So I’ve been trying to get a new Pistol build together and have been slowly picking up all the parts…
Upper Parts list so far:
Vltor MUR Upper
DSG Arms BCG
BCM MCMR 10" forend
Lantac LowPro .750" Gas block / Carbine Length
Raptor AXTS Charging Handle
… and decided to give Rosco’s 11.5" Bloodline barrel a try. I keep seeing good reviews online about these guys (namely Garand Thumbs reviews among others) and their prices are good. Stock is hard to get so when I finally found the barrel in stock I placed my order. One of the things I though I’d like is the fact they dimple the lower barrel for ease of gas block alignment/install.
I like to test fit and measure all my parts before installing and noticed that the location of the barrel dimple for the gas block was 0.295" which is inline w/spec and perfectly matches my Lantac Gas block. However, when measuring the location of the gas port hole in the barrel it is ~ 0.322" back from the shoulder of the barrel. Do you guys think this will give me any troubles? I know the Gas Block and Tube opening are much larger than the gas port hole and it may not be an issue… but I’d also like to not have any issues after getting this all assembled and test firing it. Hopefully that makes sense. What do you guys think?
Not trying to slander or flame Rosco as they asked me to send the barrel back for inspection after seeing my pics. They also offered a refund or I can wait 2+ more weeks for another barrel to be in stock and ship out to me… which takes another week+ So I’d be looking at nearly another month to get another barrel from them. Not sure it’s worth the headache to be honest.
No offense man, but this is the type of question you should be asking before hitting the buy button.
Normally, unless one of the members here has pin gauges and an exact model of your barrel, no one will know unless they’ve reached out to the manufacturer.
I will spend a few minutes with my google-fu, but I can’t make any promises
ETA: Your gasblock should have it’s port wide enough to encompass that gas port hole in the barrel. But, if the manufacturer wants you to return it, I would.
If they see something wrong in the pics, there probably is something up with it.
ETA: Remember, if you were to add a front handguard cap, that adds. .025. The dimple is set back incase your block sits further back; as in, you’re not using the handgurd cap / freefloating.
My Adam Arms block was pushed forward on the dimple by a small amount when I added on the handguard cap and it functions fine. It helps put back pressure, from the dimple and set screws trying to line up, and it holds the handguard cap well. (This was on a Bear Creek Arsenal barrel that was also pre-dimpled.)
Thanks for the info. I DID ask the manufacturer about the gas port location/specs/etc before “hitting the buy button”… it’s also posted several places on their FAQ section. I did research this before buying to make sure my Gas Block, Forend, Barrel, etc… all work together (Not sure if that was a jab at me or not doing my due diligence). This barrel apparently is out of spec and I’m going to send it back. I just wanted some assistance/opinions of others here who have more experience than I do when it comes to AR building.
I edited my post one more time after your reply, I have a better understanding of your question, after. I assure you though, it wasn’t a slap, more along the lines of: “Uh-oh, we see this a lot where we’re asked for input from people not doing their diligence.”
Overall though, it was a combination of my misunderstanding and the wording.
Hoopefully, though, my last edit will help build on why the dimple may be pushed a littler further back.
After putting all of it together in my mind, I dunno if I would send it back if they claim it’s for “inspection”. (I know I mentioned otherwise previous, but that was my misunderstanding of your question. Thanks for putting up with me.)
Those like IG may have a much better idea down to the mics, but, for myself, I would assemble and test fire based on my previous experiences with the dimples being further back than the port.
No problem. If the barrel wasn’t already dimpled I’d just make sure my gas block was positioned properly and then dimple the bottom of the barrel myself. However since this barrel is already dimpled I think they screwed up… in that the dimple should align w/the gas port on the top of the barrel. I think I’ll just send it back and won’t be giving anymore of my $$ to Rosco and just try and find another 11.5" barrel for this build.
I guess my main question was whether or not it was critical for the rifle/pistol to function if the gas port hole was not centered under the gas block tube hole… if that makes sense?
It will depend on the specs of your block. Based on the differences of almost .025 exactly, I don’t know if it really is an error, hopefully they will confirm. But, as a consumer, your comfort is the only piece that matters for higher value purchases. Sounds like Rosco will take good care of your either which way you go.
Nonetheless, I have faith that that small of a difference will be negligible and your gasblock should accommodate that without issue. Souds like most LO-PRO blocks are cut with their inner port hole at 10-32s. Seeing as lantacs are 10/32 set screws, I am inclined to believe your gas block port is as well.
That should be able to handle a .025 fluctuation without issue.
So I heard back f/ a Rosco rep saying that based on the pics it appears the barrel is out of spec. I guess I’ll send it back and figure out how to proceed from here. Not sure I want to wait another month +/- to get another barrel from Rosco or just try something different.
Thanks for the info. I’ll update when the barrel gets back to Rosco. I was able to swing by my favorite local GS on my lunch break today and he had a Ballistic Advantage 10.3" SS barrel in .223 Wylde w/gas block installed so I picked that up. I’ve read good things about their barrels but have zero experience with them. Hopefully this works out to my satisfaction this go around. I’d have preferred a 11.5" but nobody seems to have them in stock or they’re quite a bit more $$ than I have in my current budget to buy.
Rosco has been great to deal with so far… I’m sending my barrel back tomorrow and hope to get a report on what’s wrong. I’d really love to know the measurements on your gas port location (space between the shoulder and the hole) to compare it with mine. Everything else on the barrel looked great. Fit/Finish and nice packaging. Had they not pre-dimpled the underside of the barrel I would have used this one and got the ports lined up and dimpled the barrel myself. Hopefully your barrel is spot on and mine was an anomaly!
Just put the calipers on the barrel… dimple is .3025 from outside edge of shoulder to approx center of dimple. Gas port is at .3140… give or take a thou or two. I assume this is close enough to be in spec?
I would think you’re good given the dimple and gas port measurements are close… and the opening on the gas tube/block is much larger than the barrel port. Id say try it out.
I also already got my full refund (incl shipping) from Rosco so they’ve been great. I’ll followup when I hear back from them.
I got my upper assembled today and wish the new bbl I got (10.3") was an inch longer. The BCM MCMR rail is closer to 10.5" vs 10" and is a close fit with my other parts. I’ll post a pic or 2 of how it looks later. Now I need to now find an optic… but 1 thing at a time.
Here’s a couple pics of my fully assembled Pistol. I won’t know if there’s any interference w/the BCM forend and Surefire Warcomp break until I get some rounds down range. I don’t have a suppressor for this one so interference w/that is not an issue… currently. All in all I’d really have liked the barrel to be a 11.5" version and after I get some range time in w/this I may just order another barrel and replace this one. I always seem to spend more $$ than I planned on builds anyway… Ugh. Now I just need an optic … Do you guys think there will be any/some interference w/the BCM Forend and Warcomp break?
Lower is a Rainer Forged, Geiselle SSA trigger, H2 buffer, Gear Head Works Tailhook MOD2 (FDE as it’s all I could find). I really wanted to try the SBA3 but those seem to be as scarce as hens teeth. YHM Sights as I had those in my parts pile. Those might be replaced whenever I can find another set. BAD Safety Selector. Not crazy about the Red levers but it’s what I had. Those will be replaced w/black.
Update: Heard back f/ Rosco and the barrel dimple was out of spec. Had the barrel not been dimpled f/Rosco it would’ve been a non-issue and I would have spaced the gas block appropriately and then dimpled the barrel myself. The Rosco rep said this one should have never left their factory. All in all, I’d do business w/ Rosco again given their ‘internet’ & ‘social media’ good reputation and how they treated me was spectacular.
Also, I picked up a Scalarworks mount and Trijicon MRO and have a BAD-CASS-ST safety that should be at the house today so I can replace the red one that’s currently mounted up. Not really a fan of the red levers, at least not as much as I thought I might be.
it’s also posted several places on their FAQ section. I did research this before buying to make sure my Gas Block, Forend, Barrel, etc… all work together 
