I was hoping some of you AR guys could educate me if you don't mind. I have some ARs but I'm not an expert on them at all. I was wondering what would be involved in switching a basic direct imp. rifle to 300 BO from 556. Is it just a barrel switch or do I have to change the gas block, tube, bolt, or anything else. Also, is it worth the effort, how does the 300 perform? I read one thing that says its anemic & weak, then I read that its comparable to the 7.62 X 39. Just looking for opinions/help, thanks.
- Thread starter pipeinspector
- Start date
It is comparable to the 7.62x39 with like weight bullets. It is based off the .221 fireball case, which in turn was based on the .223 but optimized for 10" barrels.
It also fires sub-sonic with no alterations to the gun.
It is a very good, niche cartridge. Awesome for home defense, hunting etc... but not as long legged as a 6.8.
Some claim 400 yard effective range with the high velocity (110 to 125 grain bullets). It depends on your definition of effective.
Simple barrel swap is normally all that is required.
It also fires sub-sonic with no alterations to the gun.
It is a very good, niche cartridge. Awesome for home defense, hunting etc... but not as long legged as a 6.8.
Some claim 400 yard effective range with the high velocity (110 to 125 grain bullets). It depends on your definition of effective.
Simple barrel swap is normally all that is required.
The short answer is, it depends. The gas block and tube "could" be re-used if you buy a barrel that has the same gas block journal size and gas length. The bolt is the same size with 223/556 as it is with 300BLK and can be re-used. I guess to answer your question, it can be as simple as buying ONLY a new barrel and re-using existing parts from your 223/556 barrel IF you buy the right barrel.
Someone a little more schooled on the ballistic capabilities can chime in on that. I originally compared it to the 30-30 WIN and found that the 300BLK is a little less powerful, but still sufficient for deer/hogs out to 100yds as far as I'm concerned. When funds allow, I'm gonna build one to replace my 30-30 for brush hunting where only short range shots (<100yds) are the norm.
I had an AR in 7.62x39 and didn't understand the big fuss about the 300 Blackout. Other than a wider variety of magazine options and a better selection of bullets for reloaders, I didn't see any advantage to the 300. My 7.62x39 was cheaper to shoot, and it was slightly more powerful. However, I tried keeping an open mind as I read more about the 300. One of the things that intrigued me about the 300 was that several folks commented on its efficiency. Others said that it was fun to shoot subsonic rounds suppressed. After a lot of thought about what I wanted from a .30 cal AR, I decided to take the plunge and buy a 300 Blackout barrel. Truth be told, there wasn't that much difference between the 7.62x39 and the 300 when pulling the trigger, except that the 300 had slightly less recoil. I was pleased with the gun's accuracy and the balance of the 16" AAC tube I installed, but the icing on the cake was the first time I shot subsonic rounds suppressed. It's one thing to shoot supersonic .223, 308, or even 7.62x39 suppressed. It's a whole different ball game shooting subsonics in the 300 suppressed. A coworker had his sights on a 7.62x39 AR until he shot the 300 suppressed.
Performance wise, I think the 300 is an adequate cartridge for deer or hogs for relatively short ranges, say to maybe 150-ish yards. It's anemic when compared to something like a 300 Win Mag, but how much gun does one need for short range deer/hog? You're correct that it's approximately the ballistic equal of the 7.62x39. The available selection of factory loads is quite nice.
Performance wise, I think the 300 is an adequate cartridge for deer or hogs for relatively short ranges, say to maybe 150-ish yards. It's anemic when compared to something like a 300 Win Mag, but how much gun does one need for short range deer/hog? You're correct that it's approximately the ballistic equal of the 7.62x39. The available selection of factory loads is quite nice.
The big advantages the .300 Blackout enjoys are as I see it twofold:
1. You just have to change the barrel to enjoy the .300 Blackout, meaning you still have world class top quality magazines and bolts readily available. The appeal of the 6.8 SPC, 6.5 Grendel, and 7.62x39 will always be limited the shortage of these last two components.
2. Subsonic capability. You've got to experience this - suppressed of course - to fully appreciate it.
1. You just have to change the barrel to enjoy the .300 Blackout, meaning you still have world class top quality magazines and bolts readily available. The appeal of the 6.8 SPC, 6.5 Grendel, and 7.62x39 will always be limited the shortage of these last two components.
2. Subsonic capability. You've got to experience this - suppressed of course - to fully appreciate it.
Last edited:
IMHO the only reason to build a 300 is if you going to run Suppressed.... Fantastic Suppressed.... Otherwise there are other calibers that don't take many more components that are much more versatile in their performance. FYI 6.8 bolts and magazines are readily available.
Thanks guys, this helps. I never understood the craze but this helps put it in perspective. Question: without going through the SBR process for the ideal barrel length, how does a 16" barrel perform? Or if there was a way to pin on your Quick disconnect for your can and get the 16" total length but maybe a 14.5" barrel? Would that work? Thoughts on performance?
On steel at 50 to 100-ish yards, the 300 makes a heckuva lot more clang than does the .223/5.56, though certainly not as much as a .308. This was with a 16" barrel. I don't expect much difference with the 10.5" barrel as soon as the tax stamp arrives.
I see no reason why pinning and welding a muzzle device wouldn't work to bring a 14.5" to 16", though I believe YHM doesn't warranty their QD FHs for pinning/welding because the FH has to be removable to service the spring for the detent mechanism.
I see no reason why pinning and welding a muzzle device wouldn't work to bring a 14.5" to 16", though I believe YHM doesn't warranty their QD FHs for pinning/welding because the FH has to be removable to service the spring for the detent mechanism.
Thanks for the information guys. If its just as simple as a barrel swap I'm going to have to try it out just to satisfy my curiosity.
