Thats how you know u did it righthe mentioned regretting selling the Falkor receiver set after seeing the end result.
Hope your backs gets back to feeling better soon!
New partial AR-15 build ... not sure where it's heading
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Hope your backs gets back to feeling better soon!
gunmechanic
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My choice would be the 6mm arc. I am almost finished with a 6mm arc ar build my self waiting on the prs stock to come.Check out eagle eye shooting on you tube he several ar 6mm arc videos you will like he explains barrel freebore info that may help with the build.
The Viper PST 3-15 came in this morning so I got it installed and despite having torn ligaments in my back I couldn't resist sending ten rounds down range. I did a quick bore sight and the scope looked close enough so i loaded three rounds into one of the 17-rnd magazines, pushed the bolt release and FTF!! Tried again and same problem. OK ... I'll load one and shoot one ten times so that's what I did and therefore every shot resulted in bolt lock back. I adjusted the gas block a little a couple of times and the rifle is still over gassed but not bad. I'll back out the adjustment some more next time.
I was aiming at the center large diamond for shots 1 through 4 then dialed up 0.5 milrad and aimed at the top right diamond for shots 5 through 10.
The LabRadar couldn't track two bullets but I got 8/10 velocities shooting Hornady Black 105gr BTHP ammunition.
#1 2,654 fps
#2 2,714 fps
#3 2,693 fps
#4 n/a
#5 n/a
#6 2,695 fps
#7 2,697 fps
#8 2,714 fps
#9 2,701 fps
#10 2,706 fps
Here's the rifle as I shot it this afternoon. I have a MAGPUL MS1 sling for it but took it off for the bench test.
Here's the overall target showing all ten shots. By the last five shots the rifle was starting to show some real potential.
6-shot group is under 3/4" and last 5-shot group is under 0.4".
I was aiming at the center large diamond for shots 1 through 4 then dialed up 0.5 milrad and aimed at the top right diamond for shots 5 through 10.
The LabRadar couldn't track two bullets but I got 8/10 velocities shooting Hornady Black 105gr BTHP ammunition.
#1 2,654 fps
#2 2,714 fps
#3 2,693 fps
#4 n/a
#5 n/a
#6 2,695 fps
#7 2,697 fps
#8 2,714 fps
#9 2,701 fps
#10 2,706 fps
Here's the rifle as I shot it this afternoon. I have a MAGPUL MS1 sling for it but took it off for the bench test.
Here's the overall target showing all ten shots. By the last five shots the rifle was starting to show some real potential.
6-shot group is under 3/4" and last 5-shot group is under 0.4".
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A quick follow up to the magazine situation. The E-lander magazines seem to feed ok from the left side but not from the right. The nose of the bullet for rounds on the right side of the magazine are contacting the very bottom of the feedramp at the receceiver/barrel interface and getting hung up (see copper witness marks in photo below). By the way, no 5.56 magazine that I've tried works worth a damn and I have many different types. The E-Lander magazines have different feedlips and interior dimensions to accommodate the larger diameter Grendel and ARC rounds. I'll have to take a closer look and see if the magazine feedlips are the issue or if it's the receiver/barrel interface.
horsemen61
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6mm ARC rounds don't stack up properly in the 5 different brands of 5.56 magazines I've tried, particularly as the round count goes up. Are the magazines you're using Grendel variants? According to numerous reviews and comments by "experts", the E-Lander magazines are by far and away the best magazines for the Grendel cartridge, and hence should also be for the ARC.
Anyway, I think it's a feedramp/receiver issue and not a magazine issue. I sent an email with a bunch of photos to an engineer friend at Proof to get his opinion. It's not a big deal and I'll get it resolved soon enough. I did ask if the feedramps are the standard M4 type. You can see in the photo above that the transition from the receiver to the feedramp in the barrel extension has a discontinuity, particularly on the right side, which the tip of the bullet is catching on. It's probably a simple case of smoothing the transition there.
I did a test today using 5.56 ammunition loaded into a standard polymer magazine and the rounds feed effortlessly from both sides of the magazine. The tip of the bullet engages the feedramp above the receiver/ramp transition. The Grendel magazines push the rounds out from the centerline compared to standard 5.56 magazines and they need to do that to maintain the proper angle between the rounds. Also, the bullet tip contacts the feedramp at a lower point and actually below the feedramp in the barrel extension.
Can you post a photo showing where the left and right bullet tips make contact with the feedramp using your magazines?
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horsemen61
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I sure can but it will have to be tonight after work also to answer your questions yes I’ve only used 6.5 Grendel mags for the 6 arc
How does that expression go? Oh yeah, "Nothing easy is worth doing". Well, there has been nothing easy about this build. Even the gas block and forend have been more work than expected.
I spent two hours yesterday working on the feedramps in the barrel extension. The barrel/receiver fit is so tight that I have to use a heat gun to expand the extension on the receiver to remove or install the barrel. I was shaping, testing the fit, shaping, testing the fit numerous times to try to get the feedramps to match up to the upper receiver. I'm fairly close now with a decent transition and a wider ramp in the extension. I'm moving in the right direction since the rifle will feed 10 or so rounds well from a Bushmaster branded P-MAG but ironically is struggling with the E-Lander magazines. Feeding from at least four brands of metal tubed 5.56 magazines is unreliable still. I'm going to make a list of all the 6.5 Grendel/6mm ARC magazines available and try to order one of each to see if I can find one that works all the way from empty to full.
My engineer friend at Proof told me that the barrel extensions in the 6mm ARC barrel are standard M4 ramps and that in his opinion Falkor was too aggressive with the ramps they added to the receiver. I've seen similar ramps in other upper receivers and also seen smaller ramps. This story isn't over yet but I'll get there in the end with a reliable and accurate AR. I didn't expect all this when I started out but high $ parts doesn't always guarantee a plug and play solution.
Before and after.
I spent two hours yesterday working on the feedramps in the barrel extension. The barrel/receiver fit is so tight that I have to use a heat gun to expand the extension on the receiver to remove or install the barrel. I was shaping, testing the fit, shaping, testing the fit numerous times to try to get the feedramps to match up to the upper receiver. I'm fairly close now with a decent transition and a wider ramp in the extension. I'm moving in the right direction since the rifle will feed 10 or so rounds well from a Bushmaster branded P-MAG but ironically is struggling with the E-Lander magazines. Feeding from at least four brands of metal tubed 5.56 magazines is unreliable still. I'm going to make a list of all the 6.5 Grendel/6mm ARC magazines available and try to order one of each to see if I can find one that works all the way from empty to full.
My engineer friend at Proof told me that the barrel extensions in the 6mm ARC barrel are standard M4 ramps and that in his opinion Falkor was too aggressive with the ramps they added to the receiver. I've seen similar ramps in other upper receivers and also seen smaller ramps. This story isn't over yet but I'll get there in the end with a reliable and accurate AR. I didn't expect all this when I started out but high $ parts doesn't always guarantee a plug and play solution.
Before and after.
Another brief update. I returned all 10 Alexander Arms marked E-Lander magazines to MidwayUSA yesterday and ordered five 15-round and two 10-round ARC magazines from ASC. They make a magazine specifically for the 6mm ARC, and after talking with Proof who recommended ASC followed by a phone call to engineering at ASC to ask about the design, I'm hopeful that I'll have no feeding issues moving forward. I've decided to hold off on any more ramp work until I've tested the ASC magazines.
MidwayUSA refunded me for the 10 E-Lander magazines and the seven ASC magazines showed up a couple of days ago. They are sticky due to the coating but are way better than the Grendel E-Landers and seem to function well but I've yet to do anything other than cycle rounds manually. I plan on doing some shooting this weekend.
On another related issue, I was finally able to get through to Falkor after numerous attempts to contact someone from a gunsmith, salesman or janitor. I even called HR but no one was home. I don't like the magazine release at the moment which seems "lazy" or "sticky". This morning I was informed that the design had been changed due to issues and that no remedy was available. I took the ambi mag release apart and shook my head at the clueless engineering exhibited. They should have consulted POF on the design of an effective ambi mag release. I then tried three different brand of lowers on the Falkor upper and none worked. I tried POF, Daniel Defense and Bushmaster. This is the world you can find yourself in with propriety components but one that I never encountered with four POF ARs that I still have. I'm going to find a stiffer spring and see if that helps the mag release.
No sour grapes here, just telling it like it is. Eventually this will be a good rifle but I have to resolve a couple of issues.
On another related issue, I was finally able to get through to Falkor after numerous attempts to contact someone from a gunsmith, salesman or janitor. I even called HR but no one was home. I don't like the magazine release at the moment which seems "lazy" or "sticky". This morning I was informed that the design had been changed due to issues and that no remedy was available. I took the ambi mag release apart and shook my head at the clueless engineering exhibited. They should have consulted POF on the design of an effective ambi mag release. I then tried three different brand of lowers on the Falkor upper and none worked. I tried POF, Daniel Defense and Bushmaster. This is the world you can find yourself in with propriety components but one that I never encountered with four POF ARs that I still have. I'm going to find a stiffer spring and see if that helps the mag release.
No sour grapes here, just telling it like it is. Eventually this will be a good rifle but I have to resolve a couple of issues.
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illinoisburt
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The truth if ever was uttered!
wesmonster
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7.62x39 for cheap blasting fun. I know Russian steel is banned but there’s lots of cheap steel case 7.62x39 made in other countries.
For long range, 6.5Grendel.
Or do a build in a caliber you already stock but a different setup. If your 5.56 upper is a lightweight carbine, maybe build a 20” HBAR tabletop shooter.
9mm is fun but you really should just start from scratch once you decide what kind of mags you’ll run then go with a dedicated lower. I run 9mm ARs with Metalform (Colt smg) mags, Glock & an Endomag. The Endomag works and is a cheap solution but my least favorite. Blowbacks can be finicky with some FCGs that aren’t basic GI single stages. I’ve got a RRA National Match 2 stage that doesn’t always reset with both a RRA and a Toolcraft 9mm BCG.
For long range, 6.5Grendel.
Or do a build in a caliber you already stock but a different setup. If your 5.56 upper is a lightweight carbine, maybe build a 20” HBAR tabletop shooter.
9mm is fun but you really should just start from scratch once you decide what kind of mags you’ll run then go with a dedicated lower. I run 9mm ARs with Metalform (Colt smg) mags, Glock & an Endomag. The Endomag works and is a cheap solution but my least favorite. Blowbacks can be finicky with some FCGs that aren’t basic GI single stages. I’ve got a RRA National Match 2 stage that doesn’t always reset with both a RRA and a Toolcraft 9mm BCG.
I was going to wait before I mentioned the next step in this project but I've decided to abandon the FALKOR upper and lower and replace them with POF parts. I've owned POF ARs including two P415s and a P308 for 13 years or so with nothing but praise for their products. I'm in the process of buying a POF Gen 4 lower with a DGI upper (not the piston variant) that is used in models such as the Renegade. Every non-proprietary part currently in the FALKOR upper and lower receivers will transfer over and then I'll put the FALKOR stuff on Gunbroker.
Despite this thread, ARs really aren't my passion. I have a bunch but I'm much more interested in bolt action rifles, and favor revolvers over pistols. I guess I'm getting old.
Despite this thread, ARs really aren't my passion. I have a bunch but I'm much more interested in bolt action rifles, and favor revolvers over pistols. I guess I'm getting old.
heckuva thread, 1911. 6arc seems cool, but my days of doing new stuff are over. i spent about 20 years testing stuff, doing wildcats, first of a kind builds, etc. burnt out now. i just want things to work and work well. heck, for my latest AR project, i just bought a straight factory gun and didn't modify anything, just added optics.
the POF move is prob a good decision. hope your ligament is better
the POF move is prob a good decision. hope your ligament is better
Yep, I hear you. Part of the reason for buying a couple of CZ Bren 2S "pistols" this year was for the reason that you mention. Simply add an optic, a suppressor, a sling, a couple of stocks (since they were pistols), vfgs and call it good.
Building ARs really isn't my thing and I would never have started such a project if not for the spur of the moment decision to buy an upper and lower from a friend. But once it started I felt a compulsion to see if through to the end which means replacing parts that don't work the way I want them to. Also, I couldn't bring myself to build another 5.56 so figured the 6mm ARC would be interesting if nothing else. I can't stand hand loading for the 5.56/.223 cartridge .... never have and probably never will. I'll take .300 Blackout over the 5.56 any day of the week and twice on Sunday! Since I work in this industry I never know how these projects will help, but sometimes it all comes full circle and I find myself working on something years later that I was immersed in at one time or another. That's the way it is currently.
Thanks for asking about my back issues. I'm about 80% healed and upgrading various aspects of myself and my life to prevent or reduce the chances of this happening again. For example, I bought a stand up desk so now work on my feet all day rather than sitting in a chair. Nothing good comes from sitting down all day. I'm also working on flexibility and core strength. It's been a tough road these past couple of months but I was using a shovel yesterday to dig out some rocks and dirt next to the house and only had mild discomfort so I know I'm moving in the right direction. I have a nice Kubota MX6000 tractor but sometimes you have to go old school and use a pick and shovel.
I'll update this thread once I have the POF parts set up.
Building ARs really isn't my thing and I would never have started such a project if not for the spur of the moment decision to buy an upper and lower from a friend. But once it started I felt a compulsion to see if through to the end which means replacing parts that don't work the way I want them to. Also, I couldn't bring myself to build another 5.56 so figured the 6mm ARC would be interesting if nothing else. I can't stand hand loading for the 5.56/.223 cartridge .... never have and probably never will. I'll take .300 Blackout over the 5.56 any day of the week and twice on Sunday! Since I work in this industry I never know how these projects will help, but sometimes it all comes full circle and I find myself working on something years later that I was immersed in at one time or another. That's the way it is currently.
Thanks for asking about my back issues. I'm about 80% healed and upgrading various aspects of myself and my life to prevent or reduce the chances of this happening again. For example, I bought a stand up desk so now work on my feet all day rather than sitting in a chair. Nothing good comes from sitting down all day. I'm also working on flexibility and core strength. It's been a tough road these past couple of months but I was using a shovel yesterday to dig out some rocks and dirt next to the house and only had mild discomfort so I know I'm moving in the right direction. I have a nice Kubota MX6000 tractor but sometimes you have to go old school and use a pick and shovel.
I'll update this thread once I have the POF parts set up.
Thanks, but it might all be for naught when I move the barrel over to the POF upper ... guess I'll find out soon enough.
horsemen61
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Gtscotty
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Glad your back is on the mend, I just switched to a standing desk at work too, sitting all day really is pretty bad for you. A little bit of a pad to stand on helps btw.
I've been playing with LVR and some different bullet weights already had laying around, in my 21" ARC and have gotten some workable loads:
105gr MB, 29.2gr LVR @ ~2,700 fps
95gr SST, 29.7gr LVR @ 2,810 fps
85gr SGK, 31gr LVR @ 2,970 fps.
I finally got the the opportunity to take my 21" 6mm ARC out to the long range a few weeks ago and ran my 105gr load along with the pretty excellent 108gr factory loads at 600, 750, 1,000 and 1,250 yds. I was very impressed how the rifle/round hammered at the 750 and even 1,000 yd plates. The 105s seemed pretty well out of steam at 1,250, and the BC advantage of the 108s at about the same velocity was pretty obvious (14.6 mil vs 15.7 mil @ 1,250).
Huge target at 1,250 yds, but I kind of started at the top right and walked to the left and down. Tempered by the facts that this was the first time at that range, my rifle is not exactly top end, I'm running a 3.5 lb trigger and 12x scope, I was pretty impressed with the little cartridge.
I'm interested to see how your rifle turns out, it already looks like it shoots better than mine, it's probably going to be a real hammer once you get it all set up how you want. I have decided that I'd like an 18" barrel in this chambering that is lighter than my heavy 21" to be more of a general purpose and potential hunting rifle, kind of eyeballing the fluted Ranier Ultra-match tube.
I've been playing with LVR and some different bullet weights already had laying around, in my 21" ARC and have gotten some workable loads:
105gr MB, 29.2gr LVR @ ~2,700 fps
95gr SST, 29.7gr LVR @ 2,810 fps
85gr SGK, 31gr LVR @ 2,970 fps.
I finally got the the opportunity to take my 21" 6mm ARC out to the long range a few weeks ago and ran my 105gr load along with the pretty excellent 108gr factory loads at 600, 750, 1,000 and 1,250 yds. I was very impressed how the rifle/round hammered at the 750 and even 1,000 yd plates. The 105s seemed pretty well out of steam at 1,250, and the BC advantage of the 108s at about the same velocity was pretty obvious (14.6 mil vs 15.7 mil @ 1,250).
Huge target at 1,250 yds, but I kind of started at the top right and walked to the left and down. Tempered by the facts that this was the first time at that range, my rifle is not exactly top end, I'm running a 3.5 lb trigger and 12x scope, I was pretty impressed with the little cartridge.
I'm interested to see how your rifle turns out, it already looks like it shoots better than mine, it's probably going to be a real hammer once you get it all set up how you want. I have decided that I'd like an 18" barrel in this chambering that is lighter than my heavy 21" to be more of a general purpose and potential hunting rifle, kind of eyeballing the fluted Ranier Ultra-match tube.
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horsemen61
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@Gtscotty, thanks for the well-wishes and for the load data. What a nice range that is! I do have a bit of an update so here goes.
I received the POF lower and upper yesterday and moved everything over that wasn't proprietary to the Falkor. I apologize for the FDE KNS trigger pins but that's all I had. The good news is that this rifle now functions well with the ASC 10 and 15-round magazines with no feeding issues whatsoever. The work I did on the Proof feedramps doesn't seem to be an issue at all and the barrel and POF upper receiver blend well. I shot a couple of groups today with "meh" results. The Falkor set had no discernible play between the pieces and the the threaded barrel nut extension was much tighter than the POF. The POF does have two set screws in the lower that can be adjusted to reduce movement between the upper and lower. I didn't shot the Falkor combination enough to get a sense of whether it was a 1/2", 1" or worse rifle. I think this POF combination shooting Hornady Black 105gr BTHP ammunition might be a 1" @ 100 yards rifle at best.
I don't really like the stock. It doesn't put my head in the best position relative to the scope so I might move a MAGPUL PRS stock over to this rifle or buy a Gen 2 model since mine are 12+ years old. The rifle as shown is about 10lb-8oz but it doesn't feel that heavy. I've been adjusting the gas block but will play with the buffer spring weight and gas block some more. Recoil is very soft as you'd imagine.
Average velocity for 10 shots (Hornady Black 105gr BTHP) was 2,649 fps, both screen shots for both shot groups are shown below along with the target.
I received the POF lower and upper yesterday and moved everything over that wasn't proprietary to the Falkor. I apologize for the FDE KNS trigger pins but that's all I had. The good news is that this rifle now functions well with the ASC 10 and 15-round magazines with no feeding issues whatsoever. The work I did on the Proof feedramps doesn't seem to be an issue at all and the barrel and POF upper receiver blend well. I shot a couple of groups today with "meh" results. The Falkor set had no discernible play between the pieces and the the threaded barrel nut extension was much tighter than the POF. The POF does have two set screws in the lower that can be adjusted to reduce movement between the upper and lower. I didn't shot the Falkor combination enough to get a sense of whether it was a 1/2", 1" or worse rifle. I think this POF combination shooting Hornady Black 105gr BTHP ammunition might be a 1" @ 100 yards rifle at best.
I don't really like the stock. It doesn't put my head in the best position relative to the scope so I might move a MAGPUL PRS stock over to this rifle or buy a Gen 2 model since mine are 12+ years old. The rifle as shown is about 10lb-8oz but it doesn't feel that heavy. I've been adjusting the gas block but will play with the buffer spring weight and gas block some more. Recoil is very soft as you'd imagine.
Average velocity for 10 shots (Hornady Black 105gr BTHP) was 2,649 fps, both screen shots for both shot groups are shown below along with the target.
Gtscotty
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It will probably be a little while before I get an 18", I'm putting together a PRS type bolt gun right now, and will have to give the wallet a bit of a rest after that. I will probably just build another upper at that point, I thermofit the barrel into this one so it might not be very easy to get out
horsemen61
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Oh I want to hear about the bolt gun and yeah I understand about letting the wallet rest lol
I switched out the UBR stock for the PRS stock this morning, switched out the LaRue mount for a 20 moa ADM mount, threaded on a SilencerCo Harvester .30 cal, bore sighted and shot this 5-shot group after making a gas block adjustment. I've never shot a group this small, at least I don't think I have. I could see the first two hits but after that I wondered if I were missing the target altogether. Function is absolutely perfect with the POF receiver and ASC magazines. This is just one group, but to shoot a group like this with all rounds fed from the magazine, and the last round resulting in bolt lock back is pretty neat.
I don't know what I'm going to do with this rifle, or what role it'll play but I'm pleased with how it performs now, with one caveat and maybe two. The Geissele trigger has some creep in the second stage and this is the first time I've ever experienced that with a Geissele trigger (I have a bunch) so I might swap it out with one from a carbine I have that doesn't need such a good trigger.
The other thing that's bothering me is the reticle in the Vortex Viper PST Gen 2 3-15x scope. It's the EBR-7C version and it's just too fine and too busy, at least at 100 yards and shooting at the type of target shown above. There's not much I can do about it except change scopes.
I don't know what I'm going to do with this rifle, or what role it'll play but I'm pleased with how it performs now, with one caveat and maybe two. The Geissele trigger has some creep in the second stage and this is the first time I've ever experienced that with a Geissele trigger (I have a bunch) so I might swap it out with one from a carbine I have that doesn't need such a good trigger.
The other thing that's bothering me is the reticle in the Vortex Viper PST Gen 2 3-15x scope. It's the EBR-7C version and it's just too fine and too busy, at least at 100 yards and shooting at the type of target shown above. There's not much I can do about it except change scopes.
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