eunichron

They were already a solid deal at $69.99. My only regret so far is the lack of options for uppers.

Weird, I searched around before ordering and that thread never popped up.

Update: Of mice and men and LPKs... Sorry, bit of a wall of text ahead so here's the tl;dr - don't bother buying a bundled LPK. It'll be better to piece together your own buying single parts. Armalite pins, LR-308/SR-25 bolt catch, LR-308/SR-25 magazine catch. The rest can be AR15 parts. I ordered one each of an AR10(A) and AR10(B) lower parts kit from EveryGunPart. Great place to deal with, the parts kits were shipped quick. No complaints about them as a vendor. These are probably the fanciest LPKs I've ever purchased, and I've assembled thousands of ARs at this point (former SOT). The good news - Armalite pivot and takedown pins will work in the Ruger. They fit dimensionally, the one small difference is the heads of the Armalite pivot pins were milled slightly smaller, making for a little gap between the head of the pin and the receiver spring housing. Not a big deal, it doesn't even show up well in photos. I'll tack that up to variance in tolerances. I'll be sticking with the Ruger factory pins because of the nicer fit, and because I'm salty I spent so much on them compared to the Armalite pins. I ordered one of each kit because there was still at least one unknown; the bolt catch. Ruger told me the lowers use a standard AR10 lower parts kit, but didn't specify A or B pattern. I assumed A pattern since that is the Armalite pattern that uses LR-308/SR-25 magazines, same as the Ruger, but photos of the factory assembled SR-762 lowers look like they use either a DPMS/LR-308 or Armalite B pattern bolt catch. I bought the B pattern parts kit just to test the information I got direct from Ruger. The photo below of the 4 receivers lined up are 1. Mega Arms with an LR-308 bolt catch, SR-762 #1 with an Armalite A pattern bolt catch, SR-762 with an Armalite B pattern bolt catch, and one of my generic DPMS pattern receivers with another LR-308 pattern bolt catch (pretty sure that was a CMMG kit, could also be from a Luth-AR kit, I don't remember). The Armalite B pattern bolt catch doesn't fit, it's just slightly too wide to fit in the bolt catch slot, and I won't even bother trying to modify or force it for the following reason.The actual lip/tab/notch that catches the magazine follower is a few hundredths short on the B pattern catch. It ain't gonna work. That's what I figured considering the B pattern guns were designed to use modified M14 mags, but I wanted to be sure anyway. I did dry fit the A pattern bolt catch and inserted a magazine (PMAG), which looks like it will work, but I won't be able to do more testing of the bolt catch until I get uppers in and built. Given that it looks like Ruger used LR-308 pattern bolt catch on the factory guns, I'd go with that. Armalite A pattern bolt catch width: .445 DPMS/LR-308 bolt catch width: .442 Armalite B pattern bolt catch width: .411 +/- a few thousandths (this was really hard to measure because the tab is rounded, but it most often came in around .410) The bad news... Doing the bolt catch dry fitting presented an unexpected issue; magazine catches. Aside from the bolt catches the parts kits included standard AR15 spec parts, including the magazine catch. I don't know if this was EGP piecing the kits together, or if Armalite actually uses standard AR15 parts in their lowers, but this was the first time I'd seen an AR15 mag catch in a large frame parts kit. It's not going to work... it will install, it fits dimensionally, but the threaded portion of the mag catch is not long enough to seat properly in the magazine release and sits shallow. It works, but not good enough. I was planning to put Norgon Heavy ambi magazine releases in both lowers anyway, so I'll have to see how those fit, but I'm going to go ahead and assume that you should order an LR-308 magazine catch for these lowers. So here's what I've gathered so far: Takedown/pivot pins: Armalite pins are the proper pins. If you care about final fit and finish, try to track down some Ruger factory pins, but I'm pretty sure I bought the last ones. Any others I've seen since I ordered mine have been on scam sites that will steal your credit card info. Bolt catch: Armalite A pattern or LR-308, remains to be seen which one will actually work in a function test but my gut feeling says LR-308 is the way to go. Magazine catch: LR-308 Everything else: Standard AR15 parts will work, a spacer will be needed for the takedown pin detent and spring. I have a large collection of hex keys, 5/64 seems to be the perfect diameter to plug the hole. Length I'm guessing will need to be about 1/4", I'll refine that when I get to actually assembling. On that topic of uppers... DB10 uppers are still out of stock. The STAG10 upper I have on order with OpticsPlanet keeps having its estimated ship date pushed back. I reached out to Stag for any information on when production might pick up, to which they said they aren't sure. I have some other things to decide before I complete these lowers, namely receiver extensions and stocks, but it looks like I won't be finishing these guns any time soon.

Excellent! My only update is that I have no updates at the moment. Great to have confirmation on the DB10 upper, but they're out of stock on the website at the moment, so I haven't been able to get an order in. I have a Stag 10 upper on order that's estimated to ship in the next few weeks. I've been finishing up some AR15 builds while I wait on stock notifications.

Primary Arms discount on the SR-762 lowers is up again. $69.99 while they last. I have all the receivers I need for the builds I want, so I won't be purchasing more. I did finally get a response from Ruger customer service regarding parts availability. They only confirmed that they no longer have parts available for purchase, and that any Armalite upper should mate with their lower. A few of the parts I ordered from Numrich/Gun Parts Corp arrived today. Pivot pins and bolt catch roll pins. The pivot pins are Ruger OEM part #NS01066 and measure at 1.3500" long, not including the head. They are .2745" wide. This matches dimensions I've seen for Armalite pins. I think it is safe to say any Armalite compatible pins are good to go for these Ruger lowers. The bolt catch roll pin is listed in the manual for both the SR-556 and SR-762, and it measures within spec for a standard AR15 bolt catch roll pin. I paid $7 each for these Ruger OEM pins, don't pay that much. Use whatever you can salvage from a parts kit or order them from McMaster-Carr (3/32" x 1/2" coiled spring pin part #91598A204). Next steps will be ordering one each of the Stag10 and DB10 uppers and some more Armalite small parts to see how they match up.

Numrich Gun Parts has Ruger OEM pivot pins in stock, so I ordered two. Armalite also uses a cut pivot pin, so the AR10 parts kits should include the correct pins, if not a slightly different length. I'm going to order one parts kit just for testing's sake. At this point I'm pretty sure all Ruger (i.e. Matrix) did was machine a receiver that's 60% Armalite AR10(A) (pivot/takedown pins, bolt catch [although it may use a B pattern bolt catch], SR25 magwell) and 40% AR15 (fire control group). Shouldn't be too difficult to finish the receivers now.

🤔 Almost every DPMS parts kit I've used has fully round headed pivot pins- CMMG and LUTH-AR parts kits, and the pins that come with MATEN receivers all use fully round headed pivot pins. The Panther LR-308 that I used to own had a fully round headed pivot pin. The stock photos for the BAD pins on their website also show fully round headed pivot pins, so I'm not sure where you get that statement.

I wouldn't mind protrusion, but on closer inspection the Ruger pivot pin is flattened on one side of the head just like the Armalite pins, so I don't think the BAD pins would fit regardless. I think between Numrich and EGP I should be able to piece together a mostly correct small parts kit. Just to confirm, I got my pin gauges from the shop and both receivers measured at a snug .277. I suppose I'll also order one each of a DB10 and Stag upper and see which one fits best. On further reading, I should be able to get away with using a DPMS barrel in the DB10 upper even with Armalite threads as long as I also use a DPMS bolt that headspaces properly. In any case, here are my current build plans: Mega MATEN receiver set: 6.5CM Ruger #1: 7.62 NATO battle rifle Ruger #2: 8.6BLK SBR I'll try to document what I can here since information on using aftermarket parts with the Ruger lowers seems scant. Gonna be an expensive year.

double post

I know some topics on other forums discuss Matrix being the OEM for both Ruger and Diamondback and that they're more or less interchangeable, but that was all pre-2021. It seems Diamondback has changed their uppers since then and they're now Armalite threaded. I'd really like to stick with DPMS threads on the upper for more compatibility. I know there are companies that will sell an Armalite barrel nut with their handguards. So that brings up something else I've never been clear on; barrel extensions and headspace. I know they used to be different between DPMS and the AR10B, but did Armalite go with DPMS dimensions on the barrels for the AR10A? I.e. will an 18tpi upper and barrel nut work on a DPMS pattern barrel? I don't know how much time I spent looking around everygunpart and didn't find those. Thanks.

From the information I have that points to an Armalite pattern lower parts kit... which Armalite doesn't sell direct anymore. Any guidance on where to find one, at least the pins, is most appreciated.

Got some measurements in. Won't be able to take a pin gauge to the holes to confirm the caliper measurement until next week, but I'm pretty confident in these measurements. Takedown/pivot pin hole: .2770/.2775 Receiver width at the pivot pin hole: 1.3335 Receiver width at takedown pin hole: 1.1325 For s&gs and comparison's sake I took some pics of it next to my Mega lower:

I'm on the road right now so can't gage the pin holes for a couple days, but I did test fit my MATEN upper (a newer Zev production) on the Ruger after getting them home. The Mega's pins are just slightly oversized for the Ruger's pin holes. They will fit with some force, so that leads me to believe the Ruger receivers are sized for Armalite pins. I'll know for sure come Friday. That was exactly my thought if I wasn't able to source an original lengthened spring. I did find this listing for BAD pins with an option for a rear location spring. I might just reach out to them and see if they'd be willing to send me a few springs.

Centurion got back to me and confirmed their Mk11 upper will not mate with the SR-762 lower. He did lead me on to the Stag10 upper, which I've seen mentioned in other forums, but no confirmations that it does mate with the SR-762. Looks like OpticsPlanet has a few Stag10 uppers in stock, might pick one up for some test fitting.

Hey all. So, I'm not new to this forum, been coming here for over a decade, but I suppose there was a backend change at some point and lost my account. Anyway... I (maybe stupidly) jumped on Primary Arms' recent deal on stripped SR-762 lowers. Bought a pair of them for some builds I've had in mind. I'm no stranger to building large frame ARs, and thought it wouldn't be too difficult to find parts to finish the receivers and find matching uppers even with the rifles being out of production for several years. My hope was to find some Ruger or AR10A small parts to do some further test fitting to see what sticks... Numrich has a decent amount of Ruger small parts, but no takedown pins in stock. I reached out to Ruger but have not received a response yet. No dice on any Armalite small parts A or B series. Down to brass tacks... I'm looking for a source on these parts in order to finish the receivers and build a couple rifles: Small parts in general, but especially pivot and takedown pins, including springs - the takedown detent spring is longer on the Ruger since it is installed through the rear of the receiver. Bolt catch - as best I can tell an AR10A bolt catch should fit Upper receiver with DPMS threads - I've looked at the Centurion Mk11 and HTX Concepts SR25. Both look promising. I know the likelihood of them using the same pin size is next to nil. Thanks.