DPMS Receiver Heights

imschur · April 7, 2010

I recall a DPMS employee on another forum stating that DPMS has changed the height of the picatinny on the LR-308's. I believe this is the 3rd or 4th time this has happened.

Does anyone have specifics? The difference is measured in the area of the receiver over the charging handle.

There are implications to this height change.

98Z5V · April 7, 2010

There was a thread on ARFCOM about this that I ended up in. It kinda turned into a pissing match of sorts. I'll dig up the details of the receiver heights from that and post them up - one dude on there literally knew everthing about it, much to his credit. Numbers, heights, everything. I'll grab the details.

98Z5V · April 14, 2010

Info straight from DPMS:

Our AR15 receivers are all the same height except the High Rider and Tri-Mount.

The LR308 Platform has two heights, the A3 and Lo-Pro Raised Rail. The A3 was changed recently to better accommodate our other components. I guess in reality, with the number sold before the change, there are now 3 heights.

To find out if you have a newer model or older run, the easiest way to measure is with a caliper from the bottom surface that mates to the lower to the top of the rail. The new versions measure 2.003 and the old versions are 2.063.

Any larger receiver rail to handguard rail height difference would be due to the lack of an industry standard in the large frame AR style rifles. Everybody is still pretty much making their own thing and some measurements just don't line up between manufacturers.

imschur · April 15, 2010

Thanks for tracking this down

KellyTTE · January 28, 2011

So I have one of the new height uppers, does this mean that the JP/VTAC won't be at the correct height when I install it? Its a .063" difference which could be made up with a taller front sight post.

Any input? With the Brownells discount, the JP is a pretty hot deal.

imschur · January 29, 2011

Correct, if you run a top rail on the VTAC they wont align

guessta · January 29, 2011

Does anyone know of any company that makes rails for the new A3 height receiver? Will the companies ( Troy, Daniel Defense, etc.) make new rails to fit this new height? Why would DPMS do this? It doesn't make any sense unless they only want you to buy their rails. >:(

imschur · January 29, 2011

Does anyone know of any company that makes rails for the new A3 height receiver? Will the companies ( Troy, Daniel Defense, etc.) make new rails to fit this new height? Why would DPMS do this? It doesn't make any sense unless they only want you to buy their rails. >:(

I would be surprised if guys retooled just to accommodate DPMS. Too many other guys making uppers now.

Of course a clever manufacturer could make a quad rail with two different heights and please everyone. I also suppose FFHG like a VTAC could have two accessory rail heights

guessta · January 29, 2011

That's the same thing I was thinking. Making diffrent size accessory rail heights, as I was thinking of going with the 15" PRi Gen III. I hope they do consider this option if any. That would solve my problem but who knows.

imschur · January 29, 2011

At least for those who assemble their own uppers there is absolutely no reason to purchase a DPMS stripped upper. Lot's of options in 2011.

This does however stink for folks who buy a complete rifle. (Insert a plus 1 Armalite here)

guessta · January 30, 2011

Just a heads up, I just got off the Troy Industries website and it looks like theynow have the 13.8 battle rail avaialbe for both DPMS receiver heights <thumbsup>. Pretty excited over this. they must have just made it available because I was just in their website 2 days ago and it wasn't available then. Well this is just another option for those of us that have the newer A3 receiver.

TacBlade · January 30, 2011

That is a good move on their part to address a problem first! They may make a few bucks before someone else jumps on the wagon!!!

imschur · January 30, 2011

That also may be a sign that DPMS will be offering that option on their weapons.

guessta · January 31, 2011

Just ordered it. As soon as I get it and put it on I'll let you all know how the fittment is. I'll also post some pics.

308reloaded · February 7, 2011

this has me confused (easily done) if I check measurement as posted here I have old style receiver if I check method posted on another site " measure tab above the charging handle " then I have new .. will either one make this weapon shoot worse or better?

imschur · February 7, 2011

No, it's only relevant if your using a top rail on the handguard. Than it's an alignment and possibly an iron sight issue. Curiously do you have a link to the other site?

98Z5V · February 7, 2011

this has me confused (easily done) if I check measurement as posted here I have old style receiver if I check method posted on another site " measure tab above the charging handle " then I have new .. will either one make this weapon shoot worse or better?

The info I posted (3rd post in this thread) came directly from a DPMS employee. Everything in italics is a direct quote from them. The numbers given and the way to measure is how they say to do it - but I would like to read the other way you've mentioned. The plot thickens... <laughs>

B@Dfi$H · February 24, 2011

i have a dd 12.0 on my upper and it higher than the receiver,where can i get a receiver to work properly with my rail. im planning on building an 18 inch and ill use that receiver with the troy 13" i hate to waste the $390 rail on something that isnt right

B@Dfi$H · February 24, 2011

would i be able to use the dd rail on a mega set if so ill pick that up and put the low troy on my lr308

survivalshop · February 24, 2011

Your DD should work on the Mega, if the Mega upper is set up for a DPMS barrel nut.

You can get a Fulton Armory ,SI Defence & other 308 uppers , that will work with the DPMS lower (Fulton Armory 308 uppers are DPMS ,just have the org. rail height )

dirigoboy · February 25, 2011

Cripes....something else to struggle with.

I bought my DPMS 7.62 ap4 a couple years ago off Gunbroker. Recently, I have been looking at the hand guards and sights from Sampson Mfg., but unfortunately, they say that on my model, it won't match up. So then, I read this on Sniper's Hide:

"Samson Mfg has a new freefloat handguard out called the Evolution. Samson is making a version specific to the new DPMS .308 flattop upper rail height, and should have these ready to ship by SHOT 2011. They are also making a version for the AR10-height uppers like the older DPMS flattops, the AR10 flattops, the Mega MA-TEN, etc. So, Samson will be making the Evolution in three different versions: AR15, DPMS .308 low, and AR10."

My freakin' head is beginning to hurt. I really am not sure what height my Picatinny rail is and the description of how to measure it to find out is confusing to me.....I thought I'd be a big boy and admit that.

So, before my pisstivity level rises anymore, could someone to a photo series on the appropriate method of measuring?....or is it possible even to know what height I've got based on the serial number of my rifle?

KellyTTE · February 25, 2011

::)

You are way over thinking this.

dirigoboy · February 26, 2011

Thanks for providing the illustration. Actually, we all know the statement about what a picture paints, and secondly, others were hoping for the same thing.....they just were afraid to ask.

Like I care. Thanks again.

Triggs75 · February 27, 2011

Quick question with the low profile upper, is the actual rail height the same as all other rails? I am assuming yes so they can fit the same mounts onto them.

Chad

survivalshop · February 28, 2011

Nope .

If you look at the photo with the measurements above , the taller rail is the normal one before they(DPMS) made it lower & of course the lower one is the new version .