking, you think a wood dowel would get to hot? Better to go with some aluminum tubing?

[paladinjme]

There should be little to no heat transfer from the barrel to the mag tube (which is really the only place that heat could come from)...many manufacturers use wooden or plastic plugs...Benelli's are usually red plastic...no need for aluminum.

[M4-Desert Camo]

There should be little to no heat transfer from the barrel to the mag tube (which is really the only place that heat could come from)...many manufacturers use wooden or plastic plugs...Benelli's are usually red plastic...no need for aluminum.

 

Piece of PVC pipe, 3 1/16" long did the trick.