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KS, USA
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Posted: 3/4/2024 9:07:02 PM EDT
[Last Edit: LopeyZ]
Built a 300 BLK and put about 60 rounds of Winchester super suppressed through it so far. First couple of boxes I was working out some cycling issues so today was for sighting in. Unfortunately, I noticed the bullets were tumbling around the 3rd shot so I stopped. Verified the barrel was a 1/7 twist and the rifling looked normal. So I did a little research and someone mentioned baffle strike could cause this. Upon investigation I noticed a slight scuff on the end cap. The suppressor I'm using is a SiCo Hybrid 46M which I bought for the BOGO Omega 300 deal last year. The bullets only strike when I have the 30 cal end cap on the thing. I get tight groups with the 45 cal end cap so problem solved. Except what's going to happen if SiCo ever ships my BOGO suppressor and it ends up on this rifle like I was planning from the beginning!? What could possibly cause this issue? I'm using the ASR flash hider and everything is good and tight.
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Posted: 3/4/2024 9:11:27 PM EDT
[Last Edit: bigbore]
[#1]
What barrel?
End cap strikes happen, all my cans have nicked end caps. If you have a shitty barrel, you’ll see it more often. |
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KS, USA
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Posted: 3/4/2024 9:27:12 PM EDT
[#2]
It's just a BA 10" that I picked up last time I was at Rainier. I considered the "cheap" barrel might be an issue but not sure how to prove it or test it.
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Posted: 3/4/2024 9:28:52 PM EDT
[#3]
Alignment rod?
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Posted: 3/4/2024 9:33:46 PM EDT
[#4]
Quote HistoryOriginally Posted By LopeyZ: It's just a BA 10" that I picked up last time I was at Rainier. I considered the "cheap" barrel might be an issue but not sure how to prove it or test it. Cheap barrels like those have threads that are not concentric to the bore, which is a recipe for baffle strikes. The only real way to confirm is with a pin gauge in a lathe. |
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KS, USA
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Posted: 3/4/2024 9:34:14 PM EDT
[#5]
Quote HistoryOriginally Posted By gqllc: Alignment rod? Didn't know those existed... Let's say the alignment rod shows an issue. How would I know if it's the barrel or suppressor that is the culprit? It's probably the barrel |
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KS, USA
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Posted: 3/4/2024 9:35:49 PM EDT
[Last Edit: LopeyZ]
[#6]
Cheap barrels like those have threads that are not concentric to the bore, which is a recipe for baffle strikes. The only real way to confirm is with a pin gauge in a lathe. Wonderful. I might be able to find a machinist around here to help me out. |
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Posted: 3/4/2024 9:36:05 PM EDT
[#7]
Quote HistoryOriginally Posted By LopeyZ: Didn't know those existed... Let's say the alignment rod shows an issue. How would I know if it's the barrel or suppressor that is the culprit? It's probably the barrel Do you by chance hand load? If you have a piece of deprimed brass, there is an easy way to eyeball that’s way better than an alignment rod. |
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KS, USA
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Posted: 3/4/2024 9:38:49 PM EDT
[#8]
Quote HistoryOriginally Posted By bigbore: Do you by chance hand load? If you have a piece of deprimed brass, there is an easy way to eyeball that’s way better than an alignment rod. Yes I do. Haven't loaded for the 300 blk yet but have what I need to. |
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Posted: 3/4/2024 9:43:05 PM EDT
[#9]
Quote HistoryOriginally Posted By LopeyZ: Yes I do. Haven't loaded for the 300 blk yet but have what I need to. Take the upper and install the suppressor. Remove the BCG Install brass in chamber. Look down through the bore through the hole in the brass. If the can is off center enough for an end cap strike, you’ll see it. |
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Posted: 3/4/2024 9:48:46 PM EDT
[#10]
Quote HistoryOriginally Posted By bigbore: Take the upper and install the suppressor. Remove the BCG Install brass in chamber. Look down through the bore through the hole in the brass. If the can is off center enough for an end cap strike, you’ll see it. Years I've shot suppressed ARs and handloand AND never thought to do this. I even bore-sight this way and it never occurred to me that it would show any alignment issues. Thank you for sharing! |
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KS, USA
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Posted: 3/4/2024 10:06:45 PM EDT
[Last Edit: LopeyZ]
[#11]
Quote HistoryOriginally Posted By bigbore: Take the upper and install the suppressor. Remove the BCG Install brass in chamber. Look down through the bore through the hole in the brass. If the can is off center enough for an end cap strike, you’ll see it. Not the most scientific approach but I do see more of the inside of the end cap on one side than the other. I marked where the high side was and that's exactly where the scuff is on the inside of the cap. You nailed it. I'll bring this rig into Rainier tomorrow to see what they say... they can have the barrel back |
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Posted: 3/4/2024 10:47:53 PM EDT
[#12]
I just replaced a 10.5" psa with the ba. Government series maybe. The psa was an old one and just looking down it I thought the asr mount with the 46m and 22 endcap was favoring one side. Ba barrel was perfect. Asr mount was one of the new kaw valley ones. Ba barrel seemed accurate too. Around an inch without trying too hard since it was blowing 35mph.
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KS, USA
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Posted: 3/5/2024 12:29:49 AM EDT
[#13]
Quote HistoryOriginally Posted By campower: Years I've shot suppressed ARs and handloand AND never thought to do this. I even bore-sight this way and it never occurred to me that it would show any alignment issues. Thank you for sharing! And it never occurred to me to bore-sight this way. I sighted it in with 3 shots just looking down the bore but using an umprimed case as a peep hole is a great idea! |
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GA, USA
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Posted: 3/5/2024 12:39:15 AM EDT
[Last Edit: OTDR]
[#14]
nvrmind
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Posted: 3/5/2024 2:18:36 PM EDT
[#15]
Crush washers will cause baffle strikes as well. Every suppressor manufacturer warns against their use.
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Posted: 3/6/2024 5:15:17 AM EDT
[#16]
Quote HistoryOriginally Posted By bigbore: Take the upper and install the suppressor. Remove the BCG Install brass in chamber. Look down through the bore through the hole in the brass. If the can is off center enough for an end cap strike, you’ll see it. Good idea. Never thought of that. I remove the carrier to do a rough boresight of an optic at a bird house about 50yds off my back deck using that method. Never occurred to do it with a can. I don't have any problems with alignment with my Turbo K. But now I want to look through it without the carrier just for the hell of it. |
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Posted: 3/6/2024 7:00:48 AM EDT
[#17]
Originally Posted By bigbore: Originally Posted By LopeyZ: Yes I do. Haven't loaded for the 300 blk yet but have what I need to. Take the upper and install the suppressor. Remove the BCG Install brass in chamber. Look down through the bore through the hole in the brass. If the can is off center enough for an end cap strike, you’ll see it. Ladies & gentlemen, this is why I make every job involving barrel work/suppressor mount mounting/suppressors an Adco job rather than a DIY. Adco does good work, they're an asset to this site, and "buy once, cry once" is a real thing, especially when it comes to something for which you paid in full and have to wait 8-10 months to take possession. |
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GA, USA
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Posted: 3/6/2024 3:03:29 PM EDT
[#18]
Quote HistoryOriginally Posted By Bklyn_Irish: Ladies & gentlemen, this is why I make every job involving barrel work/suppressor mount mounting/suppressors an Adco job rather than a DIY. Adco does good work, they're an asset to this site, and "buy once, cry once" is a real thing, especially when it comes to something for which you paid in full and have to wait 8-10 months to take possession. Good for you, but some of us know what were doing and don't need ADCO. |
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KS, USA
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Posted: 3/7/2024 9:19:21 PM EDT
[#19]
Plot thickens on this issue. Went to Rainier and they swapped me out with another BA barrel after I told them it looked good. They were helpful but I didn't do a good enough job inspecting. Got home and was going to test a few rounds but decided to look again first. That's when I could see the same issue from before. So then I grabbed a 556 barrel and luckly have a flash hider for it also. Upon inspection, I could still see that shadow in the same place... Just barely since it's a smaller bore but the issue clearly repeated. Now I'm thinking it's SiCo quality control. What do you all think?
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Posted: 3/7/2024 11:23:38 PM EDT
[#20]
Quote HistoryOriginally Posted By OTDR: Good for you, but some of us know what were doing and don't need ADCO. Quote HistoryOriginally Posted By OTDR: Originally Posted By Bklyn_Irish: Ladies & gentlemen, this is why I make every job involving barrel work/suppressor mount mounting/suppressors an Adco job rather than a DIY. Adco does good work, they're an asset to this site, and "buy once, cry once" is a real thing, especially when it comes to something for which you paid in full and have to wait 8-10 months to take possession. Good for you, but some of us know what were doing and don't need ADCO. Very happy for you. I mean that. |
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Posted: 3/8/2024 8:30:56 AM EDT
[#21]
Quote HistoryOriginally Posted By LopeyZ: Plot thickens on this issue. Went to Rainier and they swapped me out with another BA barrel after I told them it looked good. They were helpful but I didn't do a good enough job inspecting. Got home and was going to test a few rounds but decided to look again first. That's when I could see the same issue from before. So then I grabbed a 556 barrel and luckly have a flash hider for it also. Upon inspection, I could still see that shadow in the same place... Just barely since it's a smaller bore but the issue clearly repeated. Now I'm thinking it's SiCo quality control. What do you all think? More likely 2 bad barrels. BA barrels and not "quality" barrels by any means. How are you mounting the suppressor? Direct thread? ASR mount? is the mount direct thread or using a shim or crush washer? |
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KS, USA
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Posted: 3/8/2024 8:36:08 AM EDT
[#22]
Quote HistoryOriginally Posted By bigbore: More likely 2 bad barrels. BA barrels and not "quality" barrels by any means. How are you mounting the suppressor? Direct thread? ASR mount? is the mount direct thread or using a shim or crush washer? ASR mount with no washer. This would have to mean 2 bad BA barrels which is certainly possible. What I have trouble believing is my 556 barrel is also bad though. So 3 barrels and 2 flash hiders... I see the same shadow in the same place on my end cap. I'll be calling SiCo today to see if they have any ideas. |
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GA, USA
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Posted: 3/8/2024 8:51:42 AM EDT
[#23]
Take your barrels and can to a gunsmith and have him figure out what isn't concentric. It will take 15 minutes. If it's your can you might be able to return it or have the smith open it up a touch.
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Posted: 3/8/2024 9:33:44 AM EDT
[Last Edit: VeritatisUnus]
[#24]
Quote HistoryOriginally Posted By LopeyZ: ASR mount with no washer. This would have to mean 2 bad BA barrels which is certainly possible. What I have trouble believing is my 556 barrel is also bad though. So 3 barrels and 2 flash hiders... I see the same shadow in the same place on my end cap. I'll be calling SiCo today to see if they have any ideas. I had friends over the years buy cheap PSA uppers off the daily deals. 3 of them off the top of my head had threads not concentric to bore. Luckily I checked with an alignment rod first, but they all would’ve had an end cap/baffle strike. Based on that experience, spending more on a barrel for suppressed gun seems like the prudent thing to do. Two of those were 300blk uppers, which we ended up using Bison Armory barrels and changed the handguard out too so the whole cheap buy was pointless in the end and cost more than just doing it right from the get-go…. Which is what I told them to do from the start, but noooOoo. ETA: I’m sure ADCO can explain it better, but you can see sometimes that threads will be shitty even before anything is mounted. Good barrels will have a relief cut behind the last thread and a nice square shoulder. Shitty barrels have threads just kind of thread to the shoulder except the last thread isn’t really a complete thread… it’s hard to explain, and I’m sure there is a more technical term/description, but once you see it, it would make sense. You can feel it too when putting on the muzzle device, it starts getting tight before it’s against the shoulder. |
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Posted: 3/8/2024 9:49:57 AM EDT
[Last Edit: Wangstang]
[#25]
Order a few sizes at the same time directly from McMaster, Bevel the ends and roll across a true flat surface to look for any wobble. If they roll smooth, you are good to go.
 Attached File |
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OK, USA
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Posted: 3/8/2024 11:30:54 AM EDT
[#26]
You could have several things going on here. You need the shoulder face square with the bore, or your can will be sitting off at an angle. It would not take much of an angle to cause a strike at the far end of the can.
A concentricity issue only side-shifts the can, it doesn't angle it. You would need a substantial side shift to cause a strike. There can also be a problem with the bore not being straight. There is a good chance you have a curve in it, so when the bullet exits, even dead center concentricity-wise, it is doing so at an angle, even if the can is sitting perfectly straight with the bore exit hole. In the past we have taken 20" barrel blanks, center turned them, and then cut them in half. You would not believe how far off-center the bore can be to the OD right in the middle of a barrel which has both ends centered. It can be substantial. Tony |
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AZ, USA
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Posted: 3/8/2024 5:27:53 PM EDT
[Last Edit: KalmanPhilter]
[#27]
Quote HistoryOriginally Posted By LopeyZ: ASR mount with no washer. This would have to mean 2 bad BA barrels which is certainly possible. What I have trouble believing is my 556 barrel is also bad though. So 3 barrels and 2 flash hiders... I see the same shadow in the same place on my end cap. I'll be calling SiCo today to see if they have any ideas. I routinely put my Hybrid 46 on 5.56 barrels with no thought to concentricity, crush washers, etc. With that much over-bored suppressor a .224 bullet is a hotdog thrown down a hallway. If your 5.56 barrel looks suspicious via bore sighting with a 46M mounted, what caliber front cap were you using to bore sight? Least suspect arrangement is a direct thread mount on the suppressor rear tube, threaded onto the muzzle threads and inspect the shoulder contact all around. Held vertical with a tight (shimmed with one end-butted wrap of thin tape if necessary) and straight (roll on a glass table) gauge rod and then clock the rod at 12, 3, 6, 9 to see rod-runout variability at the front cap. You can also put some stout ‘witness panel’ tape over or inside your “ .46 cal” front cap aperture and see where the blackout bullet passes. |
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KS, USA
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Posted: 3/8/2024 7:51:54 PM EDT
[#28]
Quote HistoryOriginally Posted By KalmanPhilter: I routinely put my Hybrid 46 on 5.56 barrels with no thought to concentricity, crush washers, etc. With that much over-bored suppressor a .224 bullet is a hotdog thrown down a hallway. If your 5.56 barrel looks suspicious via bore sighting with a 46M mounted, what caliber front cap were you using to bore sight? I don't have an issue on the 556. Bullets clear just fine but if you look close, the same side of the cap that was deflecting the 30 cal is still slightly visible... can't see the cap anywhere else looking down the bore. So it's consistently off in that same place. I might order an alignment rod but the visual method works fine. What I need to do is give SiCo a call but they are closed on Friday apparently. No wonder they can't get my BOGO can shipped after almost a year! |
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KS, USA
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Posted: 3/8/2024 10:20:09 PM EDT
[Last Edit: LopeyZ]
[#29]
Quote HistoryOriginally Posted By VeritatisUnus: ETA: I’m sure ADCO can explain it better, but you can see sometimes that threads will be shitty even before anything is mounted. Good barrels will have a relief cut behind the last thread and a nice square shoulder. Shitty barrels have threads just kind of thread to the shoulder except the last thread isn’t really a complete thread… it’s hard to explain, and I’m sure there is a more technical term/description, but once you see it, it would make sense. You can feel it too when putting on the muzzle device, it starts getting tight before it’s against the shoulder.    Took pics of a few ARs barrels... hopefully the links work. This site makes it way too hard to post pics. Anyway .. two are 556 and the BA barrel in 300 BLK. The BA and my higher quality barrel have the same style threads. The other (last pic) is an old M&P15. When I threaded the can on that barrel, it still didn't look concentric but I could see a slight difference.. still looked off though. |
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Posted: 3/9/2024 7:49:00 AM EDT
[#30]
Quote HistoryOriginally Posted By LopeyZ: https://i.ibb.co/C53DZnk/20240308-194547.jpg https://i.ibb.co/sb4XpCM/20240308-194909.jpg https://i.ibb.co/3hVjnCN/20240308-195437.jpg Took pics of a few ARs barrels... hopefully the links work. This site makes it way too hard to post pics. Anyway .. two are 556 and the BA barrel in 300 BLK. The BA and my higher quality barrel have the same style threads. The other (last pic) is an old M&P15. When I threaded the can on that barrel, it still didn't look concentric but I could see a slight difference.. still looked off though. It's not something you can eyeball, you need a lathe and the proper pin gauge and indicator. 
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AZ, USA
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Posted: 3/9/2024 3:15:26 PM EDT
[Last Edit: KalmanPhilter]
[#31]
Quote HistoryOriginally Posted By LopeyZ: https://i.ibb.co/C53DZnk/20240308-194547.jpg https://i.ibb.co/sb4XpCM/20240308-194909.jpg https://i.ibb.co/3hVjnCN/20240308-195437.jpg Took pics of a few ARs barrels... hopefully the links work. This site makes it way too hard to post pics. Anyway .. two are 556 and the BA barrel in 300 BLK. The BA and my higher quality barrel have the same style threads. The other (last pic) is an old M&P15. When I threaded the can on that barrel, it still didn't look concentric but I could see a slight difference.. still looked off though. Hard to tell at the angle those pics were taken. Without a thread relief cut at the base of the muzzle threading or sufficient counter bore at the mouth of the muzzle device, it’s possible for the muzzle device to not seat squarely against the barrel shoulder. A thick precision washer like an Accu shim can help if that is the case. Again, sighting across the muzzle device against the shoulder all around 360 degrees, if the muzzle device isn’t square to the barrel shoulder you will see this effect. Most silencer mounting muzzle devices now come with enough counter bore to handle most muzzle thread jobs that lack a thread relief cut, but not in all cases. |
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OK, USA
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Posted: 3/10/2024 9:38:38 AM EDT
[#32]
Quote HistoryOriginally Posted By KalmanPhilter: Without a thread relief cut at the base of the muzzle threading However, with a thread relief, customers bitch about their crush washer falling into the cut and going way off center. Tony |
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KS, USA
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Posted: 3/10/2024 9:41:24 PM EDT
[#33]
Believe I found the source of my problem.. the stupid ASR mount. I tried to like the mount because I just couldn't believe they'd sell a crap mount with such a nice can... but that's exactly what they did. I hate the way it locks up and doesn't feel secure at all. And now when I loosen the mount from the body by about 5 degrees... It lines up perfectly with the bore and it's still tight. I wanted a direct thread mount but none of the 5 places around here that sell SiCo accessories have them so I settled for the flash hider and ASR system. Giving SiCo a call tomorrow and I'm asking for a discount on the direct thread mount... see how good their customer service is.
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Posted: 3/11/2024 2:17:24 AM EDT
[#34]
Just ditch the ASR system all together and go plan B. Way better of a system in many ways.
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AZ, USA
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Posted: 3/11/2024 11:50:37 AM EDT
[#35]
Quote HistoryOriginally Posted By LopeyZ: Believe I found the source of my problem.. the stupid ASR mount. I tried to like the mount because I just couldn't believe they'd sell a crap mount with such a nice can... but that's exactly what they did. I hate the way it locks up and doesn't feel secure at all. And now when I loosen the mount from the body by about 5 degrees... It lines up perfectly with the bore and it's still tight. I wanted a direct thread mount but none of the 5 places around here that sell SiCo accessories have them so I settled for the flash hider and ASR system. Giving SiCo a call tomorrow and I'm asking for a discount on the direct thread mount... see how good their customer service is. That’s very unusual. Thread allowances normally wouldn’t have a tight mount that is unseated by 5 degrees. I wouldn’t shoot it in that condition as vibration is the devil’s spanner. Direct thread mount is always good to have. With any new can I take a known good muzzle and known good DT mount and check can concentricity at front cap with a tight, straight gauge rod. It’s faster than centering / fixturing / indicating in the lathe and measures what I care about with least interfaces (thread fit, can indexing to mount, and ready to test fire). DT mount will drop over 6 ounces and be shorter. |
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Posted: 3/13/2024 7:30:27 PM EDT
[#36]
Following this thread and wanted some clarification. When speaking of the BA barrel is this referring to. Ballistic advantage, or bison armory?
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KS, USA
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Posted: 3/18/2024 7:19:28 PM EDT
[#37]
Problem solved... It was the ASR mount. Finally got my hands on a direct thread and it's perfect. Plus the mount is lighter, less bulky and less finicky.
The barrel is a Ballistics Advantage. |
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MI, USA
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Posted: 3/19/2024 1:55:53 PM EDT
[#38]
Being a former engineer in the manufacturing realm ,,,a machinist as well , I'll tell you the odds of a
barrel made on any automated cnc turning center today , which is 98% is NOT going to cut a thread that is not concentric to the bore... They are made on collet chucks ...the runout is kept to .003" max .... I'd be looking at the suppressor hub and flash hider first |
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Posted: 4/13/2024 7:36:45 PM EDT
[#39]
Quote HistoryOriginally Posted By bigbore: Take the upper and install the suppressor. Remove the BCG Install brass in chamber. Look down through the bore through the hole in the brass. If the can is off center enough for an end cap strike, you’ll see it. Bloody brilliant As others have stated I've bore sighted this way but never checked can alignment Usually remove bolt, check twice, and look from business end |
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