LaRue 6.5 Grendel Rifles

[HuntTXhogs]

That McGowen won’t disappoint

[revaew]

Sorry for bit of a necro post, but I had a question about the upper kit. So I didn't order a Larue lower to go with my 6.5G UU kit as I already had several lowers laying around my house. While the Larue upper fits like a glove into the lowers, the outside of the receivers do not match very well. In some places the upper is wider and in others my lowers are wider. The back of my lowers, where the buffer tube attaches is wider than the back of the upper and i can see into the buffer tube, albeit slightly. This is true in several spots. Has anyone else experienced this? They are SAA, bushmaster, PSA, BCM, and Aero lowers and are all marketed as Milspec. I read than any milspec receivers should work fine but the fit of basically every other combo of receivers I have appears better. I may be over reacting, but I have never had an upper and lower go together like this. Am I over reacting? Thanks.

Here is a picture from both sides, looking at where the receivers meet. It is more or less like this for all lowers that I have.





This last picture I used a stripped lower so the gap could be seen more clearly.

[Sticks]

You can run it, I would just advise against doing any heavy dust and sand submersion testing.

[DuneShoot]

Their UU kit uppers fit their lowers but do not match up like their factory rifles.
This is a SURG upper on their lower. Not quite as bad as yours but still doesn't match perfectly like their factory rifles.
For $199 I'd order their lower since you have the upper.

[revaew]

That upper looks like mine. I thought that the upper kit came with the stealth? I've considered getting their lower, but I wanted to use one of the ones I've got chilling at home and get shooting. It's slightly disappointing that the fit seems so odd.

[Mesa1978]

Always good to see another producer join the Grendel platform.

Uniqueness often is part of product differentiation, though often it doesn’t result in a functional improvement.

[Kswhitetails]

I may be over reacting, but I have never had an upper and lower go together like this. Am I over reacting? Thanks.

No worries about the necro part, we love talking about our rifles.

My Rifle is perfect in form and function. The problem here is that everyone makes their own billet dimensions, and none of them are going to fit like they were made for the other unless upper and lower come from the same place, with the similar date of manufacture. Functionally, it should hold it's own rather well. If the fit of the outside dimensions is that much of a bother (as it sounds like it will continue to be) then shoot as is until the LaRue lower arrives. We now have discussions about the rifle, UU, and Surge all gumming up the works. This thread deals with the rifle, which has absolutely none of the fitment issues experienced above.

As far as the gap goes, if it passes a function test prior to firing, then fire it and see what works out. The LaRue crew obviously designed their billet pieces to be stonger in places it mattered, and lighter in the same way. If you read some of the first few posts in this thread LRRPF describes rather well how the final form of upper and lower were made for each other with subtle but surprising quirks and benefits. You will be well served by mating this upper with it's intended lower ASAP, and using another of your lowers as a place holder until then. I'd say you're on the right track.

[revaew]

My biggest concern was the fact of it being okay to shoot with the gaps. I'll just take it a bit easy and shoot it as is until the larue lower comes in. Thanks for the info.

[jonny rotton]

That McGowen won’t disappoint

it sure didnt. i finally got out the other day to shoot the 20" mcgowan and a 12" mcgowan. the 20 did produce a 1/2" group at 200 and sub moa at 100. the 12" shot subminute at 100 and 200 with factory sst. i also finally got my larue suurg 2. it was starting to shoot-in a little at the end. i will do a write up asap. my old dog died a little over a week ago, then my father passed away thursday. i was on the second hole when i got the news. i finished the nine holes i was playing in a mens league. i did get to spend time with both my parents in so calif earlier this month.

[AZHTfreak]

Stop it LRRPF52!!!! My bank account can't take it!!

+1, took a while to save the schekles, but Merry Christmas to me!!! FDE UUGrrr, matching lower and a LT204 on order. My drool cup was overflowing... 1st factory gas gun I've purchased. A fine addition to my GroupBuy 20 and 12!

[flyfish13]

Thanks for all the great info in this thread! As a result, I just ordered a Larue FDE UU with matching lower this morning. Question, being new to AR building, I ordered the UU un-assembled so I could get the experience of assembling an AR. Since all the entire AR is coming from Larue should I go ahead and have the upper assembled and then "cut my teeth" on a future build?

[Marine24]

If you have the tools to torque the barrel nut on to upper receiver, building the upper isn't difficult. Having it assembled by them and test fired is a nice bonus and it is free.

[82HALO]

No brainier...let them put it together! I would think this not your last grrr lol! Start ordering parts for your next and cut your teeth on it and you can order any tools you may need in the mean time!

[jonny rotton]

i do not think it is free. check the website for price of assembly

[rebby]

i do not think it is free. check the website for price of assembly

Assembly is free at the moment. Christmas deal going on right now. Normally it's $150 IIRC.