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Optimum barrel length?

Posted: Wed Aug 07, 2019 2:53 pm
by Thom
I am a beginner in this. Is there actually an optimum barrel length that anyone knows of? I read somewhere that the 300 was developed for 8.5 inches.

Re: Optimum barrel length?

Posted: Wed Aug 07, 2019 6:56 pm
by bangbangping
There is not a single optimum. Assuming you want to shoot subs and supers suppressed, there are only compromises.

For me an 8" barrel is too loud with subs and loses too much velocity with supers. Past 16" you get diminishing returns on velocity, and it can be unwieldy suppressed. In my opinion 11"-12" is a pretty good compromise.

Ideally, you want at least a half dozen different 300 BLK rifles so you can match the gun to the occasion. :mrgreen:

Re: Optimum barrel length?

Posted: Thu Aug 08, 2019 11:25 am
by Thom
I was thinking that an 8 inch would be good for pigs within 50 yards (with a suppressor). Do you think that is a good idea?

Re: Optimum barrel length?

Posted: Thu Aug 08, 2019 3:01 pm
by alamo5000
Not really any optimum barrel length in general, but for the stated purpose of pig hunting I would go longer barrel for velocity reasons. Opinions will vary on the subject.

Also bullet selection is important as well. Terminal effects are important and most are dependent on higher velocities.

That said shot placement is ALWAYS a thing when shooting hogs that is unless you are shooting with a really large caliber. Personally I would put that as the #1 thing. That boils down to accuracy and skill and really how many hogs you are shooting at a time. If you want to blast a sounder of them it's going to be a lot harder for clean shot placement. If you are just sniping one or two at a time it's much easier to draw down and get an accurate shot.

Re: Optimum barrel length?

Posted: Fri Aug 09, 2019 9:59 am
by Whole Bunches
Thom wrote:
Thu Aug 08, 2019 11:25 am
I was thinking that an 8 inch would be good for pigs within 50 yards (with a suppressor). Do you think that is a good idea?
IF within 50yd, I think 8" would be fine. Based on my calculations of retained velocity vs bullet maker's velocity recommendation for expansion and actual performance on deer and hogs, I had came up with general hunting (deer/hog) rules: 100yd for 8", 150yd for 9.5-10.5", and 200yd for 16". Note: sows have a lot less "shield" to penetrate than boars over 150 lb. Deer are easy to penetrate with the Blackout.

My 2nd biggest boar (272 lb) was shot at ~100yd with an 8" bbl and Nosler 125gr Ballistic Tip. The bullet went through a portion of the shield, shed its jacket about 2" from the spine, and the lead core hit the spine, but did not break it or penetrate into the spine. It paralyzed his legs. He tried to get me with his cutters, but couldn't move his body, only his head and neck. The first shot (hog was standing still) went through the neck and broke off a protrusion of a neck vertebrae, but didn't put him down. The 2nd shot (hog running) was the one that hit the spine. I stopped using the 8" Blackout on hogs in case I ran into another big boar, wanting more velocity for penetration and energy. Sows were easy to penetrate with the 8". Yes, I am more careful approaching downed hogs now!

I recommend a bbl in the 10.x" length for more velocity. Also recommend the Barnes 110gr black tips, as they penetrate in a large boar about 2" more than the Noslers if your bbl likes them for accuracy. I am doing hog control for 3 farmers and 1 rancher here in NW Florida. I use a suppressed 16" bbl with thermal, which unfortunately does not like the Barnes, but does like the Nosler. 16" gives me the velocity to do the job on any size hog at the distances I shoot.

Re: Optimum barrel length?

Posted: Fri Aug 09, 2019 11:57 am
by Eroc223
Yes do a search and thats what everyone says but me. The 300 is no different then any other bullet, you add more barrel you add velocity and ft lbs..... simple as that..... so my advice is choose the longest barrel that fits your needs and wants for whatever your intended use of it is. For me I chose 10.5 incher for my blkout pistol and it fits me as far as barrel length vs mobility and weight..... that part you will need to figure out. Also if you are handloading or just buying off the shelf ammo. Im a hand loader and I will tell you my ammo does 10x better then anything bought.... I load consistent to the grain and I can push it much hotter the most ammo out there. Just food for thought......I have also shot my 10.5 pistol out to 428.1 yards and made all hits on a steel target the size of a torso and made divots in the steel using my hand loads and 125 grain projectiles! Theres plenty o power there .......

Re: Optimum barrel length?

Posted: Sun Aug 11, 2019 6:28 pm
by bearcatrp
Am getting only a little more than 100 fps in my 16 inch barrel 300 BO compared to my 10 inch (2233 fps) shooting 110 V-Max bullets. What ever you choose, you will need to insure the bullet will expand properly at the distance you plan on killing. As mentioned above, the Barnes black tips expand at lower fps than others but cost more. Some other bullets are made to expand at slower speeds but also cost more.

Re: Optimum barrel length?

Posted: Mon Aug 12, 2019 12:34 pm
by Whole Bunches
LC formed brass
20.0gr H110
no anneal
CCI 400 primer
Barnes 110gr blacktip
2.25" oal
mild crimp

Here are velocity averages from a variety of bbls I have with the above load. Shot suppressed at 4-5' from the center of the chronograph screens. Temps 70-80 degree range.

8" bbl 2094fps (FN)
9.5" bbl 2200fps (Core15)
10.5" bbl 2202fps (FN)
16" bbl 2405fps (Noveske)
16" bbl 2419fps (RARR)
16" bbl 2393fps (another RARR)
16" bbl 2379fps (Daniel Defense)
16" bbl 2377fps (SIG MCX)

Most of my Blackouts prefer the 20.0gr H110 load, but my 16" Ruger Takedown AR prefers 20.1gr H110. I get 2402fps from it.

With my 125gr Nosler BT load (load not listed as it exceeds some published loading data, but safe in my guns, and I use a longer oal than is listed giving more powder space and lower pressure evidence):

8" 1997fps (FN)
9.5" 2076fps (Core15)
10.3" 2077fps (Delta Co, no longer in business)
10.5" 2015fps (FN)
16" 2198fps (Green Mountain)
16" 2201fps (Noveske)
16" 2278fps (RARR...same RARR as gave higher velocity with the 110gr Barnes listed above)
16" 2161fps (RARR...same RARR as gave lower velocity with the 110gr Barnes listed above)
16" 2258fps (Handi Rifle)
16" 2162fps (Daniel Defense)
16" 2252fps (Micro7)
16" 2140fps (XCR-L; not shot suppressed)

Looking at the data, one will see that some individual bbls are faster or slower than others. For example, my 9.5" Core15 416R stainless bbl is a fast bbl compared to bbls a little bit longer. While my 16" DD bbl is on the slower side, it's the most accurate bbl I own, and is a proven deer killer. I hope my real world velocities help in your quest.

Re: Optimum barrel length?

Posted: Sat Aug 17, 2019 8:38 pm
by tallburnedmidget
Thom wrote:
Thu Aug 08, 2019 11:25 am
I was thinking that an 8 inch would be good for pigs within 50 yards (with a suppressor). Do you think that is a good idea?
Like others are saying optimum is kind of relative BUT I too am in the 10.5" club.
I assembled a 6.5" long upper and when I chronyed my superosnic rounds I was not pleased at the much lower velocity.
I bumped up to the 10.5" and felt much better.

All of my 300BLK rifles must be able to hunt deer and hogs at 100-125yds and I felt limited by bullet selection and range with a barrel under 10 inches.
The 300BLK may be one of the most versatile calibers out there and now limiting myself to 110gr bullets and only the ones that perform at very low velocities for 100yd shots just felt like a step backwards for me.

I also run a 16" AR and a 16" bolt action which I would hunt with without thinking about it so 16" is going to provide more versatility than any other barrel length even though it is a bit long with a suppressor on it. That is why I now have the 10.5 inch to help with that issue... but my rifles are all hunting blind rifles. I don't get to spot and stalk... if I did then maybe I would have some different perspectives.

I hope all this info helps :)

Re: Optimum barrel length?

Posted: Mon Aug 19, 2019 2:11 pm
by GunFunZS
Thanks to the posters, above, particularly the one with all the chrono data.

I can't add data, but 10.5 give or take seems about right to me. Noise drops, and velocity is decent. Any shorter, and the ergonomics are a little wonky.

Same goes for 9mm Ars too. Not considering suppression, most ammo is going almost as fast as it would at any length by 10" and the same ergonomic considerations apply.