I have an Armalite AR10A4 upper in .243 coming, I am hoping the uper may work on my DPMS lower but it seems that information to that effect is lacking. So until I can scare up a second DPMS upper I intend to install the Armalite barrel on the DPMS upper and would like to use the A2 handguards rather than the DPMS float tube, does anyone make a standard barrel nut and delta ring set for the DPMS upper?

Has anyone tried using an Armalite AR10 upper on a DPMS lower? If so, were any mods necessary? Any info would be apreciated.

Thanks

Jeff

Armalite uppers/lowers and Dpms uppers/lowers will not interchange.An Armalite barrel will fit a Dpms upper or vice-versa.Just check headspace.I don't anyone offers a standard barrel nut for the Dpms.Yet.I believe Dpms is coming out with one.Another note,threading on the uppers are different.

I don't think you will be able to put on the delta ring either,that's what stopping me from buying a DMPS is that it willn't take handguards.
Why would they make it like that????

Better question is who would want handguards when you can have FF?  Unless you don't like accurate rifles.

What ARhabit stated was right on...AR10 platforms are not mil spec'd, so the companies offering the 308 versions have proprietary parts.  I had a hard time putting on my Badger Ord. Stabilizer handguard due to this fact.

If you need a DPMS barrel nut and 7" FF tube...I will sell you the one I have...I also have a DPMS .936 gas block...email me at [email protected] if you are interested.

Aubie,

I dropped you a line.

I wanted to use as much of the Armalite upper and parts as possible, the A2's would be fine as this will be used more for hunting than bench shooting but at this juncture I will do what is necessary to make this work, next step will be tracking down a cheap DPMS early style upper.

Jeff

Randal,

I though as much after comparing my DPMS lower to an AR10 blueprint, all critical dimensions seemed to match, I have to assume though that some dimensional tolerance differences may preclude this particular AR10 upper from fittin my particular DPMS lower, if it does I wont mind the gap

Jeff

Please take pictures if you get that beast built...you would probably have a unique rifle...that is for sure.

I am confident that Randall can fix you up.

Aubie, et al,

Will do, I have just dropped you a line.

Jeff

Well guys, here we go

I picked up my AR10A4 upper yesterday (A2 handguards, lightweight stainless barrel with bare muzzle and target crown, .243 WIN) and of course couldnt wait to get it home from the office and start tinkering

First observation: the front pivot lug was extremely tight so I ended up taking some 600 grit wet/dry paper and smooting off each side of the lug (just smooth, not through the anodizing), it now fits but is still tight enough to take effort to install. Once this was done the upper dropped into place and everything lined up.

Second observation: The front pivot pin would only go approximatley 1/3rd of the way into the hole in the lug, upon observation I could see where the hole tapered from outside to inside on each end with the center having a distinctive ring and smaller diameter which precluded the pin from passing through, a few moments (gently!) with a cylindrical diamond imbedded tool on the Dremel and then smoothing with 600 gritt wet/dry paper and it works, tight again but that is ok at least for now. The rear pin pushed through with zero resistance and now this puppy is mounted
I believe this uppers front lug was at the extreme for tolerance and maybe missed some CQ, by the way, this is a bran spanking new upper that has never been mounted.

Okay, now its mounted and its time to try the bolt/carrier group and charging handle. Being cheap and on a shoestring gun hobby budget I purchased this sans B/C and C/H after reading from different RKI's (resonably knowledgable individuals) that the DPMS B/C group would work but I had to hold my breath on the charging handle. Much to my surprise and distinct pleasure BOTH fit and function perfectly in this upper (although my carrier does not have a cuttout for the port door hoever it will work when the bolt is locked back and opens with aplumb).

Next came a big issue HEADSPACE Lacking a set of gauges I resorted to an old trick that I learned from the Gunplumber (AKA Mark Graham) from the FAL Files, this isnt truly scientific but is a good and acceptable WECSOG technique that will work in a pinch, the secret to WECSOG headspace measurement? MASKING TAPE! Gunplumber opines that a good quality factory unfired round (keep the upper off the lower for this one or things may happen) with a single layer of standard masking tape on the rear will tell you if your headspace is close enough to be safe, so I tok the plunge and taped it up and the result? The bolt would not even begin to close with this single layer of tap on the cartridge (I cant remember how thick the tape is but I THINK it is on the order of 5 - 10 thousandths). So, I would have to say that the headspace is tight and safe on this arangement

Well, so far so good, or is it?

Third observation: Now I am ready to try a mag and see how things line up in anticipation of getting some ammo for function and accuracy testing. Much to my chagrin the mags (3 steel and 1 plastic) would NOT seat and lock Close observation discovered 2 little shelves at the front of the mag well opening in the upper receiver that prevented the mags from seating, if these were cut off or relieved by 50 thousandths everthing would be hunky dory, what to do?
I can seat the plastic mag in the receiver with the upper pivoted up and close it as the plastic gives enough but that precludes normal operation and is most definitely a hinderance to enjoying my new upper

Before I cut, grind and swear at these small protruberances I need to ascertain for certain whether removing or altering them will cause this upper to NOT work with a standar AR10 lower receiver, does anyone here (Randall?) if these help to stabilize the M14 style mag? Hopefully not. If need be I can alter the plastic DPMS mag for now but I would rather not.

Observation four: There are 2 somewhat crescent moon gaps that are left at the rear of the receiver, I highly doubt they will ever be an issue outside of aesthetics but I may tyr to make some filler pieces in the future that I can attach to the upper in a secure but non-permenant way.

Overall this upper is light and feels great! It should be perfect for deer hunting and also woodchucks and maybe coyotes with lighter bullets, it is a MUCH lighter package than the 24" DPMS bull upper that weighs in at better than 14 pounds with scope, bipod and loaded mag Someday I might pick up and AR10 lower but I wanted to try this so as to increase the options for my DPMS and not have to spend a lot more money on a different feed system, I like my DPMS and think this will increase my care for it by a greater margin. If anyone else wants to try this just keep in mind the points I have raised, it will take some minor tinkering but nothing that cannot be done in an hour or so (that is if the shelves can be removed without making this upper unuseable on an AR10 lower, if you dont care about that then just grind away).

I have pictures below and will post again once I make the mods for the magazine to insert (after getting definitive information first) and firs this puppy for function.

Thanks for reading, any input will be gladly accepted but not necessarily heeded

Jeff

sweet!

this is one mean frankingun if i have ever seen one,

Randall,

Have at it! You have been a big help with this and I am most appreciative(insert bowing smiley if one was avaiable).

I did speak with a gentleman at Armalite in customer service, very nice person who thought that they did stabilize the M14 style mag, however just in speculation I would think the mag in an AR10 lower would fit and be held just as securely as any other mag in an AR style lower and not need additional support, I think it is more of a stop to prevent overinsertion of a mag or keep the mag from being pushed up to far and binding the bolt if the mag catch or mag catch opening in the mag is sloppy, say if someone rested the rifle on the magazine while shooting.

Looking at this again it appears I could remove or shave only a portion of the shelves towards the rear enough to clear the DPMS mags while still basically functioning as intended on the original parent lower.

In the mean time I will wait on Randall and if necessary will modify the cheap plastic mage first.

Jeff

Looking forward to further adventures in the home gunsmith's FrankenGun project!

Randall,

The Dpms mag is wider at the front than the M14, I have the measurments and the rough measurements needed for altering theses shelves but will hold off posting till later, my wifes grandfather passed away Friday and the funeral was today, needless to say we have been a busy family with guests and such, he had 19 children so its been a tad bit busy for working on guns of late.

Did you get a chance to look over your AR10 to see what type of interaction there is between the mag and these shelves? I am waiting to see what you find out before cutting although what cutting I do can be repaired with JB Weld if need be.

Please let me know what you find out.

Thanks

Jeff

Randall,

Perfect! I'll proceed with the operation and report how it functions.

Thanks again for the help

Jeff

Hey guys,

I did a bit of grinding last night (no swearing though), I can now seat magazines like they should be EXCEPT for the original DPMS plastic mag. I gorund the 2 shelves a bit over 50 thousandths (I didnt bother to measure as it isnt that critical, just plenty of space for the mag to insert) and left part of the shelves untouched near the chamber end which would still leave enough to prevent overinsertion of an M14 style mag in the original parent AR10 lower (if need be the shelves could easily be built back up with JB Weld and re-shaped but I highly doubt it would ever be necessary based on Randall's observations).

Everything is set for a trial run this weekend, I already zeroed the 10X Super Sniper on the .308 upper and am hoping it should be fairly close, I'll post more info on a range report later, in the meantime here is another pic of the franken10 (cool name huh) ready to go along with a very nice vintage custom Mauser in .220 swift (I took the pic in a hurry for my son and didnt have time to shoot them separately).

Thanks for watching and helping

Jeff

Success!

I was able to get to the range today and test the franken10, I only had 20 rounds (hard to find ammo in the sticks sometimes) but I made the most of them.

I couldnt do any rapid fire of course but that is not what I intend this upper for, .243 ammo is a tad expensive for mag dumps. My 10X Super Sniper was fairly close (it is sighted in for my .308 upper) and needed minimal adjustment, I'll keep a label secured the scope with the come ups from one upper to the other. I didnt shoot for accuracy but it looks like with 80 grain factory (Winchester) ammo this will give slightly over one minute accuracy but should do much better when I can really hunker down and shoot for groups.

Function was flawless and recoil was minimal considering the light weight barrel, this rig will work quite nicely for deer, woodchucks and coyotes

So, if anyone is contemplating using an AR10 upper on their DPMS lower basically all you need to do is grind those shelves down or off and your ready to roll.

I will probably pick up an Eagle Arms lower to build this upper into a rifle, this project has been interesting but I can never seem to keep a loose upper around without geting rid of it or building another rifle

If anyone has questions, etc. please let me know.

Jeff

Great post!  I've always wanted to know if that would work.