Changing Mossberg 500 forend? Design change? Help...

[IN_Sheepdog]

Ok gang,
First I will probably need a picture but I haven't got an online account yet so I am going to try and describe it first. I just bought a new Mossberg HD/Field Combo 500. I also bought on e-bay a tri-rail Promag tac forened to put on it back in December.

Problem is that I do not see any way that one is going to replace the other.

Tri rail is a ProMag, and I have stripped the whole gun down to the point of having the factory forend in my hand. (with the two arms still sticking out of it. There is no NUT holding this on, but rather a tension spring shaped in a loop which goes from one arm, up through the middle, loops back to the other arm. The arms appear to be held in place with pins of some sort.

The ProMag stock, which was advertised for the 500, with the exception of the holes drilled through it and the relief for fitting under the barrel does not appear to have any means of attaching the two metal arms, did not have instructions, nor locations for the arms... Could this really be for a Semi auto 590 and not the 500? That might make sense but in that case I've been ripped off.

Any thoughts or ideas? Did I get Hosed over on EBay?

I realize the description sucks, but I thought Id try this first and then get a picture later as it might be something obvious to a shotgun guy...

Any thoughts/suggestions?

 

[IN_Sheepdog]

NEVER MIND, went to the ProMag site and I think I have answered my own question.
Post 2008, it wont fit. sigh... HOSED again... anyone want a never used pre 2008 forend? Cheap?



PM168 - Mossberg 500 / 590 (12) Gauge Tri-Rail Fore End with Adapter

Our Price: $29.25

Product Code: PM168

Description

This heavy duty polymer forearm fits Mossberg 500 / 590 (12) Gauge pump shotguns. The Forearm has three sturdy Picatinny rails located at the bottom, left and right hand sides. these rails allow attachment of flashlights, lasers, vertical grips and other accessories directly to the shotgun. This eliminates the needs of remotes corded switches, barrel clamps and clutter. No modification is required. Uses factory hardware. Forearm wrench included.
Please note: The Tri-Rail Forearm is for Mossberg 500 series (12) gauge pre-2008 production.
The Tri-Rail Forearm will not fit new Mossberg 500 (12) gauge shotguns the new pinned action bar (Maverick 88 style) forearms.
The Tri-Rail Forearm will not fit Maverick 88 shotguns.
The Tri-Rail Forearm is only for (12) gauge shotguns.

Related Products... PM152 - Remington 870 (12) Gauge Tri-Rail Polymer Forearm Our Price: $27.50
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PM175 - Winchester 1300 / Speed Pump (12) Gauge Tri-Rail Fore End Our Price: $27.50
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[IN_Sheepdog]

Is this a possible alternative and has anyone had any experience with this ?

I am also looking for a receiver mount rail (for mounting a Red Dot) any suggestions?

 

[IndianaResident]

I have experience with it, and it was frustrating to me as well.

What you're talking about is right, but its not just depended on the year. If its a field/sporting model it will more likely have the pinned forend while the "tactical" or special purpose ones will still have the typical tube with barrel nut.

Only real options are to buy a new Operating Bar Handing Assembly (I think that's the technical name for your part), or drill rail pieces into the plastic handguard you currently have.

For me personally, I'm a little distrustful of the newer ones, but if we're being frank they're probably tested fairly rigorously.

You can use any rail section, but magpul MOE rails or ATI ones can be had pretty cheap, just don't penetrate the forend to where you're scratching the magazine tube.

 

[IndianaResident]

I am also looking for a receiver mount rail (for mounting a Red Dot) any suggestions?

If its drilled and tapped, you can get a rail base that screws in.

If not a side mount that replaces the pins with screws is very common. Similar to an AK style mount:

Or lastly (that I know of) you can get a barrel with a cantilever mount:

 

[Hookeye]

I dislike the single side mounts. Think the dual side "clamshell" type better.
I've run a few Aimtechs on 870's and they worked fine, but some needed slot touch up as they were not milled perfectly (unusable for a slot or two).

Always ended up taking the rear down 45 degrees to clear some scope bells (using low rings as the mount puts it up some). Dunno why they don't do that.

Better, IMHO, to D&T it if not already done. The base in IR's first pic allows a side saddle on the side of the receiver. I'm not into those, but it would give you that option.