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VA, USA
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Posted: 6/7/2024 10:12:21 AM EDT
[Last Edit: bmwguy]
[#1]
Need your advice as I just received this kit from Century. I've never built a roller lock before and will have one of the smiths complete my build.
If you take a look at the pics, is this something I should have century replace. For reasons unknown, they decided to cut the barrel shroud near front of the trunnion. I am okay with the trunnion in the rear (toward receiver) but not sure if the cutting in front of the trunnion will affect build. Has anyone else encounter this? Is this something a smith will be able to repair or should I ask for replacement from Century?        |
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Posted: 6/7/2024 10:15:19 AM EDT
[#2]
I would definitely say something about that. If everything else is good, I would see if they can just replace the barrel shroud/trunnion. Cant hurt to ask.
That said, it could be fixed with careful welding and blending. |
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Posted: 6/7/2024 10:26:20 AM EDT
[#3]
Yeah that could be dealt with but not without some aggravation. Looks like someone realized they messed up before they got too far.
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Posted: 6/7/2024 3:04:47 PM EDT
[#4]
Quote HistoryOriginally Posted By bmwguy: Need your advice as I just received this kit from Century. I've never built a roller lock before and will have one of the smiths complete my build. If you take a look at the pics, is this something I should have century replace. For reasons unknown, they decided to cut the barrel shroud near front of the trunnion. I am okay with the trunnion in the rear (toward receiver) but not sure if the cutting in front of the trunnion will affect build. Has anyone else encounter this? Is this something a smith will be able to repair or should I ask for replacement from Century? https://i.imgur.com/RVB6cuz.jpg https://i.imgur.com/rmRG0bl.jpg https://i.imgur.com/IZ4PZsX.jpg https://i.imgur.com/JvjY9SB.jpg https://i.imgur.com/Sy13OzU.jpg https://i.imgur.com/2Sy8Mux.jpg https://i.imgur.com/2GnLwfb.jpg Looks like someone had an oops moment and nicked it. The cut doesn’t look deep at all and can be blended and welded up. Judging by the otherwise far better than average condition of your parts…I’d hold onto it. |
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VA, USA
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Posted: 6/7/2024 3:20:55 PM EDT
[#5]
Quote HistoryOriginally Posted By cms81586: Looks like someone had an oops moment and nicked it. The cut doesn’t look deep at all and can be blended and welded up. Judging by the otherwise far better than average condition of your parts…I’d hold onto it. Agreed. My Century rep Anna is taking care of me. I emailed her and attached the photos. They will be sending me another shroud. Great that Century is taking care of their customers! |
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Posted: 6/7/2024 4:15:26 PM EDT
[Last Edit: cms81586]
[#6]
Quote HistoryOriginally Posted By bmwguy: Agreed. My Century rep Anna is taking care of me. I emailed her and attached the photos. They will be sending me another shroud. Great that Century is taking care of their customers! @bmwguy Yeah they took care of me too. Sent me a new bolt head. If you’re happy with the new shroud they send you, and you don’t have any plans for that one please let me know. I may be interested since my cocking tube is pretty messed up. I’d be willing to try to weld those cuts up and use yours instead.  Attached File |
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VA, USA
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Posted: 6/7/2024 5:59:42 PM EDT
[#7]
Quote HistoryOriginally Posted By cms81586: @bmwguy Yeah they took care of me too. Sent me a new bolt head. If you’re happy with the new shroud they send you, and you don’t have any plans for that one please let me know. I may be interested since my cocking tube is pretty messed up. I’d be willing to try to weld those cuts up and use yours instead. https://www.ar15.com/media/mediaFiles/2980/IMG_1737_jpeg-3234940.JPG Mine looks very similiar. Century requested that I return the bad barrel shroud. |
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USA
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Posted: 6/7/2024 6:13:49 PM EDT
[#8]
Stack those accessories boys
   
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Posted: 6/7/2024 6:56:16 PM EDT
[#9]
Quote HistoryOriginally Posted By bmwguy: Mine looks very similiar. Century requested that I return the bad barrel shroud. I have a feeling they’ll say they all look like that. No issues. That’s a shame. That shroud is really nice otherwise. |
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Posted: 6/7/2024 6:57:53 PM EDT
[#10]
Quote HistoryOriginally Posted By Heineken: Stack those accessories boys https://i.ibb.co/gF4NJH2/IMG-20240607-174022349-HDR.jpg https://i.ibb.co/7NqjJbV/IMG-20240607-174032163-HDR.jpg https://i.ibb.co/gRKwW4X/IMG-20240607-134829165-HDR.jpg https://i.ibb.co/xzWPLDq/IMG-20240607-134839113-HDR.jpg I’d loved to have grabbed one of those but for the price I probably would have snagged another kit instead. |
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Posted: 6/7/2024 7:32:10 PM EDT
[Last Edit: jntmjt1]
[#11]
@Heineken
Quote HistoryOriginally Posted By Heineken: Stack those accessories boys Is that one of the earlier available "very good" condition tripods, or is it one of the current "well used" ones? I have a "well-used" one on the way, and I hope it's in as good of condition as yours... it looks great! -- With that said, even if mine is rough, I will enjoy restoring it. |
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Posted: 6/7/2024 7:55:32 PM EDT
[#12]
Quote HistoryOriginally Posted By Heineken: Stack those accessories boys Crew served weapons really should have a tripod available, and those are pretty cool. I opted for a second kit though. |
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USA
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Posted: 6/7/2024 9:34:20 PM EDT
[Last Edit: Heineken]
[#13]
Quote HistoryOriginally Posted By jntmjt1: @Heineken Is that one of the earlier available "very good" condition tripods, or is it one of the current "well used" ones? I have a "well-used" one on the way, and I hope it's in as good of condition as yours... it looks great! -- With that said, even if mine is rough, I will enjoy restoring it. I got it from centerfire systems. I think they got them from Apex though cause they have the exact tag apex puts on the with the same printing etc apex uses. I just went with them cause it was free shipping, and no tax. I figured I would be doing a restore / repaint....but after having it in hand and cleaning it...I'm just going to leave it as is. |
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Posted: 6/7/2024 10:13:00 PM EDT
[Last Edit: cms81586]
[#14]
Removing the old receiver material from the trunnion now. This is a pretty slow going for me since my tiny lathe/mill combo doesn’t have coolant…so I’m having to take really small bites. Too slow and you work harden the material. Too fast and it heats up too quickly. After this I’ll clean up the old sheet metal receiver bits in the shroud and feed box. I’m about half way through.
 Attached File |
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Posted: 6/7/2024 10:17:17 PM EDT
[#15]
Reading through this thread when buying one of these kits what else would you suggest getting besides the barrel? I assume when you have one of the smiths work on it they have blank receivers to redo it?
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Posted: 6/7/2024 10:20:24 PM EDT
[Last Edit: cms81586]
[#16]
Assuming all your parts are good, at minimum you’ll need a G3 rear sight weldment, barrel, belts, a receiver, and receiver reinforcing rails. Likely you’ll need plus size rollers too. A safe bet would be to buy the RCM barrel, trunnion, and bolt head. I’m going to see what my bolt gap is with this bolt and trunnion and see if rollers will be an acceptable solution or if I should wait for the RCM trunnions to come out.
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Posted: 6/8/2024 6:53:12 AM EDT
[#17]
Dont forget you'll need a semi auto FCG unless you're making a postie.
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Posted: 6/8/2024 8:34:45 AM EDT
[Last Edit: cms81586]
[#18]
Quote HistoryOriginally Posted By Type7SOT: Dont forget you'll need a semi auto FCG unless you're making a postie. You can convert the FCG that comes with it if you want to do the work. This is always an option too….  Attached File |
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USA
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Posted: 6/8/2024 9:08:20 AM EDT
[Last Edit: Heineken]
[#19]
Quote HistoryOriginally Posted By cms81586: Assuming all your parts are good, at minimum you’ll need a G3 rear sight weldment, barrel, belts, a receiver, and receiver reinforcing rails. Likely you’ll need plus size rollers too. A safe bet would be to buy the RCM barrel, trunnion, and bolt head. I’m going to see what my bolt gap is with this bolt and trunnion and see if rollers will be an acceptable solution or if I should wait for the RCM trunnions to come out. If you can get your hands on a new barrel, bolt and locking peice, you can test bolt gap with the trunnion and if it's not good.....you pretty much know it's the trunion, as the other factors are taken out of the equation. On most of these kits I bet the bolt and or locking pieces are close to end of life. The trunnions, have a much better chance to be good to go. I know I would rather find a good used trunnion from one of these kits vs using a US made trunnion, ymmv |
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USA
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Posted: 6/8/2024 9:11:54 AM EDT
[Last Edit: Heineken]
[#20]
Quote HistoryOriginally Posted By cms81586: You can convert the FCG that comes with it if you want to do the work. This is always an option too…. https://www.ar15.com/media/mediaFiles/2980/IMG_1760_png-3235601.JPG Be careful with what trigger pack you go with, make sure able to modify for enough room for the ejector lever. No idea on the franklen, but originally I was going to use one of the US made ambi packs from HK parts, but the way it's made, there was no way to modify for the ejector lever because the pack is a 2 piece aluminum housing, and just the way it clamshelled together if I would have removed the material it would have compromised the housing to much. |
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Posted: 6/8/2024 9:48:03 AM EDT
[#21]
No binary or FRT for me in this current state. I’m out of here in a few years. Until then, I’m just using an HK semi pack inside a C/P lower. Once I have my SOT I’ll convert the original pack to work with the shelf like a registered sear pack is done. Once the SOT is relinquished I’ll destroy that pack. Thats what will work for me, but in another state it may be worth trying to get the binary working.
Two questions…is the 21E ejector lever the same as these original 21’s? If not, where can we find replacements? Also, where can we find new recoil springs? I know they’re stiffer than the 21E spring, and heavier duty than a G3 spring. Anyone make these or is there new old stock out there? |
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Posted: 6/8/2024 11:32:57 AM EDT
[#22]
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MP, USA
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Posted: 6/8/2024 12:01:06 PM EDT
[#23]
Quote HistoryOriginally Posted By cms81586: No binary or FRT for me in this current state. I’m out of here in a few years. Until then, I’m just using an HK semi pack inside a C/P lower. Once I have my SOT I’ll convert the original pack to work with the shelf like a registered sear pack is done. Once the SOT is relinquished I’ll destroy that pack. Thats what will work for me, but in another state it may be worth trying to get the binary working. Two questions…is the 21E ejector lever the same as these original 21’s? If not, where can we find replacements? Also, where can we find new recoil springs? I know they’re stiffer than the 21E spring, and heavier duty than a G3 spring. Anyone make these or is there new old stock out there? The 21e ejector lever is different. |
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MP, USA
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Posted: 6/8/2024 12:12:06 PM EDT
[Last Edit: JoshNC]
[#24]
Quote HistoryOriginally Posted By Heineken: If you can get your hands on a new barrel, bolt and locking peice, you can test bolt gap with the trunnion and if it's not good.....you pretty much know it's the trunion, as the other factors are taken out of the equation. On most of these kits I bet the bolt and or locking pieces are close to end of life. The trunnions, have a much better chance to be good to go. I know I would rather find a good used trunnion from one of these kits vs using a US made trunnion, ymmv Mike Otte told me the trunion is a nearly forever piece, that it’s the bolt and locking piece that typically wear out. I have a couple 11a1 kits. I measured one of my shroud/trunion with a new BPP barrel installed, 11a1 bolt group, 11a1 locking piece. It measured 0.20 mm. I swapped a new #9 locking piece in and used the 11a1 bolt head. 0.25 mm fit with room to spare and 0.3 mm barely did not fit. I swapped the bolt head for a new 21E with -2 rollers, new #9 locking piece and 0.4 mm fit with room to spare, 0.45 mm just barely did not fit. |
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Posted: 6/9/2024 9:33:37 PM EDT
[#25]
Quote HistoryOriginally Posted By JoshNC: Mike Otte told me the trunion is a nearly forever piece, that it’s the bolt and locking piece that typically wear out. I have a couple 11a1 kits. I measured one of my shroud/trunion with a new BPP barrel installed, 11a1 bolt group, 11a1 locking piece. It measured 0.20 mm. I swapped a new #9 locking piece in and used the 11a1 bolt head. 0.25 mm fit with room to spare and 0.3 mm barely did not fit. I swapped the bolt head for a new 21E with -2 rollers, new #9 locking piece and 0.4 mm fit with room to spare, 0.45 mm just barely did not fit. Do these use a standard G3 locking piece? |
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USA
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Posted: 6/9/2024 10:34:26 PM EDT
[Last Edit: Heineken]
[#26]
Quote HistoryOriginally Posted By cms81586: Do these use a standard G3 locking piece? No. The back part on the LP that goes into the carrier is thinner on the 21 locking peice, a G3 won't fit in the carrier. The FMP 21s, and these kits, came with a 50 degree locking pieces. Most will recommend going to the 40 or 36 degree 21e locking pieces....but I haven't been able to fully assemble and lock the bolt into the carrier using them. I have tried RCM and factor German HK 40 and 36 degree LPs. My bolts and carriers are HK marked, not FMP. I just can't twist the bolt to lock it in place in the carrier, its a solid stop and it won't go. The LPs that came with the kits however all work fine. I have had the carriers apart and back together many times, so I know how it's done. Trying to figure it out, I then tried fitting them with just the LP, bolt and carrier (no firing pin or spring)...and they fit fine. Ok, added the firing pin, and again they fit fine..but as soon as I add the firing pin spring, they won't go. They pop down only the carrier, but they won't twist to lock on. My mind is not grasping how adding that spring would stop me from locking it into place. And it's not just there is more tension, it flat out won't lock...it hits a wall, it won't go. EDIT: figured it out - you have to slightly compress the rollers to get the new locking piece to push in just that little bit further to let it turn. For whatever reason the ones that cam with the kit i dont need to do that. |
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Posted: 6/9/2024 11:47:28 PM EDT
[Last Edit: cms81586]
[#27]
Quote HistoryOriginally Posted By Heineken: No. The back part on the LP that goes into the carrier is thinner on the 21 locking peice, a G3 won't fit in the carrier. The FMP 21s, and these kits, came with a 50 degree locking pieces. Most will recommend going to the 40 or 36 degree 21e locking pieces....but I haven't been able to fully assemble and lock the bolt into the carrier using them. I have tried RCM and factor German HK 40 and 36 degree LPs. My bolts and carriers are HK marked, not FMP. I just can't twist the bolt to lock it in place in the carrier, its a solid stop and it won't go. The LPs that came with the kits however all work fine. I have had the carriers apart and back together many times, so I know how it's done. Trying to figure it out, I then tried fitting them with just the LP, bolt and carrier (no firing pin or spring)...and they fit fine. Ok, added the firing pin, and again they fit fine..but as soon as I add the firing pin spring, they won't go. They pop down only the carrier, but they won't twist to lock on. My mind is not grasping how adding that spring would stop me from locking it into place. And it's not just there is more tension, it flat out won't lock...it hits a wall, it won't go. I did it enough to where I can see where it appears to be binding on the non kit LPs...then j compared that area to the same area kit LPs, and they have what seams like a slightly different contour in the area...would prob be easy to make them work removing the smallest amount of material....but I'm not to the point where I need to worry about that yet. If anyone else tires a 36 or 40 degree please report your experience if they fit. Appreciate the schooling. That adds some complexity to the situation. Right now I’d like to replace the locking piece, rollers, and recoil spring at a minimum. The LP and recoil spring will prove challenging since everything out there is 21E related. The LP issue just adds to that challenge. Side note, someone on HK Pro mentioned of their 7 kits, two stocks had regular G3 buffers in them. So if you have a kit…it might be worth checking, not that there’s much we can do about it. The MSG90 buffer is probably closest to these early HK21 buffers, although I’m sure there are some differences. My buffer is correct, but I found another problem. The recoil rod must have came loose at some point and somebody tried the bandaid fix of welding it. At some point the weld failed…so if APEX can’t replace it I’ll have to try rewelding it. Question, are the HK-21E stock recoil rod lengths the same as these? I’d consider buying a MM21 clubfoot stock, swapping this buffer into that stock, and swapping recoil springs (from what I understand these have more stout recoil springs than the 21E recoil springs. Any chance anyone knows if this would work? According to HKParts the MM21 Clubfoot stock will work with any length buffer tube. Broken weld:  Attached FileOriginal 21 buffer in these things (what it should look like…not the shorter G3 buffer):  Attached File |
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Posted: 6/10/2024 12:48:00 AM EDT
[#28]
Quote HistoryOriginally Posted By Heineken: Be careful with what trigger pack you go with, make sure able to modify for enough room for the ejector lever. No idea on the franklen, but originally I was going to use one of the US made ambi packs from HK parts, but the way it's made, there was no way to modify for the ejector lever because the pack is a 2 piece aluminum housing, and just the way it clamshelled together if I would have removed the material it would have compromised the housing to much. My plan was a semi auto HK91 trigger box. I’m sure it will need modified in some way for the ejector lever but I’ll cross that bridge when I get there. The HKP “US Made” one has some US made compliance parts in it but it’s $100 cheaper than the German HK-91 box. |
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MP, USA
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Posted: 6/10/2024 7:34:48 AM EDT
[Last Edit: JoshNC]
[#29]
Quote HistoryOriginally Posted By cms81586: My plan was a semi auto HK91 trigger box. I’m sure it will need modified in some way for the ejector lever but I’ll cross that bridge when I get there. The HKP “US Made” one has some US made compliance parts in it but it’s $100 cheaper than the German HK-91 box. Quote HistoryOriginally Posted By cms81586: My plan was a semi auto HK91 trigger box. I’m sure it will need modified in some way for the ejector lever but I’ll cross that bridge when I get there. The HKP “US Made” one has some US made compliance parts in it but it’s $100 cheaper than the German HK-91 box. It’s an easy mod to cut the clearance for the ejector. Originally Posted By cms81586: Appreciate the schooling. That adds some complexity to the situation. Right now I’d like to replace the locking piece, rollers, and recoil spring at a minimum. The LP and recoil spring will prove challenging since everything out there is 21E related. The LP issue just adds to that challenge. Side note, someone on HK Pro mentioned of their 7 kits, two stocks had regular G3 buffers in them. So if you have a kit…it might be worth checking, not that there’s much we can do about it. The MSG90 buffer is probably closest to these early HK21 buffers, although I’m sure there are some differences. My buffer is correct, but I found another problem. The recoil rod must have came loose at some point and somebody tried the bandaid fix of welding it. At some point the weld failed…so if APEX can’t replace it I’ll have to try rewelding it. Question, are the HK-21E stock recoil rod lengths the same as these? I’d consider buying a MM21 clubfoot stock, swapping this buffer into that stock, and swapping recoil springs (from what I understand these have more stout recoil springs than the 21E recoil springs. Any chance anyone knows if this would work? According to HKParts the MM21 Clubfoot stock will work with any length buffer tube. Broken weld: https://www.ar15.com/media/mediaFiles/2980/IMG_1810_jpeg-3237348.JPG Original 21 buffer in these things (what it should look like…not the shorter G3 buffer): https://www.ar15.com/media/mediaFiles/2980/IMG_1811_jpeg-3237349.JPG The E recoil rod is not attached to the stock and is shorter. https://www.gunbroker.com/item/1053072119 |
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Posted: 6/10/2024 8:54:20 AM EDT
[#30]
Quote HistoryOriginally Posted By JoshNC: It’s an easy mod to cut the clearance for the ejector. The E recoil rod is not attached to the stock and is shorter. type Status report message description Access to the specified resource has been forbidden. Apache Tomcat/7.0.68 (Ubuntu) |
Attached File