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Posted: 7/8/2018 3:04:45 PM EDT
[#1]
I run almost exclusively Toolcraft BCGs. Depending on the current sales can always be found for $70-80. Can’t find a better carrier for the price in my opinion. Phosphate version is mil spec 158 bolt, nitride is 9310. I have run both types without issue. FWIW while I am not sure if it is still the case PSA premiums used to be made by toolcraft as well as a few others.
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Posted: 7/8/2018 3:19:39 PM EDT
[#2]
Quote HistoryQuoted:
I run almost exclusively Toolcraft BCGs. Depending on the current sales can always be found for $70-80. Can’t find a better carrier for the price in my opinion. Phosphate version is mil spec 158 bolt, nitride is 9310. I have run both types without issue. FWIW while I am not sure if it is still the case PSA premiums used to be made by toolcraft as well as a few others. CBC is not one I would trust, a few issues posted here in the past. Cheap materials/components. (Have zero persinal experience with them). TC bcgs at ~ $75ish will get you all that you need, with a lifetime warranty. |
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Posted: 7/8/2018 3:38:37 PM EDT
[#3]
Nice. Thanks for the info I remember a bunch of folks recommending TC in the past. The bolt assembly will cost me about $140 from JT, so I'd like to consider options. At $75 that's great. I might price just the carrier. Do you know if they chrome the gas key?
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Posted: 7/8/2018 3:43:42 PM EDT
[#4]
Quote HistoryQuoted:
Nice. Thanks for the info I remember a bunch of folks recommending TC in the past. The bolt assembly will cost me about $140 from JT, so I'd like to consider options. At $75 that's great. I might price just the carrier. Do you know if they chrome the gas key? |
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Posted: 7/8/2018 4:55:22 PM EDT
[#5]
Quote HistoryQuoted:
Nice. Thanks for the info I remember a bunch of folks recommending TC in the past. The bolt assembly will cost me about $140 from JT, so I'd like to consider options. At $75 that's great. I might price just the carrier. Do you know if they chrome the gas key? Eta: watch the EE, I have seen several carriers for sale alone. |
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Posted: 8/13/2018 2:38:52 AM EDT
[#6]
Thanks hombres
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Posted: 9/4/2018 5:09:34 PM EDT
[#7]
Do you guys know if I should get a Carp.158 or 9310 bolt? I've always used 158 I've heard the 9310 is slightly stronger but potentially less tensile strength? Could use advisement? Also LMT's enhanced bolt is pricey but is it worth it in your opinion? They make a 6.8mm bolt that would fit. I understand it's 50% stronger material @ twice the price or more: so I'm thinking probably not a good ROI.
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Posted: 9/4/2018 5:38:05 PM EDT
[#8]
I run both C158 and 9310, issue free.
9310 is supposed to be ~7% stronger? C158 for all things anymore, that's my mindset now. |
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Posted: 9/5/2018 11:51:45 AM EDT
[#9]
Quote HistoryQuoted:
I run both C158 and 9310, issue free. 9310 is supposed to be ~7% stronger? C158 for all things anymore, that's my mindset now. |
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Posted: 9/5/2018 12:43:37 PM EDT
[#10]
Quote HistoryQuoted:
C158 for all things anymore, that's my mindset now. C158 is proven. I see no need to deviate from that. |
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Posted: 9/5/2018 2:53:35 PM EDT
[#11]
Quote HistoryQuoted:
Thanks for the reply. Lost me on the last sentence. I have heard folks discuss that strength can be subjective depending on the type of conditions the material is subjected to. Is C158 better at taking a hammering versus 9310? I know 9310 requires more stringent tempering process, so it may be prone to QC faults. I guess if it's cheaper to make and 7% stronger it's a win but will it handle the stress fractures subjected to an AR bolt as well as C158? Quote HistoryQuoted:
Quoted:
I run both C158 and 9310, issue free. 9310 is supposed to be ~7% stronger? C158 for all things anymore, that's my mindset now. My last sentence only leans toward my own personal preference, C158 is time proven and it works. I wouldn't seek out 9310, nor would I worry about using it if the supplier were a reputable vendor. |
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Posted: 9/5/2018 2:55:42 PM EDT
[#12]
LMT EBCG or KAC e3 with corresponding barrel are all I will use in my personal rifles.
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Posted: 9/6/2018 11:25:18 PM EDT
[#13]
Getting slightly off topic but still eithin the upper. Hera uses 42CrMo4 steel barrel nut. Does anyone know what Colt uses for the barrel nut?
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Posted: 9/8/2018 5:27:48 AM EDT
[#14]
Quote HistoryQuoted:
Getting slightly off topic but still eithin the upper. Hera uses 42CrMo4 steel barrel nut. Does anyone know what Colt uses for the barrel nut? Can I ask what the concern is? |
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Posted: 9/8/2018 4:57:24 PM EDT
[#15]
I stick with C158 because it’s a proven material that has a very long history of working just as it is intended to. It also is a well known material that many manufacturers have experience with. There are no “mysteries” about how to machine or heat treat it.
9310, while not a “new” material, is relatively new to the AR world, and from what I’ve read, its greater strength is only realized with heat treatment processes that are termed “extremely tight”. I’m not a metallurgist, but I think a material that is 7-8% stronger but that takes more precise attention to realize that advantage is not quite as advantageous as it may sound. The barrel nut is only a “clamp” to retain the barrel. It has nothing to do with how the barrel and bolt function. It’s also good to keep in mind that some rails come with an aluminum barrel nut, and they work just fine. I believe the MIL-SPEC calls for 4140 steel, but I haven’t found anything that states that definitively. |
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Posted: 9/9/2018 6:27:12 PM EDT
[#16]
42CrMo4 German steel has a tensile strength of 167,000 psi. Stressproof steel has 115,000 psi. And 4140 has 95,000. My concern was that the nut is inferior to milspec, but it seems to be significantly stronger. 9310 is 187,000 psi. Carpenter 158 is 135,000 psi
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Posted: 9/9/2018 7:10:18 PM EDT
[#17]
S7 WOULD be the perfect steel for bolts except the heat treating of its “tricky”.
And unless Hera does better than their magazines......NO THANKS! |
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Posted: 9/17/2018 1:16:04 PM EDT
[#18]
Didnt know Hera made mags? Must be Nato format?
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Posted: 9/17/2018 10:33:58 PM EDT
[#19]
New to this so forgive the noob questions. Still trying to understand all the components of my new rifle. What is the rating of a LWRC BCG (I don’t have a spare BCG but see a replacement one from LWRC cost about $300)?
Also what does MIM stand for? |
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Posted: 9/17/2018 10:42:12 PM EDT
[#20]
Quote HistoryQuoted:
New to this so forgive the noob questions. Still trying to understand all the components of my new rifle. What is the rating of a LWRC BCG (I don’t have a spare BCG but see a replacement one from LWRC cost about $300)? Also what does MIM stand for? Eta: Metal injection molding (MIM) is a metalworking process in which finely-powdered metal is mixed with binder material to create a "feedstock" that is then shaped and solidified using injection molding. The molding process allows high volume, complex parts to be shaped in a single step. After molding, the part undergoes conditioning operations to remove the binder (debinding) and densify the powders. Finished products are small components used in many industries and applications. |
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Posted: 9/17/2018 11:05:13 PM EDT
[#21]
Quote HistoryQuoted:
I should have added that 9310 is touted as "stronger"...IF the heat treat is performed correctly. My last sentence only leans toward my own personal preference, C158 is time proven and it works. I wouldn't seek out 9310, nor would I worry about using it if the supplier were a reputable vendor. |
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Posted: 9/19/2018 2:55:46 PM EDT
[#22]
Quote HistoryQuoted:
I stick with C158 because it’s a proven material that has a very long history of working just as it is intended to. It also is a well known material that many manufacturers have experience with. There are no “mysteries” about how to machine or heat treat it. It is my only 9310 bolt, out of roughly 15 BCGs. I will not seek out 9310, but I do trust JP to do it correctly. |
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Posted: 9/19/2018 9:20:07 PM EDT
[#23]
Great info. I'm stuck at this point. I'd like to aquire two spare 6.8mm SPC bolts. I'm looking for Toolcraft quality. I really don't want to buy two BCGs..
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Posted: 9/19/2018 9:37:13 PM EDT
[#24]
Quote HistoryQuoted:
What is the rating of a LWRC BCG (I don’t have a spare BCG but see a replacement one from LWRC cost about $300)? I would not buy one separately though. I have one since it came with a LWRC IC-DI gun. You can almost get 4 toolcraft BCG's for the price of one LWRC bcg. Not worth it in my opinion.  LWRCi Award Winning Di BCG |
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Posted: 9/20/2018 7:42:11 PM EDT
[#25]
They sell bolts separately.
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Posted: 9/22/2018 11:35:26 PM EDT
[#26]
Just aquired a lwrc bolt for a song. A search for Toolcraft bolts came up dry. Found an upgrade for sale, win win.
1.67 ratio .67% (NASA) for lubricated barrel nut versus dry. Max. 80 ft/lbs x .67 = 53.6ft/lbs max with moly grease. Min. 35ft/lbs x .67 = 23.45 ft/lbs. wanted to share the ratio for those who use the grease like I do. I would recommend torquing to 35ft/lbs with grease but stay below 50 if you can. I have a spanner wrench so I can verify my overall torque by the time the gas tube lines up on a milspec barrel nut. (This is a throwback to the barrel nut tensile strength conversation, found a formula which has zero relevance to the issue at hand other than it explained the ratio of torque with lubrication versus dry pulled from a NASA paper). I tend to agree with their findings. Oil was found to be 30% and grease 50-67% depending on the type from multiple industry pubs confirmed the deviation between different lubes. The confusing aspect is that the friction reduction properties of lubes lowers the friction increasing the tensile load compression or distortion of the nut. The formula could be used to calculate exactly how much torque you apply to your barrel nut based on your grease used. It would also answer a host of other questions in regard to your barrel installation. You would need to know the tensile strength of the threads of the upper which is around 7500 psi and the barrel nut which ranges from 115,000 psi milspec to 167,000 psi HK. |
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Posted: 9/23/2018 10:38:12 AM EDT
[#27]
Quote HistoryQuoted:
Just aquired a lwrc bolt for a song. A search for Toolcraft bolts came up dry. Found an upgrade for sale, win win. 1.67 ratio .67% (NASA) for lubricated barrel nut versus dry. Max. 80 ft/lbs x .67 = 53.6ft/lbs max with moly grease. Min. 35ft/lbs x .67 = 23.45 ft/lbs. wanted to share the ratio for those who use the grease like I do. I would recommend torquing to 35ft/lbs with grease but stay below 50 if you can. I have a spanner wrench so I can verify my overall torque by the time the gas tube lines up on a milspec barrel nut. (This is a throwback to the barrel nut tensile strength conversation, found a formula which has zero relevance to the issue at hand other than it explained the ratio of torque with lubrication versus dry pulled from a NASA paper). I tend to agree with their findings. Oil was found to be 30% and grease 50-67% depending on the type from multiple industry pubs confirmed the deviation between different lubes. The confusing aspect is that the friction reduction properties of lubes lowers the friction increasing the tensile load compression or distortion of the nut. The formula could be used to calculate exactly how much torque you apply to your barrel nut based on your grease used. It would also answer a host of other questions in regard to your barrel installation. You would need to know the tensile strength of the threads of the upper which is around 7500 psi and the barrel nut which ranges from 115,000 psi milspec to 167,000 psi HK. First, what does it have to do with this thread? Second, the milspec minimum/maximum torque spec is 30 to 80 foot pounds with moly grease and it has worked fine for a long time. Are you saying to just ignore that and do it the NASA way? |
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Posted: 9/23/2018 3:59:06 PM EDT
[#28]
Quote HistoryQuoted:
Just aquired a lwrc bolt for a song. A search for Toolcraft bolts came up dry. Found an upgrade for sale, win win. 1.67 ratio .67% (NASA) for lubricated barrel nut versus dry. Max. 80 ft/lbs x .67 = 53.6ft/lbs max with moly grease. Min. 35ft/lbs x .67 = 23.45 ft/lbs. wanted to share the ratio for those who use the grease like I do. I would recommend torquing to 35ft/lbs with grease but stay below 50 if you can. I have a spanner wrench so I can verify my overall torque by the time the gas tube lines up on a milspec barrel nut. (This is a throwback to the barrel nut tensile strength conversation, found a formula which has zero relevance to the issue at hand other than it explained the ratio of torque with lubrication versus dry pulled from a NASA paper). I tend to agree with their findings. Oil was found to be 30% and grease 50-67% depending on the type from multiple industry pubs confirmed the deviation between different lubes. The confusing aspect is that the friction reduction properties of lubes lowers the friction increasing the tensile load compression or distortion of the nut. The formula could be used to calculate exactly how much torque you apply to your barrel nut based on your grease used. It would also answer a host of other questions in regard to your barrel installation. You would need to know the tensile strength of the threads of the upper which is around 7500 psi and the barrel nut which ranges from 115,000 psi milspec to 167,000 psi HK. Basically, using ANY decent grease will provide sufficient lubrication to facilitate smoothly applying the clamping force needed to solidly fasten the barrel to the upper. Oil, being thinner than grease, will be too easily displaced when the clamping force begins. The use of a specified grease in the TM comes down to two factors: that grease was (and has been for decades) in the DoD inventory, and it has a known set of behaviors under pressure, thus it gives a consistent amount of lubrication while applying torque to the barrel nut. And I too am completely baffled by your inclusion of this data here. It's relevant in the Build It Yourself forum, but I don't see how it has anything to do with selecting a bolt carrier group... |
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Posted: 9/23/2018 5:41:55 PM EDT
[#29]
Quote HistoryQuoted:
Just aquired a lwrc bolt for a song. A search for Toolcraft bolts came up dry. Found an upgrade for sale, win win. 1.67 ratio .67% (NASA) for lubricated barrel nut versus dry. Max. 80 ft/lbs x .67 = 53.6ft/lbs max with moly grease. Min. 35ft/lbs x .67 = 23.45 ft/lbs. wanted to share the ratio for those who use the grease like I do. I would recommend torquing to 35ft/lbs with grease but stay below 50 if you can. I have a spanner wrench so I can verify my overall torque by the time the gas tube lines up on a milspec barrel nut. (This is a throwback to the barrel nut tensile strength conversation, found a formula which has zero relevance to the issue at hand other than it explained the ratio of torque with lubrication versus dry pulled from a NASA paper). I tend to agree with their findings. Oil was found to be 30% and grease 50-67% depending on the type from multiple industry pubs confirmed the deviation between different lubes. The confusing aspect is that the friction reduction properties of lubes lowers the friction increasing the tensile load compression or distortion of the nut. The formula could be used to calculate exactly how much torque you apply to your barrel nut based on your grease used. It would also answer a host of other questions in regard to your barrel installation. You would need to know the tensile strength of the threads of the upper which is around 7500 psi and the barrel nut which ranges from 115,000 psi milspec to 167,000 psi HK. And the TM torque specs have already factored in using moly grease as a thread lubricant. |
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Posted: 9/23/2018 5:53:01 PM EDT
[#30]
What I concluded was with the formula I found, you can calculate the torque that works for your needs. Theres a bunch of folks wondering if it's best to torques 35-80ft lbs. Does the TM factor 80 ft lbs with moly? I thought the Marine Corps were the only ones who used grease?
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Posted: 9/23/2018 6:17:11 PM EDT
[#31]
Quote HistoryQuoted:
What I concluded was with the formula I found, you can calculate the torque that works for your needs. Theres a bunch of folks wondering if it's best to torques 35-80ft lbs. Does the TM factor 80 ft lbs with moly? I thought the Marine Corps were the only ones who used grease? |
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Posted: 9/23/2018 7:33:05 PM EDT
[#32]
Quote HistoryQuoted:
What I concluded was with the formula I found, you can calculate the torque that works for your needs. Theres a bunch of folks wondering if it's best to torques 35-80ft lbs. Does the TM factor 80 ft lbs with moly? I thought the Marine Corps were the only ones who used grease? And this also means EVERYONE had the same standards and requirements for maintaining the M16 family of weapons, ensuring EVERYONE had interoperable weapons. Yes, the TM factors in a maximum of 80 ft lb of torque applied per TM procedure (with the torque wrench IN LINE WITH the barrel nut wrench) with MIL-G-21164-D molybdenum disulfide grease applied to the threads of the barrel nut and upper. I STILL don't know what this has to do with bolt carrier groups. |
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Posted: 9/24/2018 9:24:20 PM EDT
[#33]
All which is part of the same assembly.
So many who neglect to moly the upper nut instal are likely not meeting the proper tensile compression. Ive read comments from many who refuse to grease and torque 35ft pounds-ish. As mentioned the upper 7075 is the lesser of the two tensile ratings that must be used. So the Germans using steel that has 167,000 psi versus the milspec nut 115,000 psi, is still more than the uppers roughly 7500 psi rating. I wonder if there is an advantage to using the German steel? Possibly for the mounting of the rail? I wonder what DD uses for nuts? It seems pretty robust. So I can take my formula and calculate the max tensile compression given 80ft/lbs max noted in the TM. But the max torque dry would seem to be given 80 with grease x 1.67 = 133.6 ft/lbs dry. I think the highest I have gone is 60 with grease. |
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Posted: 9/24/2018 9:37:28 PM EDT
[#34]
Barrel nuts are not to be torqued dry. Period.
Torque per the TM using moly grease. Done. |
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Posted: 9/24/2018 9:39:45 PM EDT
[#35]
Quote HistoryQuoted: I STILL don't know what this has to do with bolt carrier groups. |
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Posted: 9/25/2018 5:38:57 PM EDT
[#36]
We established that, now move on.
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Posted: 9/25/2018 6:31:16 PM EDT
[#37]
Quoted:
So I can take my formula and calculate the max tensile compression given 80ft/lbs max noted in the TM. But the max torque dry would seem to be given 80 with grease x 1.67 = 133.6 ft/lbs dry. I think the highest I have gone is 60 with grease. Quoted:
We established that, now move on. Good luck in whatever it is that you are attempting to reverse engineer. |
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Posted: 9/25/2018 6:37:56 PM EDT
[#38]
Psa was selling these for $80 this morning
Didnt know toolcraft made nickle boron bcgs. What yall think of these? https://palmettostatearmory.com/toolcraft-premium-carpenter-158-nickel-boron-bcg-made-in-usa-5165449629.html |
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Posted: 9/25/2018 8:06:13 PM EDT
[#39]
Quote HistoryQuoted:
Psa was selling these for $80 this morning Didnt know toolcraft made nickle boron bcgs. What yall think of these? https://palmettostatearmory.com/toolcraft-premium-carpenter-158-nickel-boron-bcg-made-in-usa-5165449629.html |
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Posted: 9/26/2018 2:55:50 AM EDT
[#40]
Quote HistoryQuoted:
Toolcraft’s retail arm is Cryptic Coatings. They offer a variety of coatings (including phosphate), and fairly recently added NiBo. |
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Posted: 9/26/2018 3:30:04 PM EDT
[#41]
Good info. Toolcraft contacted me and referred me to Cryptic Coatings.
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Posted: 9/26/2018 4:39:46 PM EDT
[#42]
Cryptic Coatings Nickel Boron bolt carriers are chromed on the inside of the carrier and the gas key... They're really nice.
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Posted: 9/26/2018 5:11:44 PM EDT
[#43]
Delta Team Tactical has stripped Stag carriers for $28.
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Posted: 9/26/2018 5:15:38 PM EDT
[#44]
Quote HistoryQuoted:
Delta Team Tactical |
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Posted: 9/26/2018 5:25:14 PM EDT
[#45]
Stag is not a decent brand?
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Posted: 9/26/2018 5:37:54 PM EDT
[#46]
Quote HistoryQuoted:
Stag is not a decent brand? DTT? Absolutely not. Do an archive search here or Google. Shady ass company operating under 3 different names. Shit peddlers that lie and misrepresent products on top of abysmal CS. |
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Posted: 9/26/2018 5:51:24 PM EDT
[#47]
Stag's parts are made by Continental Machine Tool, and are good to go. However I think the reference was to that particular vendor.
On the other hand, for a few dollars more, you can get a Rainier stripped bolt carrier ($36.92 today). Rainier is a site sponsor, and definitely good to go. |
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Posted: 9/26/2018 5:58:32 PM EDT
[#48]
Quote HistoryQuoted:
Stag's parts are made by Continental Machine Tool, and are good to go. However I think the reference was to that particular vendor. On the other hand, for a few dollars more, you can get a Rainier stripped bolt carrier ($36.92 today). Rainier is a site sponsor, and definitely good to go. |
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Posted: 9/26/2018 6:58:14 PM EDT
[#49]
Bolts and bolt parts (cam pin firing pin) are selling at a premium lately. Best to buy a complete group.
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Posted: 10/4/2018 1:47:47 AM EDT
[#50]
Quote HistoryQuoted:
Stag/CMT is gtg. Drifting further into the abyss: I called Sprinco and asked which spring they recommend. The sales rep who is always awesome, and has not steered me wrong as of yet is not sure on the spring I should use given my buffer. He recommended that I go with the lightest buffer I can, with the strongest spring? (I have always gone with a heavier buffer and tuned the spring to the system) I have an MGI buffer I plan to use: it's pretty heavy. It works well on a 6920 in 5.56 with a red spring, but this is a different animal: an H2 also works well with a 6920: the only difference is the MGI seems to aid in rapid followup shots, and is a bit milder. I swapped the H1's and H2's around and found that I like the H2 the best in a carbine with red springs: ejection pattern is GTG. I'm running an 18" rifle barrel, with full-size carrier, and carbine extension. It will be pumping .224 Valkyrie. Any thoughts? I have H,H1,H2, and MGI to test and standard, blue, and red sprinco springs and a MGI spring. I read a Valk build took H2 with a Red spring but Sprinco seems to believe it's too much spring with my MGI buffer? I believe delaying the blowback with reduce bolt wear and alot a bit more accuracy from the match barrel. I also believe in having an extra power spring on all my 5.56: I swap the springs and I don't look back. I have had zero issues with red springs. Old Colt has blue spring due to longer barrel. I had a formula for PSI and gas port distance: I'll dig it out. But I don;t have the PSI specs for the .224 so help would be appreciated from anyone who has tackled this build. |
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