Rosco Manufacturing Barrel Autopsy. This particular Barrel was fired on full Auto for 26,750 rounds. Barrel exhibited poor accuracy at the 26,000 round count.
Shout out to Rosco's for letting you use their barrel. I will be buying their products from now on. It would have been sweet had they sent you a new barrel with it for comparison. Maybe next time.
Since I found a local barrel manufacturer I've used Rosco barrels. Also props to them to send off a barrel to a RU-vid gunsmith to critique and show their stuff.... Regardless of outcome.
Chad, with someone of your knowledge, I think it would be great to see an in-depth AR style rifle cleaning video- if you ever find the time. Awesome stuff.
Drop the fieldstripped rifle in a tub of CLP, let stand for 72hrs, remove, scrub parts with nylon brush, run through parts cleaner with very mild solvent/degreaser(simple green), rinse with water, dry thoroughly with pressurized air, lube all parts and lightly coat all steel parts with CLP. We used to do that while on post deployment leave, everything but the optics, and lowers went into the bins, and when we got back you could see carbon settled on the bottom, and it was way more than you thought your rifle had. I currently have an Anderson RF-85 upper. They claim you don't need lubrication, and warn against using lubricant. I run my upper wet, and I keep it wet when at the range and at home I keep a light coat of oil. If I need more than a mag for self defense then I'm not doing it right, or it's the cops at my door, which is a slim to none chance for me. And in reality, you don't need to get every last bit of carbon, and honestly you shouldn't remove it all. It's not worth the time and effort taken to achieve, and in my opinion, it's not healthy for the firearm. Carbon isn't the enemy, your bore, chamber, barrel extension, bolt face, bearing surfaces, and BCG should be clean of build up and excessive carbon. But the first three should be the main focus for being the cleanest and the rest you can get the majority and not have any operational or excess wear issues. The biggest place I see people missing is in the FCG and buffer assembly and tube, as well as their gas tube and gas key. If you have coatings that will withstand it, break/parts cleaner works magic on carbon. I might get chastised for saying that, but I used more of that stuff in the military than I ever did as a mechanic.
@@hellcatdave1 never said it was. It's what we could use in the military and I have used gallons of the stuff. It comes down to preference and how many different products you want to use and have on hand. For most people, they want a few. I have lost count of the number of products I have or have used. For the purposes of cleaning after the range, CLP is great. You can wet the firearm, put it in the case and head home. After a couple hours it has worked it's way in to breakdown most the carbon build up, or if you kept applying it at the range and started with a well lubricated firearm you can likely wipe most the carbon off and have minimal time scraping and all that. For a deep professional cleaning I use several products and in different stages. I've never had an issue with CLP besides its heat resistance and the fact that you have to apply it more often than most oils. But in the military that was t really an issue as we had gallons of the stuff at any point in time and usually did some training with our rifles at least once a month. I've had CLP restore function to an M9 that spent 2 weeks in a humid and damp Texas summer where it was starting to rust and was inoperable. After cleaning and a little scrubbing to clear up the rust it was as good as before. I won't say new because it wasn't, but it was partly due to the basic issue cloth holster that it was stored in.
Nitride is no joke. I've drilled multiple gas blocks for taper pins and my drill press zips right through phosphated gas blocks. With a nitride gas block, I was amazed and perturbed by how hard I had to lean on it before the bit stopped chattering.
I know right & thanks to kotaboy bcg video i ran into chad as i hear people call him he definately earn$ hi$ money talk about a WEALTH of Knowledge plus the Honesty
Built a handful of my own ARs over the years, learned more from this guy in the past week of watching the videos than I have from any one Ive talked with. From cleaning rifles and reading barrels. Blows my mind how technical this can really get, but its made where anyone can pickup the knowledge. Great work
And THIS, Boys and Girls, is why I run Rosco barrels on ALL of my new AR platform builds. Good on ya, Rosco! Customer for life here. Thanks for the video and proof that I have made good choices in my barrel selections.
In short, once your gas port erosion begins to vent excessively and creates a tapered valley in the barrel, it's only a matter of time until the muzzle tolerance begins to open up significantly. Awesome video and thanks for taking the time to share your findings wit us. You've got my subscription.
as an avid ar enthusiast, this channel is a gold mine of information! thank you so much for sharing your knowledge.. now if i even had 10% of the gauges you do!
17:10 I haven't seen one of those push-pump solvent jars since I was 17 years old (a LONG time ago) repairing power supplies for NCR mainframe computers. We used them to dispense isopropanol to clean solder flux from circuit boards. As if I didn't LOVE your channel enough already ... thanks for the ear-to-ear flashback smile.
Depends on what they consider accuracy issues, there is a place in las vegas that doesn't swap the barrels until they notice tumbling at 15-20 yards with full auto mag dumps. if you are hunting you would probably swap it a lot sooner
It's really interesting to me how the erosion of the gas port occurs towards the _muzzle_ and not the chamber. That's the opposite of what I'd assume would happen. Very educational.
Yeah, me too, but then when you rethink it it makes perfect sense. The gas isn't forced through the port til after the bullet passes the port so it's like back pressure...
I'd have thought the same because the combustion contaminants arrive at the gas port from the chamber side. But I guess it's because the round drags the plume of contaminants past the gas port and the gas port is a "catch" for the stream of contaminants, eroding the muzzle-side lip of the port.
It’s like driving over a pothole. The first edge of the pothole doesn’t take the impact of your tire but the second does. The gasses are contained until they pass the chamber end of the gas port and flow over it then crash into the muzzle side of the port.
This Channel is freaking amazing. I am from Australia, we arent even allowed AR's here and I love this stuff. Brilliant content, you know your stuff by all accounts. SUBSCRIBED.
I subscribed within 2 minutes of the start of your video. I love the straight forward, technical approach and data driven analysis. I hope I'm not casting aspersions when i say it's like watching Chris from Small Arms Solutions from back in the day when he was gaining all the k knowledge he shares now. Excellent content sir, looking forward to perusing the rest of your videos.
Man...my 10.3 ballistic advantage "hansen" barrel was torched at 5,500! Of course, 90% of those were fairly hot Hornady 75bthps behind RL15 or Varget. I wonder how many more rounds it would have survived with an equivalent load of cooler burning ball powder? All academic at this point...ultimately barrels are dirt cheap compared to component prices or -god forbid- factory ammo. Good work on the autopsy! Subbed.
This is why I love and prefer Rosco barrels. They come dimpled but you can still pin the gas block if you have a jig or take it to your gunsmith. I currently have about 15k rds through my 10.5 rosco and it only sees solvent, patches and a nylon brush if needed every 1000 rounds. For those that say I should clean it more, it's my training gun and rosco has a decent price when it comes to barrels. I'll buy a new one when it's time.
Impressive! -Only barrel Ive ever shot out was a S & W CL 16" 5.45x39 that had around 15K as to round count, 70% of that number primarily ComBloc corrosive 7N6-(EXTREMELY well cared for during the rifles firing life-Windex-water wash n' flush minutes after shooting/cooling, then a deep hot-water rinse/scrub, dried, then followed by solvent clean usually no longer than 20 mins after each range trip)-....No S-L-O-W degradation in performance either! -One shot being accurate, the next: Keyhole city, but still hitting a 9" pie plate at 20 yards accurate. Every projo hitting plate sideways.... Picked up an Xtra ROSCO 10.5 pistol barrel, & although its not sitting in anything but a box & un-shot, I'm VERY impressed with just the machining/Surface finish for being a 120$ barrel!...>They are GORGEOUS!< WELL worth the cost IMHO....
@@jonathonschram3429 Stole this from the AK subreddit because I don't think I can say it any better, but I researched this on AKs and found this to be very informative: "Everything pre-AK-74 used a 45o gas block and gas port. Early AK-74s also used a 45o gas block and port until they realized it was causing bullet shearing. The AK-74 switched to using a 90o gas port and gas block because of this. Everything afterward did, too, simply because it was easier to only have to drill one kind of hole and make one kind of gas block for everything. The gas port angle is what is important. Romania used 45o gas blocks on their AK-74s, but did not experience bullet shear due to the fact the gas port itself in the barrel was drilled at a 90o angle. Basically, it doesn't matter." Also, I believe a 45 degree gas port will lead to quicker gas port erosion...look at how the gas port eroded on this 90 degree gas port...now take that and start with a 45 degree gas block, it's just gonna accelerate the erosion.
Rosco barrels are the new supplier for the colt new / latest Cr prefix assembly lineup 💪🏼💪🏼💪🏼 milspec/ civilian proof . My 6933 commando , 6920 and my full size 20 in. Rifles all have rosco stamped / proof barrels and they all print 1.5 moa or better at 100 yards depending on ammo quality and weather .
I have nothing to do with guns, I am an aerospace and AI engineer, but I love your beautifully machined gages and that little acetone squirty thingy just made me happy somehow 😄
Rosco barrels are the most underrated barrels, I got an 11 inch on a 2A armament handguard with a basic ass upper receiver, I'm getting better shot groups on my 11in then my 16in
My bet it that whatever muzzle device that was used was over torque. This is a very common problem. 25 ft/lbs is too much torque. Yet this seems to be the generally accepted consensus. According to Joe Carlos, a precision AR gunsmith, 8 ft/lbs is the most you should ever use on any muzzle device. He's done more testing on these kind of things than anyone else I've heard of. He also suggests using Loctite or Rocksett to keep your device from coming loose. He found in testing that the standard 25 ft/lb. figure constricts the barrel leading to this exact inaccuracy condition. Just my two cents.
Amazing what these little rifles will take when they're set up properly with good quality components. We several older Colt SP-1's that are used as ranch rifles, all with pretty heavy use and high round counts. They just seem to keep going and going.
I also am guessing due to it being short and the port pushing gas forward towards muzzle combined as mentioned possible increased back pressure from suppressor or similar muzzle device, that area became the hot bed for wear. Very short dwell time plus inability to expel gas aka back Pressure. Still amazing ability to demonstrate functional cohesiveness of rest of barrel. Impressive.
Just stumpled upon your channel, and I like it. I have one humble request: Please explain what the tools do, and why that means the measurement you just took is a good/bad indicator. I'm not a gunsmith, and I have no idea why "gizmo X doesn't fit perfectly to hole Y at angle Z" is a bad thing.
Basically all his tools are gauges which is created off of SAAMI specs. SAAMI was created for consistency in manufacturing of firearms and ammunition for a specific caliber. If out of spec ammo or guns are made then guns will start going boom in your hands which was one particular problem with the M1903 springfield rifle (real world example) as for the muzzle erosion gauge that just tells you how worn the muzzle and rifling are because a gun will not shoot good at all if the bullet does not have a tight fit at the muzzle which will cause "key holing" and you won't hit the broad side of a barn. Google can also be of great help with answering ya questions. I have personnel experience with head space gauges cause i have two lee Enfield rifle that have issues. One rifle has a headspace that is to tight so i will have to change out the bolt head and the other rifle was on the verge of having headcase separations (cracked case heads on my brass) and was also leaking gas from the chamber, the field gauge got eaten so i had to buy a new bolt body for that rifle and the cracking case heads and gas leaking from the chamber was solved.
Even with the gas port erosion the gas port is still smaller than many other mfg gas ports.The weapon seems to have been properly gassed.I've been overlooking Rosco and several other mfg but will be checking them out.I only buy AKs if Akoperators union clears them and now when I'm looking at barrels and bcgs I'll see if you clear them.
Great 🤦♂️🤦♂️🤦♂️🤦♂️🤦♂️, Now my OCD has me looking for ALL these wear guages. I love this bore scope. I have one that I never can seem to keep in focus. As for this barrel, 26,750 rounds of full auto. And we don't know what type of ammo they even used during this test. It goes to show you how much abuse this barrel took and how well it held up. Id bet a $1.00 to a Dozen doughnuts they tested this barrel with a can on it. And that probably caused the excessive muzzle end wear at nearly 27-K rounds. Btw, GREAT VIDEO and I'm a new SUB after watching this and several other of your videos. Your NO BS approach to just giving is the facts. And if you do involve your opion you are very admit about telling the viewers that it's just that. And thats something that its getting harder and harder to find today. Especially when you have manufacturers paying for reviews of there products. Especially in the firearms world.
I had 2 Rosco 13.7 mid .223 Wylde barrels with cycling issues so I spent 3x more and got the same sized Noveske but is the cold hammer forged flavor. Since the swap I haven't had any cycling issues. It runs like a clock.
How much would a guy need to budget for a set of gauges like you're using, and does anyone besides PTG makes these. Big PTG fan. Just wondered what the options were. THanks for your knowledge. Wish I could give you more than one thumbs up
I would like to point out one thing you may have overlooked here. With that much erosion at the muzzle, you essentially have a tapered barrel, As your erosion gauge clearly shows. This would potentially render the straightness gauge test irrelevant in this case. This could potentially prevent contact of the gauge rod at the eroded end, where it would normally contact if it were bent with minimal erosion, allowing it to slip through unimpeded. It likely is essentially straight however. Just something to consider.
I just picked up one of these 10.5” Rosco barrels on sale for $99 bucks. Can’t beat that deal. The gas port size on the barrel I bought says .75 so it’s going to be over gassed but at least it will eat anything I feed it.
0.750" is the gas block size. That is the outside diameter of the barrel where the gas block attaches. It doesn't have anything to do with the size of the gas port or the rifle being over gassed.
@@littlejackalo5326 you are 100% correct. I got a bit confused but yes that’s correct. One thing I do NOT understand though is why most companies don’t list the actual gas port size? Why is it like some secret spec they don’t want the public knowing lol. I would have liked to know my gas port size.
Very impressive. My handgun has over 30k rounds through it but non of my rifles have anything close to that number. Can't wait to see how my rifles will be when they are at those usage.
26,750 rounds f/a! That is very impressive. Anyone who thought that Rosco barrels were cheap and poor quality should seriously re-think that. This barrel is a resounding endorsement of Rosco barrels.
I can't say for certain because I've never tested the phenomena in controlled conditions but I think the accuracy issue is caused by a quasi internal version of a damaged crown. We see accuracy issues with a damaged crown because the propellant gasses are imparting an interrupted spin and or flight pattern after the bullet has left the lands. When you combine 1) the muzzle end erosion - which may mean that through part of the barrel the bullet is not being influenced, or not influenced greatly enough, by the lands: with 2) the troth cut just forward of the gas port - that irregular flow of propellant gases imparting force on the bullet may be interrupting the spin and flight path of the bullet in the same way that a damaged crown would. . It's an oddity that we would see the same phenomena occur internally like this: or at least it's an oddity with *newer* guns. This is not horribly uncommon to see in *surplus* guns in which both ware has reduced the internal diameter of the lands and erosion has left pock marks or holes which create very similar conditions. It's not something you'd ever worry about on ARs because rarely do you see AR barrels which have been worn away to an extent that lands are far away enough from the round that an internal irregular gouge like the gas port erosion would be able to greatly influence the round.
I heard you say that you don't use copper brushes to clean your barrels unless that they are really really bad with corrosion now my question is why every kit out there including those boar snakes always come with copper brushes if that's the case then I have been destroying my barrels so what type of brushes should I actually use just to remove carbon and crap after couple of trips from the range? Thank You in Advance.
After watching you clean off the loctite from the threads I would love to know if you recommend loctite or not. I saw Brunnels do a video where they pretty much stated not at all. Others have stated in certain spots, etc... I just found your channel, subbed instantly. After only a few videos I have a great deal of respect for you and your knowledge. Also, do you work on arms for the general public? Thanx for the fantastic learn.
Industry standard is Rockset is used on muzzle devices that are not pinned and welded and will (or might) have a suppressor mounted to it.... if its not going to be pinned or have a suppressor then a crush washer is generally used.... rockset is going to hold the flash hider/compensator on even under heat and recoil, that is important with a suppressor as if the muzzle dvce comes loose will firing it can cause the bullet to hit it causing damage or catastrophic failure. Rockset will also allow the muzzle device to be removed in the future if the User wishes to change it out A crush washer could fail with the added weight/stress of a suppressor on it. (13.7” -14.5” barrels will normally have a muzzle device pinned and welded on so it cant be removed and that legally makes the barrel over 16” so it is not considered a Short barrel rifle requiring a tax stamp...or pistol requiring a brace instead of a stock....if the barrel is over 16” or under 13.7” then there is no need to legally pin and weld)
Enjoying the education about barrels :). Started watching because I have a Rosco barrel waiting to be used in a build, got it because it was fairly inexpensive yet they seem to have good reviews but I have still been debating a little in my head if it was a good buy... feeling a lot better about it now! The majority of what I read/hear about Rosco is positive but most of that is just people's experience, it great to see a review/autopsy done with the proper tools. Thanks for educating us! Question about the run out check on a used barrel... would the excessive muzzle erosion negate the runout/concentricity test?
Chad has said that if you are cleaning a barrel using bronze brushes it can leave a trace of copper, that would then appear as the barrel still being dirty. When I was still in the service, if I used a bronze brush it was with CLP dripped on it and then left to sit to give the CLP 'time' to work before pulling dry patches through.
