So I made a thread about a week ago asking "What is the most powerful round i can put in an AR-10 build?" I got some good information and some that seem to think I'm an idiot for asking. That's fine lol. When it comes to this kind of knowledge i am clueless. The thread did make me curious. What determines a caliber being used in an AR-10 vs an AR-15? Is it just a matter of what fits in the magwell? I have seen some threads that talk about shooting 12 ga. and 50 beowulf from an AR-15 but some said the recoil from those would break the chassis quicker.
- Thread starter MoHobbyPlinker
- Start date
If the COAL is ~ >2.265” then you use an AR10, or hand load an AR15.
It is the length of the round and if it fits into the magazine that determines that.
Standards call for a max cartridge OAL of 2.260" for the AR15. Depending on the magazine, that can be pushed to 2.300". Standard for the large frame receivers is 2.800". Again you can go a little longer depending on the magazine.
The 50 Beowulf is the largest diameter bullet that is legal in the AR15 without it becoming a NFA regulated destructive device. Now as far as diameter of the case, it can only be so big before the barrel and barrel extension becomes too thin to hold the pressure.
Yes the 50 Beowulf fits into the AR15 since its OAL is 2.125". I have not heard of the 50 Beowulf destroying any AR15 receivers. 12 gauge is too long and will only fit the AR10 size receivers. These will only feed the 2 3/4" shells in the magazines. And there are plenty of large frame 12 gauge AR shotguns out there. Again I haven't heard about any being destroyed or damaged by shooting 12 gauge.
Standards call for a max cartridge OAL of 2.260" for the AR15. Depending on the magazine, that can be pushed to 2.300". Standard for the large frame receivers is 2.800". Again you can go a little longer depending on the magazine.
The 50 Beowulf is the largest diameter bullet that is legal in the AR15 without it becoming a NFA regulated destructive device. Now as far as diameter of the case, it can only be so big before the barrel and barrel extension becomes too thin to hold the pressure.
Yes the 50 Beowulf fits into the AR15 since its OAL is 2.125". I have not heard of the 50 Beowulf destroying any AR15 receivers. 12 gauge is too long and will only fit the AR10 size receivers. These will only feed the 2 3/4" shells in the magazines. And there are plenty of large frame 12 gauge AR shotguns out there. Again I haven't heard about any being destroyed or damaged by shooting 12 gauge.
Ehhh... don't feel like an idiot, we all started somewhere.
That said, the internet doesn't make it easy to understand the knowledge level of people. So there is a "expectation" from most here , that most people are "Gunny", and have a working knowledge of the subject at hand.
As for breaking the chassis, the bolt and barrel contain the high pressures, the chassis handles the recoil.
And just like any high power anything ( high power cars ) Its probably a better idea to install a 800HP motor in a chassis that can handle all the power. and fuss.
That said, the internet doesn't make it easy to understand the knowledge level of people. So there is a "expectation" from most here , that most people are "Gunny", and have a working knowledge of the subject at hand.
As for breaking the chassis, the bolt and barrel contain the high pressures, the chassis handles the recoil.
And just like any high power anything ( high power cars ) Its probably a better idea to install a 800HP motor in a chassis that can handle all the power. and fuss.
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This. It’s not just COAL, case head size is a player, too. Once case head diameter starts to get to a certain point, there’s not enough “meat” around the edge of the AR15’s bolt. You’ll start breaking lugs and shit.
This is true. the rim diameter of 7.62x39, 6.5 Grendel, and 6 ARC is about as big as one can go without having issues with lugs breaking on an AR15 bolt. And I have seen people have issues with lugs shearing even with 7.62x39 bolts.
And if you look at the big bore calibers such as the 50 Beowulf, they have rebated rims that are smaller diameter than the case.
Doesn’t the 450 Bushmaster have a .308 (.473”) bolt face?
There are some specialty guns such as the Ruger SFAR that are essentially AR10 type platforms but have been reworked to be closer to AR15 size / weight.
The Ruger SFAR 20" in a 6.5CM would be a very interesting platform indeed (as well as in the 6CM / .243)
Right now they only make it in .308
The Ruger SFAR 20" in a 6.5CM would be a very interesting platform indeed (as well as in the 6CM / .243)
Right now they only make it in .308
Yes the 450 Bushmaster rim diameter is 0.473" which is the same as 308. I only used the 50 Beowulf as one example that uses a smaller rim diameter.
