300 Blackout Barrel Lengths and Affects on Velocity. Silencer School EP.5 

My introduction to the .300Blk was when I purchased my BRN-180. Love the round, can't wait to get a can for it. Great video.

Great video. I'd like to see this same exact test performed with supersonic ammo in the 110gr-125gr range. Not the 150gr rounds that just use surplus .308 bullets to make the ammo as cheap as possible which makes them not particularly good at being a supersonic round and not quite subsonic yet.

Bolt actions produce slightly higher velocity as youre not loosing pressure halfway down the barrel for the gas port. You can compare a 16" carbine vs 16" mid length and the mid will have slightly more velocity although less dwell time.

The quality of your videos are simply amazing. No fluff and straight to the gun stuff. Just really getting into guns myself and purchased my first AR-15 recently and your videos have been great to watch and learn from.

Awesome. I was about to build .300 blackout with the Faxon 6” 1:5 twist. Hopefully this video points me in the correct direction. 2:52

Bought that POF Renegade Plus in 300 blk because of your review awhile back. I haven’t had a single regret since. Thanks as always for the awesome content!

You want "Effects" in the title. Affect is usually (maybe always) a verb.

music is annoying / too loud

Great video. You answered a particular question, with some good, solid numbers, without boring 😴 us (me) to death with any 'rabbit trails.'

Thank you. I'm shopping for a 300 blackout AR and didn't know what length barrel, 10.5 or 8.5 and I now know. Thank you very much

I went 10.5" for a couple reasons over a 9" or 8.5" 1) I like the length for my long arms. I have. 6'6" wing span. 2) honestly - I like the aesthetics of a little longer rifle. 3) I personally think you have less opportunity for suppressed gun Jams with more loads bc they all will fully burn down that length barrel and therefore your consistency will be there if you tune the gas block for it 4) if I want a short ass gun, I'm getting a PCC in 9mm with the radial delayed blowback laser beam shooter. 5) if I switch the barrel to a 11.5"-12.5" 5.56 round, I wont need to change my hand guard and accessory locations.

The music puts me to mind of playing "Perfect Dark" a couple decades ago. Lol.

This is the first video I’ve come across in your silencer school series. I’m sure I’ll watch them all. I’ve got a CGS Mod 9 in NFA jail right now. My first can. Aaand, I just ordered a BCA 10.5” side charging upper in 300 Blackout. It’ll be my first experience with 300 Blackout. Thanks for the great content.

I love all of your thorough videos and you have the perfect overture voice for this.. I would like to see 300 blackout against 10 mm 10 mm banshee versus 300 blackout Sig rattler

110 gr Supers are the go-to rounds for me out of my 10.5" pistol. My favorites are the Black Hills TTSX and the Barnes TAC-TX. I am getting about 2250 fps which gives great expansion and energy. With a 25 yard zero I can aim top of chest and get point and shoot results out to 300 yards.

Love these videos. Now we need one with supers please lol. With the goal of staying under the speed of sound with subs, speed loss with supers tends to peek my interest in these barrels more. Keep up the good work!

I think a great video would be running the rattler with a can on all the grain options until you find where it goes from sub to super. I would imagine it would be around the 185 grain area but a video testing velocity with different grain bullets and not different length barrels would be a good idea

Silencer School is briliant idea! Thank you for the good info!

I would argue .300blk is one of the few that allows PCC/PDW sized weapon that make sense without select fire.

I'm digging your silencer school

Nice video but I was more curious about super sonic loads. The beauty of the 300 BO is you can run the sub sonic stuff for up close and sneaky then stretch it out a bit with some supers at greater distances. I figure super sonic loads will be affected alot more by barrel length than the sub sonic stuff 🤔

Good stuff. I will add some of my data. SB 200 gr subs are in the 800 fps range out of my rattler with sig srd 7.62qd. I load 110 Varmageddon with 20 gr H110 and get just over 1900 fps with the 5.5" rattler. I really wouldn't want this bullet travelling much faster as it expands almost down to the base at 1900 fps. Same load out of 8" Ar I get around 2100 fps, and out of 10" brn-180 with nomad-30 I get 2190 fps. I load all of my subs for each gun individually to get 1020 fps average to keep it subsonic 90% of the year in MI as the speed of sound drops drastically when it gets sub zero outside. To keep factory subs actually subsonic I recommend 7-8" barrels, and if you handload get whatever length you want- barely noticeable sound difference with same bullet at same velocity with same can at rattler barrel length to 10" brn-180. Might make more difference out of a bolt gun. I do load 175 gr with trail boss for .308 14.5" pin and weld and it blows any semi auto .300 blk out of the water. As quiet or quieter than subsonic suppressed .22 with noma-30 and ebrake. A few more velocities out of 5.5" rattler: SB 124 fmj 1675 fps Sig 125 fmj 1780 fps I have gotten 125 gr bullets subsonic and cycling out of the rattler in the + gas setting I have plenty more velocity data from the rattler, 8 and 10.5" ar, and 10" brn-180 if anyone is interested.

For me the two best choices are: 1 - DD PDW - a 1/7 twist, 7” barrel and weighs 5.7 lbs. 2. - Q honey badger- 1/5 twist, 7” barrel and weighs 4 lbs 8 oz. Factors to consider / what’s more important to you: Q’s proprietary parts, DD’s parts interchangeability, Q weight savings DD better felt recoil Q’s shyt lead time Q- almost 2x the price largely aesthetic. DD- overall length advantage- pdw has multi positions w the maxim brace/stock - honey badger is only two position open and closed.. DD- best customer service in the industry.

The Sig Rattler velocities are spot on for it's length. Remington 220 subs run 980fps. Perfect for suppressed work. 125 Sig Supers run like 2300fps. That 1:5 twist builds pressure.

I'd love to see a video about why 1 and 5 twist is optimal for 300 blackout

The faster twist also puts more rotational energy on target causing more significant damage which is the thought behind Qs new 8.6blk that uses a 1/3 twist. So although the kinetic energy is telling, I’d take a mini fix or HB at 1/5 over the DD at 10.3 with the 1/8 as terminal performance may be equal or better and you get a smaller package and considerably less weight.

Love my canebrake with the Q half Nelson. Great video.

Maybe our friend Who_Tee_ Who should get this Doppler setup.......looks harder to shoot by accident than a Chronograph

Those close to 45 ACP velocities/energies is exactly why I'm not a big fan of subsonic .300 blk. I much prefer the supers because I'd rather have my rifle caliber perform more like a rifle than have pistol caliber energy. Ill sacrifice a few dbs for terminal ballistics any day. Thats just my mileage.

Wow, real data. Very interesting results. I have zero experience with 300Blk, however, I’m taking a lot of interest in sub-sonic rounds for PDW’s. It’s more likely to be an indoor situation where ballistic noise would be magnified due to confined space. Excellent video, thanks.

Interesting video. Any chance of doing this again but with supersonic rounds?

10.3 DD all day. Both in 300 & 5.56. Chefs kiss for real

Great video Tim. I'd love to see a 16" .300 BLK in the mix. I know most folks will scoff, but I think it would be cool to see how the velocities change. Since there is so little powder, and it's burned up way before exit, I wonder if the velocity increases due to barrel length will be minimal? Also, I know you love testing budget gear to see if it's worth the money (same as I like to do)... Any chance of doing an Arken scope review? For the money, I'm beyond impressed. I just ordered my 3rd SH4 Gen2 6-24x50 VPR MIL scope yesterday.

This is like scratching the surface of velocity and barrel length of the .300 BLK out. Would love to see a update with 16" and lower length 12.5 10.0 also. Thanks

I'm sure I'll be the millionth person to say this, but please do this with supers. Preferably the 110gr variety. Underwood Varmageddon, to be even more specific. But maybe a velocity difference between a 110gr (with an advertised velocity of 2400fps) in these barrels, and a 120-125gr (something with an advertised of 2200fps or so) in these barrels. You have to at least do the 110gr test. This was really just a tease.

Around 10.5" is the ideal length for .300 because the entire purpose of the caliber is that it can be effective at both suppressed/sub short and super/long, all with a simple ammo change.

Plenty of .45 ACP ammo out of a 5.5 inch barrel will have more than 460 foot pounds of energy. On top of that .45 ACP hollowpoints will have greater expansion than .300 BLK hollowpoints, which matters alot more than kinetic energy at that velocity. I struggle to see the point of super short .300 BLK AR pistols when PCC's exist and can do 95% of what the Rattler can do with cheaper ammo and even smaller size.

Can you do a 300 Blackout twist rate video?? Please and thanks!

Awesome video

A 5.56 with a 7" barrel is still strolling along at over 1800fps and delivering over 500 ft/pounds of energy. (even with the worst ammo) This is of course, quite a bit lower than optimal, but it still has enough pep in to put an ouchie on someone....Not sure why folks dwell on it being under-powered on the short barrels.... Good video - I was wanting to see the .300 blackout info. (I do not own one of these and am considering it with a 7" barrel) I have an AR with a 7" barrel, and I absolutely love it, and for me, it does everything that I expect of it. (Of course, I have no delusions about the effectiveness of it at distance.... When I bought it, the thought was it would be ideal to repel borders, so I never anticipated using it beyond about 25-35' at most)

I’ve heard it all before. Only this time I will listen. For you guys- I will listen.

I love video's around 10 minute's long, thanks.

Love this series. Keep em coming

Lil gun powder for the ultimate velocity and cfeblk for the because reliability cycling subs. (For 300black) P.s. I have got my Barnes tactx 120g (boat tail) loads going 2639 fps outta my Ruger ranch 300black (5000ft elv. In the dry high desert) that is my 300 yard mule deer load for next year. I shot a line of pumpkins this year full of water(to catch the projo) and it only lost the tip. Expanded to about a inch and the weight after the tip was 118.5grs total weight retention!!! Love that 300 black! I can't wait for 8.6 black! I just got done watching Qs live stream and I didn't win 😢. I would have answered the phone screaming at the tip of my lungs! But I guess we can't all win. But yeah the most fun caliber ever. To load and shoot is 300 black by far!!! Thanks for all you do Tim! And thanks again for turning me into a Q and 300blk O-holic! I thank you... My wallet does not 😆😆!!

I love 300blk just got a reloading setup so finally making it more practical it shouldn't be as expensive as it Is online considering it uses the most common brass and the most common caliber projectile

This really helped determine what barrel length to go with, preciate it

Learned something new today…def earned a sub

What is rarely mentioned in these comparisons is muzzle flash.

Absolutely proper video content! Great job guys thank you and keep up the great work!

that SMG 45 tho......another great video Happy Thanks giving

"I've been looking forward to this" 👍

I had wondered about 300 Blk and loss of speed with very short barrels. Thanks for the video!

Amazing video. To the point and informative, answered my questions and more. Thanks!

Do y'all find very short barrel DI AR's to foul up real quick? I'm having problems with several.

Pure barrel length change isn’t linear because you have to look at the ratio of loss. The 7” to a 5.5” is a 21% loss in effective length. For example a 2” drop from 20” to 18” isn’t as impactful as a 1” drop from 8” to 7” (10% vs. 12.5%)…

Really enjoyed this but I run a Maxim 5.5” shorty with supers - thinking of running the same test supersonic to see how supers change results?

Once you have a 300 Black Out and a can, you need a JP Spring kit to make it really quiet.

I love this new series........

Been looking for just this type of video. Thanks homie!

Comparing a bolt action in the same lot with gas guns doesn't make much sense. You are going to lose velocity in a semi because the powder is returning back to run the action and the bolt gun doesn't have that disadvantage. You would be more accurate to have this test with the same gas system length from the chamber to the gas port. This is a bit misleading.

7.5" 556 is making a hit for PDW. Practicing with it over 300 makes monetary sense. I train 3/4 of my rounds on a 7.5" barrel and switch to 8.5" 300 blackout to finish training. If you shoot every week it makes a huge $ difference.

You also went from bolt to semi from the 8 to 7 inch.

Great video! Love the .300 blk!

Happy Thanksgiving brother and thanks for the videos!

Nicely Done…Damn you got your hair did. 😜 My favorite length for 300BO is 12.5 for best do it all.

See, this video wasn't too bad! Interesting that the shorty is only slightly better than a good 9mm for energy.

The powder burn rate will have an impact on those velocity drops per barrel length. My guess is that with a faster powder you will see your biggest velocity change from the 10.3" to the 8" barrel. Less so from 7 to 5.

Hey, you mentioned the Rattlers 1:5 twist rate, im making that Hera CQR space gat 😁 and I'm looking at barrels, for this to match the handguard the barrel is 7.5 and I'm seeing two options from Faxon, one of the main significant differences is 1:8 vs 1:5. I don't know what application the 1:5 would serve. Why does 1:5 make sense on the Rattler and in general?

Great vids! Waiting on my first suppressor to get out of jail. Dead Air Nomad Lt. This video makes me even more impatient to start playing around with it on my rifles.

great topic. Great consistent channel 💪🏾

Does an 18" barrel work for 300 blackout for hunting???? Thank you.

Now can you meter them all back to back?

Supersonic me please!! Thats the test that we are all waiting to see!

Could you do this in supers as well. I've taken deer with my rattler using grindhard subs expanding bullet still got a through shot at 25 yards.

Curious as to why you didn't try a 9" barrel when the .300 reaches full velocity at 9"? Thank you for taking the time to make this video.

Thanks for the video. Helpful for my future build!

Always have wondered about this topic. Thank k you

All depends on the manufacturer’s powder choice for chamber pressure and burn speed.

Well put together video yall, thanks.

Would really like to see you guys test the Sig 120gr Supersonic 300BLK SBR Elite Copper Duty out of the Canebrake, and compare it to some other supers. Supposed to burn powder faster -- intended for short-barreled guns.

Great video. I agree I’d like to see a supersonic 100-125 grain video.

This is why you roll your own. I get 1050fps out of my 5.5” 300 BLK (190gr Sub-X). Still way inside the “safe” load specs.

Good idea on this series, great info.

Those reports during your test sounded like they were pretty loud - was that comfortable for you without ear pro?

My Sig Rattler is fast becoming my new favorite pistol maybe one I'll SBR it.

Speaking of powder for 300 BLK - I have a Canebrake I'm breaking in, and it does feel like I'm lobbing rounds in at 125 yards during my last range day. I have 1500 220gr projectiles that I'm going to find a powder for that will get me a more complete burn out of the 5.5" barrel...hopefully. Ultimately my goal is to dial in Subsonic rounds close to 1000fps, specifically for the Canebrake.

Man I wish you’d of shot a couple different SuperSonics and seen what difference was and how well the 1-5 twist stabilize like 110 grain Barnes

I’ve been pleasantly surprised with my Honey Badger out to 100y with Underwood 200gr subsonic.

7.5 is the way!

Nice scientific approach

I have a Q Sugar Weasel, YHM R2, and run 220g Subs and love the setup and combo. I do not understand the amount of 16" 300 BLK available??? 7 inch to 9 inch is the ideal length, most ballistic tests show only a tiny difference between a pistol 300 BLK and a 16" 300 BLK.

Comparing velocity drop with super sonic ammo would have been much more useful

Just for a full comparison, I would have liked to seen a 16" barrel used and tested. But the results show a proportional decrease as barrel length gets shorter. And I wonder how a long(er) barrel fits into the results. (& knowing that .300 Blk. Out, gets it's full burn in a 9 +/- inch barrel.)

It would have been interesting to calculate the effective range between the barrel lengths.

Can you check the velocity & performance on THE WILSON COMBAT PROTECTOR??? Will it reach a significant distance??

Thank you for the great video.

At least perps breaking into my house can't outrun any of those.

Natal - RN , Brasil 🇧🇷🇧🇷🇧🇷

Definitely going with the HB and Trash Panda for my 300blk set up eventually.

Excellent video my friend!!!