Can you swap a 6.5 upper with a 5.56 and interchange them anytime you please?

[IN33DAMM0]

Hello all. I wanted to know what the best 5.56 upper is that can be interchanged on a 6.5 Grendel rifle? (or if at all) Say I'm out in the field and want to keep the cost of ammo down, so I change the upper to a 5.56. When I need to switch to a accurate and larger round, switch it with the 6.5 Grendel upper. Is that possible? & what would the best 5.56 upper be that can be swapped? Thanks a lot guys

[Drifter]

With few exceptions, any 5.56 upper and 6.5 Grendel upper will work on the same lower. Just need different magazines for the lower.

If the primary purpose of the 5.56 upper is to shoot at a lower cost, a 5.56 upper that resembles your Grendel upper (style, barrel length, weight, etc) should serve as a nice practice weapon. When the switch is made to the larger round, everything would feel familiar.

[Variable]

With few exceptions, any 5.56 upper and 6.5 Grendel upper will work on the same lower. Just need different magazines for the lower.

If the primary purpose of the 5.56 upper is to shoot at a lower cost, a 5.56 upper that resembles your Grendel upper (style, barrel length, weight, etc) should serve as a nice practice weapon. When the switch is made to the larger round, everything would feel familiar.

Ditto everything Drifter said. The only difference between a 5.56 and a Grendel is the bolt, barrel, and magazine. The lowers are the same, so you can pretty much switch with impunity...

[Whelenon]

Currently I have two Grendel uppers and one AR lower. I will be selling one of the Grendel barrels and replace it with a 556 barrel. The 556 upper will be a light weight blaster that cheaper to shoot, while my Grendel is my go to rifle for hunting. Best of both worlds all on one platform, how sweet is that.

[RangerRick]

You might want to consider the Templar Fast Rail system. It allows ou to quickly change calibers without buying multiple uppers and rails.

It allows you to quickly change barrels from Grendel, Beowulf and 5.56 on the same upper. The barrel change takes about 3 minutes.

To go to 5.56, you also need to swap out the bolt, but that only takes a few minutes too.

The advantage is that you get to use the same, rail, scope, charging handle, carrier,iron sights, etc. You just print out a cheat sheet for each caliber of the scope settings for that caliber and use the same optics.

The system works by using an elongated barrel nut. The rail clamps to the barrel nut and is extremely strong.

You just have to be sure and use a gas block on each barrel that the rail can slide over. Any low profile block will do.

To take off the rail you loosen two allen screws and slide it off.

You just need the rail and a barrel nut for your existing barrel, then any new caliber barrel you get with the extended barrel nut.

You can buy the barrels from Templar too.

See: http://templarcustom.com/products/railshandguards

RR

[IN33DAMM0]

Alright so another question> I know the Grendel and Beowulf are both made by Alexander Arms, so I'm going to assume that they are both interchangeable uppers, Is that saying that EVERY combination of the Grendel and Beowulf can be swapped? No matter where you find it or what it was designed for?

[Dogue]

The beauty of the AR platform is that any AR15 upper assembly will mount to an AR15 lower...so yes, you can have 1 lower and have multiple uppers (6.5 Grendel, Beowulf, 300 Blackout, 458 SOCOM, 6.8, .22, .223, etc, etc, etc.).

[mlmiller1]

You can interchange ALMOST any upper & lower combination. Certain Colt AR's have larger front & rear pins than the rest of the AR world. You can even interchange those but you need a bushing or adaptor to make them work. I believe Colt is the only one to have done that.
You may find slight differences in the fit but they work. I also found that my grendel mags worked much better in one lower than the other. My grendel 26rd mags don't feed very well from the lower I choose to have it on right now. They worked fine in my other lower but I want it on this lower so compromise time!
MLM

[wiuprof]

Yes, what mlmiller1 said. I have had this Colt HBAR Match (heavy barrel) since about 1990 or 1991 and it has a larger diameter front pin. I bought the double diameter pin that's pictured so as to allow the use of all the other uppers out there. It got to be a pain in the butt, so I just wound up getting a couple of other AR's to more easily swap out uppers. It wasn't that big a deal, but it was a reason to get some more rifles!

I still have the Colt, of course.

[LRRPF52]

Colt Started that practice with the civilian SP-1 in 1963, so that they wouldn't be compatible with M16 uppers. The SP-1 upper also does not have a machined recess for the AUTO sear to articulate in underneath the upper by the takedown pin lug. If you hold an SP-1 upper next to any other AR15 upper, you'll see the difference, though it makes no relevance to those of us who don't own registered machineguns.

[IN33DAMM0]

How much are you selling the Grendel barrel's for? I'm looking for any 6.5 barrel that is bigger then 16.5"