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Posted: 5/20/2023 10:56:53 PM EDT
[#1]
Quoted: Let’s say you found the perfect barrel but it’s 16” instead of 14.5”. Chrome lined, mil-spec material and finish. Is this doable? Any downsides if done properly? Will the threads and shoulder being bare metal present a problem? And most importantly, who’s the go to to cut down, re-crown and re-thread? Carbine gas or mid? 5.56? |
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Posted: 5/20/2023 11:01:58 PM EDT
[#2]
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Posted: 5/20/2023 11:09:56 PM EDT
[#3]
Quote HistoryQuoted: Carbine gas or mid? 5.56? Mid |
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Posted: 5/21/2023 7:24:19 AM EDT
[#4]
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Posted: 5/21/2023 9:47:51 AM EDT
[#5]
Quote HistoryThat’s probably who I would use. He just did a pin/weld for me. Unbelievable work. |
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Posted: 5/21/2023 12:12:21 PM EDT
[#6]
Quote HistoryI've never used him, but EVERYONE on here who has raves about his work. If I were looking to do what you are, this would be my first call. |
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Posted: 5/21/2023 7:03:57 PM EDT
[#7]
As to the OP's original question ... once a barrel has been cut & threaded, shouldn't there be some kind of treatment to the raw, bare steel? I have a barrel I want threaded, but was concerned about whether a treatment should be done.
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Posted: 5/21/2023 7:26:25 PM EDT
[#8]
not everyone would cut down a chrome line barrel
the chrome can chip off when cutting with that said, ive never had any problems doing it or noticed accuracy degrade after i pretty much cut all of my barrels unless they are customs from somewhere like craddock or cle or have a gunsmith spin them up |
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Posted: 5/21/2023 7:27:42 PM EDT
[#9]
Quote HistoryQuoted: As to the OP's original question ... once a barrel has been cut & threaded, shouldn't there be some kind of treatment to the raw, bare steel? I have a barrel I want threaded, but was concerned about whether a treatment should be done. the majority of the 416r match grade barrels have not had any coating or treatment on them at all or on the muzzle threads specifically either |
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Posted: 5/21/2023 7:36:21 PM EDT
[#10]
I've cut/rethreaded 2 now. 1CL'd and one non lined. I've noticed no change in accuracy. I grease the new threads but do not refinish. I haven't noticed any issues yet.
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Posted: 5/21/2023 11:29:18 PM EDT
[#11]
Quote HistoryQuoted: not everyone would cut down a chrome line barrel the chrome can chip off when cutting with that said, ive never had any problems doing it or noticed accuracy degrade after i pretty much cut all of my barrels unless they are customs from somewhere like craddock or cle or have a gunsmith spin them up Well you just sent me down a rabbit hole on the interwebs. Found detailed posts from ADCO and Terry Cross as well. The consensus? If a chrome lined barrel is going to flake or chip…it’s gonna happen regardless if it’s cut down or not. The majority of competent AR gunsmiths have been reworking CL barrels for years. Crane cut down barrels for MK18 for years as well. On a quality barrel and a good gunsmith, shouldn’t be an issue at all. |
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Posted: 5/22/2023 10:13:21 AM EDT
[#12]
Quote HistoryQuoted: not everyone would cut down a chrome line barrel the chrome can chip off when cutting with that said, ive never had any problems doing it or noticed accuracy degrade after i pretty much cut all of my barrels unless they are customs from somewhere like craddock or cle or have a gunsmith spin them up This is often said, but have not seen any evidence to back it up. Chrome lining isn't like chrome plating on the bumper of your car. |
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Posted: 5/22/2023 11:02:00 AM EDT
[#13]
Quote HistoryQuoted: Mid You may need to open up the gas port a hair, depending on what exists there now. |
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Posted: 5/22/2023 11:40:15 AM EDT
[#14]
Quote HistoryQuoted: As to the OP's original question ... once a barrel has been cut & threaded, shouldn't there be some kind of treatment to the raw, bare steel? I have a barrel I want threaded, but was concerned about whether a treatment should be done. I have not had any problem, I keep a direct thread suppressor on mine. The threads are not exposed to any elements. |
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Posted: 5/22/2023 12:02:57 PM EDT
[#15]
Quote HistoryQuoted: You may need to open up the gas port a hair, depending on what exists there now. I think it's actually the other way around. The gas port on the 16" is roughly .004" larger than the 14.5". If anything, I'd have to use a BRT gas tube to try to match it. |
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Posted: 5/22/2023 12:37:40 PM EDT
[#16]
Quote HistoryQuoted: I think it's actually the other way around. The gas port on the 16" is roughly .004" larger than the 14.5". If anything, I'd have to use a BRT gas tube to try to match it. When you shorten a barrel you lose dwell time that the bullet is in the bore after passing the gas port, which often requires a larger hole to make up for the pressure lost. The gas port may already be large enough as many barrels are over gassed to begin with. |
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Posted: 5/22/2023 1:55:36 PM EDT
[#17]
Quote HistoryQuoted: When you shorten a barrel you lose dwell time that the bullet is in the bore after passing the gas port, which often requires a larger hole to make up for the pressure lost. The gas port may already be large enough as many barrels are over gassed to begin with. That's how I thought I remembered it, but looking at the gas port shared doc got me confused. It's probably mostly chalked up to people trying to measure gas ports with calipers and drill bits versus actual pin gauges. Take DD for example, there 14.5" middy definitely has a larger port than their 16" middy. But with Criterion (and a few others), there are opposite instances. |
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Posted: 5/22/2023 4:37:33 PM EDT
[#18]
Quote HistoryQuoted: That's how I thought I remembered it, but looking at the gas port shared doc got me confused. It's probably mostly chalked up to people trying to measure gas ports with calipers and drill bits versus actual pin gauges. Take DD for example, there 14.5" middy definitely has a larger port than their 16" middy. But with Criterion (and a few others), there are opposite instances. Yep, Geissele is an example of that. They advertise their 14.5 as .076 and their 16 as .078. |
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Posted: 5/22/2023 4:49:34 PM EDT
[#19]
I had a 16" chrome lined 300 BO cut down by ADCO. They parked the threads and shoulder.
It has never flaked. I'm not even sure hard chrome can "flake". It's not like it's decorative bumper chrome! It is a pistol gas and has worked fine with supers. And a 300 BO doesn't have much gas to spare... |
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Posted: 5/22/2023 5:03:28 PM EDT
[#20]
Quote HistoryQuoted: I had a 16" chrome lined 300 BO cut down by ADCO. They parked the threads and shoulder. It has never flaked. I'm not even sure hard chrome can "flake". It's not like it's decorative bumper chrome! It is a pistol gas and has worked fine with supers. And a 300 BO doesn't have much gas to spare... Applied chrome lining can fail. (Chip/peel/flake). Once the chrome loses it's bond with the parent metal. Note the lands in this pic:  Attached File |
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Posted: 5/22/2023 5:06:44 PM EDT
[#21]
Quote HistoryQuoted: Applied chrome lining can fail. (Chip/peel/flake). Once the chrome loses it's bond with the parent metal. Note the lands in this pic: https://www.ar15.com/media/mediaFiles/416992/Screenshot_20230522-160021_Gallery_jpg-2825517.JPG Do we have a "before" pic? Wonder if that was not applied properly to begin with. That is some fugly there. |
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Posted: 5/22/2023 5:16:48 PM EDT
[#22]
Quote HistoryQuoted: Do we have a "before" pic? Wonder if that was not applied properly to begin with. That is some fugly there. Quote HistoryQuoted: Quoted: Applied chrome lining can fail. (Chip/peel/flake). Once the chrome loses it's bond with the parent metal. Note the lands in this pic: https://www.ar15.com/media/mediaFiles/416992/Screenshot_20230522-160021_Gallery_jpg-2825517.JPG Do we have a "before" pic? Wonder if that was not applied properly to begin with. That is some fugly there. I do not. Came across it on an M14 forum once, found it interesting and screen grabbed it. Fugly indeed. |
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Posted: 5/23/2023 8:50:16 AM EDT
[#23]
Quote HistoryQuoted: Yep, Geissele is an example of that. They advertise their 14.5 as .076 and their 16 as .078. Quote HistoryQuoted: Quoted: That's how I thought I remembered it, but looking at the gas port shared doc got me confused. It's probably mostly chalked up to people trying to measure gas ports with calipers and drill bits versus actual pin gauges. Take DD for example, there 14.5" middy definitely has a larger port than their 16" middy. But with Criterion (and a few others), there are opposite instances. Yep, Geissele is an example of that. They advertise their 14.5 as .076 and their 16 as .078. My 12" mid gas with Micro MOA adjustable gas plate has .055 suppressed, .073 regular, .082 dirty gun or weak ammo. |
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Posted: 5/23/2023 11:22:58 AM EDT
[#24]
Quote HistoryQuoted: Yep, Geissele is an example of that. They advertise their 14.5 as .076 and their 16 as .078. Could it be that they are anticipating suppressor on the shorter barrel? |
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Posted: 5/23/2023 11:41:07 AM EDT
[#25]
Quote HistoryQuoted: Could it be that they are anticipating suppressor on the shorter barrel? Possibly. They did the same with the 10.3 and 11.5. The 10.3 is .063 and the 11.5 is .070. I built an upper with the 10.3 using 100% Geissele parts (except gas tube) and it runs well unsuppressed with a standard carbine buffer with H1 and 193/855. Does not run my apparently light reloads and doesn't lock back on standard .223 55gr. I have some hotter reloads that work fine. It runs all the hotter stuff well with a YHM Turbo T2 and Super 42/H3. |
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Posted: 5/23/2023 12:19:13 PM EDT
[#26]
Quote HistoryQuoted: Applied chrome lining can fail. (Chip/peel/flake). Once the chrome loses it's bond with the parent metal. Note the lands in this pic: https://www.ar15.com/media/mediaFiles/416992/Screenshot_20230522-160021_Gallery_jpg-2825517.JPG Only Chrome Lining I have seen fail like in the photo, was on a bunch of old Chrome Lined M1 carbine barrels being sold as surplus, this was mid 1980's. Real crap! |
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Posted: 5/23/2023 4:35:41 PM EDT
[#27]
Quote HistoryQuoted: Possibly. They did the same with the 10.3 and 11.5. The 10.3 is .063 and the 11.5 is .070. I built an upper with the 10.3 using 100% Geissele parts (except gas tube) and it runs well unsuppressed with a standard carbine buffer with H1 and 193/855. Does not run my apparently light reloads and doesn't lock back on standard .223 55gr. I have some hotter reloads that work fine. It runs all the hotter stuff well with a YHM Turbo T2 and Super 42/H3. I really don’t want to do it if the 16” is going to have a larger port than the 14.5”. That’s kind of stupid. I asked a few vendors that sell them and they don’t know or don’t care to tell. I can try Criterion but I bet they’ll be tight lipped. |
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Posted: 5/25/2023 7:08:05 AM EDT
[#28]
Quote HistoryQuoted: I really don’t want to do it if the 16” is going to have a larger port than the 14.5”. That’s kind of stupid. I asked a few vendors that sell them and they don’t know or don’t care to tell. I can try Criterion but I bet they’ll be tight lipped. Criterion is cool about that stuff if you ask them ime. |
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Posted: 5/25/2023 12:49:56 PM EDT
[#29]
I really don’t want to do it if the 16” is going to have a larger port than the 14.5”. That’s kind of stupid. You can regulate the gas with a gas block or brt gas tube. |
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Posted: 5/28/2023 2:15:11 PM EDT
[#30]
Just Buy a 14.5" and save time & aggravation.
GnBroker has OK prices. Then keep the 16 as a spare. In my experience, you'll need it after you sell it. |
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Posted: 5/28/2023 5:58:01 PM EDT
[#31]
Quote HistoryQuoted: Just Buy a 14.5" and save time & aggravation. GnBroker has OK prices. Then keep the 16 as a spare. In my experience, you'll need it after you sell it. Link to 14.5” CORE barrel on GunBroker? I’ve been looking. |
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