300 BO 8.5 inch barrel
- Thread starter KnotRight
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Yes,
Subjectively, 8.5" is the best .300blk
Objectively, 8-9" is the best .300blk.
Source for opinion: 16", 10.5", 8.5", 7.5" and the 8.5" is the best.
Subjectively, 8.5" is the best .300blk
Objectively, 8-9" is the best .300blk.
Source for opinion: 16", 10.5", 8.5", 7.5" and the 8.5" is the best.
OP
I think that was a Classic Firearms video that I watched the other day.
This is going to be a truck or house gun and shots should be within 15 yards.
Thanks
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Yes, it was my 'truck gun' until Bidet's brace BS, it runs well. I could easily point it at an 8 o'clock position sitting in the driver's seat. The brace is at a remote location waiting for the ruling to be overturned.
If I was to do it again, I'd probably do an ~8" barreled 350 Legend= bigger hole
If I was to do it again, I'd probably do an ~8" barreled 350 Legend= bigger hole
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I run a 9 inch barrel on mine. It's a blast to shoot suppressed subs. I've also killed a bunch of wild hogs and a few deer with it using 110gr Barnes bullets. So it's got the punch for HD.
OP
If you are a member of GOA or/and FCA, the courts gave their members the right to own pistol ARs. in an injunction. I covered 3 of my pistols to SBR and would do the 3rd but I want tp be able to carry it across state lines without any approval from the ATF.
I am, and I’m aware of that. It’s not worth the potential Barney Fife at a drivers license check point ruining my life. Away from home, the handgun will have to do for now.
That is the way I look at it.
Just carry the Glock 17 for now and a AR 556 or 300 BO with slick tube as a pistol if I need more.
Cole_McD
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Yup! I have, and seriously enjoy a 8.3" 300 blk.
Made shots out to 400 this weekend with 110 gr supers, and subs are crazy quiet with my Sandman S.
I love the thing!
Ps. 8.3" Hanson profile barrel from BA for reference.
Made shots out to 400 this weekend with 110 gr supers, and subs are crazy quiet with my Sandman S.
I love the thing!
Ps. 8.3" Hanson profile barrel from BA for reference.
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Cole_McD
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I think @Gnash.Hyena is also a huge 300blk fan and has been cooking up some loads recently?
That's right.
I have a 10.5" 300blk AR that I built with a Criterion barrel that shoots very well for me with 110gr V-Max supersonic handloads I've worked up. I did intentionally go with a 10.5 after selling off the 8.5 that I had prior to that. Yes I know 8.5 is better for subsonic. 100% not here to debate that. I run supersonics primarily though so that doesn't matter as much to me. But while the 10.5" does give a bit more velocity for supersonics, my primary reason to go with a 10.5 was actually handling. I have short arms. So even on my full length rifles I keep my handstop farther back because that's where I can reach it to pull into my shoulder in a squared stance. What I found was that with a 10.5 300blk, I can keep the handstop at the exact same spot as on my 14.5 and 16 5.56 ARs so I don't have to change my setup, and on top of that the 10.5 then has enough rail space for me to mount my WML the way I want to. All of these things I could not do with the 8.5 I had. I ran out of rail space with the 8.5 unless I wanted to pull the handstop back and have to change my forend configuration to something that wasn't as stable for me when shooting offhand. So for me the 10.5 is a win-win. I get more velocity from the supers I prefer to run, and I don't have to change my setup that I've come to like on my longer ARs.
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Ive run every barrel length there is. I know I keep hearing that the round was designed for 8-9" which is total hooey. Like about every other round you get more velocity the longer you go. If you are shooting supers then you'll get more velocity with a longer barrel. If you are shooting subs then it doesn't matter at all what the barrel length is. If you want a nice middle ground then 8-9" is it.
Aero/BA 8.5” are the perfect 300BLK IMO. I had 3, now just 1, but they shoot 110-220gr subs and super, suppressed and unsuppressed without issue.
That said, 8.5” is a compromise. It’s short which is handy but you won’t get the velocity needed for most 110gr to perform optimally. I have a 10.5” that gets me above that velocity threshold just because I can. I had a 6” Honey Badger upper and while it looked super cool and was handy being 2.5” shorter, I feel it’s really tailored towards subs. Personally, I shoot 10x more supers than subs.
That said, 8.5” is a compromise. It’s short which is handy but you won’t get the velocity needed for most 110gr to perform optimally. I have a 10.5” that gets me above that velocity threshold just because I can. I had a 6” Honey Badger upper and while it looked super cool and was handy being 2.5” shorter, I feel it’s really tailored towards subs. Personally, I shoot 10x more supers than subs.
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maven
10MM is best MM
Assuming you are handloading specifically to maximize the extra barrel length. The ammo our CAG boys use sees only a modest fps gain from a 9in to 16in. Supers coming out of 8-9in barrel are just fine after "not making too much noise" is no longer a concern.
Furthermore, the Sig MCX Rattler they are using now has a 5.5in barrel.
8"-9" is literally the sweet spot for what the round was actually designed to do. If you want to maximize velocity for supers- get a bolt gun.
When you say designed to do Im assuming you meant what JD Jones designed it for which was largely subsonic use. The supersonic platform idea didn't really come until well later when AAC stole the design. Been loading on the same dies for 20+ years.
FWIW Ive seen 2500 FPS out of a 16" barrel shooting 110 supers with no (bad ) pressure signs.
My Rattler upper on the MG lower sees more like 2150 fps from the same loading but that gun cycles on anything.
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This.
In my experience, specifically with factory loaded subs, I have had my bolt action 16" give a report that sounded akin to a supersonic crack, which otherwise would not occur out of my 8.5-7.5. Not using a chronograph to verify, this is mostly speculation and opinion, but with a suppressor, there is a pretty clear difference between supersonic crack lack there of.
When searching for a specific result, barrel length certaily will affect the outcome for better or worse, especially for subsonic.
I've also seen my non-bolt action 16" require tuning to cycle most subs at all, then ultimately requiring tuning to go back to cycling supersonic. which otherwise my 8.5-7.5 are turn key for cycling subs and supers without making adjustments to gb and buffer weight.
objectively, 8-9" is the best 300blk.
Unlikely its supersonic. Transonic has a feeble crackle to it. Thats why you build tailored loads. If its built right with a pistol length gas system a 16" will cycle all day with subs. Build it with a carbine length and you are asking for problems.
Cole_McD
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Not to sidetrack the conversation too much, but anyone here running a 12.5 300blk?
Is the additional velocity going to be meaningful? Seems like a nice and handy length for a general purpose build.
Is the additional velocity going to be meaningful? Seems like a nice and handy length for a general purpose build.
That being why I said "akin"
That also being why I specified "factory loaded subs"
Followed by "Searching for a specific result"
My 16" non bolt action has a pistol length gas system, and requires adjusting the gas block to cycle subs, or supers reliably.
Sure, if I dial the system in to cycle subs, it will cycle all day. But if change to supers, it won't cycle them reliably without making adjustments the gas block again.
My 8-9" is still turn key with either, can or no can. And would seem to be, is the best.
That's fine, I'm not going to be the guy justifying the use of a 16" 300blk barrel as a do all be all. Because it's not.
I do have a bolt action and ar pattern 16", so I'm quite privy to their uses, nor did I imply that there might not be any usage for them.
I'm advocating for 8-9" primarily because OP asked about 8.5" - my opinions and preferences really mean nothing shy of facts and evidence sprinkled throughout.
What adj gas block do you have? Mine will cycle suppressed subs all day but I struggle to get it to shoot suppressed supers even after almost closing the AGB. It gunks up the internals to the point of failure before a mag is complete.
I just take off the suppressor if I'm hog hunting and blast away. Deer hunting wont matter as I will just have 2-3 rounds max anyway.
In my 16" I am using a SLR Sentry gb and Odin Works heavy profile adjustable buffer weight. with adjustments, i can cycle supers suppressed. Though, I had alot of issues cycling anything reliably until I went with an H2 weight and inevitably, the adjustable weight. Primarily though, I do only run supersonic in my 16" ar, can on these days.
What is the nature of your cycle malfunction with supers and buffer weight do you run?
It may behoove you also to recheck your gb placement over the gas port, and depending on if your malfunction is ejection but failing to pick up the next round, not ejecting cases fast enough, or not cycling the bolt at all. You might try looking at your buffer weight.
It gets locked into battery. I have to mortar the round out. It's just way over gassed w. supers suppressed. The remaining rounds in the mag get filthy which I think leads to the lock up.
Running JP silent carbine spring, rugged surge which is known to have a lot of back pressure. It's a side charger. No hole where a charging handle would normally be, so there's not a lot of places for gas to escape but the side and down.
I've got an Aero AGB I'm about to try. If that doesn't work might go for one of the bleed off ones. Gonna look at a heavier buffer too.
Hmm, you should be fine with the JP and agb but maybe being a side charger, it's not enough routes for excess gas to escape..Certainly does sound like you're getting gummed up.
Personally, If i were to dig in to it, I'd try putting the jp in something else and then tune the agb with a different weight just to rule anything out. But it does sound like a ventilation issue.
OP
Here is my family of 300 BOs. The top one is the baby, the middle one is a SBR 10" and the bottom is a 16", my first one. I have another 300 can coming in. Now to the reloading bench to reload some 208 Hornady bullets.
