Never have seen a plastic buttplate on one.
I've one(steel BLR 81) that was a touch rough (22-250 Donor).
BLR's in OEM guise have a longer LOP than most things. I bucked a chunk off,to make it easier for the kids and to speed up handling in general.
Rebarreled it with an OEM NIB 7-08 spout,from Midwest. They are steeped in BLR parts,including complete stocks and internals. Then I hit it with about $3 in paint,for long term protection.
I floated the schit out of the fore arm and with 162A-Max at 2500fps,it do purty nice thangs. Haven't had it out much past 1000yds. Had the guy I got from in tow the other day and he was shaking his head,when I was slapping schit around at the 800yd line
Originally had 2pc flat mounts on it and that really robbed from the MK4 M3,only granting 30MOA of erector travel,from a 200yd zero. I ordered an EGW 20MOA rail to replace same,in order to eek more erector travel.
The EGW 20MOA Picatinny rail wouldn't mate to the 22-250 Donor Receiver,so I ended up cutting a window out of it and using it as a 2pc base. That exchange netted another 15MOA of erector travel,at the same zero range and opened windows of opportunity.
[img]http://imagizer.imageshack.us/v2/1280x1024q90/538/5pNM6k.jpg[/img]It is a wickedly wonderful and very handy parcel now,that is a VERY sneaky Sleeper of the highest order. While I had the guts out of it,I stoned the trigger a smidge and smoothed it up,which didn't hurt the equation at all.
Floating and re-SEALING the fore arm is key,to yielding round groups ala MPAJ or any other means.
Hint................
Midwest RINK(Float query Addendum)
I'd liken it akin to a FF tube on a Krunchenticker. While the butt section of the fore arm mates the receiver,the fore arms channel also mates the barrel's underside in OEM guise,as well as incorporating a barrel band. Throw the 'band as far as you can offa the nearest cliff...then simply relieve the 'channel.
It will yield a float and less doing so,they will string like a Mad Woman running to take a schit. Couple same with moisture intrusion and ALL bets are off,when the warp occurs.
In final form,I'll craft an aluminum fore end,that's a touch broader in cross section,for a Ninja Float and to add a stud on the bottom,to support a bipod.
Nothing to it................